Partial replacement of barley and soya hulls with wheat and nutritionally improved straw (NIS) on the performance

of intensively finished bulls

by

E. P. Jones

being an Honours Research Project submitted in partial fulfilment of the requirements for the BSc (Honours) Degree in

Agriculture with Farm Business Management

2016

i

Table of Contents

Abbreviations ........................................................................................................................ vi

Acknowledgements .............................................................................................................. vii

Abstract............................................................................................................................... viii

1.0 Introduction .................................................................................................................. 1

2.0 Background .................................................................................................................. 2

2.1 UK Beef Industry ..................................................................................................... 2

2.2 Production Systems ................................................................................................ 2

2.2.1 Intensive Cereal Beef ....................................................................................... 2

2.2.2 Intensive Silage Beef ....................................................................................... 3

2.2.3 Semi Intensive ................................................................................................. 3

2.2.4 Extensive ......................................................................................................... 4

2.2.5 Breeds ............................................................................................................. 4

2.2.6 Gender............................................................................................................. 4

2.3 Ruminant Digestive Anatomy .................................................................................. 5

2.3.1 Rumen ............................................................................................................. 6

2.3.2 Reticulum ......................................................................................................... 6

2.3.3 Omasum .......................................................................................................... 6

2.3.4 Abomasum ...................................................................................................... 6

2.4 Ruminant Nutritional Requirements ........................................................................ 7

2.4.1 Energy ............................................................................................................. 7

2.4.2 VFA ................................................................................................................. 8

2.4.3 Protein ............................................................................................................. 8

2.4.4 Vitamins and Minerals ...................................................................................... 9

2.4.5 Fibre ................................................................................................................ 9

2.5 Intensive Beef Diets .............................................................................................. 10

2.6 Metabolic Disorders .............................................................................................. 11

2.6.1 Bloat .............................................................................................................. 11

2.6.2 Acidosis ......................................................................................................... 11

2.7 Nutritionally Improved Straw ................................................................................. 12

2.7.1 NIS and Animal Health ................................................................................... 14

2.7.2 Production trials with NIS ............................................................................... 14

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3.0 Methodology .............................................................................................................. 16

3.1 Location ................................................................................................................ 16

3.2 Data Collected ...................................................................................................... 16

3.3 Treatments ........................................................................................................... 16

3.4 Feed Analysis ....................................................................................................... 18

3.5 Faecal Analysis ..................................................................................................... 19

3.6 Slaughter .............................................................................................................. 19

3.7 Liver Assessment.................................................................................................. 19

3.8 Statistical Analysis ................................................................................................ 20

4.0 Results ........................................................................................................................ 21

4.1 Faecal Analysis Results ........................................................................................ 21

4.2 Digestibility ........................................................................................................... 21

4.3 Animal Performance ............................................................................................. 22

4.4 Carcase Performance ........................................................................................... 23

4.5 Feed Intake Performance ...................................................................................... 24

4.6 Financial Performance .......................................................................................... 24

5.0 Discussion .................................................................................................................. 26

5.1 Animal Performance ............................................................................................. 26

5.1.1 Start Weight ................................................................................................... 26

5.1.2 Slaughter Weight ........................................................................................... 26

5.1.3 Days to Slaughter .......................................................................................... 26

5.1.4 Daily Live-Weight Gain .................................................................................. 26

5.2 Carcase Performance ........................................................................................... 26

5.2.1 Carcase Weight ............................................................................................. 26

5.2.2 Killing Out ...................................................................................................... 27

5.2.3 Daily Carcase Gain ........................................................................................ 27

5.2.4 Carcase Conformation and Fat Classification ................................................ 27

5.2.5 Liver Scores ................................................................................................... 27

5.3 Feed Intake and Feed Conversion Ratio ............................................................... 27

5.4 Financial Performance .......................................................................................... 28

5.5 Limitations and Further Research ......................................................................... 28

6.0 Conclusions ............................................................................................................... 30

7.0 References ................................................................................................................. 31

8.0 Appendices ................................................................................................................ 38

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Appendix 1. Typical breed performance and finishing systems ........................................ 38

Appendix 2A. Feed Sample Analysis Techniques carried out by HAU laboratory ............ 38

Appendix 2B. Feed Analysis carried out by HAU laboratory ............................................ 40

Appendix 3. Feed Analysis carried out by external laboratory (Rumenco) ....................... 41

Appendix 4. The theoretical nutrient analysis as stated by the manufacturer (Wynnstay) 41

Appendix 5A. Faeces Sample Analysis Techniques carried out by HAU laboratory ......... 41

Appendix 5B. Faecal Analysis carried out by HAU laboratory .......................................... 43

Appendix 6. Digestibility Measure .................................................................................... 43

Appendix 7. Carcase Price (£/kg) for bulls sold from January – May 2016 ...................... 45

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List of Tables

Table 1: Performance targets for Holstein and Continental x Holstein bulls on an intensive

12-14 month cereal fed bull beef system .......................................................................................... 3

Table 2: Performance of bulls, steers and heifers reared on an intensive cereal beef system 5

Table 3: ME (MJ/d) requirements of late maturing housed bulls on a diet with an ME of 12

MJ/kg DM ............................................................................................................................................ 10

Table 4: Analysis of different feed source (% DM or MJ/kg DM for ME) ................................... 10

Table 5: Compound inclusion report for both the cereal and NIS diet ....................................... 17

Table 6: Distribution of the breeds following randomisation among the treatments groups ... 18

Table 7: Mean results of the nutritional analysis (kg as fed) from the HAU laboratory and

Rumenco ............................................................................................................................................. 18

Table 8: The EUROP grid converted into numerical values ........................................................ 19

Table 9: Liver scoring scale .............................................................................................................. 20

Table 10: Mean faecal analysis results ........................................................................................... 21

Table 11: Results from washing and sieving the faeces .............................................................. 21

Table 12: Digestibility analysis of the treatments .......................................................................... 21

Table 13: Animal performance analysis.......................................................................................... 22

Table 14. Effect of Breed and Diet on Slaughter Weight (kg) and its relationship with Starting

Weight (kg) .......................................................................................................................................... 23

Table 15: Carcase performance analysis ....................................................................................... 23

Table 16. Effect of Breed and Diet on Carcase Weight (kg) and its relationship with Killing

Out (g/kg) ............................................................................................................................................. 24

Table 17: Feed intake analysis ........................................................................................................ 24

Table 18: Financial performance analysis ...................................................................................... 25

Table 19. Penalty/Bonus per classification (p/kg) ......................................................................... 45

Table 20. Carcase price per classification score (£/kg) ............................................................... 45

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List of Figures

Figure 1: Ranking of breed and gender on slaughter weight and rate of maturity ..................... 4

Figure 2: Ruminant’s digestive system showing the feed journey ................................................ 5

Figure 3: Energy pathway - from gross Energy to net Energy ...................................................... 7

Figure 4: Protein metabolism and digestion ..................................................................................... 9

Figure 5: Effect of sodium hydroxide on cell structure ................................................................ 13

Figure 6: Manufacturing process of nutritionally improved straw ............................................... 13

Figure 7: The implements used in the trial ..................................................................................... 16

Figure 8: Layout of the trial ............................................................................................................... 17

Figure 9: The beef unit at Harper Adams University .................................................................... 17

Figure 10: Mean DLWG of the bulls ................................................................................................ 22

Figure 11: Rejected NIS present in the trough .............................................................................. 28

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Abbreviations

ADF - Acid Detergent Fibre

AEE - Alcohol Ether Extract

AIA - Acid Insoluble Ash

ANOVA - Analysis of Variance

CP - Crude Protein

CV - Coefficient of variation

DG - Daily Carcase Gain

DLWG - Daily Live-Weight Gain

DM - Dry Matter

DMI - Dry Matter Intake

DUP - Digestible Undegradable Protein

FCR - Feed Conversion Ratio

g/kg DM- Grams per Kilogram of Dry Matter

HAU - Harper Adams University

ME - Metabolisable Energy

MJ/kg DM- Mega Joules of Metabolisable Energy per Kilogram

MP - Microbial Protein

NDF - Neutral Detergent Fibre

NIR - Near Infra-red Spectroscopy

NIS - Nutritionally Improved Straw

RDP - Rumen Digestible Protein

SARA - Sub-Acute Ruminal Acidosis

SEM - Standard Errors of Means

VFA’s - Volatile Fatty Acids

VIA - Video Imaging Analysis

vii

Acknowledgements

Sincere thanks is express to the project supervisor Mr Simon Marsh for his advice and

support.

Thanks must also be given to the farm staff at Harper Adams University Beef Unit, in

particular Mr Giles Vince and Ms Nicola Naylor for their assistance in conducting the trial.

A big thanks to the laboratory staff, in particular Mr Amjad Ali and Ms Rachel France for their

help and assistance during the feed and faeces analysis.

Thanks to Mr Chris McLachlan at ABP Shrewsbury for allowing access into the abattoir and

advising on the liver assessments.

Thanks to Mr David Cubitt the Managing Director of Sundown Products Ltd for sponsoring

the trial.

Finally, many thanks are reserved for all other staff, friends and family who have shown

support and encouragement throughout the authors’ studies at Harper Adams University.

viii

Abstract

Partial replacement of barley and soya hulls with wheat and nutritionally improved straw (NIS) on the performance of intensively finished bulls E.P Jones and S.P. Marsh BSc (Honours) Agriculture with Farm Business Management

Introduction: Starch is a significant key nutrient driver of intensive finishing diets (Marsh and Brown, 2007). Barley is the predominant cereal used in the diets and typically contains 590g starch/kg dry matter (DM). Wheat is higher than barley in starch content (690g starch/kg DM), but is rarely fed, unless its inclusion rate is limited. This is because it is more rapidly digested in the rumen which can cause metabolic disorders in excessive amounts (Fiems et al., 1999), having a detrimental effect on performance. Hence it is assumed that reduced rumen acidosis will result in better performance. Dietary fibre, such as straw, in the diet can help reduce fermentation and the risk of acidosis. However, it is of low nutritional value and can dilute the energy content of the ration. A product called nutritionally improved straw (NIS) is available which results in an increased metabolisable energy (ME) value of 7.0 MJ/kg DM and improved nutritional value. The process of NIS manufacture also converts sodium hydroxide to sodium bicarbonate, which may act as a rumen buffer to reduce acidosis. As a result, the incorporation of NIS in the diet may enable wheat to be included in intensive beef diets with potential improvements to animal performance and profit.

Materials and Methods: The trial started on the 22nd

July 2015 using a randomised block design with 34 January and February 2015 born Beef x Holstein or Holstein bulls, randomised according to live-weight and breed. There were two treatments either the barley (635kg/1000kg) and soya hull (150kg/1000kg) diet or the barley (313kg/1000kg), wheat (312kg/1000kg) and NIS (150kg/1000kg) diet with both formulated to contain 404g starch/kg DM (34.9% as fed). All feed was fed ad libitum, with the amount weighed and recorded to calculate intake levels and FCR. Straw was available ad libitum to each treatment. Bulls were weighed on monthly intervals until slaughtered at fat classification 3 at 13-14 months old.

Results: The trial found no significant difference in animal performance (slaughter weight, DLWG, days to slaughter) or carcase performance (carcase weight, killing out, daily carcase gain, conformation, fat class and liver score) between the treatments.

Table 1. Animal and carcase performance of bulls statistical analysed.

Cereal NIS SEM (df=28) CV % P Value Sig

Start Weight (kg) 239 243 15.5 24.9 0.926 NS

Slaughter Weight (kg) 581 592 9.5 6.8 0.641 NS

Days to Slaughter 257 251 8.5 15.7 0.701 NS

DLWG (kg) 1.32 1.40 0.043 12.1 0.309 NS

Carcase Weight (kg) 309.1 317.6 6.64 8.7 0.536 NS

Killing Out (g/kg) 532 537 5.5 4.3 0.623 NS

Daily Carcase Gain (kg) 0.77 0.81 0.027 14.1 0.275 NS

Conformation1 6.6 6.7 0.37 24.8 1.0 NS

Fat Class1 6.9 6.6 0.33 21.5 0.175 NS

Liver Score2 1.07 1.07 0.11 24.2 1.0 NS

1. EUROP carcase classification: Conformation: P- =1 and E+ =15, Fat Class: 1- =1, 5+ =15 2. Liver assessment: 1= Healthy liver and 5= Severe abscesses NS = Not Significant

Conclusion: There was no significant difference in any performance characteristics. Both treatments had similar DM digestibility, refuting the claims in the literature that a diet including NIS improves digestibility. There was a large increase in NDF and ADF digestibility, but this did not decrease intakes. The NIS group had slightly higher intakes (+35kg) and feed costs (+£18), but with a higher carcase value of £30 per head a higher margin over feed was achieved (+£12 per head). However, it does illustrate NIS and wheat to be a similarly effective alternative when included in intensive beef diets.

References: Fiems, L.O., De Campeneere, S., Cottyn, B.G., Vanacker, J.M., D’Heer., B.G. and Boucque, C.H.V. 1999. Effect of amount and degradability of dietary starch on animal performance and meat quality in beef bulls. Journal of Animal Physiology and Animal Nutrition, 82, pp.217-226.

Marsh, S.P. and Brown, S.T. 2007 Effect of feeding a compound feed with a reduced starch content on the performance of intensively fed beef cattle. Proceedings of the British Society of Animal Science, Paper 127

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1.0 Introduction

Diet composition and utilisation are key factors for profitable and efficient beef production, with starch being a significant key nutrient driver of finishing diets (Marsh and Brown, 2007). Barley is the predominant cereal used in intensive diets, which typically contain 590g starch/kg dry matter (DM). Wheat is higher than barley in starch content (690g starch/kg DM), but is fed in moderation, because it is more rapidly digested in the rumen (Lardy and Dhuyvetter, 2000). Consequently, excessive amounts can cause metabolic disorders (Fiems et al., 1999), which can have a detrimental effect on performance.

Introducing dietary fibre, such as straw, to the diet can help slow down fermentation and reduce the risk of acidosis. However, due to its lignified nature, it is of low nutritional value and can dilute the energy content of the ration. When straw is chopped and milled, the particle size is reduced and the surface area increased, allowing for better incorporation of the sodium hydroxide treatment resulting in an increased metabolisable energy (ME) value of 7.0 MJ/kg DM and improved nutritional value (Sundown Products Ltd, not dated); this product is called nutritionally improved straw (NIS). In the latter stages of NIS manufacture during cooling, sodium hydroxide converts to sodium bicarbonate, which may act as a rumen buffer to reduce acidosis. As a result, the incorporation of NIS in the diet may enable wheat to be included in intensive beef diets with potential improvements to

animal performance and profit.

The objective of this study was to investigate these proposals and the effect of partial replacement of barley with wheat and the replacement of soya hulls with NIS with blends formulated to contain 404g starch/kg DM (34.9% as fed) on intensively finished dairy-bred bulls. Thus, the hypothesis is that the partial replacement of barley and soya hulls with wheat and NIS will show an increase in performance in intensively finished bulls.

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2.0 Background

2.1 UK Beef Industry

The latest figures published by the Agriculture and Horticulture Development Board (AHDB, 2016) state that prime cattle slaughtering has increased by 2% to 1.98 million. Prime cattle supplies 80.5% of the British beef industry, with the remaining 19.5% made up by culled cows and bulls (Marsh, 2016a). In total, 12.7% of prime cattle (20.1% of males) in 2014 were intensively finished as bulls (Marsh, 2016a), and 46% of cattle were slaughtered when 24-36 months old (extensively finished). Approximately 25% of extensively reared steers are intensively finished for a 3-4 month period due to the inability to finish off grass or silage; therefore around 45% of male cattle are intensively finished (Marsh, 2016c).

The Department for Environment, Food and Rural Affairs (DEFRA, 2015) and Ryan (2015) report that the beef suckler herd is in continuing long term decline; however, DEFRA assert that for the first time since 2005, the dairy herd has increased by 3.3%. Approximately 52% of cattle supplied to the British beef industry come from the dairy industry (Marsh, 2016a), therefore the research reported here in the trial consisting of pure dairy bred bull calves or beef bred dairy bull calves is relevant.

Townshend (2015) reported that industry growth has been slow, with inflation responsible for the 6.3% growth in British unprocessed red meat retail sales over the last 5 years. Since late 2014 wage growth has outpaced inflation, which could have resulted in increased demand. However, this did not occur as imports also increased, coupled with an unexpected lacklustre demand, resulted in a higher volume of beef available on the UK market compared to previous years (AHDB, 2015a). This was unfavourable for producers, with the average prime beef base price dropping to £3.25/kg, having previously been around £4/kg during the horsemeat scandal (AHDB, 2015a). This was also the case at the start of 2016 with a saturated market resulting in challenging prices, demonstrating the volatility present in the market and the need for producers to remain competitive.

2.2 Production Systems

There are many beef production systems (Marsh, 2016a), depending on breed, gender, age, time of year, husbandry and type of feed (NGFL, 2016). The following sections describe the main beef production systems.

2.2.1 Intensive Cereal Beef

This is a 12-14 month finishing system feeding concentrate ad libitum to reach a live-weight of 540-600kg (Marsh, 2016b) and was used in this trial. Diets using this system predominantly consist of rolled barley mixed with a protein concentrate or soyabean/rapeseed meal and minerals. However, other energy sources can be used, for example rolled wheat, grain maize or distillers grains (more in chapter 2.5 titled ‘Intensive Beef Diets’). Bulls require a high energy ration of 12.5 or greater ME (mega joules of Metabolisable Energy per kg of dry matter (MJ/kg DM)) with high starch levels of around 35%.

Health problems can arise caused by the high starch diet, including acidosis, bloat and lameness. To minimise metabolic disorders, it is vital that the barley is lightly rolled and not ground, and that troughs do not become empty in order to reduce gorging. To maintain rumen function, straw or silage can be offered ad libitum, and intakes are approximately 0.75 and 5kg/head/day respectively (Marsh, 2016b) (more in chapter 2.6 titled ‘Metabolic Disorders’).

Late maturing breed types are best suited to this system; however, Friesian and Holstein bulls are often used due to the supply of calves from the dairy industry (Soffe, 2003).

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Young bulls accounted for 7.6% of the total UK beef production in 2015 (DEFRA, 2016). As a result of their temperament, the majority of bulls are sold deadweight and slaughtered upon arrival at the slaughterhouse to reduce the incidence of dark cutting beef. Year round housing facilitates the use of bulls, which achieve superior growth rates compared to steers (AHDB, 2015c). Bulls should be housed in well bedded and well ventilated yards, with a minimum of 4.6 m2 space allowance per 600kg bull (2.3 m2 for slatted yards). Pens should hold no more than 20 bulls, although this number can be higher for suckled bulls, and mixing groups of bulls should be avoided (AHDB, 2013a). As a result of the year round housing, a high capital investment is needed for set up, but it can create a regular turnover of animals helping cash flow. It should be noted that this system is very sensitive to market fluctuations in cereal and beef prices (NGFL, 2016).

Table 1 shows examples of the performance targets provided by the AHDB (2015c), which are key performance indicators enabling benchmarking of the performance of the trial.

Table 1: Performance targets for Holstein and Continental x Holstein bulls on an

intensive 14 month cereal fed bull beef system

Holstein Bulls Continental x Holstein Bulls

Slaughter (months) 14 14

Slaughter weight (kg) 560 600

DLWG* from birth (kg) 1.22 1.31

DLWG from 12 weeks (kg) 1.34 1.40

Carcase weight (kg) 285 335

Daily carcase gain from birth (kg) 0.66 0.78

Killing out % 51 56

Carcase grade -O3 R3

Concentrates (t/head) 2.50 2.42

FCR (from 12 weeks old) 5.5 5.0

*DLWG = Daily live-weight gain, FCR = feed conversion ratio

2.2.2 Intensive Silage Beef

Intensive silage fed beef production is a similar system to the intensive cereal-fed system; however, silage is substituted for a proportion of cereals, and cattle are slaughtered later (14-16 months) and heavier (590-630kg) (Marsh, 2016b). Slaughtering later could cause problems as bulls become more aggressive and abattoirs reject bulls aged over 16 months (Promar International, 2012).

The amount of concentrate fed is determined by silage quality; therefore, high quality silage is important, with a target of 11 or higher ME (MJ/kg DM) (Marsh, 2016b). Browne et al., (2000) also states that maize silage can be used which may increase the DM intake and daily live-weight gain (DLWG) in comparison to grass silage.

2.2.3 Semi Intensive

If autumn born cattle achieve high growth during the grazing season then they can be finished at winter at around 18 months on forage and concentrate supplementation (MVF, 2015) to weigh 500-575kg (Marsh, 2016c). Spring born cattle are grazed for two seasons and finished on grass with supplement (NGFL, 2016) to achieve a weight of 450-525kg for early maturing breed types (Marsh, 2016c). A target of 0.9kg DLWG should be achieved over the whole rearing period (MVF, 2015). It can be difficult to finish spring born late maturing breed types off grass at 18 months old, due to them being difficult to get fat cover from grass alone.

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2.2.4 Extensive

Early maturing breeds with smaller frames are best suited to an extensive system (Rutherford, 2009). These systems have two grazing seasons and two housed winter periods, with the first winter often referred to as the ‘store period’ (Marsh, 2016c), when compensatory growth can be capitalised upon, allowing for low cost frame growth to occur (Phillips, 2010). The theory is that cattle will grow at a faster rate than otherwise expected after accessing quality feed, following a period of under-nutrition (Jennings, 2014). Good grassland management is the key to achieving a DLWG of 1kg or higher. This can include utilising grass via grazing systems (e.g. strip grazing or rotational grazing), and assessing grass sward heights (Marsh, 2016c). Autumn born cattle are becoming increasingly uncommon on a 30 month system, due to the third wintering period (MPW, 2014).

2.2.5 Breeds

The most predominant beef breeds in the UK are the Limousin, Angus, Charolais and British Blue; however, over recent years, native (early maturing) breeds have gained in popularity. Angus numbers increased by 81.1% between 2003 and 2014 and Hereford numbers by 40.4%; whereas the Charolais decreased by 35.4%, and Limousin by 20.2% (Marsh, 2016b). This is due to market forces demanding better eating qualities and offering premiums. However, Phillips (2010) asserts that the Holstein-Friesian is the most prominent breed in Britain as a result of the dairy influence. The Friesian influence has decreased in dairy herds since the 1970s in favour of the Holstein which has resulted in more angular, poorer quality carcase traits infiltrating the beef industry (NGFL, 2016). However, despite poorer carcase quality and killing out percentage (Kempster et al., 1988) their lower purchase price and availability make them a popular choice to finish intensively at 11-13 months (Phillips, 2010). Research by Allen (1992) contradicts that of Southgate et al., (1988) and classifies the Friesian breed as early rather than late maturing, but there has been no more recent research on this matter.

Late maturing breeds (e.g. Charolais) are better suited to an intensive system than early maturing breeds (e.g. Angus), as shown in Figure 1 (Soffe, 2003). On an intensive system early maturing breeds would get too fat before reaching an acceptable slaughter live-weight, achieve poorer DLWG and be less efficient feed converters, consuming more feed per unit of weight gained (Warren et al., 2008; Keane et al., 2008). Allen (2001) stated that continental breeds have a 10% higher feed intake than native breeds.

Heifers Steers Bulls

Early Late

Angus, Hereford, Sussex, Friesian, Limousin, South Devon, Charolais, Simmental

Figure 1: Ranking of breed and gender on slaughter weight and rate of maturity

(Source: Soffe 2003)

2.2.6 Gender

Both breed and gender affect the muscle to bone ratio of an animal (AFRC, 1993); however, gender has a larger impact on maturity than breed (Marsh, 2016a). Males have higher testosterone levels, which result in better muscle growth and a reduced rate of fat deposition (Irshad et al., 2012).

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Table 2: Performance of bulls, steers and heifers reared on an intensive cereal beef

system

(Source: Marsh 1997)

Bulls Steers Heifers

Slaughter weight (kg) 583 534 488

Days to slaughter 316 283 280

DLWG (kg) 1.44 1.36 1.26

Slaughter age (months) 13.6 13.0 13.1

Carcase weight (kg) 317 283 261

Carcase grade R/-U4L R/O+4L O+/R 4L/4H

FCR (kg feed DM: kg LWG) 5.43 5.69 5.81

Several research studies (Marsh, 1997, Juniper et al., 2007; Solanas et al., 2005) found that bulls are better feed converters and weight gainers compared to steers and heifers (Table 2). In a comparison between bulls and steers, it was found that bulls produced larger carcase gains while being significantly younger at slaughter (Kirkland et al., 2006). It was also found that when compared at the same weight, the feed conversion ratio (FCR) of bulls were significantly higher (Kirkland et al., 2006); however, Allen (2001) notes that bulls’ feed intake is 10% higher than steers. It must be noted that carcase conformation or fat classification are not affected by gender rather that these are affected by genetics, diet and age (Keane et al., 2001; Anderson and Ingvartsen, 1984). Appendix 1 presents a summary of the different breeds, gender and their suitability for the systems discussed.

2.3 Ruminant Digestive Anatomy

As shown in Figure 2, ruminants have four stomach compartments; the rumen, reticulum, omasum and abomasum (DairyCo, 2015).

Figure 2: Ruminant’s digestive system showing the feed journey

(Source: Addison Wesley Longman Inc, 1999)

6

2.3.1 Rumen

Making up over 65% of the total stomach volume of adult cattle, the rumen is by far the largest chamber (DairyCo, 2015). It is divided into numerous sacs filled with micro-organisms, and has several little papillae which increase the surface area and absorption capacity (Moran, 2005). It can hold between 50-130 litres of chewed feed and acts as a holding vat (DairyCo, 2015; Moran, 2005).

At 38°C the rumen’s condition promotes microbial growth, which digests and ferments ingested feed, providing optimal condition for digesting fibre (Moran, 2005). Microbes digest cellulose and hemicellulose, the fibre component of roughages (Cecava, 1995). Bacteria and other micro-organisms ferment carbohydrates under anaerobic conditions in the rumen, breaking them down (hydrolyse) into accessible energy, such as volatile fatty acids (VFAs), which promote protein synthesis (Chamberlain and Wilkinson, 1996). Most VFAs are produced by fermentation and the breakdown of starch, and are absorbed through the rumen wall and into the liver (Hamilton, 1991). Undigested starch proceeds to the abomasum and small intestine to be broken down by enzymes. VFA absorption in the rumen can be improved by increasing starch and sugar levels in the diet (DairyCo, 2015); however, acidity will increase if too much if fed too quickly. The optimum rumen pH for fibre and starch digestion is around 6.0, with fibre digesting bacteria preferring a pH of 6.0-6.8 and starch digesting bacteria a pH of 5.5-6.0 (DairyCo, 2015). If the rumen pH falls below 5.5, then there is a risk of sub-acute ruminal acidosis (SARA) (Phillips et al., 2010). Failure to recover the pH balance will result in diarrhoea and decreased performance (e.g. dry matter intake (DMI) and DLWG).

2.3.2 Reticulum

The reticulum is attached to the rumen, and ingesta can move freely between both chambers. The reticulum has a honeycombed structure to increase its surface area, which is aimed at trapping larger feed particles and moving digested feed into the omasum. Large feed particles can be further digested by regurgitation, as shown in Figure 2 (Radunz, 2012), increasing the surface area by mechanical digestion and saliva (McDonald et al., 2011). The saliva aids chewing and swallowing, and being alkaline helps maintain a higher pH in the rumen (Blair, 2011) while enzymes break down fat (salivary lipase) and starch (salivary amylase) (Parish et al., 2009). The time spent ruminating depends upon the amount of fibre present in the diet (McDonald et al., 2011).

2.3.3 Omasum

The omasum functions similarly to a filter, and as the rumen consists of 80% water, cattle need to drink up to 130-150 litres per day to maintain its environment (Radunz, 2012). As a result, the omasum squeezes the water and nutrients out of the feed to prevent it entering the remainder of the digestive tract (Cecava, 1995). A compacted ball can occur if excessive minerals or low quality fibre (e.g. sunflower hulls) is consumed (DairyCo, 2015; Fubini and Ducharme, 2004).

2.3.4 Abomasum

This is also known as the ‘true stomach’ and is very acidic at pH 3.5-4 (Parish et al., 2009), with hydrochloric acid and digestive enzymes breaking down any feed that has escaped microbial digestion (Dairy Co, 2015), despite approximately 60-70% of the feed being already broken down before reaching the abomasum (Blair, 2011). Enzymes, such as pepsin, aid the breakdown of protein (microbial and dietary), together with pancreatic lipase from the pancreas which breaks down fats (Parish, 2011).

The resulting amino acids are then absorbed in the small intestine (Radunz, 2012), while VFAs and water are absorbed by the large intestine after bacterial fermentation occurs on any undigested feed (DairyCo, 2015).

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2.4 Ruminant Nutritional Requirements

Correct nutrition is vital to meet production and financial targets (Allen, 2001). Chamberlain and Wilkinson (1996) write that the main basic nutritional requirements can be subcategorised into carbohydrates and fats (energy), protein, macro elements, trace elements and vitamins.

2.4.1 Energy

Carbohydrates are the main source of energy in ruminants’ diet. They can be categorised into four main groups: glucose, starch, pectin and cellulose (Chamberlain and Wilkinson, 1996).

Starch is a major energy source for ruminants, as digested starch creates VFAs that are used as energy for ruminal microbes and the synthesis of microbial protein. This results in higher methane production and as a result, will cause some energy loss (Cecava, 1995). Not all energy consumed is utilised as energy, as it can also be lost through heat, faeces or urine. ME is the energy available to an animal and is calculated by subtracting the energy lost as urine and as gas due to microbial fermentation from the digestible energy (DE) (McDonald et al., 2011) (Figure 3). Energy prediction equations, such as those proposed by the AFRC, ARC, CSIRO and NRC, are distinct in their formulation; however, they all similarly use the underpinning philosophy that energy is foremost used for maintenance, before being used for reproductive and growth functions.

Figure 3: Energy pathway - from gross Energy to net Energy

(Source: Pilliner, 1999)

A slow rate of fermentation will increase the quantity of starch that bypasses the rumen, which can lead to 42% more energy being produced in the small, due to less methane loss and more efficient use of VFAs (Erjaei et al., 2012). When starch is fermented by microbes, propionate acid is produced and is absorbed through the rumen wall into the bloodstream and to the liver. Here it is converted to glucose by gluconeogenesis (McDonalds et al., 2011). Glucose provides the main energy for cell functions.

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When in the rumen pectins are rapidly degraded into VFAs (Chamberlain and Wilkinson, 1995); however, unlike starch, the pectins’ rate of fermentation decrease when the pH declines (Ferguson, 2014). Pectins are high in diets such as sugar beet pulp and citrus pulp, while forage based diets contain fibrous carbohydrates in the form of cellulose. These can have a large variation in nutritional value due to lignification and rumen conditions (e.g. pH) (Cecava, 1995). Carbohydrates are degraded to hexose and pentose, which are then metabolised to pyruvate in the rumen, which in turn produces VFAs (McDonalds et al., 2011).

Fat is a long term energy source for when nutrition is poor (Chamberlain and Wilkinson, 1996), and is stored within the subcutaneous connective tissue, intramuscular connective tissue, and abdominal cavity (Cecava, 1995). Fats are hydrolysed to fatty acids and glycerol in the rumen, where unsaturated fatty acids are also changed into saturated fatty acids by the microbes present. In addition, Cecava (1995) states that ‘true fats’ provide sources for the fat soluble vitamins A, D, E and K.

2.4.2 VFA

Within the rumen, microbial fermentation produces three types of VFAs (acetate, propionate and butyrate) which are used as animals’ main energy source (DairyCo, 2015), and these VFAs can supply more than 70% of animals’ energy supply (Bowen, 2009). Concentrates yield propionate acid, while fibre leads to acetate and butyric acid production. The majority of VFAs are absorbed via diffusion through the rumen wall, while approximately 35% pass through and are absorbed in the omasum and abomasum.

Normal bovine ruminal pH is 6-6.5, with the average fermentable products breaking down to 70% acetate, 20% propionate and 8% butyrate (Blowey, 1999). These proportions achieve stable fermentation when the buffer is alkaline saliva. High propionate levels may suggest a high starch and low fibre diet, which will increase fermentation (DairyCo, 2015). This can run the risk of increased lactic acid levels and reduced rumen pH, resulting in a negative effect on performance (Moran, 2005). However, the energy needed for a high growth rate is obtained from propionate and as a result it is vital for an intensive beef system. Increased butyrate levels will increase the production of ketone bodies in the liver. These are used as energy for fatty acid synthesis and can be used as an alternative energy source (Moran, 2005); however, ketosis may occur if levels become too high.

2.4.3 Protein

Protein is an important aspect in intensive system diets, with a deficiency causing a decrease in growth and carcase performance (Parish, 2009). Microorganisms present in the rumen also need protein (Allen, 2001) in order to synthesise peptides and amino acids for maintenance and growth (Cecava, 1995). Protein is characterised by the part and rate of digestion and degradation in the digestive system (Webster, 2011). It can be differentiated into two categories: protein that is degraded in the rumen is called rumen degradable protein (RDP), while protein that is not degraded is called digestible undegradable protein (DUP) (Figure 4). An example of DUP is soyabean protein, while feed grade urea is an example of RDP (AHDB, 2008). Both are influenced by the time spent in the rumen, with feed with a higher RDP level moving through the rumen faster.

When the RDP is degraded in the rumen it creates ammonia. This, along with amino acids and peptides made by protozoa and proteolytic organisms, is used by rumen organisms to produce microbial protein (MP) which promotes microbial growth and reproduction. MP becomes available after digestion and absorption in the abomasum and small intestine.

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Figure 4: Protein metabolism and digestion

(Source: Herdt, 2014)

2.4.4 Vitamins and Minerals

Correct vitamins and minerals are equally fundamental, as insufficient levels can cause deficiencies and a reduction in performance and health, possibly even death (Allen, 2001). Requirements depend upon the availability and quality of feed, water availability, while losses occur through urine, faeces and production (Chamberlain and Wilkinson, 1996). In the barley based finishing ration, minerals (included at 25kg/t) should include a high level of calcium (24%), low phosphorous and magnesium (3% or below) and 8-10% sodium, together with the usual trace elements (Marsh, 2015b).

Generally, vitamins cannot be synthesised but are necessary for normal growth and maintenance (Phillips, 2010). An intensive finishing diet should also have a vitamin content of 300,000, 60,000 and 800 iu/kg for vitamins A, D3 and E, respectively. However, when grain is moist, then vitamin E levels should be 1,500+ iu/kg (Marsh, 2015b).

2.4.5 Fibre

The fibre element of feed has the greatest impact on digestibility, with both amount and chemical composition of the fibre being important (McDonald et al., 2011). Digestibility is important, as it impacts on feed intake, which needs to be high for a high performance. Mertens (2009) states that a high neutral detergent fibre (NDF) digestibility will result in lower intakes due to the rumen fill and increased rumination time will; however, a lack of fibre will inhibit rumen functions and cause digestive upsets, e.g. acidosis (Moran, 2005). Rumination increases with roughage consumption, as regurgitation, remastication, and re-insalivation will occur. Since saliva has a neutralising effect, the risk of digestive upset is further reduced (McDonald et al., 2011).

The structure of straw predominantly consists of cell walls, which are comprised of cellulose, hemicellulose and lignin. To break these down, the enzymes cellulase, hemicellulase and ligninase are needed (McDonald et al., 2011). An animal cannot produce these enzymes, but instead provides a suitable environment in the reticulorumen

10

for microorganisms that do produce cellulose and hemicellulase. There is however a lack of ligninase in the rumen and as a result, lignin cannot be broken down, although even if it were degraded the energy content would be minimal (Sarnklong et al., 2010).

2.5 Intensive Beef Diets

Table 3: ME (MJ/d) requirements of late maturing housed bulls on a diet with an ME

of 12 MJ/kg DM

(Source: AFRC, 1993)

Metabolisable Energy (ME) requirement (MJ/day)

DLWG 200kg 300kg 400kg 500kg 600kg

0.50 39 52 63 74 83

0.75 44 58 71 82 93

1.00 50 66 80 93 105

1.25 57 74 90 105 118

1.50 65 84 102 119 134

Table 3 shows the typical ME requirements of a bull on an intensive system (AFRC, 1993). The energy value of live-weight gains varies widely in cattle, and can be from below 10MJ/kg for a young weaned bull calf, to over 30MJ/kg in finishing heifers over 400kg, with the reason for this attributed to the proportion of fat in the gains. Another reason is the muscle to bone ratio, which varies between breed and gender. However, the protein content of the gain varies little in comparison, decreasing from 170 to 140g/kg for 100kg to 500kg cattle (AFRC, 1993). Despite this the higher ME requirement and poor FCR achieved at higher weights are such that the cost of the final kilogram of meat may exceed the price per kilogram, and thus up until that point a positive albeit diminishing margin is achieved.

No significant difference was found between the treatments when feeding Holstein bulls different levels of protein in the ration (12%, 14% or 16% ‘as fed’) (Marsh, 2008). Therefore, protein levels can be reduced to 12% from 280kg live-weight to slaughter. This can make a considerable difference to the margins when the price of protein is high. However, with better genetics, Marsh (2015a) found that in continental breeds a protein level of 14% could improve DLWG by 0.06kg. Table 4 shows the ME and other nutritional values for the feeds.

Table 4: Analysis of different feed source (% DM or MJ/kg DM for ME)

(Adapted from: AHDB, 2013b; Sundown Products Ltd. not dated.)

Feed DM ME CP NDF

Oil (AH)

Starch Sugar

Wheat 86.0 13.8 12.8 14.0 2.0 69.0 3.5

Barley 86.0 13.2 12.1 21.1 3.0 59.0 3.0

NIS 89.0 7.0 4.5 75.0 1.5 1.5 1.0

Soya Hulls 89.0 11.9 12.2 67.5 2.4 5.0 3.0

Distillers Grain

89.0 12.7 26.0 42.0 9.2 3.2 2.0

Soya Hi-pro 88.0 13.8 52.0 13.0 9.4 4.0 10.0

Molasses 75.0 12.6 6.0 0 0.2 0 65.0

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Marsh and Brown (2007) found that significantly higher slaughter weights, carcase weights, and DLWG were achieved by bulls fed a diet containing 38.3% starch compared to a nut containing 9%. Marsh (2013) also reported that reducing starch had a negative impact on performance and margins. Consequently, high ME and high starch are vital for an intensive finishing system. Barley is the predominant feed grain used in intensive finishing diets due to its availability and high starch content (Nikkhah, 2012). Wheat, in comparison to barley, is higher in starch (Table 4). However, wheat is often fed in moderation and in combination with slower fermenting feed feedstuffs (Lardy and Dhuyvetter, 2000), as wheat is more rapidly digested in the rumen (McAllister et al., 1990), increasing the risk of metabolic disorders (Cheng et al., 1998).

It was recommended by Lardy and Dhuyvetter (2000) that no more than 40% of the diet DM should be wheat in order to avoid digestive problems; however, He et al., (2015) claim that wheat can replace up to 89% of barley grain in finishing diets. They also state that replacing barley with wheat had little impact on nutrient digestibility or rumen fermentation, although it decreased the daily period when the rumen pH was below 5.8. He et al., (2015) suggest that if both grains are processed in a similar way then there will be little difference in the ruminal fermentation or digestibility of both grains, contrary to the majority of the other reports in the literature (Lardy and Dhuyvetter, 2000; Nikkhah, 2012; McAllister et al., 1990; Cheng et al., 1998). It is essential that cereal grains are lightly processed (often via rolling) in order to crack the grain before feeding, thereby making the starch available to the microbes present in the rumen (Dehghan-Banadaky et al., 2006). Unprocessed grain will remain undigested and be seen unutilised in the faeces. In contrast, over processed grains will cause rapid fermentation further increasing the acidosis risk.

To complement the starch there are a variety of fibre sources available. These can include for example palm kernel, crop residue, beet pulp. Often fed alongside cereals are soya hulls to provide a source of fibre. Soya hulls can be high in fibre, but can be difficult for the rumen to digest (Marsh, 2016d). Research by Grigsby (1992) reported that soya hulls can have a positive effect on fibre digestion in high starch diets. However, Ludden et al., (1995) found that as the inclusion rate of soya hulls increased in the diet, the DLWG decreased (P=0.03) and DMI increased (P=0.003), leading to decreased gain efficiency (P<0.001).

When the costs of cereals increase producers often resort to alternative feedstuffs to remain profitable, such as using grain maize and co-products to successfully finish beef cattle on an intensive system (Stock et al., 2000). These feedstuffs are very popular in North America.

2.6 Metabolic Disorders

2.6.1 Bloat

Bloat is the build-up of gas in the rumen caused by rumination (Laven, 2014), and can occur when gas cannot escape via the oesophagus either due to blockages (e.g. foreign objects, potatoes) in the gullet or foam build-up on top of the rumen (Wang et al., 2012). Foam is caused by the fermentation of readily digestible feeds and can be influenced by the amount of fibre, cereal selection (e.g. wheat or barley), grain processing technique, time adapting to diet, and various additives (e.g. ionophores) (Cheng et al., 1998). Straw or silage is frequently offered ad libitum to minimise problems with bloat and maintain rumen function (Marsh, 2016d).

2.6.2 Acidosis

Acidosis is when the body fluids become more acidic (Soffe, 2003), caused by excessive eating of cereals and concentrates which are high in readily fermented carbohydrate (Owens et al., 1998 and Fiems et al., 1999). Over processing grain can also contribute to acidosis, as it creates fine particles which can lead to increased fermentation (Castrillo et

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al., 2013). Lactic acid production increases with increased fermentation, which creates an undesirable environment for most protozoa and microbial bacteria (Scott et al., 2011). Acidic conditions can kill fibre digesting bacteria and damage the papilla lining the rumen wall. The surviving acid tolerant bacteria (Streptococcus bovis) produce more lactic acid which is more potent than VFAs and will further reduce the rumen pH.

High starch diets can cause liver abscesses which are a result of acidosis and can be seen following slaughter in the abattoir. A clinical diagnosis is given when the blood pH falls below 7.35 (Owens et al., 1998). The symptoms of acidosis can include anorexia, diarrhoea, variable feed intake, ruminal pH, and lethargy, all of which will negatively impact upon feed intake and performance (Nagaraja and Titgemeyer, 2007; Owens et al., 1998). The rumen pH should be kept between 5.5 and 7, and an animal will be at risk of SARA if the pH falls below 5.5 (Phillips et al., 2010). A fall in pH prevents the rumen from moving and makes it atonic, impacting production and intake. Increasing the acidity will also encourage acid producing bacteria, which will worsen the situation as the acid is absorbed through the rumen wall, causing metabolic acidosis (Laven, 2003).

It is important to maintain the ratio of starchy carbohydrates to cell wall (fibrous) carbohydrates in order to reduce the risk. This can be accomplished through feeding straw or forage, although this can reduce DM intake and dilute the energy content of the ration. When cattle are fed a low forage to concentrate diet then they can be at risk of ruminal acidosis, but increasing the amount of forage will help prevent this through increased chewing time and a decrease in ruminal acid production. Increasing forage chop length also raises the ruminal pH; however, in a low forage diet this will not help prevent SARA as the fermentability of the diet will be too high (Yang and Beauchemin, 2009).

When a choice of hay and wheat-barley pellets was given to SARA induced dairy cows, a greater affinity for hay was seen during SARA weeks (Keunen et al., 2002). However, in another trial by (Keunen et al., 2003), when given the choice of ground sodium bicarbonate the cows did not select it in an attempt to attenuate SARA.

2.7 Nutritionally Improved Straw

Straw is a very lignified material, which gives the stalk strength. However, the cell structure prevents ruminal liquid from reaching the cellulose present in the cells. As shown in Figure 5, sodium hydroxide denatures the cell structure and breaks down lignin-carbohydrate linkages, which results in lignin associated with polysaccharides being solubilised and cellulose broken into smaller units, making the majority of nutrients more available (Ramalho-Ribeiro, 1994).

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Untreated ‘Raw’ straw Intact cell wall structures preventing access of digestive enzymes and rumen microorganisms resulting in low digestibility.

NaOH Treatment only Some cell structures disrupted as NaOH dissolves lignin in cell walls but still significant amount of intact cell wall structure

NaOH Treatment + Extrusion Almost complete loss of cell structure after NaOH plus extrusion. ‘Slab like’ structure indicates destruction of lignin bonds and enhanced availability of cellulose for microbial digestion

Figure 5: Effect of sodium hydroxide on cell structure

(Source: Sundown Products Ltd, not dated)

Figure 6 shows the NIS manufacturing process; straw is chopped and milled to reduce particle size, and to increase the surface area available for sodium hydroxide and rumen micro-organisms. Sodium hydroxide treatment is applied and during the high-pressure extrusion stage it is forced into close contact with the plant cell walls. Treated straw is pelleted and packed together without a cellular structure, thus rendering the cellulose available to animals due to the lack of cell structure (Sundown Products Ltd, not dated).

Figure 6: Manufacturing process of nutritionally improved straw

(Source: Sundown Products Ltd, not dated)

The effectiveness of NaOH in improving the nutritional value of low quality forages and crop residues is agreed by many (Fahley et al., 1993; Braman and Abe, 1976; Pirie and Greenhalgh 1978). Braman and Abe (1976) saw an increase in DM intake of 21% with a treated wheat straw consisting of 50% of the diet. In a trial conducted by Pirie and Greenhalgh (1978) with 40 Friesian steers, an improvement in total DM intake was 12% when milled straw comprised 40% of the diet, and 32% when it comprised 60% of the diet,

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an improvement in DM digestibility from 47 to 67% was also observed. It is stated by Fahey et al., (1993) in a 24 study summary that sodium hydroxide treated straw improved DM intake of crop residue by 22% and DM digestibility by 30%.

In contrast, a trial by Kishan et al., (1973) found no difference in DM and ADF digestibility, or DM intake when feeding 9 month old buffalos with both treated and untreated straw. However, Lesoing et al., (1981) states that different crop residues may not react the same way to chemical treatment, as the greater the lignification, the greater the positive effect of sodium hydroxide on cell wall availability. Kjos et al., (1987) concurred with this when asserting that different straw types and quality will produce variable results (e.g. weather damaged).

2.7.1 NIS and Animal Health

Treated straw will normally be at a pH of 10, while 1% of alkali added to the treatment will increase the sodium content by 0.6% on a DM basis (Shacklady, 1979). The extra sodium digested is excreted in the urine with no changes to faeces excretion or blood sodium levels (Shacklady, 1979; Choung and McManus, 1976). Nonetheless, it was noticed by Choung and McManus (1976) that urine volume and water intake increased. Alkali treatment can cause water intake to increase and this can be partly associated to the increased DM intake, although the intake of water per kg DM intake is also higher, with the results suggesting an increased intake of approximately 47 ml/g Na (Pirie and Greenhalgh, 1978; Choung and McManus, 1976).

Alkali treatment can increase the rate and extent of digestion of straw and the total VFA concentration in the rumen fluid (Koers et al., 1970; Ololade and Mowat, 1975). Ololade and Mowat (1975) stated that 2-4% treated straw saw propionate levels increase and acetic acid levels decrease. It was also observed that lactic acid increased, isovaleric acid decreased, and the pH was lower when fed treated straw (Koers et al., 1970; Ololade and Mowat, 1975); however, pH was reported higher by Shin et al. (1975), which also saw a reduced rumen and blood urea levels with the treatment.

2.7.2 Production trials with NIS

Lesoing et al., (1981) stated in a trial conducted with 36 lambs that the lambs fed the higher concentration of sodium hydroxide (4%) treated straw were the best performing when compared to straw based diets consisting of lower concentrations of sodium hydroxide. The lambs showed an increased intake, and faster and more efficient gains (P<0.05), although the exact figures were not given. Chaudhry and Miller (1996) reported similar results for 36 Dorset Down X Mule store lambs, with voluntary straw intake, live-weight gain and digestibility increasing linearly (P<0.001) with the increase in sodium hydroxide from 0 to 50g/kg in straw based diets. The DLWG (g) per lamb increased by 34, 59, 74 146 as the sodium hydroxide concentration increased by 0, 8.33, 25, 50 g/kg DM, respectively, and the DM intake per g increased by 563, 638, 755, 813, similarly.

Shreck et al., (2012) conducted a trial with 336 steers of a variety of breeds. A significant (P<0.01) difference was noticed between the treated (T) and untreated (U) wheat straw for slaughter weight (T=641kg; U=586kg), DLWG (T=1.82kg; U=1.61kg) and hot carcase weight (T=388kg; U=367kg). This was supported by Peterson et al. (2015) in their trial with 480 steers of a variety of breeds on a feedlot system, where an alkaline treatment increased the DMI, DLWG (P<0.01), and FCR (P<0.05). In particular, the treated wheat straw diet for the steers resulted in increases of 25.7% for DLWG and 3.4% for slaughter weight, compared with the untreated wheat straw diet. However, Cuthbert et al., (1977) reported in a trial with 64 British Friesian steers on a straw based diet that the inclusion of treated straw did not significantly affect DLWG when cattle were fed equal quantities of diets with 0-60% pelleted alkali treated straw.

The majority of the literature states that an alkali treatment for straw will improve nutrition, while offering a source for slow fermentation. Therefore, when comparing similar diets where untreated straw has been directly swapped for treated straw a better performance

15

can be expected. However, when treated straw is compared to an alternative feedstuff the difference becomes more unclear. Shreck et al., (2012) found noticeable differences in the results between a control diet (C) and treated wheat straw (T) diet, where the straw replaced maize grain and was fed a 20% diet DM. This resulted in the control diet containing a greater quantity of maize grain (46 vs 36%) and less roughage (10%). Whilst there was an improvement, the statistical significance of this was not stated; the figures reported were slaughter weight (C= 624kg; T=641kg), DLWG (C= 1.72; T=1.82kg) and hot carcase weight (C= 378kg; T=388kg).

In contrast, research by Pirie and Greenhalgh (1978) found the inclusion of straw increased intake, but decreased growth in a trial which involved 40 Friesian steers with four treatments. The control diet was barley and soya bean and where the other diets included 40% untreated straw, or 40% or 60% alkali-treated straw. The inclusion of straw increased the intakes (DM kg/d) 7.88, 8.6, 9.67, 9.23, respectively; however, in comparison to the control diet DLWG (kg/head) fell from 1.16 to 0.78, 1.03, and 0.82 respectively. Therefore, despite the control diet having the lowest intake, it achieved the highest weight gain.

The trial conducted in this report will compare two intensive diets, aiming to prove the hypothesis stated in the introduction that the partial replacement of barley and soya hulls with wheat and NIS will show an increase in performance in intensively finished bulls.

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3.0 Methodology

This study looked at the effect of partially replacing barley and soya hulls with wheat and NIS in the diet of intensively finished bulls. The trial was carried out using a randomised block design with 34 January or February 2015 born Continental x Holstein or Holstein bulls. It commenced on the 22nd of July 2015 with bulls which weighed approximately 240kg at 6 months old. They were weighed on monthly intervals using the on farm weighing scales in order to calculate their DLWG. All feed was fed ad libitum via a bin, with the amount weighed and recorded to calculate intake levels and FCR. Straw intakes were recorded for November when the bulls were 9-10 months old.

Figure 7: The implements used in the trial

(Authors own, 2016)

3.1 Location

The trial took place at Harper Adams University Beef Unit, Newport, Shropshire, TF10 8NB.

3.2 Data Collected

Data was collected in order to perform statistical analyses:

Animal live-weight at the start of the trial

Monthly weight to calculate DLWG

Slaughter weight

Carcase weight

Slaughter conformation and fat classification

Carcase daily weight gain (CDG)

Killing out percentages

Liver scores

The CDG was calculated by multiplying the stated live-weight by 0.47 to estimate the start carcase weight (Patterson et al., 1995). Intakes were collected on a group basis and therefore statistical analysis cannot be carried out on these. Intake data allows the calculation of FCRs.

3.3 Treatments

The treatments were a cereal (control) and NIS diet, and the differences are highlighted in Table 5.

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Table 5: Blend inclusion report for both the cereal and NIS diet

(Source: Wynnstay, 2015)

Cereal Per 1000kg NIS Per 1000kg

Rolled Barley 635 Rolled Barley 312

Rolled Wheat 313

Soya Hulls 150 NIS 150

Soyabean Meal 70 Soyabean Meal 75

Distillers Dark Grains 70 Distillers Dark Grains 75

Molasses 50 Molasses 50

Minerals 25 Minerals 25

All treatment groups had straw available ad libitum and easy access to water. The bulls were all fed on the control diet before the trial, with the treatment ration introduced over a 10-day period via the hoppers. Bulls on each treatment were grouped housed on straw in 9.8m x 4.6m pens, as shown in Figure 8.

9.8m x 4.6m

NIS (8 Bulls)

Control (8 Bulls)

NIS (9 Bulls)

Control (9 Bulls)

////////////////////////////////////// Feed Fence ///////////////////////////////////

Feed Hopper Feed Hopper Feed Hopper Feed Hopper

Figure 8: Layout of the trial

(Authors own, 2016)

Figure 9: The beef unit at Harper Adams University

(Authors own, 2016)

The experiment was set up with seventeen bulls allocated by live-weight and breed in a randomised block design, with two pens of bulls per treatment (8-9 bulls per pen). The distribution of the breeds is shown in Table 6.

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Table 6: Distribution of the breeds following randomisation among the treatments

groups

NIS Control NIS Control Total

Holstein 2 2 4

British Blue 3 4 4 3 14

Simmental 1 1 2

Aberdeen Angus

1 2 2 1 6

Limousin 1 1 3 3 8

Total 8 8 9 9 34

3.4 Feed Analysis

A sample of both treatments was taken on three different occasions for analysis in the laboratory at Harper Adams University (HAU) using wet chemistry methods based on techniques by Wendt Thiex (2000), Van Soeat et al., (1991) and Van Keulen and Young (1977). More detail is available in Appendix 2A for assessment of the following:

Dry matter (DM) - Method 934.01 (Wendt Thiex, 2012)

Crude protein (CP) - Method 968.06 (Wendt Thiex, 2012)

Neutral detergent fibre (NDF) - (Van Soeat et al., 1991)

Alcohol ether extract (AEE) - Method 2003.05 (Wendt Thiex, 2012)

Acid detergent fibre (ADF) - (Van Soeat et al., 1991)

Ash - Method 942.05 (Wendt Thiex, 2012)

Acid insoluble ash (AIA) - Van Keulen and Young (1977)

Metabolisable energy (ME) was unable to be calculated at HAU laboratory as they were unable to source the NCGD reagent required for its calculation. The following aspects were analysed by an external laboratory (Rumenco Ltd) using Near Infrared Reflectance Spectroscopy approved by the UK advisory services (Offer et al., 1996):

ME

Starch content

Sugar content

Analysis was performed to certify that the nutrient values as stated in the manufacturer’s specification were being fed. Appendix 4 shows the predicted analysis.

Table 7: Mean results of the nutritional analysis from the HAU laboratory and

Rumenco

Control NIS

HAU Rumenco HAU Rumenco

DM (%) 85.3 85.2 85.1 84.7

Oil A (%) - 2.1 - 2.0

Oil B (%) - 2.5 - 2.6

CP (g/kg) 143 141 142 140

NDF (g/kg) 193 256 287 289

ADF (g/kg) 112 - 209 -

Ash (g/kg) 77 109 53 69

Acid Insoluble Ash (g/kg) 2.8 - 5.6 -

AEE (g/kg) 15.6 - 17.6 -

Starch (g/kg) - 327 - 338

Sugar (g/kg) - 81 - 83

NCGD (g/kg) - 787 - 799

ME (MJ/kg DM) - 12.3 - 12.4

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Table 7 shows the mean results for the ‘as fed’; the NDF and starch figures vary substantially and were analysed to be much lower for the control diet. Full results for the HAU analysis are available in Appendix 2B, while the full results for the external analysis are available in Appendix 3.

3.5 Faecal Analysis

Eight faeces samples were collected from different bulls from each treatment and were analysed using wet chemistry methods based on techniques by Wendt Thiex (2000), Van Soeat et al. (1991), Van Keulen and Young (1977) and MAFF (1986). More detail is available in Appendix 5A for assessment of the following:

DM - Method 934.01 (Wendt Thiex, 2012)

pH - (MAFF, 1986)

NDF - (Van Soeat et al., 1991)

ADF - (Van Soeat et al., 1991)

Acid insoluble ash - Van Keulen and Young (1977)

Ash (to determine diet digestibility) - Method 942.05 (Wendt Thiex, 2012)

Particle size and fibre length were also examined by washing and sieving, to indicate the level of undigested straw present in the faeces. The sieve sizes were set at 4mm, 2mm, 1mm and 0.6mm.

3.6 Slaughter

The bulls were selected for slaughter by Mr Simon Marsh (Principal Beef Lecturer at Harper Adams University), with a target fat class of 3= on the EUROP grid (Table 8) and were sent to ABP Shrewsbury to be slaughtered. Liveweight at slaughter was predicted to be approximately 540kg and 590kg at 13-14 months of age for Holstein and Continental cross Holstein bulls respectively.

Table 8: The EUROP grid converted into numerical values

Conformation Classification

EUROP Grid P- P= P+ O- O= O+ R- R= R+ U- U= U+ E- E= E+

Numerical value 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Fat Classification

EUROP Grid 1- 1= 1+ 2- 2= 2+ 3- 3= 3+ 4- 4= 4+ 5- 5= 5+

Numerical value 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

3.7 Liver Assessment

Livers were scored by Mr Chris McLachlan (abattoir manager at ABP Shrewsbury) using the scale shown in Table 9. An assessment was made regarding the degree of discolouration, abscesses and/or swelling, to determine the relationship between treatment and acidosis.

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Table 9: Liver scoring scale

(Source: Pers. Comm. Mr S. Marsh is a Principal Lecturer and a beef cattle specialist at Harper Adams University)

Assessment Score

1 2 3 4 5

Description Healthy liver

Minor discolouration/ swelling

Slight abscesses, discolouration and/ or swelling

Abscesses and/or severe discolouration

Severe abscesses

3.8 Statistical Analysis

Data was analysed by ANOVA using GenStat 17th edition

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4.0 Results

4.1 Faecal Analysis Results

Table 10 shows the mean results from the eight samples, and the complete results are shown in Appendix 5B.

Table 10: Mean faecal analysis results

Cereal NIS

DM (%) 18.6 17.1

pH 6.0 6.4

NDF (g/kg) 487 523

ADF (g/kg) 275 349

Ash (g/kg DM) 115 100

Acid Insoluble Ash (g/kg DM) 10.3 19.7

The results show that the NIS diet resulted in a greater quantity of NDF and ADF present in the faeces, revealing that more fibre passed through the animal undigested. This was supported by the findings from the washing and sieving, as presented in Table 11, which shows a higher percentage per 100g of undigested straw in the faeces. NIS also had a higher pH (+0.4), similar to the findings by Shin et al. (1975), indicating higher levels of digestible fibre, but also lower levels of starch (Parish, 2007).

Table 11: Results from washing and sieving the faeces

Washing and Sieving %/100g %/100g

mm Cereal NIS

4 1.25 0.77

2 3.44 4.73

1 15.73 22.5

0.6 25.25 23.7

Total 45.67 51.7

4.2 Digestibility

The digestibility measures assess the animals’ feed utilisation and calculations are shown in Appendix 6.

Table 12: Digestibility analysis of the treatments

Cereal NIS

Dry Matter Digestibility 72.8 73.1

NDF Digestibility 31 51

ADF Digestibility 33 55

Both diets resulted in a very similar DM digestibility. This indicates that similar DM was digested by the bulls, which was not expected following claims about improved digestibility of NIS by Fahey et al. (1993) and Braman and Abe (1976). There was however a noticeable increase in NDF and ADF digestibility, 20% and 22% respectively, disagreeing with the findings of Kishan et al., (1973). Mertens (2009) states that a rise in NDF digestibility will reduce feed intakes because of reduced fermentation causing rumen fill; however, this was not true in this trial as the NIS bulls had similar intakes, albeit 0.33kg higher per day.

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4.3 Animal Performance

Daily live weight gain (DLWG) was calculated by the difference from slaughter weight to start weight. The performance data was statistically analysed and the results are shown in Table 13. No significant difference was found between the two diets for any of the animal performance characteristics.

Table 13: Animal performance analysis

Cereal NIS SEM

(df=28) CV % P Value Sig

Start Weight (kg) 239 243 15.5 24.9 0.926 NS

Slaughter Weight (kg) 581 592 9.5 6.8 0.641 NS

Days to Slaughter 257 251 3.1 15.7 0.059 NS

DLWG (kg) 1.32 1.40 0.044 12.1 0.309 NS

NS = Not Significant

As shown in Figure 10, both treatments followed similar DLWG patterns; however, the DLWG trend followed a series of peaks and troughs and the reasons for this will be discussed later.

Figure 10: Mean DLWG of the bulls

An analysis of covariance was used to see the relationship between slaughter weights and starting live-weights with regards to the different diets and breeds. A significant difference was found between breed and slaughter weights (P<0.001). However, there was no significant difference found when analysing breed and diet with slaughter weight, albeit being almost significant (P=0.053).

There was no significant correlation between slaughter weight and starting live-weight (P=0.236).

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

29 64 98 141 181 211 239 271 306

NIS mean DLWG Control mean DLWG

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Table 14. Effect of Breed and Diet on Slaughter Weight (kg) and its relationship with Starting Weight (kg)

Diet

Breed Cereal NIS Mean (Breed)

Aberdeen Angus 574.7 575.0 576.7

British Blue 566.4 593.3 579.1

Holstein 538.0 513.0 523.3

Limousin 602.0 576.0 594.9

Simmental 598.0 700.0 635.7

Mean (Diet) 581 592

SEM (19 df)

Treatment 6.49

Breed Min rep = 19.28

Max rep = 8.22

P Value

Breed <.001

Treatment 0.492

Breed x Treatment 0.053

Covariate 0.236

CV% 4.3

Note – The means from Output were adjusted for the covariate. The means from the Summary Table were not.

4.4 Carcase Performance

As shown in Table 15, no significant difference was found between the two diets for any of the carcase performance characteristics.

Table 15: Carcase performance analysis

Cereal NIS SEM

(df=28) CV % P

Value Sig

Carcase Weight (kg) 309.1 317.6 6.64 8.7 0.536 NS

Killing Out (g/kg) 532 537 0.6 4.3 0.623 NS

Daily Carcase Gain (kg) 0.77 0.81 0.027 14.1 0.275 NS

Conformation1 6.6 6.7 0.37 24.8 1 NS

Fat Class1 6.9 6.6 0.33 21.5 0.175 NS

Liver Score2 1.07 1.07 0.11 24.2 1 NS

1. EUROP carcase classification: Conformation: P- =1 and E+ =15, Fat Class: 1- =1, 5+ =15

2. Liver assessment: 1= Healthy liver and 5= Severe abscesses NS = Not Significant

An analysis of covariance was used to see the relationship between carcase weights and killing out (g/kg) with regards to the different diets and breeds. A significant difference was found between breed and carcase weights (P<0.001), and a significant difference also was found when analysing breed and diet with carcase weight (P=0.025).

There was a significant correlation between carcase weight and killing out (g/kg) (P=0.038).

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Table 16. Effect of Breed and Diet on Carcase Weight (kg) and its relationship with Killing Out (g/kg)

Diet

Breed Cereal NIS Mean (Breed)

Aberdeen Angus 298.6 292.9 306.7

British Blue 315.1 332.4 317.4

Holstein 280.8 262.5 281.4

Limousin 326.5 315.7 319.4

Simmental 318.9 383.7 351.5

Mean (Diet) 309.1 317.6

SEM (19 df)

Treatment 3.63

Breed Min rep = 11.62

Max rep = 4.95

P Value

Breed <.001

Treatment 0.474

Breed x Treatment 0.025

Covariate 0.038

CV% 4.5

Note – The means from output were adjusted for the covariate. The means from the Summary Table were not.

4.5 Feed Intake Performance

On average, the NIS fed bulls consumed 35kg more than the cereal diet. The straw intakes were recorded for 30 days between October and November when the bulls were 11-12 months old and show that the NIS bulls consumed 0.63kg of straw per bull per day compared to the cereal fed bulls eating 0.7kg. The data could not be statistically analysed, as individual feed intakes for each treatment were not recorded; however, it can be seen that overall feed intakes and FCRs were similar (Table 17).

Table 17: Feed intake analysis

Cereal NIS

Total Concentrate Intake (kg) 2063 2098

Total DM Intake (kg) 1754 1783

Daily Concentrate Intake (kg) 8.03 8.36

Total Straw Intake (kg per day) 0.70 0.63

FCR (kg feed: kg live-weight gain) 6.03 6.01

FCR (kg feed: kg carcase gain) 10.42 10.32

The FCRs (kg feed: kg live-weight gain) were higher than the targets of 5.5 (Holstein) and 5.0 (Continental X Holstein Bulls) as listed in Table 1; however, the trial did not record the growth between 110-240 kg. Marsh (2012) states that dairy bred bulls between 110-240kg would achieve a FCR of 3.1:1 and a DLWG of 1.42kg.

4.6 Financial Performance

As shown in Table 18 there was no significant difference in carcase price or value however the NIS fed realised and extra £30 in carcase value. The mean feed intakes and mean gains were used to calculate the average cost as individual intakes were not recorded. There was an increase in the margin over feed for the NIS fed bulls of £12.

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Table 18: Financial performance analysis

Cereal NIS SEM (df=28) CV % P Value Sig

Carcase price (£/kg) 3.08 3.08 0.038 5.9 0.841 NS

Carcase value (£) 953 983 29.0 13.4 0.706 NS

Feed cost (£/tonne) 198 203

Feed cost (£/bull) 408 426

Margin over feed (£/bull) 545 557

Feed cost per kg live-weight gain (£/kg)

1.19 1.22

Feed cost per kg carcase weight gain (£/kg)

2.08 2.10

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5.0 Discussion

5.1 Animal Performance

5.1.1 Start Weight

The bulls mean weights at the start of the trial were 239kg and 243kg for the cereal and NIS diet, respectively. There was no significant difference between the groups meaning that any performance variation recorded would be as a result of the treatment.

5.1.2 Slaughter Weight

There was no significant difference in slaughter weight, with an 11kg difference between the mean values. Shreck et al., (2012) reported a greater difference in slaughter weights, but did not state if it was significant. With cereal bulls achieving 581kg and NIS bulls achieving 592kg, both were around the targets set by AHDB (2015c), of 560kg for Holstein bulls and 600kg Continental x Holstein bulls.

A significant difference was found between breed and slaughter weights (P<0.001), with the Simmental bulls averaging 112.4kg over the Holstein bulls. This shows that the choice of breed will have an impact on the system. However, there was no significant difference found when analysing breed and diet with slaughter weight, despite it being almost significant (P=0.053). There was also no significant correlation between slaughter weight and starting live-weight (P=0.236), therefore the starting weight had no influence on the slaughter weight.

5.1.3 Days to Slaughter

There was no significant difference between the two treatments, with the NIS group taking 6 days less to slaughter. This was a surprise as the NIS diet had a higher starch content as shown in the feed analysis (Table 7). Marsh and Brown (2007) suggested that significantly better DLWG were achieved with a higher starch diet; however, both feeds had similar DM digestibility and ME content.

5.1.4 Daily Live-Weight Gain

By achieving a DLWG of 1.40kg the NIS bulls met the DLWG target of 1.4kg set by AHDB (2015c) for Continental x Holstein bulls; however, the cereal bulls by achieving 1.32kg were below this and the Holstein target of 1.34kg. However, with a difference of 0.08kg, this was not statistically significant. Shreck et al., (2012) saw a big improvement in DLWG, but did not state its significance, while Pirie and Greenhalgh (1978) saw a decrease in DLWG. The results of this trial disagrees both these reports, and is most similar to the findings of Cuthbert et al., (1977) which stated that alkali straw would not significantly affect DLWG.

Several factors could have influenced the peak and troughs observed in the DLWG trend as shown in Figure 10. The level of muck building up in December and March hindered intakes and could not be cleared more regularly due to staff commitments and available space for the muck. No difference in muck build-up was seen between treatment groups despite the concerns of Choung and McManus (1976) regarding increased urine volume. Another factor could be that as the best performing, most dominant bulls got sent to slaughter then this gave a chance for the less dominant bulls to increase their intake, briefly boosting mean DLWG.

5.2 Carcase Performance

5.2.1 Carcase Weight

There was no statistical difference found for carcase weight as the NIS bulls produced a carcase weighing 317.6kg, some 8.5kg heavier than the cereal bulls (309.1kg). These results were also below the 335kg target for Continental x Holstein bulls, but higher than the target of 285kg for Holstein bulls.

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A significant difference was found between breed and carcase weights (P<0.001), with the Simmental bulls on average the heaviest (351.5kg) and the Holstein the lightest (281.4kg). There was also a significant correlation between carcase weight and killing out (g/kg) (P=0.038), showing that killing out improved as carcase weights got heavier. It can be seen in Table 16 the heavier breeds are later maturing breeds and better suited to intensive meat production (Soffe, 2003). This highlights that the choice of breed will impact the system output.

5.2.2 Killing Out

The NIS diet achieved a killing out of 537g/kg, while the cereal diet achieved 532g/kg. This result was not significant as there was only a 5g/kg difference. These results were below the 560g/kg target for Continental x Holstein bulls, but higher than the target of 510g/kg for Holstein bulls.

The bulls were weighed gut full before slaughter, which may negatively influence the killing out result. According to Fahey et al., (1993) and Braman and Abe (1976), sodium hydroxide treatment helps increase DMI in diets, and a higher DMI should result in a higher killing out (AHDB, 2015b). However, as shown in Table 17 the DMI was only higher by 29kg.

5.2.3 Daily Carcase Gain

The DCG was not significant between the two treatment groups; the NIS bulls recorded a mean DCG of 0.81kg, while the cereal bulls achieved 0.77kg.

5.2.4 Carcase Conformation and Fat Classification

Conformation showed identical results, with both treatment groups recording a similar conformation score and therefore an average grade between an O+ and a R-.

The cereal diet achieved a fatter classification with a score (6.9) higher than that for the NIS diet (6.6), but this was also not statistically significant. The cereal diet averaged a classification of 3- while the NIS diet average was 2+.

The carcases were graded by Video Image Analysis (VIA) which improved the consistency and reduced the risk of human error when compared to an MLC grader.

5.2.5 Liver Scores

Identical liver scores were produced for both diets (1.07), indicating that both treatment groups had healthy livers and had not suffered from acidosis. It was predicted that there would have been a difference between the two groups with the NIS buffering the acidic conditions in comparison to the cereal diet, but this was not seen. The trial could be repeated with increased starch content in both diets to see if any benefits can be seen in rumen conditions through the use of NIS.

5.3 Feed Intake and Feed Conversion Ratio

Intake could not be measured on an individual basis and as a result the statistical analysis cannot be carried out. Individual feed bins would be preferably used to accurately record the intake of individual animals.

Fahey et al., (1993) and Braman and Abe (1976) saw an increase in DMI of 20% with NIS, therefore a noticeable increase in the total concentrate intake was expected. However, with the NIS bulls consuming 35kg more in total concentrate intake, the DM intake only increased by 1.65%. The FCRs were also very similar, with the NIS diet having a better live-weight FCR by 0.02 (kg feed: kg live-weight gain), while both carcase FCRs were similar (kg feed: kg carcase gain).

It was observed that the bulls occasionally rejected the NIS (Figure 11), agreeing with the conclusion of Keunen et al., (2003). This could be because they were selectively eating the NIS to attenuate acidosis, as found by Keunen et al., (2002), and there was too much

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NIS in the diet. Therefore, it can be suggested from looking at this, the performance and the liver scores that less NIS and more starch could be included in the diet.

Figure 11: Rejected NIS present in the trough

(Authors own, 2016)

5.4 Financial Performance

With a similar conformation and fat class between the two treatments, the £/kg was similar. However, the NIS achieved a higher carcase value of £30 per head, due to heavier (albeit not significant) slaughter weights. As a result of higher intakes (+35kg) and more expensive feed (+£5/t), the NIS total mean feed cost per bull was £18 more expensive than the cereal diet, consequently improving Margin over Feed by £12 per head for the NIS fed bulls. It was calculated that the NIS diet had a slightly more expensive feed cost per kilogram of live-weight gain (£0.03) and per kilogram of carcase weight gain (£0.02). A sensitivity analysis would show a financial benefit for NIS if wheat prices falls in relation to barley.

5.5 Limitations and Further Research

A limitation to the trial was that it was not possible to record individual feed intakes and as a result statistically analyse intakes and FCRs. An individual feeder could be used to measure individual animals’ intake and a weigh plate could be placed under where an animal stands to eat. Large quantities of weight data could then be gathered on each animal, allowing better tracking of animals’ weight gain and reducing the effect stomach fill has on weight variation.

Feed accessibility was also a limitation, as there was a build-up of muck in the pens. The level of muck made accessibility to the feed harder for the bulls and may have had an impact on intake. The reason the pens could not be cleared as often as desired was due to the availability of space for the muck and the availability of staff.

From the evaluation of this trial, looking at performance, intakes and liver scores it was observed that there is the potential to increase the wheat (starch) present in the diet, and decrease the NIS content as bulls tended to reject the NIS. Hence it would be proposed that further research could be carried out varying the inclusion of wheat and NIS in the

29

diet to determine the optimum level of performance. Indwelling pH probes could also be swallowed to monitor rumen health for the purposes of assessing the benefit of NIS on the rumen. The research could be beneficial for large arable farmers growing wheat, as rejected wheat could be fed to intensive beef finishing. Further research could include steers and heifers, as farmers may find this more beneficial as only 20% of male calves are finished as bulls (Marsh, 2016a). It would also be beneficial to include more replicates and use the same breed for all trial animals as this would reduce variation within breed and eliminate variation between breeds.

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6.0 Conclusions

The trial shows that there is no significant difference in animal or carcase performance when partially replacing barley and soya hulls with wheat and NIS in an intensive bull beef diet. There was a numerical improvement in DLWG, slaughter weight and carcase weight with NIS but this was not statistically significant. In addition, the study showed that the use of NIS when fed with wheat had a similar level of acidosis to the control diet based on barley with both treatments recording similar liver scores.

Both treatments had similar DM digestibility, refuting the claims in the literature that a diet including NIS improves digestibility. There was a large increase in NDF and ADF digestibility, but this did not decrease intakes as suggested by Mertens (2009), as total concentrate intakes increased by 35kg.

The NIS treatments had slightly higher intakes and feed costs (+£5/t), and the total feed cost per bull was £18 higher than the cereal group. Both treatments achieved a similar £/kg, although the NIS diet achieved a higher carcase value of £30 per head, due to heavier (albeit not significant) slaughter weights. Therefore, the higher feed costs was negated by the price advantage, leaving a financial margin difference of £12 per bull.

This study therefore disproved the hypothesis that partial replacement of barley and soya hulls with wheat and NIS would show an increase in performance in intensively finished bulls. However, it does illustrate NIS and wheat to be a similarly effective alternative when included in intensive beef diets Nevertheless, it is recommended that breed, gender and market conditions should be considered in order to achieve similar results.

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8.0 Appendices

Appendix 1. Typical breed performance and finishing systems

Bulls Bullocks Heifers

Breed Age (months)

Weight (kg)

Age (months)

Weight (kg)

Age (months)

Weight (kg)

Holstein/Friesian 12-14 550 15-18 600

Charolais 12-14 650-700 15-18 650-700 18-24 600-625

Belgian Blue 12-14 625-675 15-18 650-675 18-24 600-625

Simmental 13-14 625-675 15-18 650-675 18-24 600

Limousin 13-14 625-650 15-18 625-650 18-24 575-600

Aberdeen Angus

18-24 575-600 20-26 550-575

Beef Shorthorn 18-24 575-600 20-26 550-575

Hereford 18-24 575-600 20-26 550-575

Welsh Black 18-24 575-625 20-26 525-575

Key:

Intensive Semi-Intensive Extensive

12-14 months 15-24 months Over 24 months

(Source: MPW, 2014)

Appendix 2A. Feed Sample Analysis Techniques carried out by HAU laboratory

Dry Matter (DM) - Method based on AOAC Official Method 934.01 (Wendt Thiex, 2012)

50g feed sample was weighed and placed in oven at 100°C for 24 hours. Once cooled it was reweighed.

DM % = Dried Sample Weight x 100 Fresh Sample Weight

Crude Protein (CP) – Method based on AOAC Official Method 968.06 (Wendt Thiex, 2012)

0.15g of milled sample was weighed into a thin aluminium cone and placed in the Leco nitrogen testing machine. The sample is incinerated with the gases measured for nitrogen, which gives a crude protein value.

Neutral Detergent Fibre (NDF) – Method based on techniques by Van Soeat et al. (1991)

A P1 crucible was weighed empty. Into which 0.5g of dried milled sample was weighed.

These were then placed into the Fibretec apparatus. All valves were closed and a tight fit ensured.

25ml of cold neutral detergent reagent and a few drops of Octanol were added. The heat was then turned on to full until boiling and then turn down to 3.5 (medium) to digest for 30 minutes.

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The heat was then turned off and 25ml of neutral detergent reagent and 2ml of alpha amylase added. Again the heat was then turned on to full until boiling and then turn down to 3.5 (medium) to digest for 30 minutes.

The heat was then turned off completely. The samples were then filtered and washed three times with 20-30ml of hot distilled water to remove the neutral detergent reagent.

After filtering 2ml of alpha amylase was added with 25ml of hot water. This was left to stand for 15 minutes, after which it was filtered 3 times again with hot distilled water.

Once cooled the crucibles were put in the oven at 100°C over night. After which they were placed in a desiccator to cool and reweighed.

The samples were then ashed at 500°C in the furnace overnight, cooled and reweighed.

NDF (g/kg) = NDF Weight x 1000 Sample Weight

Acid Detergent Fibre (ADF) – Method based on techniques by Van Soeat et al. (1991)

1.0g of dried milled sample was weighed and out into a P2 crucible which was weighed empty. This was then placed into the Fibretec apparatus. All valves were closed and a tight fit ensured.

100ml of acid detergent reagent was added and boiled. After reaching the boiling point the heat was turned down to 3.5 (medium) and left for 60 minutes.

After which the digest was filtered and washed three times with hot distilled water and with acetone once.

The crucibles were put in the oven at 100°C over night. After which they were placed in a desiccator to cool and reweighed.

The samples were then ashed at 500°C in the furnace overnight, cooled and reweighed.

ADF (g/kg) = ADF Weight x 1000 Sample Weight

Alcohol Ether Extract (AEE) – Method based on AOAC Official Method 2003.05 (Wendt Thiex, 2012)

A Soxtec system was used. The unit was turned on to 150°C and the condensers were allowed to fill.

1g of milled sample was added to the thimbles and plugged with cotton wool.

The extraction cups were weighed and 25ml of 40-60°C petroleum ether was added to the cups in the fume cupboard.

The Soxtec unit was put in the rinsing position and the thimbles placed in the condenser.

The unit was then put into the boiling position with the thimbles fastened by the magnets. The unit was then put to the rinsing position to raise the thimbles.

The taps were opened, the extraction cups inserted and the handle clamped.

The unit was the put to boiling position and cover the thimbles in the solvent for 30 minutes.

After which the unit was set at rinsing position and the solvent rinsed out.

The taps were then closed to collect condensed solvent for 15 minutes.

The evaporation valve was opened and closed after 5 minutes.

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The extraction cups were removed and placed in the fume cupboard to remove and further traces of solvent.

The extraction cups were then weighed to give the fat.

AEE (g/kg) = Weight of Fat x 1000 Weight of Sample

Acid Insoluble Ash (AIA) - Method based on techniques by Van Keulen and Young (1977)

5g of dried milled sample was put in a crucible and ashed overnight at 450°C. The ash was weighed and put in a 500ml beaker with 100ml of 2N HCl.

The mixture was then boiled for 15 minutes.

Then it was filtered through a Whatman No.4 filter paper. The beaker required flushing out to remove all the residue. The filter paper was then folded, put back in the same crucible and ashed overnight at 450°C.

These were then weighed, and the crucibles when empty re weighed.

AIA (g/kg) = (Crucible and ash weight – Empty crucible weight) x 1000 Weight of Sample

Ash – Method based on AOAC Official Method 942.05 (Wendt Thiex, 2012)

An empty crucible was weighed. 2-3g of dried milled sample was added and placed in the furnace overnight at 500°C.

After which they were placed in a desiccator to cool and reweighed

Ash (g/kg) = Ashed Weight x 1000 Sample Weight

Appendix 2B. Feed Analysis carried out by HAU laboratory

Date Treatment DM (%)

CP (g/kg)

NDF (g/kg)

ADF (g/kg)

Ash (g/kg)

AIA (g/kg)

AEE (g/kg)

22/11/2015 Control 85.07 145.3 193.9 111.5 77.1 2.11 17.1

14/02/2016 Control 85.27 143.4 190.6 113 76.3 2.78 11.5

06/04/2016 Control 85.48 141.1 193.2 112.6 77.3 3.54 18.2

Average Control 85.27 143.27 192.6 112.37 76.90 2.81 15.6

22/11/2015 NIS 85.59 141.6 257.2 194.7 53.8 4.88 17.2

14/02/2016 NIS 85.17 141.8 310.2 201 51.4 6.08 18.1

06/04/2016 NIS 84.63 143.1 293.8 234 53.7 5.77 17.5

Average NIS 85.13 142.17 287.1 209.9 52.97 5.58 17.6

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Appendix 3. Feed Analysis carried out by external laboratory (Rumenco)

Treatment Control NIS

Date 26/10/2015 24/11/2015 Average 26/10/2015 24/11/2015 Average

DM (%) 86 84.5 85.25 85 84.4 84.7

Oil A 1.9 2.2 2.05 1.7 2.3 2

Oil B 2.4 2.6 2.5 2.2 3 2.6

Crude Protein (g/kg) 141 141 141 138 142 140

Crude Fibre (g/kg) 118 64 91 89 62 75.5

Ash (g/kg) 79 140 109.5 66 73 69.5

Starch (g/kg) 328 326 327 329 347 338

Sugar (g/kg) 82 79 80.5 82 85 83.5

NCGD (g/kg) 753 822 787.5 772 827 799.5

NDF (g/kg) 351 164 257.5 319 259 289

ME (MJ/kg DM) 12.32 12.28 12.3 12.35 12.45 12.4

Appendix 4. The theoretical nutrient analysis as stated by the

manufacturer (Wynnstay)

Control NIS

Nutrients (as fed) (DM) (as fed) (DM)

ME (MJ) 11.0 12.7 10.6 12.2

Protein (g) 143 165 134 154

Starch (g) 342 396 356 412

Sugar (g) 50 58 54 62

NDF (g) 206 238 194 224

Crude Fibre (g) 80 93 74 85

Appendix 5A. Faeces Sample Analysis Techniques carried out by HAU laboratory

Dry Matter (DM) - Method based on AOAC Official Method 934.01 (Wendt Thiex, 2012)

50g faecal sample was weighed and placed in oven at 100°C for 24 hours. Once cooled it was reweighed.

DM % = Dried Sample Weight x 100 Fresh Sample Weight

pH – Method based on techniques by MAFF (1986)

50g of fresh sample put in a 500ml beaker and 125ml of distilled water added and stirred.

The mixture was left for an hour

Extract was decanted into the beaker and the electrodes from the pH meter were inserted for 30 seconds for reading

Neutral Detergent Fibre (NDF) – Method based on techniques by Van Soeat et al. (1991)

42

A P1 crucible was weighed empty. Into which 0.5g of dried milled sample was weighed.

These were then placed into the Fibretec apparatus. All valves were closed and a tight fit ensured.

25ml of cold neutral detergent reagent and a few drops of Octanol were added. The heat was then turned on to full until boiling and then turn down to 3.5 (medium) to digest for 30 minutes.

The heat was then turned off and 25ml of neutral detergent reagent and 2ml of alpha amylase added. Again the heat was then turned on to full until boiling and then turn down to 3.5 (medium) to digest for 30 minutes.

The heat was then turned off completely.The samples were then filtered and washed three times with 20-30ml of hot distilled water to remove the neutral detergent reagent.

After filtering 2ml of alpha amylase was added with 25ml of hot water. This was left to stand for 15 minutes, after which it was filtered 3 times again with hot distilled water.

Once cooled the crucibles were put in the oven at 100°C over night. After which they were placed in a desiccator to cool and reweighed.

The samples were then ashed at 500°C in the furnace overnight, cooled and reweighed.

NDF (g/kg) = NDF Weight x 1000 Sample Weight

Acid Detergent Fibre (ADF) – Method based on techniques by Van Soeat et al. (1991)

1.0g of dried milled sample was weighed and out into a P2 crucible which was weighed empty. This was then placed into the Fibretec apparatus. All valves were closed and a tight fit ensured.

100ml of acid detergent reagent was added and boiled. After reaching the boiling point the heat was turned down to 3.5 (medium) and left for 60 minutes.

After which the digest was filtered and washed three times with hot distilled water and with acetone once.

The crucibles were put in the oven at 100°C over night. After which they were placed in a desiccator to cool and reweighed.

The samples were then ashed at 500°C in the furnace overnight, cooled and reweighed.

ADF (g/kg) = ADF Weight x 1000 Sample Weight

Acid Insoluble Ash (AIA) - Method based on techniques by Van Keulen and Young (1977)

5g of dried milled sample was put in a crucible and ashed overnight at 450°C. The ash was weighed and put in a 500ml beaker with 100ml of 2N HCl.

The mixture was then boiled for 15 minutes.

Then it was filtered through a Whatman No.4 filter paper. The beaker required flushing out to remove all the residue. The filter paper was then folded, put back in the same crucible and ashed overnight at 450°C.

These were then weighed, and the crucibles when empty re weighed.

AIA (g/kg) = (Crucible and ash weight – Empty crucible weight) x 1000 Weight of Sample

43

Ash – Method based on AOAC Official Method 942.05 (Wendt Thiex, 2012)

An empty crucible was weighed. 2-3g of dried milled sample was added and placed in the furnace overnight at 500°C.

After which they were placed in a desiccator to cool and reweighed

Ash (g/kg) = Ashed Weight x 1000 Sample Weight

Appendix 5B. Faecal Analysis carried out by HAU laboratory

DM (%) PpH NDF (g/kg)

ADF (g/kg) Ash (g/kg DM) AIA (g/kg DM)

Control 18.9 5.83 481 273 88.4 10.91

Control 17.3 6.47 491 263.9 119.6 10.08

Control 19.8 6.01 467 258.7 99.1 9.31

Control 18.3 5.54 508 305.6 152.6 11.09

Average 18.6 6.0 487 275.3 114.9 10.3

NIS 17.8 6.62 445 328 102.3 11.48

NIS 16.8 6.82 555 330.4 107.5 19.29

NIS 16.4 5.66 505 402.4 96.4 19.79

NIS 17.5 6.64 586 338.9 94.3 28.36

Average 17.1 6.4 523 349.9 100.1 19.7

Appendix 6. Digestibility Measure

All digestibility calculations are as recommended by Dr Robert Wilkinson (Wilkinson, 2016. Pers. Comm. Dr R. Wilkinson is a Principal Lecturer specialising in Animal Nutrition at Harper Adams University).

Dry Matter Digestibility

DMD % = Acid Insoluble Ash (Faeces %) – Acid Insoluble Ash (Feed treatment %) Acid Insoluble Ash (Faeces %)

Cereal = 10.3-2.8 = 0.728 = 72.8% DM Digestible 10.3

NIS = 19.7-5.3 = 0.731 = 73.1% DM Digestible 19.7

44

NDF Digestibility (NDFD)

NDF Digestibility = NDF Intake – NDF Output (Faeces) NDF Intake NDF Intake = DMI/Head x NDF (g/kg DM)

NDF Output = DMI/Head x DM Digestibility = Digestible DM Intake

DMI/Head - Digestible DM Intake = Indigestible DM Intake

Indigestible DM Intake x Faeces NDF (g/kg) = NDF Output

Cereal Intake = 8.5 x 192.6 = 1637.1 Output = 8.5 x 0.728 = 6.188 8.5 – 6.188 = 2.312 2.312 x 487 = 1125.944 =1637.1-1125.944 =31% NDFD 1637.1

NIS Intake = 8.5 x 287.1 = 2440.35 Output = 8.5 x 0.731 = 6.2135 8.5 – 6.2135 = 2.2865 2.2865 x 523 = 1195.84 =2440.35-1195.84 =51% NDFD 2440.35

ADF Digestibility (ADFD)

ADF Digestibility = ADF Intake – ADF Output (Faeces) ADF Intake ADF Intake = DMI/Head x ADF (g/kg DM)

ADF Output = DMI/Head x DM Digestibility = Digestible DM Intake

DMI/Head - Digestible DM Intake = Indigestible DM Intake

Indigestible DM Intake x Faeces ADF (g/kg) = ADF Output

Cereal Intake = 8.5 x 112.37 = 955.145 Output = 8.5 x 0.728 = 6.188 8.5 – 6.188 = 2.312 2.312 x 487 = 636.5 = 955.145-636.5 = 33.4% ADFD 955.145

NIS Intake = 8.5 x 209.9 = 1784.2 Output = 8.5 x 0.731 = 6.2135 8.5 – 6.2135 = 2.2865 2.2865 x 349.9 = 800 = 1784.2-800 = 55% ADFD 1784.2

45

Appendix 7. Carcase Price (£/kg) for bulls sold from January – May

2016

As can be seen the base price was 3.22 £/kg

Table 19. Penalty/Bonus per classification (p/kg)

Fat classification

2- 2= 2+ 3- 3= 3+

Co

nfo

rmatio

n

R+ -5 -5 5 5 5 5

R= -10 -10 BASE BASE BASE BASE

R- -15 -15 -5 BASE BASE BASE

O+ -20 -20 -15 -15 -15 -15

O= -40 -40 -30 -30 -30 -30

O- -60 -60 -45 -45 -45 -45

P+ -80 -80 -60 -60 -60 -60

P= -90 -90 -80 -80 -80 -80

P- -100 -100 -100 -100 -100 -100

Table 20. Carcase price per classification score (£/kg)

Fat classification

2- 2= 2+ 3- 3= 3+

Co

nfo

rmatio

n

R+ 3.17 3.17 3.27 3.27 3.27 3.27

R= 3.12 3.12 3.22 3.22 3.22 3.22

R- 3.07 3.07 3.17 3.22 3.22 3.22

O+ 3.02 3.02 3.07 3.07 3.07 3.07

O= 2.82 2.82 2.92 2.92 2.92 2.92

O- 2.62 2.62 2.77 2.77 2.77 2.77

P+ 2.42 2.42 2.62 2.62 2.62 2.62

P= 2.32 2.32 2.42 2.42 2.42 2.42

P- 2.22 2.22 2.22 2.22 2.22 2.22

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