10. Animal Sustainability

RSNR403/503 Sustainable Land Management - 10 - 1 ©2009 The Australian Wool Education Trust licensee for educational activities University of New England

10. Animal Sustainability

Russell Pattinson

Learning objectives At the end of this topic you should be able to:

• Demonstrate a thorough understanding of the factors that impact on sustainable production for an animal (specifically sheep) enterprise

• Discuss the impacts of management practices relating to animal welfare, animal health, pest management, grazing systems, production levels and the resource base

• Access and utilise recent research and extension efforts describing sustainable production systems

Key terms and concepts Sheep behaviour, animal welfare, grazing management, chemical use, integrated pest management, production levels and quality, animal impacts on the resource base, managing native vegetation, rivers and riparian areas.

Introduction to the topic Profitable animal production systems are largely based on converting rainfall into grass and then grass into either food or fibre. If only it were that simple! Inherent within any animal production system is the need to balance an array of factors so that the enterprise is ‘sustainable’ in the longer term. For example, while animal production may be able to be increased significantly in the short term by increasing stocking rates, such a strategy on its own may also degrade the resource base and impact negatively on animal health or product quality, especially in a tough year. The primary focus of this topic is on sheep production systems and examining the balance required to maintain the sustainability of the production system and that of the business enterprise. The concept of sustainability is complex as discussed in other topics in this unit. It is a process of continuous improvement rather than an end-point. A good approach is to first remove those practices from a farming system that are obviously ‘unsustainable’.

10.1 What makes a sustainable production system? Until recently (largely over the last decade) the term ‘sustainability’ was not a term frequently used by farmers. However, that is now rapidly changing. Indeed it could well be argued that it always has been an important component of farming systems, but probably just via a different name. There are numerous definitions of the term ‘sustainability’. For this topic we will use the definition provided in the Meat and Livestock Australia Book, Towards Sustainable Grazing – The Professional Producers Guide (Mason et al. 2003) which relates to sustainable grazing systems:

10 - 2 – RSNR403/503 Sustainable Land Management ©2009 The Australian Wool Education Trust licensee for educational activities University of New England

A sustainable grazing system is a process of continuous improvement that balances the following six general requirements and prioritises them for a particular farm situation: 1. increase productivity and profit from the grazing system 2. increase water use in the grazing system 3. protect the on-farm natural resources 4. create more opportunities for biodiversity 5. reduce off-site impacts from the grazing system 6. improve producer satisfaction, motivation and capacity to implement change. To this definition, we could add a seventh point: 7. improve the welfare of livestock While profit is obviously a major objective, there are numerous environmental and animal welfare issues that farmers need to take into account. As mentioned earlier – an unceasing attempt to remove unsustainable practices is a good place to start. As major custodians of a significant proportion of Australia’s natural resources (over 25% of our land, water and vegetation), broadacre farming in Australia must proactively respond and demonstrate their environmental credentials to regulators, society and consumers. This is not a threat to Australian agriculture but indeed an opportunity, as sustainability, ‘from fibre to fashion’ or ‘paddock to plate’ will become an increasingly important marketing criterion in the future. Proactive investment can help ameliorate the likelihood of commercially unrealistic environmental legislation, policies and targets. At the same time, the community quite rightly expects our natural resources to be maintained and enhanced and not negatively affected by farming practices. The same can be said in relation to animal welfare. The recent mulesing ‘debate’ in the wool industry is clear evidence of how external factors can impact on an industry.

10.2 Animal welfare While animal welfare has always been a key objective for any farmer (because it makes financial and ‘moral’ sense), it is now becoming a more public issue and will undoubtedly become an increasingly important marketing principle in the future. It is also a legal obligation as Section 9 of the Prevention of Cruelty to Animals Act defines cruelty and provides for proper and sufficient food and shelter being made for animals. Subsection (f) states that a person who: ‘is the owner or has in the possession custody of an animal which is confined or otherwise unable to provide for itself and fails to provide the animal with proper and sufficient food, drink and shelter…’ commits an act of cruelty and is guilty of an offence. There is an array of Codes of Practice relating to the welfare of livestock. The Victorian Department of Agriculture has developed a Code of Practice for the welfare of sheep which is provided in the readings (Bureau of Animal Welfare 2001). The Code lists the basic requirements for the welfare of sheep as: 1. A level of nutrition adequate to sustain good health and vigour. 2. Access to sufficient water of suitable quality to meet physiological needs. 3. Social contact with other sheep; but with sufficient space to stand, to lie down and stretch

their limbs. 4. Protection from predation. 5. Protection from pain, injury and disease.


6. Protection from extremes of weather which may be life threatening. 7. Provision of reasonable precautions against the effects of natural disasters (e.g. firebreaks

and fodder storage). 8. Handling facilities which under normal usage do not cause injury and which minimise

stress to the sheep. Each of these areas will be touched on in this topic. However, it is recommended that students review the information contained in websites such as the Victorian Department of Agriculture (www.dpi.vic.gov.au) so as to better familiarise themselves with this issue.

10.3 Sheep behaviour

‘…. handling facilities which under normal usage do not cause injury and which minimise stress to the sheep’ (Bureau of Animal Welfare 2001). Sheep are herd animals and their behavioural traits have an impact on how they interact with the environment, their welfare and indeed, the sanity of farmers handling them. Sheep are sometimes categorised as ‘stupid’, purely because they do not wish to go in the direction intended. This could hardly be seen as stupidity! Indeed it is a protective mechanism as they do not wish to wander into a sheep dip or shearing shed based on a previous ‘bad’ experience. A basic understanding of sheep behaviour will make the job of managing sheep easier, especially as it relates to grazing management. Equally, sheep behavioural traits need to be included into sheep yard and shearing shed design. Behavioural traits – management In the 1960s, 70s and 80s, the then Australian Wool Corporation funded considerable research into sheep behavioural patterns, especially as it related to animal management and yard and shed design. Barber and Freeman (1986) provide a useful summary of this early work which is summarised below. • Sheep are herd animals. They are relatively defenceless animals and have evolved protective

mechanisms against predators • Sheep exhibit both flocking and following behaviour • A single sheep will almost always seek to get back to the mob • Sheep will naturally ‘circle’. This is thought to be associated with the need to keep visual

contact with other animals in the mob. This behaviour is ‘exploited’ in some curved yards, although early research suggests that this behaviour only applies in narrow races (500 mm wide)

• Sheep have good eye-sight and by moving their neck can look virtually all around their body. However, sheep are reluctant to move from light to dark and abhor strong contrasts in light including shadows

• Sheep have good hearing. Some suggest that low volume sounds to make sheep move may be more effective than loud noises. Sudden loud sounds scare sheep and this can have an impact on shed design in relation to clanging gates etc.

There is also an excellent website by Dr Temple Grandin which further explains the principles of livestock handling (www.grandin.com). Dr. Grandin is a designer of livestock handling facilities and an Associate Professor of Animal Science at Colorado State University. Facilities she has designed are located in the United States, Canada, Europe, Mexico, Australia, New Zealand, and other countries.


One of the main concepts she discusses relates to the ‘point of balance’ and ‘flight zone’ in handling livestock. The point of balance is at the animal's shoulder. All species of livestock will move forward if the handler stands behind the point of balance. They will back up if the handler stands in front of the point of balance. Many handlers make the mistake of standing in front of the point of balance while attempting to make an animal move forward in a chute.

Figure 10.1 Point of balance and flight zone concepts. Grandin (2005).

The above diagram also illustrates the general flight zone of an animal. The actual flight zone of an individual animal will vary depending on how ‘tame’ the animal is. The flight zone gets bigger when an animal becomes excited or when you approach ‘head on’. Handlers who understand the concepts of flight zone and point of balance will be able to move animals more easily. To keep animals moving in an orderly manner, Dr Grandin proposes that the handler alternates between penetrating the collective flight zone and withdrawing from the collective flight zone. Alternating pressure on the flight zone is more effective than continuous pressure. Sheep handling guidelines As a result of the flocking and following traits of sheep, a summary of sheep handling guidelines listed by Barber and Freeman (1986) are listed below: • Oncoming sheep should not be able to see the operator • Following sheep should be able to see the sheep ahead even as it is disappearing around a

corner • Advancing sheep must not be able to see the sheep behind them or else they will turn and run

back • Sheep forced to look down are less alarmed • The front end of a raceway should be open so that sheep don’t see a dead end • Avoid the situation where a sheep is casting its own shadow • Sheep flow better around blind corners • Sheep prefer to move up an incline or slope • Follower sheep should see treated sheep escaping • Sheep want to move away from sheep handling areas even if there are no workers present • Sheep tend to fill faster through a wide race • Sheep do not like ‘nasties’ like dips.


Behavioural traits – grazing A working knowledge of the grazing behaviour of sheep not only assists in ensuring their nutritional needs are met but it can also help to minimise any pasture or soil damage – especially under set stocking regimes. The behaviour of sheep is well documented in Lynch et al. (1992). There is also useful information in Crean and Bastion (1997). Under a set stocking regime (see Section 10.6), even at low stocking rates some plants will remain ungrazed for long periods of time and their quality may decline or they may become problem infestations. Other more palatable plants may be overgrazed and die out. Some useful aspects about sheep grazing behaviour from Lynch et al. (1992) and Crean and Bastion (1997) include: • The time a sheep spends grazing is controlled by a multitude of factors, especially the quality of feed. In a highly digestible pasture they tend to graze for periods of 20-90 minutes and then ruminate or rest for 45-90 minutes. Sheep graze most very early in the morning and late in the afternoon • Average stocking rate is not a good indicator of grazing intensity within a paddock. For example, studies referred to by Lynch et al. (1992) show that some parts of a paddock are rarely grazed while others are grazed at eight times the average stocking rate • The frequency of drinking depends on the available plants. If saltbush (Atriplex spp) is the prevailing plant, sheep need to drink at least once a day. This limits the distance they are prepared to move from a watering site. In non-salty pastures, sheep may not drink for 2 or 3 days • In hot conditions sheep may spend up to 10 hours a day resting under shade, especially under trees along riparian areas. If no shade is available, they will often rest on a dam wall. In both cases the potential for erosion of these sites exist • Sheep tend to graze into the wind (mustering is easier if sheep are moved into the prevailing wind) • Sheep camp on high ground in compact mobs. They also tend to camp on easterly facing slopes, especially in cold conditions. This can lead to ‘sheep camps’ which become bare and subsequently infested with weeds such as cape weed. Careful management of these areas can be needed to avoid erosion.

10.4 Sheep nutrition ‘….a level of nutrition adequate to sustain good health and vigour’ (Bureau of Animal Welfare 2001). It is not the role of this topic to provide a detailed examination of the nutrition of sheep. However, some basic key points are covered so as to provide background to maximising the welfare and productivity of sheep. There are numerous references available which cover sheep nutrition. Two primary references used to obtain information for this paper were Crean and Bastion (1997) which provides a good simple overview of nutritional requirements of different classes of sheep and the Veterinary Education and Information Network website at Sydney University (VEIN 2005) which provides more technical detail. It is recommended that students also obtain and read Chapter 9 of MLA’s Towards Sustainable Grazing – The Professional Producers Guide (Mason et al. 2003) as this provides an excellent summary of matching production to market needs. It is not only the direct impacts of nutrition on welfare and productivity that are important, but there are ‘hidden’ impacts as well. For example the ‘Lifetime Wool’ project (http://www.woolinnovation.com.au/LivePage.aspx?pageId=1966 and http://www.dpi.vic.gov.au/dpi/nrenfa.nsf/FID/-21AB54B275F76F8DCA 256D71000A2744?OpenDocument#sub) is exploring the impact of poor nutrition for pregnant ewes on the development of wool follicles in the lamb and the impacts on both wool quality and production for the rest of its life. It seems the impacts on the lamb are larger than thought and the


cumulative effects over the lifetime are economically significant. Early results indicate that under-feeding of the pregnant ewe causes her offspring to produce less wool which is of a broader micron compared to the progeny of ewes fed to maintain maternal liveweight during pregnancy. Ewes fed to lose about 5 kg – 0.7 of a condition score – during pregnancy, had lambs that produced 0.2-0.3 kg less clean wool per annum which was also up to 1 µm broader at each shearing during their lifetime. Energy As ruminants, sheep have a modified gut which allows them to digest cellulose (plant fibre) and produce energy. As a plant matures, much of the cellulose is converted to lignin and this is far less digestible. Sheep tend to graze quickly and do not initially chew their food finely. After grazing, they will regurgitate larger food particles and re-chew it (chewing their cud) before re-swallowing it. Microbes in the gut ferment material in the rumen. The crucial role of these microbes impacts on what and how sheep are fed. For example, when supplementary or drought feeding sheep, it is important to change the feed base slowly (usually over a week) so as to allow the rumen microbes to adapt. Crean and Bastion (1997) list the factors which impact on a sheep’s requirement for energy including: • Liveweight (heavier sheep require greater energy for maintenance) • Growth rate (faster growth rates require more energy) • Whether pregnant or dry and the stage of pregnancy or lactation (highest in the last 6 weeks of

pregnancy and when lactating) • Wool covering and weather conditions (highest off shears or when very cold) • Distances walked each day • The digestibility of the feed (low digestibility requires more energy for digestion). The amount of energy required is measured in megajoules (MJ) per day. Energy requirement tables such as those included in Crean and Bastion (1997) provide a useful ‘ready reckoner’ especially when related to dry sheep equivalents (DSEs) (Table 10.1). Obviously, not all energy of ingested feed is converted into energy that an animal can use for maintenance or growth. Figure 10.2, taken from VEIN (2005), provides a good overview of energy losses from a sheep. Table 10.1 Daily energy requirements of various classes of sheep. Source: Crean and Bastion (1997).

Class of Sheep Energy

Requirement (MJ)

DSE Requirement

Dry sheep – 45 kg

Dry sheep – 60 kg

Hogget – 30 kg and gaining 50 g/day

Hogget – 30 kg and gaining 150 g/day

Ewe – 55 kg and last month pregnancy

Ewe – as above with twins

Ewe – 50 kg – lactating

Ewe – as above, with twins

8.7

10.8

8.1

12.2

12.7

14.6

23.5

32.6

1.0

1.3

0.9

1.5

1.5

1.7

2.5

3.1


Figure 10.2 Energy flows in sheep. Source: VEIN (2005).

The gross energy (GE) levels for a wide range of pastures, conserved forages and grains is reported by VEIN (2005) as usually falling between 17 and 20 MJ/kg with an average of about 18.8 MJ/kg. Table 10.2 The metabolisable energy (ME) levels of a range of feeds. Source: VEIN (2005).

Protein Similarly, protein requirements vary for each class of livestock. The protein content of pastures and supplementary feed also varies and getting the balance right between the two has a large impact on an animal’s productivity. The digestion of microbes as they pass from the rumen to the gut also provides sheep with a portion of their protein needs. Tables 10.3 and 10.4 provide an indication of the level of protein required by different classes of sheep and the levels found in different feeds. Table 10.3 Protein requirements of various classes of sheep. Source: Crean and Bastion (1997).

Feed ME (MJ/kg DM) (approximate)

Grass

Grass – late vegetative

Grass – flowering

Dry grass

Lucerne hay

Oaten hay

Oats

Lupins

12.6

9.5

7.5

6 – 7

9.1

8.7

12.1

14.2

Class of Sheep Protein Requirement (%)

Dry sheep

Weaner – 25kg and gaining 50 g/day

Weaner – 25kg and gaining 100 g/day

Ewe – last month pregnancy

Ewe – lactating

6.0

11.0

12.3

8.0

12.0


Table 10.4 Protein content of various feeds. Source: Crean and Bastion (1997).

Again, there are potentially complex factors involved as ‘more may not always be better’. There is some evidence (R. Weatherly, pers. comm.) that as we endeavour to increase production with higher rates of fertiliser, some pastures will deliver 2-3 times the required animal needs for protein. The excretion of excess protein requires high amounts of energy, often unobtainable from the pasture at the time. At some times of the year, ME may need to be provided by supplementary feeding to alleviate animal health problems caused by high protein levels. Sheep grazing these pastures are effectively on the ‘Aitkens Diet’ – they may do poorly, scour heavily, exhibit low resistance to disease, parasites and foot problems, and cut less wool. Their breeding efficiency can drop to a third of their potential or less. Pasture quality changes Not only do animal requirements change depending on their state, and differing feeds having different levels of protein and energy, but pasture availability also alters during the year. While pasture production varies enormously around Australia, it does tend to follow a similar pattern, especially in southern Australia. As shown in Figure 10.3, growth rates are highest in spring, while low temperatures and sometimes lack of moisture, limit winter growth. Lack of effective rainfall (precipitation less evaporation) limits pasture growth in late summer and early autumn.

Figure 10.3 Pasture production over time. Source: VEIN (2005).

Feed Protein Content (%)

Young grass and legume pasture

Grass and legume pasture – max. leaf area

Grass and legume pasture – flowering

Most cereal grains

Lupins

Quality lucerne hay

Cereal hay

Oaten straw

20

10 – 14

8 – 10

9 – 12

32

16 – 20

6 – 7

4


Water ‘….access to sufficient water of suitable quality to meet physiological needs’ (Bureau of Animal Welfare 2001).

Good quality water is critical for productive sheep and the land bordering waterways is often the most productive on the farm. Depending on diet, weather conditions and distances sheep need to walk, they can consume up to 6 L/day. Several overseas studies (e.g. Lardner et al. 2005) have shown that stock drinking clean water showed liveweight gains up to 25% higher compared with those drinking poor quality dam water. Many of these studies have been based on cattle. The intake of dry feed by stock is closely related to their water intake. Sheep do not like drinking poor quality water and this is particularly important in summer where feed quality is low. Animals that reduce their intake of poor quality feed because of poor quality water will lose body condition and reduce wool growth quicker than should be the case. However, the issue with the provision of water for stock is not one of productivity alone. Australia is the world’s driest inhabited continent and farmers manage a large proportion of the country’s water supplies. As water is a shared resource, farming practices can have a significant impact on the quantity and quality of water in a catchment. Unrestricted or poorly managed sheep access to dams, rivers and streams can degrade the resource base. This is covered further in Section 10.7. The Australian Wool Innovation (AWI) and Land and Water Australia (LWA) research program ‘Land Water and Wool’ has a dedicated subprogram looking at river and riparian management on wool producing properties. They are just finalising an excellent resource that is available in hard copy or electronic versions called ‘Land Water and Wool River Guides’. These guides describe the uses and sustainable management of rivers and riparian management on wool properties. These guides are free and can be ordered from Canprint Communications on 1800 776 616 or from the website at: www.landwaterwool.gov.au. Matching nutrition to requirements As sheep satisfy the majority of their nutritional requirements from pasture, it is important to match pasture availability and quality with the nutritional requirements of the animal. As briefly indicated by the information provided above, this is not an easy task. To complicate matters more, it is also important to avoid providing more pasture than is required and thereby wasting opportunities to produce more meat or wool by adding more animals. In general, the more pasture that is offered to animals, the more they will eat. Pasture availability is measured in kilograms or tonnes of pasture (expressed in terms of dry matter (DM)) per hectare. The general relationship between feed intake and pasture availability is shown in Figure 10.4. Pasture intake of sheep is strongly influenced by availability below 700 kg/ha but increases only slowly over 900 kg/ha. While the general shape of this relationship remains fairly constant, it is influenced by pasture quality (the four coloured lines)


Figure 10.4 Relationship between feed intake and pasture availability. D = Digestibility, M/D = MJ ME/kgDM. Source: VEIN (2005).

However, sheep eat less pasture when the digestibility is low, as shown in Figure 10.5. While one would expect that a sheep would try to compensate by eating more, the factor that limits the intake of low energy feeds is the rate at which feed is broken down and leaves the rumen. In the example shown below, with poor quality feed it is clear that sheep will lose condition as they simply cannot eat enough. Figure 10.5 Feed intake versus metabolisable energy (ME) of the diet. Source: VEIN (2005).

10.5 Managing predators and toxins

‘... protection from predation’ (Bureau of Animal Welfare 2001).

The management of predators and toxins is an important but costly component of any wool production system. Predators The AWI web site (http://www.woolinnovation.com.au/LivePage.aspx?pageId =1632) refers to current research efforts to better manage sheep predators (AWI 2005a). Feral dogs and foxes maim and kill sheep, especially at lambing time. In certain areas of Australia, sheep production is significantly impacted by these predators. In the past, dogs and foxes were often controlled by baiting with sodium fluoroacetate (1080). However, 1080 has come under pressure from groups concerned that it does not provide a humane death or it could impact on other non-predator native species.


The AWI website (AWI 2005a) refers to two major projects focussing on dog and fox control: • Development of a new canid (dog and fox) toxin. The toxin under study causes a rapid and

humane death and is highly specific to canids. A commercial product may be launched by 2008.

• Development of a new canid lure, FeralMone®, by Pestat Pty Ltd. FeralMone® contains abbreviated synthetic fermented egg, a powerful attractant for dogs and foxes which has performed very well in field trials. This product was released in 2005.

One of the most important aspects of predator control using baiting is the palatability of the ‘vector’ being used. Trials in late 1990s in Victoria (R. Weatherly, pers. comm.) indicated that after baiting over 260 contiguous farms for a period of 6 weeks, Fox-Off® had effectively only removed all foxes of less than 2 years old. These were the ones with the lowest hunting proficiency and therefore the hungriest. They tended to eat Fox-off®. Because the vector lacked palatability, older foxes (better hunters, less hungry) were inclined to carry the baits and cache them. Thus mortality was low in proficient foxes which filled vacant fox territories of younger foxes, exacerbating the local fox problem. Management The NSW Department of Agriculture has developed an AgNote which provides a good summary of developing a system based management plan to control animal pests (Braysher and Saunders 2002). Some of the key points listed in this AgNote include: • Rather than trying to just kill as many pests as possible, pest management needs to be

carefully planned and coordinated • Most pests are highly mobile and can readily replace those that are killed in control programs.

Unless actions are well planned and coordinated across a broad area, individual control programs are unlikely to have a lasting effect

• Pest control is unlikely to be effective unless there is strong local community or political will to take action and commit the necessary resources

• Determine what is the problem? Identify, as best you can, the pest animal distribution and abundance in each area

• Estimate, as far as is practicable, the damage caused by the pest or pests to production and to the environment

• Determine what the pest management plan is meant to achieve in terms of reduced damage • Define management objectives and select management options (such as local eradication,

containment, sustained management, targeted management, one-off action and taking no action)

• Implement the program and then monitor its success against the stated objectives. Toxins Certain pasture species can cause poisoning of livestock in particular conditions. The poisoning is often due to contamination of the plant with an organism such as a fungus or bacterium. Annual ryegrass toxicity (ARGT) causes many sheep deaths and significant production loss in Western Australia and, to a lesser extent, South Australia. It occurs when stock graze Wimmera ryegrass (Lolium rigidum) at or after heading and the seed heads are infected with a particular type of nematode and species of bacterium. The bacteria produce a toxin that is fatal to stock. From a management perspective, it is best to graze pastures heavily before the development of seed. Destruction of rye grass by burning or the use of herbicides for at least two seasons can also be used to eliminate the nematode (VEIN 2005). Investigations are also taking place to examine the possibility to develop a vaccine for ARGT.


Perennial ryegrass toxicity (PRGT) has caused significant sporadic losses in the eastern States. It is totally different to ARGT. The Tasmanian Department of Primary Industries, Water and Environment website has a useful section on perennial ryegrass (http://www.dpiwe.tas.gov.au/inter.nsf/WebPages/RPIO-4ZU79U?open). This website (TDPIWE 2005) advises that PRGT is caused by a toxin that accumulates in the leaf sheaths of perennial ryegrass. The toxin is one of those produced by a fungus called ryegrass endophyte, Acremonium loliae, which grows within the leaves, stems and seeds of perennial ryegrass. As the fungus and the toxin occur mainly in the leaf sheaths, very close to the ground, hard grazing of infected pasture is likely to induce ryegrass staggers. The symptoms of ryegrass staggers usually develop 7-14 days after stock start grazing the toxic parts of the plant. Animals that are not severely affected recover 2-3 days (sometimes up to 14 days) after they are transferred to ‘non-toxic’ pasture. The management of areas around waterways can also have important implications in relation to potential toxins for animals. For example, excess fertiliser entering waterways can lead to blue-green algae blooms (R. Weatherly, pers. comm.). Toxins released by blue-green algae as they die and their cell walls break down, can be lethal and cause substantial liver damage in animals drinking from it. This underlines the fundamental management issue of balancing fertiliser application and implementing practices (see Section 10.7) to keep excess fertiliser from reaching streams or rivers.

10.6 Sheep health

‘….protection from pain, injury and disease’ (Bureau of Animal Welfare 2001).

Obviously, healthy sheep are critical to any sustainable wool production enterprise. Maintaining animal health is typically a minor component of the ‘upfront’ costs of producing wool (drenches, vaccines, dips). However, some impacts of disease are masked (e.g. worms) while others if they occur (e.g. Ovine Johne’s Disease, Footrot) can have devastating financial and animal welfare consequences. Sheep health is becoming more important in wool enterprises because: • Stocking rates have increased or intensive grazing systems are being utilised • Parasites are acquiring resistance to treatments • Consumer views on pesticides, animal welfare etc. are changing. The ‘mulesing debate’ is an

example of how certain husbandry practices are impacting on perceptions about the integrity of wool as a product.

The AWI website (AWI 2005b) has a good listing of projects that they are investing in to find commercial solutions to an array of animal health issues (http://www.woolinnovation.com.au/LivePage.aspx?PageId=139). Their strategies in animal health and welfare (AWI 2005b) are: 1. encourage better use of existing technologies (e.g. in parasite control) 2. develop new products and practices (e.g. new insecticides) 3. develop new diagnostic tests (e.g. for footrot, lice, sheep pox) 4. replace or improve undesirable practices (e.g. mulesing) 5. contribute to crisis planning (e.g. exotic diseases).


They also list the anticipated benefits for Merino sheep producers as coming from: • lower cost of sheep production • improved wool and sheepmeat quality • ability to run more sheep and boost production • reduced threats to market access • opening-up of new markets. It is strongly recommended that students visit the animal health section of the AWI website (AWI 2005b). Internal parasites – integrated pest management As a result of the ‘breakdown’ of some chemicals in controlling specific animal health threats, especially worms, combined with consumer and society concern in relation to the use of chemicals in the production of food and fibre, Integrated Pest Management (IPM) is becoming increasingly important. IPM seeks to bring together an array of chemical and non-chemical methods to provide effective control of a particular pest. For this topic we will use the example of worms in sheep. The AWI website (AWI 2005c) claims that in 1995, internal parasites (worms and fluke) were estimated to cost the Australian sheep industry $222 million per year (http://www.woolinnovation.com.au/LivePage.aspx?pageId=1630). However, the impact of internal parasites is undoubtedly escalating and within the next 5 years that figure is more likely to be around $700 million per year. The reason for this blow-out is drench resistance. Resistance by worms to the 'white' and 'clear' drench groups is long established. Now resistance to the newest major drench group, the macrocyclic lactones or MLs (the 'mectins'), is spreading rapidly. AWI (2005c) also consider that it is unlikely that new drenches will be developed in time to solve the resistance problem as sheep are not a priority for investment by multinational animal health companies. Recently, AWI and the Australian Sheep Industry Cooperative Research Centre (Sheep CRC) released a new website called WormBoss (www.wormboss.com.au) to help producers meet these challenges. WormBoss (AWI/Sheep CRC 2005) is represents the national knowledge on sheep worms and their management, and is an excellent example of IPM. Again, it is highly recommended that students visit this site. The following is reproduced from this site (AWI/Sheep CRC 2005): WormBoss recommends four general management practices: • Monitor worm populations using worm egg counts to detect infestations early • Do regular drench resistance tests so you know which drenches are effective on

your property • Maximise the use of non-chemical management strategies • If you are unsure of anything - seek professional advice. Sustainable control of sheep worms involves a combination of planned stock and farm management, monitoring worm levels using worm egg counts, regular drench resistance testing, maximising the use of non-chemical worm management strategies, the strategic timing of effective drenches and breeding worm resistant sheep Without sustainable worm management, drench resistant worms will keep increasing and economic loss will be greater The aim of WormBoss is to reduce drenching and minimise the onset of drench resistance while increasing animal productivity and profitability.


WormBoss has a ‘decision support tool’ built into the site to assist farmers make the right decisions. The site also contains detailed information on the various components of the WormBoss IPM as summarised below (AWI/Sheep CRC 2005). Worm egg count (WEC) – WECs estimate the burden of adult worms in monitored sheep and are usually expressed as 'eggs per gram' (epg) of dung. They provide a useful guide to check the overall worm status of a mob to decide if treatment is necessary, to decide if previous treatments were effective or to assess the levels of worm contamination being put into paddocks. Individual sheep WECs can also be used as the basis for selecting worm resistant sheep. Smart grazing for winter rainfall districts – A simple and reliable strategy for the control of worms in weaner sheep during their first winter in winter rainfall districts. An example of a smart grazing timetable is shown in Table 10.5 below. Table 10.5 Smart grazing timetable. Source: AWI/Sheep CRC (2005).

Month Strategy October Select the 'smart grazing' paddock – choose one with a history of

good winter pasture November Give the first summer drench (MUST be an effective product), then

intensively graze the paddock at 2.5-3 times the normal stocking rate

December Remove the sheep to another part of the farm after 30 days intensive grazing. Ideally, the pasture residue should be 800-1000 kg DM/ha (2.2-3 cm)

January Paddock remains unstocked until the second summer drench February Give the second summer drench, then intensively graze the 'smart

grazing' paddock with the drenched sheep (again, not > 30 days) March Paddock remains de-stocked until the autumn break Autumn break (March-April)

Drench weaners and set-stock on the 'smart grazing' paddock when pasture > 600 kg DM/ha (1.5 cm). Weaners can remain there until spring but monitor their worm egg counts every 4-6 weeks

Merino weaners are very susceptible to worms in their first winter. Consequently, they need to graze pastures that have as few worm larvae as is practicable. 'Smart grazing' combines intensive grazing for 30 days with each of the two 'summer' drenches to ensure that virtually no worm eggs are deposited on a chosen pasture from the first summer drench (November) until after the autumn break (March-April), when the weaners are put into these pastures. Results from a controlled experiment over 2 years in western Victoria (as quoted in WormBoss (AWI/Sheep CRC 2005) show that, compared to weaners grazing paddocks prepared the usual way (grazed by wethers over the summer/early autumn), weaners grazing 'smart grazing' plots: • grew 13% more clean wool (2.29 vs. 2.03 kg) which was 3.5% broader (17.1µm vs

16.5µm) • were 3 kg heavier in October (46.5 vs. 43.2 kg). Cross grazing with cattle – Alternating grazing between cattle and sheep has been demonstrated to be an effective means of reducing worm infection. This process relies on the fact that most worms are host specific – most worms are only able to successfully infect either sheep or cattle, not both, and ingestion by the non-preferred host results in death of the larvae. A notable exception is the ability of Barber’s Pole Worm (Haemonchus contortus) and Stomach Hairworm (Trichostrongylus axei) to successfully reproduce within sheep and young cattle (i.e. pre-weaning). Using adult cattle for cross grazing is preferable. Grazing sheep on pastures that had been grazed by cattle for the previous 6 months increased annual weight gain and greasy fleece weight by 65% (7 kg) and 25% (0.7 kg) respectively as quoted in WormBoss (AWI/Sheep CRC 2005).


Spelling – Short term spelling is of little use in worm control. Some time ago, it was believed that short term spelling for 3 weeks or so would reduce the numbers of infective worm larvae on a pasture. These are the spelling periods typically seen in rotational or cell grazing strategies, or when leaving pastures unstocked after the autumn break in winter rainfall areas ('autumn saving'). However, studies in the 1960s quoted in WormBoss (AWI/Sheep CRC 2005) clearly showed that this was not the case. Following these studies, it was shown, as quoted in WormBoss (AWI/Sheep CRC 2005) that unless pastures were spelled for more than 10 weeks in autumn/winter there was no useful reduction in numbers of worm larvae. Nutrition – Nutrition has a major impact on how well sheep cope with worms. Good nutrition is a vital component of good non-chemical worm management. 1. Sheep with worms eat less.

2. Worms damage the lining of the intestinal tract and lower the absorption of some nutrients.

3. Worm-infected sheep lose protein by seepage across the damaged intestinal lining.

4. In worm-infected sheep, extra protein is diverted away from wool and meat towards the immune response against the worms and to repair the damaged intestines.

Recently it has been demonstrated that protein, and to a lesser extent energy, influences the development of resistance and resilience by sheep to worm infection. Improved animal nutrition can improve the resistance of sheep to worm infection and this will reduce the dependency on drenches to control worms. The greatest effect of improved nutrition is to reduce the time required for sheep to reject established adult worms, and to increase the efficiency of this. How improved nutrition enhances resistance to worm infection is uncertain. It is thought it may enhance the immune responses of sheep against worms. Treat classes of sheep differently – Different classes of sheep have different levels of risk in terms of the impact of worms. Young sheep are generally the most susceptible, particularly if nutrition is lacking. Mature wethers tend to be able to withstand challenge from worms much better. Rotational and cell grazing – The use of rotational or cell grazing to assist sheep worm control needs careful consideration of the time that non-grazed paddocks are left empty. As mentioned above, traditional cell grazing systems, with frequent rotations between paddocks, generally do not leave enough time between grazings for significant reductions in pasture worm contamination levels. During the cooler, wetter months of the year paddocks could require several months stock-free. It is critical to monitor worm egg counts to detect any increase in worm infestations before production losses or impacts on animal health occur. Genetics (breeding worm resistant sheep) – Resistance to worms in sheep is in part due to genes. As a result, improved worm control in sheep can be achieved by selecting and breeding with sheep that have greater genetic resistance to worms. Breeding worm resistant sheep is possibly the most sustainable worm management tool that can be used. Combined with other non-chemical management strategies, the need to drench can be reduced greatly. Commercial sheep breeders can use rams from studs that are selecting for worm resistance, and, over time, their sheep will become more and more resistant to worms and therefore they will require less drenching. Fodder crops and crop stubbles – Cropped paddocks normally have extremely low levels of worm contamination. Ploughing, fallow, planting and the period until the crop can be grazed reduce worm larvae to very low levels. By the time a fodder crop or stubble is ready to graze, there should be very few surviving larvae available to infest stock and thus are very useful for grazing susceptible sheep such as weaners.


Control with drench – Drenching is currently an important component of a worm control program. Effective drenching means: • Using the right drench (one that a drench resistance test has shown to be effective against the

target worms at the time) • Drenching at the right time (given the recommended local worm management program and

current WEC monitoring results) • Using the right dose rate • Administering to the animal in the correct way. Holding sheep off feed prior to and following treatment – Fasting sheep for up to 24 hours before treatment can be used to improve the efficacy of treatments with BZ, ML or closantel products as it slows the flow of digesta through the gut of the sheep and therefore keeps the drench in the gut for a longer period of time, allowing greater absorption of the active ingredient. Keeping sheep off feed for up to 6 hours after treatment can also assist drench efficacy. Fasting strategies should not be used when treating with levamisole or naphthalophos as this could increase the risk of toxicity with these products. Fasting should not be used in heavily pregnant, stressed or poor sheep and they should have access to water during the fasting period. When to drench – A WEC is the best practical guide currently available to decide on the need for treatment. WECs tell you whether worm burdens are likely to be affecting production and will highlight potential worm problems, often before any signs such as scouring, anaemia or obvious weight loss become visible. Regular WEC coupled with drench resistance testing allows good planning and effective treatment if needed. External parasites and chemical residues The AWI website (AWI 2005d) provides a good overview of the cost, control and implications of lice and blowflies (http://www.woolinnovation.com.au/ LivePage.aspx?pageId=1631). AWI (2005d) states that in 1995, lice were estimated to cost the Australian sheep industry $169 million per year and blowflies about $161 million per year. Control of lice relies on preventing them from being introduced to the flock. If lice are found to be present then treatment with an effective lousicide is needed. For flies, a number of tools are available to prevent blowfly strike, including mulesing, tail docking, jetting with chemicals, and breeding for fly-resistant sheep. However, the AWI (2005d) points out that the management of external parasites is threatened in a number of ways: • Gradual development of resistance to chemicals by insects • Possible restrictions on market access, in the European Union (EU) in particular, if wool

contains pesticide residues • Changing public expectations of animal welfare in regard to mulesing and associated

procedures • Increased scrutiny of the occupational health and safety implications of certain chemicals,

notably diazinon • Increased scrutiny of the on-farm environmental implications of sheep dips. As a result of these pressures, significant research is being undertaken to reduce the use of procedures which are coming under public scrutiny such as mulesing and practices to minimise the potential of having chemical residues left on the wool at shearing time. For example, AWI (2005d) recommends that woolgrowers should avoid late-season treatments as much as possible, and also avoid applying products more than once during the year unless it is absolutely necessary. Equally ‘dipping’ should only be undertaken if sheep are known to be infected. To assist in this regard new lice detection tests are under development.


AWI (2005d) also recommends that as the EU pollution control legislation is set to come into effect in 2007, woolgrowers should start to consider having their main fleece lines tested for residues before 2007, so they can understand the residue implications of their treatment regimes and start to make changes if needed. Residue testing can be ordered through any major wool broker as an additional test when wool is delivered to the Australian Wool Testing Authority (AWTA) after shearing. AWTA will then forward a sample to CSIRO Textile and Fibre Technology for residue analysis (see http://www.tft.csiro.au/main.htm).

10.7 Managing the resource base in a grazing system Australia’s agricultural systems are based on a very variable climate and a thin level of fertile soil that can be easily degraded. An excellent reference for all aspects of broadacre agriculture is the book Dryland Farming – A Systems Approach. An Analysis of Dryland Agriculture in Australia, edited by Squires and Tow (1991). This is suggested reading for all students. Chapter 11 (‘Maintaining the resource base’) in Squires and Tow (1991) provides a summary of land degradation in Australia and the processes that led to it. It also discusses the history, status and control methods for erosion and salinity. Chapter 17 discusses monitoring of farming systems while Chapter 21 examines ‘Future directions’. The purpose of this section of the topic is to provide a simple overview of some key resource issues in relation to sustainable agriculture in a sheep system. It considers grazing management, protection of animals, native vegetation and the management of our rivers and riparian areas. Grazing management - general Other topics in this unit cover sustainable grazing in detail. However, it is appropriate to briefly mention some key aspects as they relate to sustainable animal production. For a comprehensive review of grazing practices and their impacts, students should access and read Chapter 8 in the MLA book Towards Sustainable Grazing – The Professional Producers Guide (Mason et al. 2003). There is also a very good summary included in VEIN (2005) referred to in Section 10.4. You can be assured of an argument about the virtues of the various types of grazing management practised in Australia. Even the two sources listed above have some differing views. The object of grazing management is simply to convert pasture into animal product. Section 10.4 has already shown how it is important to match the nutritional needs of the animal with both the quantity and quality of pasture. In addition, the type of grazing management used can impact on the resource base and thus the sustainability of the system. As a reminder, the main grazing methods are: Continuous grazing – Perhaps the simplest form of grazing management. A set number of sheep graze a paddock year round. Rotational grazing – Regular movement of stock between paddocks. This can be practised using either ‘time based rotations’ (e.g. grazing a paddock intensively at a high stocking rate for, say, several days and then 60 days rest) or ‘plant based rotations’ (e.g. allowing a plant species to recover to a four leaf stage). Cell grazing – A form of rotational grazing which involves having a large number of paddocks or cells (40 or more), and grazing at very high stocking densities with frequent movement of the stock. Sheep are rotated rapidly around the many cells during periods of rapid growth and more slowly during periods of slow growth.


Some sustainability issues related to grazing management are listed below. • Groundcover (or inversely the amount of bare ground) is probably the most important

sustainability indicator for grazing systems • Overgrazing, resulting in bare ground, can lead to: - reduced water use efficiency (greater run off) - potential erosion (wind and water) - potential alteration of pasture species - potential invasion by weeds (e.g. capeweed) • At least 70% ground cover should be maintained at all times (Mason et al. 2003) • In a Sustainable Grazing Systems (SGS) experiment, rotationally grazed pastures averaged

85% groundcover compared to 73% for continuous grazing at the same stocking rate. This resulted in 53 mm of rainfall lost as run off compared to less than 3 mm for the rotation

• With continuous grazing, pasture is rarely spelled and animals (especially sheep) concentrate on preferred pasture species. If the stocking rate is too high then these species (often the valuable perennials) may be eliminated

• On the other hand, set stocking can be highly sustainable, providing the stocking rate is lower, paddocks do not vary enormously in topography and low ground cover in autumn does not pose an erosion risk

• Set stocking is also generally used at the time of lambing as it results in less mis-mothering. It is also preferred by those producers who are single sire mating and for whom progeny identification is important.

Grazing management – rangelands (pastoral areas) Harrington et al. (1984) in their book Management of Australia’s Rangelands (available at UNE library) provides an excellent review of the management of rangeland ecosystem. Management of pastoral country is different to that required in sheep/cereal or high rainfall zones. The output of animal products is low due to the low and variable nature of forage and its associated nutritional value. Chapters 1, 2 5 and 9 are certainly worth reviewing. In rangeland areas, the interaction between animal and plants is crucial. The aim is to maintain the vegetation ’within the bounds of resilience to grazing and thereby in a form which will achieve the highest long term productivity from the animal population’. Issues such as stocking rate are more ’tactical’ in the rangelands as the ability to make short term decisions based on seasonal conditions and pasture availability are crucial in relation to the impact on relatively long term land condition and animal productivity. In Chapter 9, Wilson, Harrington and Beale (1984), discuss the impact of stocking rate on animal productivity. They suggest that ‘the growth or productivity of each animal declines as the stocking intensity increases’. This theoretical relationship is shown in Figure 10.6 (in figure 9.1a) below (from Wilson et al. 1984). As stocking intensity increases, the productivity of each animal declines (phase 2 in figure 9.1a within Figure 10.6) as pasture intake and quality is limited.


Figure 10.6 Theoretical relationships between animal productivity, economic productivity and stocking intensity. Source: Wilson et al. (1984).

In contrast, the productivity of the whole mob rises as stocking rate increases (in figure 9.1a within Figure 10.6 below – per hectare). As you will see, the maximum total productivity per hectare occurs at about half the maximum number of animals that may be carried. At lower stocking rates total production is depressed by low animal numbers while at higher stocking rates total production is depressed by the poor performance of individual animals. Figure 9.1b within Figure 10.6 shows the theoretical relationship between economic productivity and stocking rate – with maximum profit in the short term occurring where the margin between gross returns and variable costs are the greatest (shaded area). Note that this zone of maximum profitability always occurs at stocking intensities lower than those for maximum productivity (see figure 9.1a within Figure 10.6). Figure 9.1c within Figure 10.6 shows the relationship between stocking rate and productivity in a pasture that has undergone a major change in its resilience due to over grazing. This is shown as phase 3 in figure 9.1a within Figure 10.6 below. In essence, this pasture has changed in quality and quantity and productivity is lowered substantially. The impact of this will depend on the resilience of the pasture species and the nutritional value of what replaces them. A key learning suggested by Wilson et al. (1984) is that by keeping stocking rate near the economic optimum, both conservation and productivity objectives can be best met.


Protection of animals ‘….protection from extremes of weather which may be life threatening’ (Bureau of Animal Welfare 2001).

Sheep are insulated from the weather conditions by their fleeces, although this is of course dependent on staple length. Situations can arise when shelter for sheep can be particularly useful (Bureau of Animal Welfare 2003). These include: 1. extreme heat 2. extreme cold – especially if sheep are recently shorn, lambing or in poor body condition. Merino sheep tend to be better adapted to hot weather than British breeds. While heat stress is not a common occurrence, extreme cold is certainly an area that farmers must remain vigilant about. Recently shorn sheep are at risk if there is a sudden onset of wet and windy conditions, especially in the first 2-3 days (or nights) after shearing; some risk can remain for up to 2 weeks. The stress of shearing may also be a factor. Similarly, poor weather conditions at lambing, especially within the first 3 days of life, can account for losses up to 20-30% – mainly as a result of 'mismothering-exposure-starvation' complex (Bureau of Animal Welfare 2003). It should be noted that lambing ewes may not seek shelter, or individual ewes may seek out an isolated (albeit exposed) spot to lamb. Sheep coming out of a drought in poor body condition may also be more susceptible in wet, windy and cold conditions (Bureau of Animal Welfare 2003). Under such circumstances, the provision of shelter (shelter belts, forested paddocks, artificial wind breaks, undulating paddocks or sheds) is extremely important. If possible, plan shearing and lambing for times when such cold snaps are less likely (although they have been known to occur in the middle of summer in southern Australia). Also ‘sheep alerts’ issued by the Bureau of Meteorology should be taken into account. Native vegetation A separate topic in this unit discusses in detail the role of remnant native vegetation. Without repeating information contained in that topic, native vegetation has a significant role in sustainable sheep production systems (Williams 2004). Native plants form the basis of many pastures, especially in the high and medium rainfall zones of NSW, Tasmania and Queensland. Of course, they are almost totally the base of ‘pastures’ in the pastoral zone. Some points in relation to sustainable systems and the role of native pastures include: • Because native pastures generally contain a diverse range of species, they have the ability to

provide a ‘green pick’ throughout much of the year. This fairly even supply of feed greatly helps in providing the even plane of nutrition which results in high tensile strength wools grown in such areas

• The majority of native grasses are perennials and this greatly assists in maintaining ground cover and reducing the potential for salinity to arise

• As native grasses historically were grazed intermittently, they respond better to rotational grazing than set stocking where selective grazing can alter the diversity of the pasture

• Native pastures tend to be ‘low stocking rate/low production’. However, they do respond well to fertiliser application but high use of fertiliser can alter the mix within the pasture and reduce the contribution from native species.

Further details about practical experience with native pastures and native vegetation on commercial woolgrowing properties can be found via the Land Water and Wool project (www.landwaterwool.gov.au) run by AWI and LWA (Anon. 2005a, Anon. 2005b).


Native trees and shrubs also play key roles in relation to animal sustainability, especially in relation to providing shade and shelter (see Reid and Thompson 1999 and earlier sections on ‘Protection of Animals’ and ‘Sheep Nutrition’). Shelter, especially from cold, wet and windy days, is critical to sheep survival at lambing time and when straight off shears. Cleugh (2003) provides an excellent report on the impact of windbreaks for shade and shelter. She summarises the advantages from windbreaks as:

• Wind erosion. Below a threshold speed very little soil movement occurs; then doubling the wind speed causes an eight-fold increase in erosion. As most of the nutrients and organic matter are in the fine soil fractions, even low levels of erosion will gradually reduce soil fertility.

• Animal production losses. Cold weather and strong winds can be a deadly combination for newborn lambs and newly shorn sheep. Even where stock survival is not threatened, shelter from cold wind makes animal production more efficient.

• Physical damage to plants. This can result from leaves and other plant parts rubbing together as wind blows them around, leaves being stripped from plants, and sandblasting — wind-blown soil striking and damaging plants.

• Plant knockdown (lodging). This is most common at later stages in plant development. Reduced yields are likely if a mature crop lodges.

• Influencing temperature, humidity and evaporation in the sheltered area. Slight increases in air and soil temperature and in humidity are important aspects of the changed ‘microclimate’ in the lee of a windbreak. So there is a tendency for soil moisture to be conserved as a result of reduced evaporation and protection of plants from high levels of evaporative demand.

• Providing shade. This is particularly important for reducing heat stress in stock in tropical and subtropical climates. Further potential benefits of windbreaks include (Cleugh 2003): • Helping control waterlogging and dryland salinity • Providing protection from erosion by water during heavy rain • Serving as an income source — from sale of timber and other tree products • Providing fodder during drought • Enhancing biodiversity and scenic diversity.


Figure 10.7 Summary of shelter effects on microclimate and plant growth. Source: Cleugh (2003).


The research of Cleugh (2003) indicated that the distance protected downwind is proportional to the height of the windbreak. On flat land, the speed of wind blowing perpendicular to a windbreak is reduced, at ground level, in an area extending from around 5 windbreak heights (H) upwind of the sheltering trees to as much as 30 H (sometimes even further) downwind. So, a 10 metre high windbreak will provide protection over an area extending perhaps 300 metres downwind. The biggest wind speed reduction occurs in what is known as the ‘quiet zone’, which may extend to about 10 H downwind. Wind speed gradually increases in the ‘wake zone’, downwind of the quiet zone, until the impact of the windbreak disappears. Furthermore, Cleugh (2003) stated that a windbreak’s foliage density, and hence its porosity, is the main influence on the size of the wind speed reduction. In a wind tunnel experiment, the maximum wind speed reduction behind the most porous windbreak (70% open) was less than 40%, compared with about 75% for the least porous (30% open). Field and wind tunnel studies showed windbreak porosity had no significant effect on the size of the area sheltered, disproving a widely held notion that the denser the windbreak, the smaller the area protected. The field and wind tunnel measurements of Cleugh (2003) showed that, if a windbreak is long enough (more than 20 times its height), shifts in wind direction up to an angle of about 30 degrees from the perpendicular produce only small reductions in the distance sheltered. At greater angles the shelter distance declines rapidly. The degree of shelter typically becomes greater as the angle increases, because the wind has to pass through more foliage. Multiple windbreaks, planted parallel to one another, were found to each progressively reduce the wind speed, providing a high degree of shelter. WestVic Dairy (www.westvicdairy.com.au) also provides an excellent chapter on the role of shade and shelter on farms (Bird 2003, see Readings.). WestVic Dairy is one of three regional development boards for the dairy industry in the main dairying regions of Victoria. Within their review of previous research (further references given within this document) they note that gains reported from shelter can include:

• Reduced energy to maintain an animal (with shorn sheep, shelter that reduces wind speed by 50% can reduce energy losses by 20%)

• The average of trials done in SA showed that effective shelter can reduce lamb losses by 50%. In fact the greatest animal response from shelter reported in Bird (2003) was found with sheep in Armidale where Lynch and Donnelly (1980) found that wool production in well stocked plots partially sheltered by a 1 m high iron fence was 43% greater than in open plots. While such spectacular results have not been found since, they give an indication of the value that can be gained. There are also numerous other benefits that native vegetation can offer grazing systems (R. Weatherly, pers. comm.) including benefits of harbouring beneficial species, with an emphasis on predatory insects (for instance, in blowfly control); potential improvements in pasture palatability, lessened moisture loss and improved growth rates, and the benefits to soil in moisture retention. To be balanced, shelter breaks also have some negative effects, including cost to establish, loss of grazing area, reduced pasture growth near the belt and as a harbour of pests. As well, even though a shelter belt may be put in, that is not to say that sheep will use them on cold wet and windy days. Rivers and riparian areas Because wool production is a major land use in many important catchments within Australia, it also has a substantial impact on water quality and stream health. Equally, water quantity and quality has a large impact on the well-being of sheep (see Section 10.4). Individual woolgrowers can do much on their own property to maintain the quality of their water and waterways, delivering benefits to themselves, to downstream users, as well as benefits to biodiversity and landscape amenity.


The Land, Water and Wool (LWW) ‘Wool Industry River Management Guides’ (www.landwaterwool.gov.au – in production) suggest that:

grazing management is probably the most important single factor influencing the condition and productivity of riparian pastures. As a general rule, set stocking is not recommended for riparian areas unless the overall stocking rate is low and there is no obvious symptom of degradation of the pasture, such as a slow decline in palatable species, a lack of their regeneration, or obvious areas of bare soil and/or erosion.

A summary of some of the uses and management techniques for these areas are summarised from LWW (in production) in Table 10.6.

Table 10.6 Uses of, and Management Techniques for, Riparian Areas on Farms. Source: LWW (in production).

Uses/Values Benefits and Management Provide adequate supplies of water for stock and domestic use

Streams and creeks are important sources of drinking water for stock and for domestic use. However, uncontrolled stock access to riparian areas is a major cause of poor water quality, bank instability and erosion, and declining in-stream health.

Maintain good water quality

Good management of riparian land can decrease the amount of soil and nutrients moving from upslope cultivated or grazed paddocks into the stream. When soil and nutrients and other contaminants are trapped in riparian land, water quality is improved and the loss of in-stream habitat through siltation is prevented. Shade from riparian trees helps reduce nuisance algae and weed growth in the stream.

Provide fodder for stock

In many situations riparian lands support the most productive pastures on the farm due to deeper soils and retained moisture, and may provide good fodder for stock when feed is short on other parts of the farm at certain times of year.

Providing shelter and shade for stock and pastures

The shelter and shade that riparian vegetation creates can help to reduce deaths in newborn or newly shorn sheep under extreme weather, and lead to improved growth and productivity through reduction of heat or cold stress. Shelter from wind can also increase pasture growth.

Decreased erosion of riparian land and stream channels

Streamside vegetation stabilises riverbanks and protects them in times of flood. Erosion of channel banks can lead to the loss of valuable agricultural land and infrastructure such as roads, bridges, and buildings, as well as lead to sedimentation of the stream or creek.

Lowered water tables

Deep-rooted riparian vegetation may, in some circumstances, act to lower water tables along riverbanks, reducing the movement of salt and nutrients into streams from sub-surface flows, and helping to further stabilise the bank.

Decrease in insect pests

Healthy vegetated riparian land provides habitat for insect-eating birds and insect parasites that can help to protect pastures, crops and stock from damage.

Maintaining biodiversity

Native vegetation on riparian land plays an important role in the lifecycle of many native animals and plants, including some that cannot live in other areas. Riparian corridors of healthy native vegetation are important for movement of birds and other animals around the landscape. Healthy riparian vegetation also helps maintain good habitat for aquatic animals, including insects and the fish that feed on them, and provides essential food such as leaves, fruit and twigs that fall into the stream

Increase in capital values

Anecdotal evidence from real estate agents suggests that well managed riparian frontage can add up to 10% of the market value of a rural property, a valuable contribution to business finances and woolgrowers’ ‘superannuation’.

Recreation, cultural and tourism

Riparian areas provide an important recreational resource for fishing, canoeing, swimming or simply relaxing. They are often a farming family’s ‘favourite spot’ on the property. They provide people with connection to the environment and potential tourism opportunities.


Environmental best management practices on farm The increased interest in Environmental Management Systems (EMS), Best Management Practices (BMPs) and Current Recommended Practices (CRPs) in farming systems has led to the development of a number of schemes for various issues for agricultural enterprises (e.g. river management for the cotton, sugar and wool industries). Other topics in this unit provide further details about such systems. However, to complete this topic, students may wish to access a copy of the Victorian Department of Primary Industries (DPI) Environmental Best Management Practices Project on Farms (McFarlane et al. 2003). This program is an education and awareness project specifically designed for landholders in the South West Region of Victoria. The project involves two components: 1. Workbook 1 takes participants through a self assessment and benchmarking process. Participants are able to benchmark themselves against a variety of topics such as water management, weed management, vegetation management, soil management, animal management, nutrient management, farm waste management, effluent management, chemical management and green house gases.

2. Workbook 2 is designed to assist farmers to develop an action plan to address specific topics where they wish to improve. These workbooks are available for a minimal cost from Geoff McFarlane, DPI, Geelong on (03) 5226 4722.

Readings !

The following readings are available on CD: There are numerous references available which deal with the issues covered throughout this topic. Seven main readings are recommended for this topic. A number of other key resources are provided in the useful websites and reference list. 1. Bird, P.R. 2003, ‘Shelter and productivity, health and welfare of livestock’, Chapter 5 in Sustainable systems of dairy production – a review of water quality, biodiversity, soil salinity/acidity, farm forestry, shade/shelter and productivity issues, and the likely impact on these of revegetation of dairy farms, as a component of WestVic Dairy’s GHCMA/NAP project: Investigations into the role of trees in protecting water quality and biodiversity on dairy farms in SW Victoria, Department of Primary Industries, Victoria, pp. 173-208.

2. Williams, J. 2004, Productive Resource Management for Woolgrowers, Managing Native Vegetation and Biodiversity. Land and Water Australia, Canberra. Retrieved Dec, 2006 from www.lwa.gov.au/downloads/publications_pdf/PK040727.pdf. This pdf document provides a very useful summary of projects around Australia which are examining the role of native pastures and vegetation on commercial sheep production properties. The following readings are not provided on CD:

• Crean, D. and Bastion, G. 1997, Sheep Management and Wool Production, Inkata Press, Melbourne, 121pp. This book provides a good simple overview of sheep management and wool production. It provides a useful summary of the nutritional requirements of different classes of sheep.

• Land Water and Wool (LWW) In production, Wool Industry River Management Guides, Land and Water Australia, Canberra. Shortly available via the web (www.landwaterwool.gov.au) or Canprint Communications on 1800 776 616. Provides a comprehensive summary of the function and management of waterways on sheep properties – High Rainfall and Sheep Cereal versions available.


• Mason, W., Warn, L. and Cahill, G. (Eds.) 2003, Towards Sustainable Grazing – The Professional Producers Guide. Meat and Livestock Australia, Sydney. A resource recommended by other topics in this unit. A contemporary assessment of grazing practices.

• Squires, V. and Tow, P. (Eds.) 1991, Dryland Farming – A Systems Approach. An Analysis of Dryland Agriculture in Australia. Sydney University Press, 306pp. An excellent reference book that can be found in most University libraries. Covers farming systems, cropping and livestock integration, pest and weed control, soil and fertiliser management and environmental issues.

• Veterinary Education and Information Network (VEIN) 2005, ‘The energy and protein nutrition of grazing sheep’, Chapter 6 in Sheep Health and Production, available at http://vein.library.usyd. 1. edu.au/sheephealth/Chapter6.html#introduction. This site provides more technical detail

about sheep nutrition and diseases.

Activities Available on WebCT

Multi-Choice Questions Submit answers via WebCT

Useful Web Links Available on WebCT

Assignment Questions Choose ONE question from ONE of the

topics as your assignment. Short answer questions appear on WebCT. Submit your answer via WebCT

Summary Summary Slides are available on CD This topic provides an overview of the complexity of sheep production systems and examines the balance required to maintain the sustainability of the production system and that of the business enterprise. It discusses the concept of sustainability and then provides a short summary of key components including: • animal welfare • sheep behaviour • sheep nutrition • predators and toxins • sheep health and the role of integrated pest management • grazing management and the function and role of native vegetation and riparian areas • best management practice systems. This topic does not claim to be comprehensive as the subject is enormously broad and complex. It provides an introduction to the array of issues involved and provides references for further information or reading. References Anon 2005a, Wool Production and Biodiversity Working Together for Tim and Karen Wright: Case

Study, Land, Water and Wool, Northern Tablelands Project. Anon 2005b, Wool Production and Biodiversity Working Together for Rob and Annabel Dulhunty:

Case Study, Land, Water and Wool, Northern Tablelands Project. AWI 2005a, ‘Other endemic problems’, in Health and Welfare, Australian Wool Innovation,

retrieved 1st October 2005 from http://www.woolinnovation.com.au/LivePage.aspx?pageId=1632.


AWI 2005b, ‘Health and Welfare’, in Wool Production, Australian Wool Innovation, retrieved 1st October 2005 from http://www.woolinnovation.com.au/LivePage.aspx?PageId=139.

AWI 2005c, ‘Internal parasites and scouring’, in Health and Welfare, Australian Wool Innovation, retrieved 1st October 2005 from http://www.woolinnovation.com.au/LivePage.aspx?pageId=1630.

AWI 2005d, ‘External parasites and residues’, in Health and Welfare, Australian Wool Innovation, retrieved 1st October 2005 from http://www.woolinnovation.com.au/LivePage.aspx?pageId=1631.

AWI/Sheep CRC 2005, WormBoss Website, available at: http:///www.wormboss.com.au/ LivePage.aspx?pageId=371.

Barber, A.A. and Freeman, R.B. 1986, Design of Shearing Sheds and Sheep Yards, Inkata Press, Melbourne.

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Glossary of Terms

Cell grazing

A form of rotational grazing which involves having a large number of paddocks or cells (40 or more), and grazing at very high stocking densities with frequent movement of the stock. Sheep are rotated rapidly around the many cells during periods of rapid growth and more slowly during periods of slow growth

Continuous grazing A set number of sheep graze a paddock year round

Dry sheep equivalent (DSE)

A ‘short hand method’ of estimating the energy requirements of different classes of animals or the carrying capacity of land. A 50 kg dry sheep is equivalent to one DSE

Flight zone The distance around an animal which when entered will result in the animal moving. The tamer the animal, the smaller the flight zone

Integrated pest management (IPM)

Seeks to bring together an array of chemical and non-chemical methods to provide effective control of a particular pest

Metabolisable energy Measured in MJ, the level of energy available for use by an animal (i.e. after energy losses in faeces, urine and methane have been allowed for)

Point of balance Relates to sheep (or animal handling) and is the point along an animal (usually the shoulder) which will influence the direction an animal takes (backward or forward)

Riparian areas Any land which adjoins, directly influences, or is influenced by, a body of water

Rotational grazing

Regular movement of stock between paddocks. This can be practised using either ‘time based rotations’ (e.g. grazing a paddock intensively at a high stocking rate for say several days and then 60 days rest) or ‘plant based rotations’ (e.g. allowing a plant species to recover to a four leaf stage)

Spelling A term used to indicate that pasture in a paddock is not being grazed

Stocking rate The ‘average’ number of animals per hectare of land. The more productive the land the higher the stocking rate that it can run. Is not always a good indicator of grazing pressure

Worm egg counts (WEC)

WECs estimate the burden of adult worms in monitored sheep and are usually expressed as 'eggs per gram' (epg) of dung

Documents

10. Animal Sustainability