Dossier

Optimizing feed efficiency and metabolism in ruminants

editorial

Feed efficiency in ruminants is an ever-current topic, chal-

lenging nutritionists and scientists all over the world for

various reasons.

Indeed, feeding the world is an important objective today –

and always has been. The rising global population comes

with an increasing demand for food such as meat and milk

as source of protein and, partly, basic foods. In recent years,

the consumption of dairy products alone has increased by

more than 2.5 % per year globally. The constantly increasing

need for animal protein, including the explosively growing

demand of the middle class in Asia, South America and in

developing countries, are driving the feed and production in­

dustry to provide efficient and sustainable solutions to meet

these requirements.

Due to their first stomach fermentation, ruminants have the

ability to utilize and enhance cellulosic feed, to convert solu­

ble nitrogen into valuable microbial protein, and to synthesize

vitamin B. However, on the down side, ruminants also produce

undesirable gases as part of their digestion (e.g., methane,

ammonia) that come along with high energy and protein

losses for the animal. Though scientists and nutritionists are

steadily striving to improve feed conversion ratios of livestock,

still about 0.5 to 1.8 kg of dry matter intake are required for

the production of one liter milk, depending on genetics and

feed stuff. In beef production, it even takes about 5 to 10 kg

of dry matter intake to produce 1 kg of meat. It goes without

saying that improved feed efficiency will lead to reduced pro­

duction costs due to raised animals’ performance. Farmers will

achieve more milk and meat without increasing their number

of animals at all. Moreover, enhanced feed efficiency will

reduce pollutive emissions like methane and ammonia. In

dairy cows, about 4 to 10 % of the energy losses account

for methane. This highly reactive greenhouse gas has a

negative impact on the ozone layer and ammonia, containing

phosphorus, causes eutrophication of waters.

Finally, improved feed efficiency reduces the need for con­

centrates and forage to produce 1 liter of milk or 1 kg of

meat, and above, it reduces the competition with humans

and other non­ruminant animals regarding crop. 10 % impro­

vement in feed efficiency would lead to savings in amount of

dry matter of some 700 to 800 kg per cow per year.

Therefore, the aim is to globally pursue this strategy of opti­

mizing feed efficiency in ruminants. Achieving improvements

whilst staying in line with the demands of humans and ani­

mals, is not only based on the genetic level of livestock, but

also on feed and animal management likewise.

Thierry Aubert

Species Leader Ruminants,

Delacon

Efficient ruminant production: opportunities and challenges

2 3feed efficiency Dossier

While a cow needs to consume 6-8 kg

of feed to produce 1 kg of meat, pork

only needs to consume 3 kg of feed,

poultry 2 kg of feed and fish 1 kg of

feed to produce 1 kg of meat. Even

within one animal species, feed

efficiency is not the same: younger

animals have the highest feed

efficiencies, as these animals are

growing and will direct most of the

energy they consume into growing,

but as they get older, more energy will

be directed to maintain a basal level

and less is directed to performance.

Specialized microbial ecosystem

So why do ruminants have the lowest

feed efficiency? It is related to their

digestive system and the way feed is

broken down. Monogastrics (e.g., pigs

and poultry) rely on enzymatic diges­

tion in their stomachs before nutrient

absorption in the gut, with minor micro­

bial fermentation taking place in the

ceacum. Contrary, ruminants have a

big microbial fermentation vessel, the

rumen, were feed is fermented before

nutrient absorption takes place. In the

rumen, a whole microbial ecosystem

has evolved and specialized in diges­

tion of forage. This microbial ecosystem

is very complex with protozoa, archea

(the methane producers), bacteria

and fungi, and it is not easy to target

changes in one microbial population

without affecting the whole ecosystem.

All ruminal microbial populations have

very important tasks and are very well

interconnected in terms of substrate,

enzymes and co­factors. But this eco­

system is expensive to maintain as the

first nutrients becoming available from

ruminal fermentation are to support the

ruminal microbes. To overcome this loss

of nutrients to the ruminal ecosystem

is one of, if not the major, challenge for

ruminal nutritionists.

Energy losses

Besides losses of energy to maintain

their ruminal ecosystem, ruminants still

have additional losses of energy for

maintenance, activity, milk production,

body condition, pregnancy and growth.

More than 50 % of the feed is used for

maintenance and this makes selection

for feed efficiency more difficult than

for pigs and poultry, as it is difficult to

predict what is going to happen in the

big black box, the rumen. Evolution in

the selection for efficient ruminants has

been slower than for monogastrics,

because facilities for the trials are

expensive and individual feeding is re­

quired. Further, it is difficult to compare

animals at different body compositions

as the reasons for these differences are

vast: dairy vs beef, production system,

feed management, activity, socialization

& hierarchy, age, type of feed, etc.

Why do ruminants have low feed efficiency?

Marta Lourenço, DVM, PhD

Laboratory of Animal Nutrition,

Faculty of Veterinary Medicine,

Ghent University, Belgium

Laboratory for Animal Nutrition

and Animal Product Quality,

Faculty of Bioscience Engineering,

Ghent University, Belgium

Scientific and Logistic Consultancy –

Sciloco, Belgium

feed efficiency

How can we measure feed efficiency

in ruminants?

First of all, it is important to clarify two

concepts: efficiency and conversion.

Efficiency expresses how much one

gets per unit of input. Conversion is

the opposite, how much input is need­

ed for a unit of output. But why these

two concepts? For a farmer, the con­

version is important as it is a measure

to evaluate his costs, and hence calcu­

late his return on his investment quite

easily. On the other hand, efficiency is

important to evaluate improvements in

productivity. But how can this impro­

vement be measured? It all depends

on the type of production system one

is considering. In beef production sys­

tems one could use the 1) gain to feed

ratio; 2) kg weaned/cow covered; 3)

kg weaned/kg cow weight (the wean­

ing ratio) or 4) the no. of calves wean­

ed/cow covered. In growing animals,

one could use the 1) feed conversion

feed efficiency of different animal species

Efficiency

1.2

1

0.8

0.6

0.4

0.2

Fish

Chicken

Pork

Cattle

feed efficiency of cattle for different production systems and at different ages

0.45

0.4

0.35

0.3

0.25

0.2

0.15

0.1

0.05

Efficiency

calves on milk

weaned calves

young heifers

young bulls, 12m

young bulls, 15mheifers on TMR

older heifers

ratio [DM intake/average daily gain

(ADG)]; 2) partial efficiency of growth

[ADG/average feed intake (FI) minus FI

maintenance]; 3) relative growth rate;

4) Kleiber ratio (ADG/kg metabolic

weight); 5) residual feed intake (actual

intake minus predicted intake) or 6) re­

sidual average daily gain (actual ADG

minus predicted ADG).

Defining feed efficiency in lactating

animals is more difficult than for grow­

ing animals in their linear phase,

as dairy cows have cycles of rapid

catabolism post­calving followed by

anabolism of reserves until next calv­

ing. Nevertheless, one could also use

the 1) feed conversion ratio, but most

commonly one would use 2) milk pro­

duction/kg body weight (BW); 3) feed

intake/kg BW; 4) dry matter efficiency

(energy corrected milk production/DM

intake); 5) crude protein efficiency (milk

protein yield/crude protein intake);

6) residual feed intake or 7) residual

solids production (actual milk solids

production relative to expected solids

production).

There is no consensus on the best

parameter. All have advantages and

limitations. Some will be correlated

with the growth and the size of the

animals (e.g., feed conversion ratio),

or lead to the selection of slow

growing animals (e.g., residual feed

intake), while others are only of value

if animals are fed the same diet (e.g.,

relative growth rate and Kleiber ratio).

To overcome these limitations a new

parameter was proposed, where no

correlation between ADG and residual

FI, and between residual ADG and

FI exists: residual intake and gain,

where residual FI and residual ADG

are taken into account together. This

new concept reduces the probability of

selecting for a slow growing animal.

4 5Dossiereffect of health management

Improved dairy cow health directly increases nutrient use

efficiency because of sustained milk output and no additional

nutrient costs required for animal recovery. If improved

dairy cow health also results in a longer lifetime (and

higher production), nutrient costs for rearing young stock

to replace the lactating dairy herd will be diluted.

High productive lifetime within a dairy herd is related to a low

rate of involuntary culling. Involuntary culling (replacement)

rates in herds with high-yielding dairy cows can be easily

as high as 35 % with low reproduction, mastitis, locomotion

problems and low productivity being the main causes. Thus,

improving longevity and consequently feed efficiency neces-

sitates a substantial reduction of these health disorders.

Prevention of metabolic disorders

The incidence of health disorders is relatively high in early lac­

tation, a period that is also characterized by a high incidence of

metabolic disorders (ketosis, fatty liver). Metabolic disorders du­

ring the transition period are related to an excessive mobiliza­

tion of energy from adipose tissue after calving. Although ener­

gy mobilization from adipose tissue directly after calving can be

regarded as a normal physiological process, selecting breeding

sires based on the first 100 days in milk performances of their

daughters has resulted in high­yielding cows with an excellent

capacity for fat mobilization at the start of lactation. Metabolic

disorders at the start of lactation result from an extreme mobili­

zation of fatty acids to which dairy cows are obviously not well

adapted. Therefore, preventing metabolic disorders should not

exclusively focus on feeding strategies to improve the supply of

energy and nutrients from feed, but also on strategies to pre­

vent massive fat mobilization and to support fat metabolism.

Relationship between metabolic stress and immune response

Obesity research in humans and transition research in dairy

cattle have revealed the relationship between fat metabolism

and immune response. Research in rodents and humans has

shown that obesity results in an increase in the number of

immune cells in adipose tissue. Also during a negative energy

balance (fasting) a rise in immune cells in adipose tissue has

been observed. This “enriched” adipose tissue can release

cytokines (adipokines) stimulating the formation of acute­

phase proteins, resulting in a so­called “metabolic inflamma­

tion”. During the transition period, increased plasma levels of

tumor­necrosis factor α (a cytokine) and acute­phase proteins

have been reported, especially in cows that were postpartum

diagnosed with a high liver fat content. Thus, it seems that also

in dairy cows extreme changes in fat metabolism coincide with

changes in immune response. Such a relationship may not only

result in metabolic stress, but may also be the linkage between

metabolic and infectious health disorders (e.g., mastitis).

Because of the relationship between metabolic stress and

immune response during the transition period, nutritional

management to minimize this metabolic stress will not only

improve dairy cow health during early­lactation, but also the

immune status. Consequently, minimizing metabolic stress

will reduce the incidence of diseases that results in involun­

tary culling. A healthier cow with a longer lifetime production

contributes to a more effective nutrient use and a sustainable

dairy production.

Better dairy cow health management improves feed efficiency

A.M. (Ad) van Vuuren PhD,

DVM, dipl. ECVCN

Scientist dairy cow nutrition,

Wageningen UR Livestock

Research, Wageningen, the

Netherlands

R.M.A. (Roselinde) Goselink

DVM MSc

Researcher ruminant

nutrition & physiology,

Wageningen UR Livestock

Research, Wageningen, the

Netherlands

feeding strategies

Feed efficient ruminant production is a key topic in the

further development of ruminant husbandry all over the

world. Ruminants substantially contribute to human

nutrition by providing milk and meat.

The microorganisms in the rumen are able to process

lignocellulose from low quality roughage into volatile fatty

acids hence energy, to transfer non­protein nitrogen, such

as urea into microbial protein and to synthesize B vitamins.

Therefore, ruminants are able to produce food of animal

origin without competition for feed with non­ruminants

and humans.

Optimizing the advantages of ruminants

On the other hand, methane (CH4) with a high greenhouse

gas potential is an unavoidable by­product of rumen

fermentation. Furthermore, growing ruminants are charac­

terized by a low growing potential (daily yield in edible

protein < 0.05 % of body weight). The objectives of rumi­

nant breeding, nutrition and keeping, respectively manage­

ment, should therefore focus on maximizing and optimizing

the advantages of ruminants and to minimize the disadvan­

tages. Feed efficient ruminant production is regarded as a

complex system starting with plant and animal breeding.

Strategies to turn animals with better utilization of feed into

animal­derived food while concomitantly decreasing emis­

sions per product have to be developed.

Potential feeding

strategies for more feed efficiency in livestock

Therefore, the following strategies are

intended:

• A greater feed intake of animals to

improve the ratio of energy/nutrient

requirements for maintenance and

animal yields.

The amount of feed intake depends

on the animal species and production

categories, physiological stage, body

weight, feed quality and structure, and

many other factors. This strategy will

be interesting if the milk production

can be increased, but in ruminants this

strategy may reduce the digestibility

of organic matter (OM) to a certain

degree.

• A decreased energy/nutrient require-

ment for maintenance of the animals

may contribute to a more efficient

conversion of feed into performance.

These maintenance requirements

depend on animals’ species and

production category, body composition

and other factors. The requirements

are usually given per kilogram of

metabolic body weight.

DMI, kg/d

Item 10 15 20 25 30

Energy intake, MJ of NEl/d 70 105 140 175 210

Maintenance, 37.7 MJ of NEl/(cow/d);

% of total NEl intake 53.9 35.9 26.9 21.5 18.0

Milk yield, 3.3 MJ of NEl/kg 9.8 20.4 31.0 41.6 52.2

NE/kg of milk, MJ of NEl/kg of milk 7.1 5.1 4.5 4.2 4.0

Methane emission1

g/d 240 360 480 600 720

g/kg of milk 24.5 17.6 15.5 14.4 13.8

Carbon footprint2, g of CO2eq/kg of milk 825 605 530 495 475

6 7feeding strategies

Thierry Aubert

Species Leader Ruminants,

Delacon

(according to Prof. Dr. G. Flachowsky)

• A decreased energy need for protein

synthesis in the body or increased

anabolic processes and reduced cata-

bolic processes in the animal.

In this context genetics play an

important role.

• A decreased fat content in animal

bodies, reduced fat content in milk, or

reduced excretion of lactose in milk.

But fat is important for the taste of the

product (milk and meat) and lactose

has little variation due to the osmolarity

process in the udder.

• A reduction of energy losses in the

digestive tract (e.g., methane, ammonia).

During the fermentation some energy

is lost via methane production from

CO2 and H2. The losses vary between

4 and 10 % of the gross feed energy

and increase with increasing fiber di­

gestibility. Few studies show the impact

of the genotype on methane fermenta­

tion in the digestive tract of ruminants.

• A greater digestibility of feed,

respectively nutrients could be

obtained both by breeding animals

with a better digestibility and by

specific plant breeding programs

to increase the nutritive value

of feed plants.

A greater digestion of feed in the

gastro­intestinal tract of livestock

animals due to more specific

digestive enzymes is also beneficial

for a more efficient conversion of

feed or nutrients including cellulase,

xylanase, amylase, etc.

• Improved animal health, as espe-

cially animals with higher resistance

against biotic and/or abiotic stressors

and lower losses during production

contribute to a more efficient feed

conversion.

For example, the milk production

decreases with a higher level of

somatic cell count (SCC) in milk.

model calculation to show the influence of dry matter intake [DMI, 7.0 MJ of Nel/kg of dry matter (DM)] of dairy

cows [BW: 650 kg; 4 % milk fat; GfE (Gesellschaft für Ernährungsphysiologie), 2001] on energy intake, percentage

of maintenance, milk yield, and energy per kilogram of milk as well as emissions per kilogram of milk

1 According to Flachowsky and Brade

(2007): 24 g of CH4/kg of DMI for all diets.

2 Calculated on the base of the greenhouse

potential of CH4 (x23) and the calculations

by Daemmgen and Haenel (2008).

Dossier

rumen microbiota manipulation

Manipulation of gut microbial fermentation in ruminants to

improve feed efficiency requires a different type of approach

compared to monogastrics. The ruminant gastro-intestinal

tract has a lot in common with monogastrics: the presence of

a secretory acid stomach (abomasum) followed by small and

large intestines. The key difference with ruminants however

is that ingested feedstuff first enters a nonsecretory foresto-

mach, allowing a pregastric microbial fermentation to be

carried out. This forestomach is divided into three compart-

ments (reticulum, rumen and omasum) of which the largest

is the rumen, with a maximum volume of approximately 15 l

and 100 l in sheep and cattle respectively. This organ acts

as a microbial fermentation vessel enabling the digestion of

complex, bulky dietary fibers and roughage, which are often

beyond the digestive capabilities of monogastrics. In return

for providing this anaerobic habitat the host is supplied with

an array of microbial fermentation products, of which volatile

fatty acids (VFA) represent a key source of energy for the

host. The microbial biomass leaving the rumen also provides

the host with a high quality source of protein being utilized in

the small intestine.

Microbial ecosystem in the rumen

The microbiota of the rumen consists of a dynamic popula­

tion of bacteria (up to 1011 per ml of rumen contents), meth­

anogenic archaea (106­108 per ml), protozoa (105­106 per ml)

and anaerobic fungi (105 per ml). Bacteria are considered to

be the main microorganisms responsible for the wide variety

of fermentation processes that occur within the anaerobic

environment of the rumen, and either have a primary role

(i.e., breakdown of dietary carbohydrates, protein and lipids)

or a secondary role (i.e., utilizing the end products generated

from primary processes). Although protozoal and anaerobic

fungal numbers are less than bacteria, under certain dietary

conditions they can account for almost half of the rumen

microbial biomass due to their larger cell sizes and structures

respectively.

The role of protozoa in the rumen is not entirely clear al­

though it is known that they can engulf rumen bacteria and

starch granules, and ferment plant carbohydrates for energy.

Anaerobic fungi are well established to play an important role

in fiber degradation, breaking down complex lignocellulosic

feedstuff by both, enzymatic and physical means. Methano­

genic archaea in contrast do not utilize the feedstuff itself,

instead they generate methane by beneficially removing

microbial waste products (i.e., acting as a hydrogen sink).

The complexity of the rumen microbiota has become increas­

ingly apparent in the last decade due to the use of cultiva­

tion independent techniques, as only a minor proportion of

rumen microbes have been able to be isolated to date. For

example early studies attributed rumen microbial processes

to a collection of approximately 20 bacteria, whereas now it

is currently estimated that at least 300­400 different bacterial

species exist. This complexity is likely to underpin the resil­

ience of the microbiota to perturbation, a beneficial trait when

it comes to the health and well­being of the host. This resil­

ience also makes the manipulation of the rumen microbiota

more challenging however, particularly when trying to target

known inefficiencies associated with the rumen microbial

breakdown of feedstuff.

The rumen microbiota and their manipulation to increase feed efficiency

8 9rumen microbiota manipulation

Energy and nutrient losses

Energy and nutrients are known to be lost from rumen micro­

bial fermentation in a variety of different ways. Ruminal meth­

ane production can result in up to a 10 % loss of the gross

energy available to the host from the diet, as well as being the

main agricultural source of this potent greenhouse gas. Rumi­

nal degradation of dietary protein limits its intestinal availabi­

lity, and often much is lost to the environment as nitrogenous

waste due to excessive ruminal production of ammonia.

Excess microbial production of lactic acid in the rumen when

diets are rich in soluble carbohydrates is also an issue, in

terms of feed efficiency as well as animal health (i.e., ruminal

acidosis and liver abscesses). As diet can influence the com­

position of the rumen microbiota (see table), strategies to limit

ruminal inefficiencies have focused on developing feedstuffs

that modify the extent and rate of ruminal digestion, as well as

manipulate microbial fermentation end products.

Protein protection and improved energy supply

Protection of protein to reduce its extent of degradation in

the rumen has been attempted through protein modification.

Protection mechanisms have included the complexing of plant

proteins with tannins, or in the case of red clover protection

by the addition of quinones through the action of the plant en­

zyme polyphenol oxidase. Improving the timing and/or supply

of carbohydrates has been shown to decrease ruminal produc­

tion of ammonia, enhancing the assimilation of ammonia into

microbial biomass. This has been achieved through

Dr Joan Edwards

Rumen Molecular Biologist,

IBERS, Aberystwyth University, UK

Dr Alejandro Belanche Gracia

Research Scientist,

IBERS, Aberystwyth University, UK

Dossier

rumen microbiota manipulation

effect of dietary energy source (fiber or starch) and protein intake (high or low) on the rumen microbiota of dairy cattle1

1 Data source: Belanche et al. (2012) J. Nutr. 142: 1684–1692. Microbial abundances were determined by quantitative PCR,

and within a row means (n = 12) without a common superscript differ (P<0.05). P values above 0.05 are not shown (NS).

Microbial Taxa High Protein Low Protein p Value

Fiber Starch Fiber Starch SED Protein Energy PrxE

Bacteria (mg) 2.93 2.95 2.59 2.53 0.167 0.004 NS NS

Protozoa (mg) 0.71 0.47 0.54 0.44 0.084 0.021 0.005 NS

Anaerobic Fungi (ug) 1.70a 1.40b 1.58ab 0.66 0.126 <0.001 <0.001 0.002

Methanogenic Archaea (107 copies) 4.87 3.94 3.60 2.80 0.311 <0.001 <0.001 NS

Ruminococcus albus 1.08 0.94 0.72 0.50 0.137 <0.001 NS NS

Ruminococcus flavefaciens 3.01b 4.13a 1.89c 4.61a 0.405 NS <0.001 0.009

Fibrobacter succinogenes 11.6b 13.5a 10.5bc 9.27c 0.847 <0.001 NS 0.044

Butyrivibrio fibrisolvens 14.0 15.7 10.9 10.6 1.128 <0.001 NS NS

Prevotella ruminicola 112 117 107 125 19.22 NS NS NS

Prevotella bryantii 1.64 1.53 1.21 0.77 0.393 0.014 NS NS

Selenomonas ruminantium 0.20 0.36 0.26 0.29 0.061 NS 0.035 NS

Streptococcus bovis 0.90ab 0.77a 1.59a 0.46b 0.371 NS 0.025 NS

Megasphaera elsdenii 0.001 0.10 0.05 0.37 0.141 NS 0.050 NS

Anaerovibrio lipolytica 0.15 0.18 0.10 0.15 0.058 NS NS NS

DNA concentration (per g DM)

Relative abundance (103 x 2­ΔCt)

10 11rumen microbiota manipulation Dossier

modifying carbohydrate quality and/

or form in formulated diets, or in the

context of grassland based production

systems increasing the water soluble

carbohydrate content of forage. The

provision of readily available energy

however is a fine balance. For example

the use of starch as an energy source in

place of fiber results in increased popu­

lations of lactic acid producing bacteria

(e.g., Selenomonas ruminantium) (see

table), and if lactate utilizing bacteria

(e.g., Megasphaera elsdenii) are not si­

milarly increased then the risk of ruminal

acidosis development becomes greater.

Direct manipulation of the rumen micro­

biota, rather than the feedstuff provided

to them, has also been used to over­

come ruminal inefficiencies.

The role of feed additives

Feed additives such as ionophores,

antibiotics and methane inhibitors have

all been used to beneficially change

ruminal metabolism ­ acting either on

a wide or specific range of microbial

taxa. Ionophores for example act on

a wide range of bacteria that have a

gram­positive cell wall structure, and

cause a favorable shift in ruminal VFA

production by increasing propionate

(a glucogenic precursor) relative to a

decrease in acetate. This shift in VFA

profile also results in decreased meth­

ane production, as propionate formation

is a hydrogen consuming process.

Ionophores have also been reported

to decrease ruminal ammonia and

lactic acid production, although other

antibiotics have been shown to change

these ruminal fermentation parameters

more specifically (i.e., flavomycin and

virginiamycin respectively). As the use

of antimicrobial feed additives for the

purpose of animal growth promotion

purposes has been banned in the EU

since 2006 however, there has been

increasing interest in the use of plant

extracts as alternative feed additives to

modify the rumen microbiota.

Plant saponins have been shown to

decrease ruminal protozoal numbers,

slowing down protein turnover in the

rumen (i.e., decreasing bacterial pre­

dation) and increasing transport of

microbial nitrogen to the small intes­

tine. Due to the intimate association of

methanogenic archaea with protozoa,

decreasing protozoal numbers can also

decrease ruminal methane production.

Plant essential oils are thought to have

a similar mode of action to ionophores,

whereas polyunsaturated fatty acids

(PUFA) reduce methane emissions by

incorporating hydrogen during their

ruminal biohydrogenation. There is also

a lot of interest in the ruminal biohydro­

genation of PUFA due to their associ­

ated health properties, as the rumen

has been shown to be important in

influencing the lipid profile and content

of meat and milk. Probiotics have also

been shown to be beneficial to ruminal

metabolism, with the ability of live yeast

(Saccharomyces cerevisiae) to stimu­

late rumen bacterial populations being

primarily associated with their ability to

scavenge oxygen entering the rumen

with ingested feed.

Improved efficiency, reduced emissions

Current research to improve feed

efficiency is being driven by the need to

increase the sustainability of ruminant

livestock production, whilst reducing

its environmental footprint in terms of

detrimental methane emissions and

nitrogenous waste. A key factor un­

derpinning this is the increasing global

consumption of livestock­derived pro­

ducts, particularly in developing coun­

tries, with demand for meat and milk set

to double by 2050. The application of

recent advances in ‘omic technologies

(i.e., metagenomics, metatranscripto­

mics and metabolomics) to directly stu­

dy the genetic material and metabolism

of rumen microbes without the need

for cultivation will provide new insights

into the structure and complexities of

the rumen microbial ecosystem in the

near future. The challenge for research­

ers will then become transforming this

knowledge into the identification of

novel targets for manipulation and/or

the development of new approaches

to beneficially modify the rumen, whilst

ideally improving product quality.

nitrogen efficiency

Nitrogen efficiency in ruminants

Compared to other livestock, the

efficiency of nitrogen (N) utilization in

ruminants is rather low (around 25 %)

and thus, affecting animals’ perfor-

mance as well as the environment.

Nutritional improvements in N

efficiency of ruminants come along

with improvements in performance,

reduction of feed costs and protein

levels of diets, and decreased N los-

ses to the environment.

According to calculations of Tamminga

(1992), 75­85 % of the ingested N is

excreted in faeces and urine arising

from:

• urea content in urine as a conse­

quence to an excess of ammonia in

the rumen

• indigestible N and endogenous N

excretion in feces and urine

• N excretion in urine due to an ineffi­

cient utilization of absorbed protein

for maintenance and for the synthe­

sis of milk and body protein

In the rumen, NH3 is produced via

deamination of amino acids and

non­protein nitrogen compounds

(NPN, e.g., urea and amides). In case

of sufficient energy supply, NH3 may

be used for rumen microbial growth

and accordingly being available for

the animal in the following sections of

the gastro­intestinal tract, such as the

small intestine. As ammonia, being a

cytotoxin, would destroy somatic cells,

excesses are immediately absorbed

through the rumen wall and trans­

ferred to the liver via blood circulation,

where it is converted into urea.

The originated urea subsequently is

either transferred back to the rumen

through salivary glands and direct

The research on improved N utiliza tion in

the rumen is focused on two approaches:

To optimize microbial protein synthesis

on the one hand and to limit protein

degradation on the other hand.

Protein degradation in the rumen

Ruminal protein degradation was

recently characterized as the ‘catabolic

cascade of proteolysis’, since many dif­

ferent microorganisms (e.g., bacteria,

protozoa and anaerobic fungi) or even

plant enzymes are involved. However,

in this case the ruminal bacteria are

playing the most important role.

return diffusion over the rumen wall,

or it is excreted via urine. Upon this

process, the energy supply plays a

key role, as for the microbial synthe­

sis, using amino acids and ammonia

as source material requires a measure

of available energy. In case of poor

energy provision, amino acids will

be deaminated. Several nutritional

systems regarding ruminants’ feeding

demands proved the importance of a

ruminal N balance in view of rumen

degradable protein and fermenta­

ble energy (e.g., NRC system, INRA

system, Dutch System, Scandinavian

system).

schematic illustration of protein metabolism in ruminants

Bacteria

Protozoa

Organic matter

Saliva

Urea

Liver

Amino acids

Milk

Mammary gland

ATP + Carbon skeletons

RUP

RUP

RUMEN

SMALL INTESTINE

Microbial protein

Microbial protein

Amino acids

Peptides

Crude protein

Endogenous protein

Ammonia

NPNPure protein

Metabolizable protein (absorbed AA)

12 13nitrogen efficiency

The process of proteolysis follows

these steps:

• Adhesion resp. adsorption of bacte­

ria to the feed particles

• Hydrolysis of protein → formation of

oligopeptides → hydrolyzed to small­

er peptides. Upon the hydrolysis,

different proteolytic microorganism

are involved, such as bacteria (Pre-

votella spp., Streptococcus bovis

and Ruminobacter amylophilus),

protozoa and anaerobic fungi.

• Peptides can either function as

source of food for the ruminal

bacteria or being further hydrolyzed

into amino acids. Many protozoa

and bacteria, such as Prevotella

spp., Fibrobacter succinogenes,

Megasphaera elsedenii and Lach-

nospira multiparus, are involved

in the course of this cleavage of

dipeptide to amino acids.

• Amino acids being used for the

build up of microbial protein are

either transaminated or deaminated

and thus, regenerating ammonia.

In the deamination of amino acids

mainly the hyper ammonia produ­

cing bacteria (HAP), Prevotella spp.,

and the protozoa are involved.

Prevotella spp., being involved in most

steps of protein degradation, are the

most abundant bacteria population in

the rumen. They are able to ferment

amino acids hence producing NH3,

even though in a relatively low rate.

Nevertheless, due to their high quanti­

ty in the rumen, they are considered as

major deamination bacteria.

Another important bacteria group

is represented by the HAP bacteria,

which are non saccharolytic amino

acid fermenters and rapid producers of

ammonia out of amino acids. The first

isolated HAP species were Clostridium

aminophilum, Clostridium sticklandii

and Peptostreptococcus anaerobius.

In the rumen they are present in low

concentrations but their high deami­

nation rates explain their key role in

deaminating ruminal bacteria.

Therefore, the reduction of ruminal

NH3, without affecting microbial

protein synthesis, and an increase

in dipeptides and amino acids might

be an effective strategy to improve

the efficiency of N utilization in the

rumen (ENU­R) and thus, decreasing

N precipitation via the urea content

of milk.

proteolysis in the rumen

BacteriaProtozoa

Fungi

H.A.P.Prevotella sp.

Protozoa

Prevotella sp.S. Bovix

R. amylophilus

Prevotella sp. F. succinogenes,

M. elsedenüProtozoa

hydrolysis

Transamination

Deamination

hydrolysis

hydrolysis

Protein

NH3

Oligopeptides

Dipeptides

Amino acids

Dossier

Thierry Aubert

Species Leader Ruminants,

Delacon

(according to A. Foskolos: Strate­

gies to Reduce Nitrogen Excretion

from Ruminants: Targeting the

Rumen. Universitat Autonoma de

Barcelona, Bellaterra, Spain, 2012)

nitrogen efficiency

Efficiency of nitrogen utilization in

the rumen

The efficiency of the rumen is gene­

rally assessed by the efficiency of the

microbial protein synthesis (EMPS),

and expressed as g of bacterial N per

kg of fermentable energy. However,

EMPS is calculated according to the

available energy and does not pro­

vide an estimation of the efficiency

at which microbials catch available

N in the rumen. Bach et al. (2005)

described the use of the efficiency

of N utilization in the rumen, which is

measured as the ratio between bac­

terial N (in g) and ruminal available N

(in g), whereby the available N com­

bines rumen degradable protein (RDP),

endogenous N and recycled N.

Strategies to reduce ruminal protein

degradation

For years, many strategies and trials

addressing the reduction of rumen

protein degradation have been car­

ried out and thus, can be categorized

into those that affect feed protein

and those targeting rumen microbial

populations. The first group of stra­

tegies includes methods that intend

to change the ruminal availability

of crude protein (CP) by decreasing

RDP and increasing rumen undegrad­

able protein (RUP) content of rations.

Those targeting the rumen microbes

include different feed additives that

act as modulators of the rumen micro­

bial population.

• Heat processing is the most com­

mon method to decrease the RDP

by denaturation of proteins and the

formation of protein carbohydrates

(maillard reactions) and protein

cross links (e.g., roasting, flaking,

extruding, expanding). However,

heat treatments may also reduce

the digestibility of RUP. For exam­

ple, intestinal protein digestion of

soybean meal treated by various

techniques ranged from 57.7 % to

83.8 %, hence suggesting a consi­

derable variation caused by pro­

cessing (Stern et al., 2006).

• Chemical treatment of feed protein

includes 3 categories: chemicals

that induce cross links with pro­

teins, chemicals that alter protein

structure by denaturation, and

chemicals that bind proteins but

with little or no interaction on the

protein structure (e.g., sodium

hydroxide, formaldehyde; Santos et

al., 1999).

• Ionophores have successfully

reduced N losses and consequently

improved animal performances,

but due to the increasing public

awareness of potential transfer into

meat and milk, the EU prohibited

its use in 2006. Several iono­

phores registered as feed additives

(laidlomycin, lasalocid, monensin

and narasin) inhibit the deamination

of amino acids due to the sensiti­

vity of HAP bacteria to ionophores

addition.

• Essential oils are blends of

secondary plant metabolites

obtained by hydrodistillation. The

efficiency of nitrogen utilization dependent on the efficiency of the microbial protein synthesis

Efficiency of

nitrogen utilization

in the rumen (%)

EMPS (g of bacterial

N/kg of OM fermented)

85

80

75

70

65

60

55

50

45

10 15 20 25 30 35 40 45

14 15nitrogen efficiency

volatile fractions of plants show an

antibacterial activity and lipophilic

properties. It has been suggested

that gram­positive bacteria were

more susceptible to EO than

gram­negative as gram­negative

have an outer shell that limits the

access of hydrophobic compounds.

EO compounds may alter protein

metabolism mainly through

the inhibition of peptidolysis or

deamination.

• Probiotics may provide beneficial

effects to the host by improving the

environment of the endogenous

flora. They have no effects on

protein degradation, the main

effect is a stimulation of the growth

of ruminal bacteria.

• Tannins reduce ruminal proteolysis.

Hydrolysable tannins can be toxic

for animals, as their degradation

products are absorbed in the

small intestine. Condensed tannin

extracts reduce proteolysis and

inhibit the growth of proteolytic

effects of some essential oil compounds on nitrogen metabolism in the rumen as indicated by in-vitro studies

(source: Foskolos, 2012, based on Calsamiglia et al., 2007)

Essential oil N­ metabolism References

Thymol deamination ↓ Borchers, 1965; Cardozo et al., 2005; Castillejos et al., 2006

Eugenol peptidolysis ↓ Busquet et al., 2005c

deamination ↓ Busquet et al., 2006; Castillejos et al., 2006

Cinnamaldehyde proteolysis ↓ Cardozo et al., 2004; Ferme et al., 2004

deamination ↓ Busquet et al., 2005a; Ferme et al., 2004

Anethol peptidolysis ↓ Cardozo et al., 2004

deamination ↓ Cardozo et al., 2005

Garlic oil deamination ↓ Cardozo et al., 2004, 2005; Ferme et al., 2004

Capsaicin deamination ↓ Cardozo et al., 2005

Carvacrol peptidolysis ↓ Busquet et al., 2005c

bacteria such as Prevotella

ruminicola and Streptococcus

bovis.

In conclusion, protein degradation

and deamination can be controlled

either with respect to the feed or by

influencing the microbial population

of the animals. Monensin success­

fully suppresses some HAP bacteria,

and therefore reducing ammonia

accumulation in the rumen, but its

use has been prohibited in the EU

in 2006. The major alternatives to

ionophores to control N metabolism

in the rumen are EO compounds that

have the proven potential to modu­

late ruminal protein degradation and

deamination.

Dossier

effect of feed additives

Additives to improve performance and feed efficiency in ruminants

In ruminants, improvements in perfor­

mance and thus effectiveness may

be achieved through the use of feed

additives that may directly affect the

rumen but also having overall effects on

the metabolism of the animal through a

direct action or by the consequences of

changes in ruminal function.

a) Affecting the rumen

Effectiveness of additives in the rumen

of ruminants can be achieved by seve­

ral approaches. On the one hand, the

growth efficiency of specific targeted

strains of bacteria favorable to ruminal

digestion may be obtained with pro­

biotics (e.g., Saccharomyces cerevisiae

yeast). On the other hand, extracts of

plants, herbs and spices (e.g., essential

oils) show the ability of damming un­

desired bacteria population in behalf of

ruminal digestion.

Live yeasts

Live yeasts, like Saccharomyces cere-

visiae, are used in all species of rumi­

nants (dairy cows, beef cattle, sheep,

goats, buffalo) because they have the

particularity to positively influence the

fermentation processes of the rumen.

Yeasts stimulate the cellulolytic bacte­

ria, hence increasing the digestibility of

the organic matter (especially high fiber

contents), and they enhance the syn­

thesis of volatile fatty acids (VFA) whilst

reducing the concentration of lactic

acid, because of their ability to use it,

and thus, reducing the risks of acidosis.

The literature review of Desnoyers et al.

(2010) including 157 trials dealing with

different strains of yeast supplemen­

tation in ruminants, showed significant

effects of yeast on milk production

(+ 2.6 %), feed intake (+ 1.15 %) and on

milk fat composition (+ 1.3 %) in dairy

cows. The effect on milk production

was increased in animals being fed high

levels of concentrates and neutral de­

tergent fiber (NDF) in diets. In another

trial, feed efficiency was increased by

2.95 % in dairy cows when supplemen­

ting live yeast to their rations (Ondarza

et al., 2010). However, this increase

was lowered (+ 2.25 %) with rising milk

production above 33 kg fat corrected

milk (FCM).

Live yeast products have to pass a

registration process before entering the

European market. Actually, only four

producers in Europe possess the autho­

rization for merchandizing. As live yeast

shows rather poor results regarding its

stability during the pelletizing process,

heat treated yeast and yeast by­pro­

ducts are preferred commodities.

Essential oils

Essential oils are aromatic substances

and known for their inhibitory effect on

some pathogenic bacteria. They are

used to modify the rumen microbial

population in respect of improving

the efficient synthesis of the desired,

beneficial bacterial flora. Khiaosa­ard

and Zebeli (2013), showed (according

to a database of 34 trials) that essential

oils reduced the number of protozoa

in the rumen as well as the amount of

butyrate whilst increasing the ruminal

pH of all animals. In beef cattle, the

use of essential oils may reduce meth­

ane production and increase acetate

and propionate ruminal production.

In contrary, this meta­analysis did not

show any effects on feed intake or

feed efficiency. As this report is based

on the application of different types of

essential oils, the effects on the ruminal

flora may differ depending on the oils’

main substance group (e.g., alcohols,

aldehydes, phenols), and the type of

production process (natural extract or

nature identical substance). Moreover,

their action may be affected by the

type of diet (concentrate:forage ratio).

Enzymes

Another possibility of supporting the

ruminal flora in nutrient digestion is the

use of enzymes. In ruminants espe­

cially fibrolytic enzymes (e.g., cellulase,

hemicellulose, xylanase) and amylolytic

enzymes (e.g., α­amylase, gluco­

amylase) have been experimentally

tested.

In general, the effectiveness of enzymes

depends on the type of enzyme and

its dosage, on pH, temperature and

incubation time, but also on the form

(liquid / powder) and the way of appli­

cation (mixed in the concentrate of the

ration or on top).

In a study of Bedford and Partridge

(2011), amylases showed a significant

lowering effect on the milk fat content

(­0.8 g / l), though this significance could

not be demonstrated in milk production

(+0.4 l). However it appears that the

effects of amylases largely depend on

16 17effect of feed additives Dossier

their natural origin:

Amylase obtained from Aspergillus

oryzae increased feed intake [+0.9 kg

dry matter intake (DMI)/d] and milk

production (+0.8 kg / d) but led to a

lower fat content (­1.5 g / l). Amylase

originated from Bacillus licheniformis

even reduced feed intake (­1.2 kg),

resulting in decreased milk produc­

tion (­0.2 kg /day) and milk fat content

(­0.2 g / l). Overall efficiency (milk/feed)

is however increased in most situ­

ations. The fibrolytic enzymes may

improve the digestibility of neutral

detergent fiber (NDF), acid detergent

fiber (ADF) and protein in the gastro­

intestinal tract. Moreover, they did not

only lead to significantly improved milk

production (+0.9 l / day) and feed effi­

ciency (+0.02 kg milk / kg DMI), but also

benefited ingestion and fat/protein ra­

tio. Like live yeast, enzymes require an

evaluation and authorization process in

order to get a European registration. To

date, only the enzyme obtained from

Aspergillus orizae has been authorized

in Europe.

b) Affecting the metabolism

Feed additives are able to beneficially

affect the hepatic metabolism and

liver function. Like choline, being a

quaternary amine, may support the

removal of fat and cholesterol from the

liver by providing methyl groups. This

important function turns choline into

a crucial tool for the protection of the

liver from steatosis, especially during

the transition period.

Sales et al. (2010) reviewed the effects

of rumen­protected choline with regard

to 12 trials and found out that choline

could linearly increase milk protein

synthesis per day, depending on the

daily dosage (+ 1 g / l hence 55 g of

choline per day). Milk production was

increased by an average of 2 l when

supplementing a dose of 15 g / day.

Generally, the effects of choline depend

on the mode of protection, stage of

lactation and the level of methionine

in the diet.

Effective vitamins

Vitamins like Biotin (also referred to

as vit. B7 or vit. H), primarily known for

its effectiveness in the prevention of

lameness in cows, also plays an im­

portant role in the energy metabolism

of ruminants. It is particularly used by

microbial population to synthesize

propionic acid and to stimulate gluco­

neogenesis.

Therefore, the results (14 trials) of

Lean et al. (2011) showed that biotin

applicated at a level of 20 mg / day

significantly stimulated milk production

(+1.29 l / day or +3.72 %), though neither

significantly affecting milk composition

(fat and protein) nor feed intake. How­

ever, the effect of biotin in ruminants

mainly depends on the amount of

milk production, stage of lactation and

lactation number.

The described additives have been

selected due to their established

effects on milk production or synthesis

of milk protein, respectively compo­

nents. With respect to feed efficiency,

significant effects may be reduced

due to stimulation of feed intake. So

far, only few studies combining several

additives have been made, though

probably would be of interest in regard

to further beneficial effectiveness.

Of course, this list of additives being

used in ruminants is just a selection.

There are a lot of other in­feed sub­

stances, including those that ­ for

instance ­ contribute to an optimized

amino acid supply and discharging fat

effect in the liver, respectively (e.g.,

methionine, L­carnitine).

Dr. Philippe Schmidely

Professor, Animal Science,

AgroParisTech

genetics and feed efficiency

Genetic gain is responsible for ap-

proximately half the observed gains

in performance in most species sub-

jected to artificial selection. Interest

therefore is increasing in the possible

contribution of breeding programs

to improving feed efficiency in rumi-

nants. The contribution of breeding

programs to improved efficiency in

Genetics to improve feed efficiency

two­dimensional plane of expected feed intake based on metabolic live­weight and average daily gain (ADG)

animals eating more than expected

positive RFI (i.e., inefficient)

animals eating less than expected

negative RFI (i.e., efficient)

Feed intake

Metabolic live weight

ADG

poultry breeding is well recognized.

Recent strains of broiler chickens

require only one third of the duration

to reach market weight eating

only one third the quantity of feed

when compared to strains from 1957.

85 - 90 % of this gain was attributed

to genetic selection.

Important breeding goals

Animal feed intake can be relatively

easily reduced by selecting for animals

that yield less output (i.e., milk yield

or meat yield). This however impacts

food security and therefore the interest

in breeding programs is to reduce

feed intake without compromising

18 19Dossiergenetics and feed efficiency

Donagh Berry, BAgrSc, MSc, PhD

Principal Investigator in Quantitative

Genetics, Animal & Bioscience

Research Department, Animal &

Grassland Research and Innovation

Centre, Teagasc, Moorepark, Ireland

performance. Although feed conversion

efficiency is commonly used as a

management tool for assess ing feed

efficiency at an individual animal

level or herd level, it is not without

disadvantages. For mature animals in

particular, feed conversion rate does

not take cognizance of the contribution

of body tissue mobilization. Moreover,

ratio traits, such as feed conversion

ratio, have poor statistical properties

making them unsuitable for inclusion

in breeding programs. Many cite the

inappropriateness of feed conversion

ratio in breeding goals because it

will result in a correlated response

in increased mature cow size. This

argument however is mute because

such correlated responses to selection

can be easily negated against by

including mature cow size in the

breeding goal.

Residual feed intake

Much interest now revolves around

the use of an apparent feed efficien­

cy trait, residual feed intake (RFI), in

breeding goals to improve feed effi­

ciency. Residual feed intake is defined

as the difference between energy in­

take and demand. The figure gives an

example of a two­dimensional plane

predicting the expected feed intake

for each combination of metabolic

live­weight and average daily gain.

Animals above the plane (i.e., dots)

eat more than predicted based on

their performance (i.e., positive RFI)

and are therefore deemed to be in­

efficient. Animals below the plane (i.e.,

triangles) eat less than predicted based

on their performance (i.e., negative

RFI) and are therefore considered to

be efficient relative to the average

population. Residual feed intake is as

equally heritable as growth rate and

milk yield but the genetic variation

present is less than for most other

performance traits. This implies that

genetic gain will be slow. The lower

genetic variation in RFI is because this

trait is independent of performance

traits. On its own however RFI is not

a good measure of animal efficiency

and should not be subjected to single

trait selection. RFI is strongly corre­

lated with energy balance and thus

selection for improved (i.e., negative)

RFI, especially in early lactation, will

result in mature animals in greater

negative energy balance which has

well known consequences for animal

health and fertility.

Tremendous potential

The potential to improve feed effi­

ciency in ruminants through breeding

is immense as evidenced from the pig

and poultry industry. Individual animal

feed intake measurements on a large

population of animals are however

required to implement a successful

breeding program targeting net feed

efficiency.

An example of feed efficiency improvements in France – the CCPA group

The CCPA (Conseils et Compétences en Productions Ani-

males) group in France is a company specialized in animal

nutrition and health, providing innovative products and

services to feed manufacturers and breeding distributors.

One of their aims is to increase the margin of dairy farms by

improving feed efficiency in animals. In 2009 CCPA decid-

ed to measure feed efficiency in dairy cows based on new

criteria and calculated with CREA = ECM [energy corrected

milk (in kg/day)/dry matter intake (DMI in kg/day)], from this

time on.

Increased productivity and margin

In fact, this new formula combining the mentioned criteria, is

a combination representing the productivity (milk production)

and the economy (feed costs). In order to create this new

access, CCPA gathered the feed efficiency of 150 dairy farms

and in 11,000 dairy cows over a 3 year period. Thereby they

collected all main parameters of production (milk yield, fat

content, protein content) as well as the feed intake (DMI/day)

with analyzing the total mixed ration (TMR).

Results showed a feed efficiency varying between 0.9 and

1.8 kg of ECM/kg DMI with an average of about 1.35 kg. In

France, feeding represents 75 % of the production costs. An

improved feed efficiency of +0.2 kg/kg DMI already increases

the margin by 13 € per 1000 l of milk. This means an impro­

vement of milk production of about 15 %, respectively savings

of forages and concentrates of some 15 %, or the possibility

to reduce the number of dairy cows by about 15 %.

As 80 % of the involved farms kept dairy cows showing poten­

tial to improve energy and protein losses, respectively conver­

sion, it was possible to increase feed efficiency by 15 %.

About 10 % of the poorest performing dairy farms even

were losing 10 l of milk per cow per day, which of course

represents an undesired and unnecessary waste whilst

decreasing the farms’ margin. However, there are several

factors, like genetics, health status, housing, water and

feed quality and feeding techniques that have a great im­

pact on feed efficiency.

In regard to feed quality, CCPA particularly checked the

following needs of dairy cows:

• The balance of energy to prevent acidosis: A low fiber

content increases the level of intake and thus, can

provoke acidosis. But also high levels of fast digestible

carbohydrates increase the risk of metabolic disorders

and bad efficiency. Chopping and grinding of roughages

however can save the high level of efficiency of the

neutral detergent fiber (NDF).

• The level of protein and its quality: CCPA analyzed the

effect of the protein concentration of the diet on the

feed efficiency. Whereas the amount of bypass protein

increas es feed efficiency, a balanced and adjusted amino

acid pattern will also contribute to an improvement in

protein efficiency.

• The balance between roughages and concentrate in

rations to control the feed intake: CCPA showed the

possibility of reaching the same milk yield in dairy farms,

despite differences in feed intake of more than 6 kg dry

matter (DM) per day (see graphic). This would suggest

that, in fact feed efficiency largely depends on the feed

intake of cows.

feed quality

Vincent Ballard

Sales Engineer Service Ruminants,

CCPA (Conseils et Compétences

en Productions Animales), France

20 21feed quality

An example of feed efficiency improvements in France – the CCPA group

same milk production, despite a difference of 6 kg DMI between dairy farms

(source: CCPA)

Dossier

Feed intake (kg DMI/day)

Energy corrected milk production (kg/day)

Feed efficiency as criteria in genetic selection

Regarding genetics, the French National Institute for

Agricultural Research (INRA) demonstrated that feed efficiency

was improved in cows with a low body weight, hence raising

the question of how high milk production conforms to low

body weight. However, in future, daily feed intake measures

are required in order to integrate feed efficiency as selection

criteria in genetic selection.

45

40

35

30

25

20

1715 19 21 23 25 27

feeding by­products

Prospective and present developments of feed for dairy cows in Japan

The total number of dairy cows in Japan was 1,467,000 and

forage crop planted acreage was 26.3 hectares (ha) per

household in fiscal year 2011 (Ministry of Agriculture, Fores­

try and Fisheries 2014a). Both milk production and number

of houses for feeding dairy cows was 7.53 million tons and

22,000 households in 2011, respectively (Ministry of Agri­

culture, Forestry and Fisheries 2014b). The total costs for

the production of raw milk tend to increase with the price

of materials such as feed (Ministry of Agriculture, Forestry

and Fisheries 2014b).

3,254 thousand tons of formula feed were produced for

dairy cows in 2011 (Ministry of Agriculture, Forestry and Fish­

eries 2014a). However, the feed self­sufficiency rate was at

26 %. The feed self­sufficiency rate of concentrate diet (12 %)

is lower than the feed self­sufficiency rate (26 %) in 2011 (Mi­

nistry of Agriculture, Forestry and Fisheries 2014a). In order

to improve the low self­sufficiency rate, the development of

high value­added technology of domestic livestock products,

which was based on self­sufficient feed in Japan has been

promoted for 5 years (from 2010 to 2014). The use of feed

rice has been promoted in particular. Planted areas in Japan

of both rice whole crop silage and forage rice was 33,955 ha

and 23,086 ha in 2011, respectively (Ministry of Agriculture,

Forestry and Fisheries 2014a). Additionally, forage crop acre­

age in Japan was 933,000 ha in 2011 (Ministry of Agriculture,

Forestry and Fisheries 2014a).

The use of by­products resulting from the food industry has

been promoted for improving the feed self­sufficiency rate

as an eco­feed in Japan. In 2011 9,580,000 tons of food

by­products were used as feed (Ministry of Agriculture,

Forestry and Fisheries 2014a). In order to ensure a thor­

ough implementation for the prevention of occurrence of

bovine spongiform encephalopathy, "Guidelines for pre­

venting contamination of ruminant animals such as proteins

derived from to ruminant feed" have been established in

Japan. At present, the utilized feed is classified into ‘A’ feed

(to avoid contamination of protein derived from animal as it

is fed to ruminants), and ‘B’ feed (others).

Japanese milk production industry is going for a further

increase in milk production (Ministry of Agriculture, Forestry

and Fisheries 2014b). Feed efficiency is not a keyword in

Japan ­ however the feed development to improve milk

production with lower cost is the most important issue at

this moment. Therefore, the following feed developments

are presented here.

1. Feeding rice to dairy cows

Studies on feeding feed rice to dairy cows and the storage

technology of feed rice have been carried out in Japan. Inoue

et al. (2013) reported that the fermentation quality of the silage

prepared with the brown rice or an unpeeled rice with lactic

acid bacteria was excellent. Nishimura et al. (2014) reported

that the grain rice was a good substitute for corn in fermented

total mixed ration (TMR), when prepared for fermented TMR

using flaked rice grain at 12 % dry matter (see table).

Miyaji et al. (2014) reported that substituting brown rice for

corn decreased urinary N losses and improved N utilization,

but caused adverse effects on milk production when cows

were fed high­grain diets at 40 % of dietary dry matter. On

Ingredients of fermented total mixed ration (% DM)

(source: Nishimura et al., 2014)

High moisture

Low moisture

Low moisture Italian ryegrass silage 25

High moisture Italian ryegrass silage 25

Corn whole crop silage 15 15

Flaked barley 15 15

Beet pulp pellet 9 9

Soybean meal 11 11

Cotton seed 3 3

Flaked corn 10 10

Flaked rice 12 12

Total 100 100

22 23feeding by­products

exerted on the milk production, when

ear­corn silage was fed to dairy cows

instead of flaked corn.

2.2 Feeding of food by-products

Studies on feeding food by­products

have been performed in Japan. Eruden

et al. (2003) reported that the digestibi­

lity of crude protein was low, when fed

fermented TMR prepared with green

tea beverage residues to dairy cows.

This effect was reported to be caused

by the tannin content of the residues

of green tea beverages. Miyazawa et al

(2007) reported there were no differen­

ces in the milk yield, milk protein,

lac tose, soluble non­fat content and

number of somatic cells, but conjugated

linoleic acid ratio was increased when

brewers’ grain was fed to dairy cows.

3. Study of methane suppression

technology

Chung et al. (2011) reported that the

addition of an enzyme additive led to

increased efficiency of corrected milk

yield in a study in Canada. However,

there was no correlation between

meth ane production, volume of cor­

rected milk yield per kg, and addition

of enzyme to silage. Studies on the

amount of methane are also being

conducted in Japan. Cao et al. (2012)

reported that when the fermented

TMR was prepared by mixing raw rice

bran with rice whole crop, the methane

fermentation was suppressed. More­

over, Mitsumori et al. (2014) reported on

an effect on the meth ane fermentation

suppression of dairy cows due to the

addition of cashew nut shell oil. lactone content in milk

(according to Ueda et al., 2014)

1.01

γ­Dodecalactoneγ­Decalactone

Diet with flaked corn

Diet with ear­corn silage

2.87

8.17

5.13

9

8

7

6

5

4

3

2

1

0

Dossier

the other hand, Tagawa et al. (unpub­

lished) reported there was no tenden­

cy to increase oleic acid contents of

milk produced from dairy cows, which

were fed with a flaked and pelleted

type of formula feed (including 38.5 %

brown rice of raw matter). However, a

tendency of increasing vitamin E con­

tent of the milk was observed.

2.1 Feeding self-sufficient roughage

to dairy cattle

From the viewpoint of effective utili­

zation of paddy fields, the develop­

ments of grass cultivation technology

in paddy fields have been carried

out. Yamamoto et al. (2005) reported,

when comparing the milk productivity

between the TMR containing 21.5 %

DM of the rice whole crop silage and

Sudan grass used in Japan, the 4 % fat

corrected milk yield of the former was

inferior, because the grain covered

with husks was excreted in the feces.

Kono et al. (2014) reported that the

nutritional value and rumen degrad­

ability of rice (cultivar “Tachisuzuka”)

whole crop silage was superior than

cultivar “Kusanohoshi”, when fed to

dry cows. And more, Touno et al. (2011)

reported that when low moisture silage

(haylage) prepared from two cultivars

of festulolium and timothy were pre­

pared, it was found that milk yield of

dairy cows fed festulolium (‘Paulita’) was

higher. Villeneuve et al. (2013) report­

ed that the milk taste was affected by

the forage type (pasture, silage, hay)

of timothy when being fed to cows in

Canada. Ueda et al. (2014) reported

that lactones content in the milk was

higher, although the difference was not

Shin-ichi Tagawa PhD

Chief, Manufacturing

Division, Ishinomaki

factory, Shimizuko Shiryo

Co. Ltd., Miyagi, Japan

www.delacon.com

Delacon is the world's most-trusted

provider of top-class phytogenic

solutions for animal nutrition. For

already more than 25 years, we have

pioneered a natural way to keep

animals healthy and performing.

What started as a phytogenic

alternative to antibiotic growth

promoters became a line of reliable

and award-winning products that

have seen consistent results in raising

performance while also providing a

sustainable solution for the future.

Delacon is continuously working to

deliver the full potential of natural

substances in order to make livestock

production more profitable and to

create safe consumer products.

–

Detailed references and further

information upon request.