Animal Production Science Animal Production Science Society
Food, fibre and pharmaceuticals from animals
Animal Production Science

Animal Production Science

Volume 54 Number 9 2014

Harnessing the Ecology and Physiology of Herbivores

This paper reviews influences including nutrition during pregnancy and/or lactation within pasture-based systems on postnatal productivity of beef cattle, within the economic context of maternal productivity and efficiency. Applications of wireless sensor networks including measurement of pasture intake, the input trait that underpins livestock production efficiency, are also discussed.

Researches in animal welfare are carried out in various disciplines (ethology, animal health, sociology...) that rarely exchange with each other. We argue that it is time to reinforce links between disciplines and develop interdisciplinary projects (between scientific disciplines) or even transdisciplinary projects (beyond scientific disciplines and with stakeholders) to address animal welfare in a holistic way and to be able to efficiently improve the welfare of animals.

Temperate dairy systems in southern Australia and New Zealand are underpinned by the efficient use of the home-grown feed-base and purchased supplements. While established principles exist to nutritionally balance such rations, the variable supply of nutrients under grazing often results in suboptimal performance. This review discusses the key factors that affect responses to supplementation in grazing systems, and considers where future research may be directed to improve animal performance from pasture-based systems.

Dietary manipulation is a key approach to reduce methane emissions from ruminant livestock, but its application in grazing systems is poised with challenges. We reviewed findings from research in New Zealand aimed at characterising ‘low methane’ feeds for grazing ruminants. Although some progress is evidenced from animal experiments, on-farm productivity and profitability are yet to be integrated in the meaningful evaluation of mitigation approaches.

When toxins produced by moulds are ingested by ruminants, the adverse impacts may range from sub-clinical effects to overt disease manifestations. This paper covers such effects which are not only witnessed at the farm level but which may also result in public health concerns should such metabolites be transferred into milk.

AN14470Nutritional programming and the reproductive function of the offspring

P. Chavatte-Palmer, C. Dupont, N. Debus and S. Camous
pp. 1166-1176

Various evidence show hat conditions during prenatal development affect the metabolic health of individuals once adults. Data in humans, non-ruminant and ruminant species indicate clearly that reproductive function is also affected by pre-natal developmental conditions, although direct effects on fertility are yet relatively scarce. This is an important parameter to take into consideration in establishing nutritional planes in breeding animals.

AN14479Influencing the future: interactions of skeleton, energy, protein and calcium during late gestation and early lactation

Ian J. Lean, Peter J. DeGaris, Pietro Celi, David M. McNeill, Rachael M. Rodney and David R. Fraser
pp. 1177-1189

The surprising findings in mice of an important role in energy metabolism of osteocalcin raised the question ‘why would a bone-specific hormone (osteocalcin) regulate energy metabolism’. We identify evidence to support a similar role for calcium and bone in energy metabolism of cattle to that found in mice. These relationships, identified in mice and cattle, and probably represent important adaptations of metabolism in mammals to the challenges of lactation.

The paper deals with the reduction in voluntary food intake (anorexia) that accompanies infection with pathogens. Its thesis is that the phenomenon would become more predictable if a causal and a functional approach to anorexia are combined. This is tested in the development of a simulation model that predicts the consequences of a gastrointestinal parasite in grazing sheep.

Increasing interest in dairy goat and milk has fuelled by their contribution to nutrition, food security and improved livelihood of resource-poor small farmers. The opportunities for farmers to scale up, expand and commercialise production is enormous. The establishment of the Asian-Australasian Dairy Goat Network provides stands ready to join member countries to develop strategies for sustainable dairy goat production.

Increased incidence and severity of disease during the transition period decreases the production efficiency of dairy cattle. A major underlying factor responsible for the development of transition cow disorders is metabolic stress, which occurs when cows fail to adapt physiologically to an increase in nutrient requirements needed for parturition and the onset of copious milk synthesis and secretion. The ability to detect signs of metabolic stress early enough in the dry period to implement needed management adjustments prior to calving will be the key to successful monitoring and intervention programs.

AN14152Including essential oils in lactating dairy cow diets: effects on methane emissions

S. J. Meale, A. V. Chaves, T. A. McAllister, A. D. Iwaasa, W. Z. Yang and C. Benchaar
pp. 1215-1218

Methane emissions from ruminant livestock have increased five-fold over the past century, heightening efforts to investigate the mitigation potential of feed additives. This study found no effects of dietary essential oils on methane and carbon dioxide emissions from lactating dairy cows. Identifying dietary additives which can consistently reduce methane emissions without compromising animal performance is a primary focus of most mitigation strategies.

AN14133Target feeding for improved smallholder beef production in the Mekong region: lessons from Cambodia and Lao PDR

R. D. Bush, B. Page, T. Macdonald, J. R. Young, S. Nampanya, S. Suon, S. Khounsy, L. A. Henry, P. C. Thomson and P. A. Windsor
pp. 1219-1223

Increased demand for red meat throughout the Greater Mekong Subregion (GMS) presents smallholder cattle and buffalo farmers with an opportunity to supply better-quality animals to expanding regional markets. Cattle were target-fed introduced forages in Cambodia to gain 0.19 kg/day and over US$60 in value compared with traditional cut-and-carry feeding practices where animals lost 0.04 kg/day. To increase supply for the growing demand for red meat, as well as poverty reduction, an ongoing, multi-disciplinary extension program should be a priority for livestock improvement programs in the GMS.

The complex metabolic interactions that control efficiency of animal production requires the use of systems biology research and mathematical models. An existing metabolic model of metabolism in the dairy cow was expanded to include more detail in describing adipose tissue metabolism and reproductive processes. Changes in adipose tissue metabolism alterthe energy expenditure of the animal, which altered the degradation of steroids and changed the pattern of cyclicity.

AN14335Rice straw, cassava by-products and tree legumes provide enough energy and nitrogen for liveweight maintenance of Brahman (Bos indicus) cows in Indonesia

R. Antari, G. P. Ningrum, D. E. Mayberry, Marsetyo, D. Pamungkas, S. P. Quigley and D. P. Poppi
pp. 1228-1232

Indonesian smallholder farmers require cost-effective and accessible supplements to increase the liveweight and body condition score of Brahman cows fed rice straw-based diets. Cows fed rice straw supplemented with cassava by-products plus urea or a tree legume, were able to gain liveweight and maintain a body condition score of 2.2 on a 1–5 scale. Better supplementation strategies are required for cows to maintain a higher body condition score.

AN14376Effects of restricted time allocation to pasture on feeding behaviour, intake and milk production of dairy sheep rotationally grazing Italian ryegrass (Lolium multiflorum Lam) in spring

G. Molle, M. Decandia, V. Giovanetti, C. Manca, M. Acciaro, G. Epifani, L. Salis, A. Cabiddu, M. Sitzia and A. Cannas
pp. 1233-1237

The effects of restricting time at pasture on intake and performance of dairy ewes are poorly known. To fill this gap, a study was conducted in rotationally grazing milked ewes, finding that time restriction below 6 h/day and depletion of herbage quality at the end of grazing period constrained intake and milk performance. Further studies are needed to evaluate the implications of these results at system level.

AN14227Impact of severity of ruminal acidosis on feed-sorting behaviour of beef cattle

T. J. DeVries, T. Schwaiger, K. A. Beauchemin and G. B. Penner
pp. 1238-1242

Beef feedlot cattle, fed high-grain diets with limited forage content, often experience ruminal acidosis challenges, particularly when transitioning from a forage-based diet. As theorized, it was found that greater experience of ruminal acidosis resulted in a greater change in dietary selection for higher-fibre dietary particles. The results provide further evidence cattle will alter their diet selection behaviour in response to rumen discomfort.

AN14319Sheep of divergent genetic merit for wool growth do not differ in digesta kinetics while on restricted intakes

I. De Barbieri, R. S. Hegarty, V. H. Oddy, M. C. Barnett, L. Li and J. V. Nolan
pp. 1243-1247

We hypothesised that as digesta retention time affects rumen microbial protein outflow, differences in digesta kinetics may contribute to genetic divergence in fleece weight of sheep. However, sheep of divergent genetic merit for wool growth differed in wool growth rate but not digesta retention time. Feeding level affected both wool growth and digesta kinetics consistently, irrespective of animal genetic merit.

Previous modelling has shown that ewes with increased fecundity can increase production and reduce net farm greenhouse gas emissions. This study showed that a prime lamb enterprise incorporating high-fecundity ewes can also increase annual whole-farm profit compared with a baseline system typical of those in south-western Victoria. However, risk, or variability in farm profit, increased. Assuming higher fertility and weaning rates could be achieved consistently, ewes with high-fecundity offer producers the potential to increase profit with decreased emissions.

Holstein-Friesian dairy cows, identified as either efficient or inefficient for feed use during growth have been evaluated during lactation to measure changes in live-weight post-partum. The groups retained their divergence for efficiency during lactation, and post-partum live-weight losses were not affected by selection. Selection for efficiency should not affect tissue mobilisation, or contribute to consequences of excessive weight loss.

AN14101Comparison of goat, sheep, cattle and water buffalo leptin (LEP) genes and effects of the Intron 1 microsatellite polymorphism in goats

Paola Di Gregorio, Adriana Di Trana, Pietro Celi, Salvatore Claps and Andrea Rando
pp. 1258-1262

This study compares the partial genomic sequence of goat, sheep, cattle and water buffalo leptin (LEP) genes and evaluate the effects of the genetic variation at this locus on some metabolic, hormonal, and dairy traits in goats. All the four species showed a microsatellite region in Intron 1. Our data bring further evidence for the role of leptin as an indicator of metabolism and mammary gland health in dairy ruminants.

AN14259Rumen degradation characteristics of ryegrass herbage and ryegrass silage are affected by interactions between stage of maturity and nitrogen fertilisation rate

J. A. H. Heeren, S. C. Podesta, B. Hatew, G. Klop, H. van Laar, A. Bannink, D. Warner, L. H. de Jonge and J. Dijkstra
pp. 1263-1267

In the rumen of dairy cattle, fibre-rich feed such as grass is degraded by microbes, and products of degradation represent the major supply of nutrients to the cow. We evaluated the effect of rate of nitrogen fertilisation and grass maturity stage at harvest on rumen degradation, and found significant interaction effects. The present findings indicate that the effect of nitrogen fertilisation rate on nutrient supply to the cow is not constant but depends on grass maturity stage.

AN14269Can a single rumen sample really diagnose SARA in commercial farms?

E. Trevisi, A. Minuti, S. Cogrossi, P. Grossi, S. Ahmed and P. Bani
pp. 1268-1272

Subacute rumen acidosis (SARA) is a subclinical digestive disorder, which reduces welfare and performance (milk production, milk fat content, fertility) of dairy cows. A single measurement of the ruminal pH has been proposed to diagnose SARA, but our study supports the inconsistency between the ruminal pH 6 h after feeding and several markers of performance (milk yield and composition) and health status (large metabolic profile). Thus, more sensitive and specific rumen or metabolic indices should be investigated to identify herds at risk of SARA.

AN14325Survey of Bali bull fattening practices in central Lombok, eastern Indonesia, based on feeding of Sesbania grandiflora

Dahlanuddin, Baiq T. Yuliana, Tanda Panjaitan, Michael J. Halliday, Elske van de Fliert and H. Max Shelton
pp. 1273-1277

Farmers in central Lombok Indonesia have uniquely integrated cattle fattening with intensive paddy rice production by planting the forage tree legume Sesbania grandiflora along the paddy bunds. This research provides the first detailed analysis of the production parameters of the system including: area of rice paddy and number of sesbania trees planted; harvesting and feeding practices; cattle purchases and sales; and monthly liveweight gain. This work has confirmed the high productivity of the feeding system and has highlighted the opportunity for its wider adoption, both in Indonesia and other regions in South-east Asia.

In Uruguay, spring-born lambs are weaned in summer, when native pastures present low energy and protein content. Some feeding alternatives, such as supplementation and grazing on summer annual crops (soybean and brown midrib sorghum) have been tested. Brown midrib sorghum is selected for its high energy content, and good responses have been obtained when protein supplements are supplied. However, protein supplements are expensive, and it is essential to determine performance response curves of lambs to increasing levels of protein sources.

AN14285Characterising barrier function among regions of the gastrointestinal tract in Holstein steers

G. B. Penner, J. R. Aschenbach, K. Wood, M. E. Walpole, R. Kanafany-Guzman, S. Hendrick and J. Campbell
pp. 1282-1287

Barrier function of the gastrointestinal tract (GIT) is an essential component of the innate immune system and for efficient nutrient transport. The objective of this study was to characterise the regional variation in the barrier function of the GIT in Holstein calves. This study indicates that the translocation of inulin across the omasum and rumen is greatest while the translocation of mannitol and Gt were greatest in the jejunum.

Developing processes which reduce enteric methane production while increasing animal productivity has become critical for sustainable livestock production. Cysteamine hydrochloride, a naturally derived metabolic compound of cysteine, is capable of achieving both goals by reducing methane emissions while increasing wool growth and weigh gain in sheep. Therefore, CSH has the potential to meet the global rise in livestock product demand with a reduced greenhouse gas footprint.

AN14246Tropical cattle methane emissions: the role of natural statins supplementation

C. A. Ramírez-Restrepo, C. J. O'Neill, N. López-Villalobos, J. Padmanabha and C. McSweeney
pp. 1294-1299

This study examined the dose-dependent supplementation effects of fermented-Monascus purpureus red rice (FRR) containing the natural lovastatin monakolin K and other secondary compounds on dry matter intake, rumen fermentation, body growth, animal safety and methane emissions. Although to our knowledge this is the first trial that reports the anti-methanogenic potential of FRR in cattle, it is recognised that tolerance and abatement efficacy are required to be assessed in the long term. Our findings provide a framework to assess potential additive opportunities for improving the environmental performance of livestock and develop further research.

Feeding nitrogen in the form of nitrate, rather than urea, reduces methane emmissions by ruminants. This paper discusses why this particular abatement strategy may be considered attractive to the extensively managed, grazing beef cattle industry. The potential for adverse consequences arising from nitrate supplementation may be elevated in this environment, necessittating further investigation prior to this strategy being considered effective and safe.

The intake of pasture by sheep is influenced by its height. This study showed that the relationship between pasture height and mass differs between pasture types, but is highly variable within pasture types. Prediction of intake and liveweight change by sheep can be improved if appropriate pasture height for mass is used, and the relationships shown in this study may assist with the development of simulation models.

AN14355Metabolisable energy requirements for maintenance and gain of liveweight of Bali cattle (Bos javanicus)

S. P. Quigley, Dahlanuddin, Marsetyo, D. Pamungkas, A. Priyanti, T. Saili, S. R. McLennan and D. P. Poppi
pp. 1311-1316

Indigenous cattle species may possess traits that are beneficial in the face of declining global ruminant feed availability. The energy requirements for maintenance and gain of liveweight of Bali cattle, indigenous to Indonesia, were determined across a range of diets.

Australian Merino bloodlines are known to vary in their wool production and potential for meat production, as such, the process of identifying more profitable bloodlines needs to consider the impact of wool and meat market price changes. This study defines the price risk profiles of Merino bloodlines which are influenced by fibre diameter and clean fleece weight, and to lesser extent bodyweight. By using this process, sheep producers have the capacity to identify more profitable and risk-efficient bloodlines.

AN14224Evaluation of growth hormone response to insulin-induced hypoglycaemia in dairy cattle during a 670-day lactation

L. C. Marett, M. J. Auldist, W. J. Wales, K. L. Macmillan, K. DiGiacomo and B. J. Leury
pp. 1323-1327

Marked variation exists between cows in their ability to maintain extended lactations which is partly regulated by hormones that affect nutrient partitioning. Growth hormone promotes milk production and persistency and was measured following infusion of insulin in dairy cows during an extended lactation, with the greatest response occurring in early-mid lactation. The insulin tolerance test could potentially be used to identify cows with greater growth hormone secretory responses and improved milk production.

AN14346Storage stability of raw chevon chunks packaged in composite, bioactive films at refrigeration temperature

Manish Kumar Chatli, Surabhi Kaura, Mohan Jairath, Nitin Mehta, Pavan Kumar and Jhari Sahoo
pp. 1328-1332

Composite, bioactive packaging films developed from potato starch and chitosan as base material impregnated with antimicrobial substances nisin (60 000 IU/g) and cinnamaldehyde (0.5% v/v) extend the storage life of meat and meat products while keeping the product free from antimicrobial substances. These films inhibit post-processing surface spoilage and provide oxidative stability, leading to improvement in colour, flavour and maintenance of the sensory attributes during storage.

Effects of dietary protein restriction during the peri-conception period and first trimester in yearling heifers on conceptus growth and development were evaluated. Early conceptus development was altered by dietary treatment in a gender-dependant manner. Altered fetal growth could have long-term implications for offspring metabolism and development and warrants further investigation.

Brazil is the world’s largest beef exporter and has the biggest commercial bovine herd. This study aimed at evaluating the development of the Brazilian cattle industry in the different regions and showed that it has migrated to Midwest and North. Fortunately the technology in the agricultural frontier has been adopted at the same rate as the cattle have migrated into it.

AN14199Comparison of enantiomers of organic acids for their effects on methane production in vitro

L. G. Reis, A. V. Chaves, S. R. O. Williams and P. J. Moate
pp. 1345-1349

Organic acids and their enantiomers (L-tartaric acid, D-tartaric acid, DL-tartaric acid, L-malic acid, DL-malic acid, fumaric acid and citric acid) were investigated at four concentrations (0, 5, 10 and 15 mM) using in vitro incubations for their methane mitigation potential as feed additives. None of the organic acids and their enantiomers were identified as potential mitigation agents.

Rapid, short term estimates of methane production are needed to develop feeding management strategies to lower emissions, and to screen and identify low-emitting cattle. This study measured effects of intake and feeding frequency on the daily pattern of methane production in beef heifers fed lucerne silage, and showed a 6-fold variation in methane production rate at low intakes. This variation diminished as intakes increased, suggesting screening is best undertaken in well-fed, productive animals.

Dairy farmers should be more aware of the benefits arising from an improved business approach to their dairy enterprise. Data collected from 30 farms in Peninsular Malaysia highlight the economic benefits from a series of improved on-farm management practices. The ‘bottom line’ is that better feeding and herd management is very profitable.

The medical profession recommends consumers source meat with low levels of saturated fats and lean lamb, trimmed of all salvage fat, can provide this. This is generally applicable to lamb produced across a range of environments despite variation due to diet (grain based diets higher) and breed types. The results show that if consumers eat lean lamb and remove salvage fat, which is now common practice, the meat will have acceptable levels of saturated fat.

AN14326Digestion of forages in the rumen is increased by the amount but not the type of protein supplement

T. Panjaitan, S. P. Quigley, S. R. McLennan, A. J. Swain and D. P. Poppi
pp. 1363-1367

Beef production based on tropical pastures is influenced by the rate of digestion of material in the rumen. The effect of the form and amount of novel nitrogen supplements on the rate of digestion of tropical forages in the rumen was evaluated. The amount but not the form of supplement increased rate of digestion in the rumen which is important when considering supplementation strategies for tropical beef production systems.

AN14165Evaluation of village-based diets for increasing the weight and condition of Ongole (Bos indicus) and Bali (Bos javanicus) cows in Indonesia

R. Antari, T. M. Syahniar, D. E. Mayberry, Marsetyo, D. Pamungkas, S. T. Anderson and D. P. Poppi
pp. 1368-1373

The reproductive performance of cows can be improved through better nutrition. We evaluated the potential of village-based diets to increase the weight and condition of cows in a short period of time, but none of the diets contained enough metabolisable energy or protein for high liveweight gains. Increasing condition of cows quickly is difficult within village-based systems and a more efficient strategy would be to maintain condition of cows during pregnancy and lactation.

We tested the whether duration of low plane of nutrition would affect the composition of milk protein and casein, and whether any effects would persist after re-feeding. A 9 week period of reduced plane of nutrition caused greater changes in protein composition than a 3 week duration. These effects did not persist after re-feeding.

Beef breeding cows in New Zealand are inefficient because of their high maintenance requirements, but their efficiency can be improved by increasing their output of weaned calves. This experiment assessed Angus-cross-dairy cows relative to Angus cows and quantified the heterosis effects; beef-cross-dairy cows weaned heavier calves and showed heterosis advantages for milk intake and weaning weight of calves. The inclusion of beef-cross-dairy cows in beef breeding herds would increase production from those herds.

Understanding how a grazing cows rumen deals with legume pastures is important if we are to better predict intake and digestive processes of these cows. This experiment examined the relationship between the amount of Persian clover pasture offered to grazing cows and how full their rumens were at several times of the day and found increasing the amount of pasture offered, and thus the amount eaten, had no effects on rumen fill. This information will assist with the development of computer models that are capable of simulating the changes in intake and rumen fill over the day of cows in grazing systems.

AN14344Effects of 25-hydroxyvitamin D3 on localisation and extent of gastrointestinal calcium absorption in dairy cattle

V. Oehlschlaeger, M. Wilkens, B. Schroeder, S. Daenicke and G. Breves
pp. 1394-1398

Vitamin D metabolites are important regulators of Ca and P homeostasis. The study aimed at characterising the potential role of 25-OHD3 on gastrointestinal Ca and P absorption and it could be demonstrated that the intestinal absorption of both minerals was stimulated by 25-OHD3. These results provide evidence for new concepts on the biological activity of 25-OHD3.

The present study examined the effects of concentrate level and protein supplementation on performance of crossbred bulls fed a whole-crop barley silage-based diet. The effects of increasing concentrate level on production responses were similar as reported with grass silage-based diets. Protein supplementation had no effects on growth and did not improve carcass traits. Therefore, there is no reason to use protein supplementation for growing/finishing bulls at more than 300-kg liveweight when they are fed with good quality whole-crop barley silage and barley-based concentrate.

AN14232Feeding a partial mixed ration once a day did not increase milk production compared with feeding grain in the dairy and forage in the paddock

M. M. Wright, L. C. Marett, J. S. Greenwood, M. Hannah, J. L. Jacobs, W. J. Wales and M. J. Auldist
pp. 1405-1411

Milk production responses of dairy cows in early lactation grazing perennial ryegrass and offered supplements in different ways were investigated. Feeding supplements as a partial mixed ration (PMR) once a day did not result in any production advantages over the more traditional twice daily bail feeding system under the conditions imposed in this experiment. This information will be important for farmers feeding supplements as a PMR.

Maximising efficiency and meeting carcass market specifications are important goals for today’s beef producers. Selection for increased whole body muscling within a British-bred herd resulted in improved feed efficiency, adequate fatness and higher retail meat yield in steer progeny. Increasing the levels of whole body muscling in poorly muscled herds could help producers achieve improved efficiency and superior carcasses.

AN14207Mitigation of enteric methane for French cattle: potential extent and cost of selected actions

M. Doreau, L. Bamière, S. Pellerin, M. Lherm and M. Benoit
pp. 1417-1422

Each country is committed in the reduction of greenhouse gases emissions through efficient actions. This study focuses on decreasing enteric methane emissions in cattle; two actions were selected (inclusion of unsaturated fats and nitrates in the diet) and the extent of abatement and cost were evaluated at country level. This work shows the possibilities and limits of the implementation of abatement actions.

AN14616Relationship between CH4 and urinary N outputs in ruminants fed forages: a meta-analysis of the literature

D. Sauvant, M. Eugène, S. Giger-Reverdin, H. Archimède and M. Doreau
pp. 1423-1427

It is important to know if there is any relationship between productions of methane and urinary nitrogen in ruminants. A statistical work was performed on a database to elucidate this issue. For diets including only forages, dietary factors such as dry matter intake level and the organic matter digestibility induce a positive relationship between the productions of these two potential pollutants.

AN14220Growth, feed intake and maternal performance of Angus heifers from high and low feed efficiency selection lines

S. T. Morris, F. Y. Chan, N. Lopez-Villalobos, P. R. Kenyon, D. J. Garrick and H. T. Blair
pp. 1428-1431

Residual feed intake (RFI) is a measure of animal-level feed efficiency. The objective was to measure growth, feed intake and maternal performance of Angus heifers sired by bulls selected for low or high estimated breeding values for RFI. This experiment shows that beef cattle selected for low RFI have higher growth rates and heavier live weights than cattle selected for high RFI but similar calf production at first breeding.

AN14339The acute effect of addition of nitrate on in vitro and in vivo methane emission in dairy cows

P. Lund, R. Dahl, H. J. Yang, A. L. F. Hellwing, B. B. Cao and M. R. Weisbjerg
pp. 1432-1435

There is an ongoing quest for identifying a feeding strategy that persistently can reduce enteric methane (CH4) production from ruminants without compromising production. The aim of the present study was to determine the acute effect of feeding nitrate to dairy cows on enteric CH4 production. Enteric CH4 production decreased with 31% as a result of feeding nitrate and subsequently increased with 34% when nitrate was stopped, and it is concluded that nitrate addition is a potent mitigation strategy.

Intramuscular fat in beef is an important factor in its flavour and texture, and hence price. We have used the analysis of the expression of genes in muscle to identify the source of the fat; either synthesised in the muscle fat cells, or taken up from circulation. We have shown that age, diet and breed affect the amount and source of the fat and predict consequential impacts on fat composition.

Muscle score (MS) is highly heritable (56–63%), with an estimated genetic correlation of 99% between weaning and yearling MS. Estimated genetic correlations with eye muscle area are moderate (55%). Estimated breeding values for MS could help make beef production more efficient and profitable, given its favourable relationships with meat yield and feed efficiency without detrimental effects on meat quality or maternal productivity.

AN14337Feeding management in early life influences microbial colonisation and fermentation in the rumen of newborn goat kids

L. Abecia, E. Ramos-Morales, G. Martínez-Fernandez, A. Arco, A. I. Martín-García, C. J. Newbold and D. R. Yáñez-Ruiz
pp. 1449-1454

Events occurring in the early life of an animal have potential implications later in life. This work aimed at describing the temporal sequence of microbial colonisation during the first month of life in goat kids reared in two different feeding systems (natural with the dam and artificial with milk replacer). The results confirmed substantial microbial colonisation from first day of life in the undeveloped rumen and identified the first 14 days as the most sensitive window of time for potential manipulations.

Roughage intake within 3 h of wheaten straw and barley grain being offered was greater when sheep were offered finely chaffed (6 mm) than either coarsely chaffed (15–25 mm) or unprocessed straw. Rumen pH and total volatile fatty acid concentrations 3 h post-feeding did not differ between roughage types. Over 10 days of grain feeding, daily roughage intake was greater in sheep offered fine than coarse chaff, while sheep offered unprocessed roughage had an intermediate intake. Shorter particle lengths for roughage may play a role during grain introduction.

AN14200Whole-tract dry matter and nitrogen digestibility of lactating dairy cows selected for phenotypic divergence in residual feed intake

J. B. Thornhill, L. C. Marett, M. J. Auldist, J. S. Greenwood, J. E. Pryce, B. J. Hayes and W. J. Wales
pp. 1460-1464

It is important for dairy farmers to optimise milk production per kg of feed consumed due to the high cost of feed. We compared the whole-tract digestibility of DM and N in Holstein-Friesian dairy cows selected for divergent RFI and it was identified that digestibility of DM and N did not differ among RFI treatment groups. Therefore, emphasis on selection for phenotypic divergence in RFI may not contribute to improved utilisation of consumed nutrients in Australian Holstein-Friesian dairy cows.

AN14217Pregnancy nutrition does not influence lamb liveweight in developmentally programmed ewes

P. R. Kenyon, R. A. Corner-Thomas, S. W. Peterson, S. J. Pain and H. T. Blair
pp. 1465-1470

Plane of nutrition of the dam in pregnancy in a pastoral-based system can alter the ewe offspring’s mammary gland development and milk production at its first lactation and the liveweight of the grand-offspring. However, this apparent developmental programming effect on grand-offspring liveweight has not persisted. The present study aimed to determine if nutrition of the programmed ewe in pregnancy caused the variation in grand-offspring liveweight. However, the study found no effect of ewe nutrition on this response, under conditions in which ewes were either offered controlled or ad-libitum feeding conditions in mid- to late pregnancy.

Knowledge on nutrient passage through the digestive tract of ruminants is important to predict nutrient supply to the animal. We quantified rumen passage rates of carbon stable isotope (13C)-labelled concentrate dry matter and fibre fractions in beef heifers fed a high-concentrate diet. Our results suggest rumen passage kinetics for these two fractions were similar in beef heifers receiving a high-concentrate diet, and were comparable to those based on the more commonly used external marker chromium-mordanted fibre.

AN14150Seasonal changes in the body surface temperature of Hanwoo (Bos taurus coreanae) steers

N. Y. Kim, S. J. Kim, J. H. Park, M. R. Oh, S. Y. Jang, D. H. Kim, S. H. Sung, B. T. Jeon and S. H. Moon
pp. 1476-1480

Body surface temperature (BST) of cattle using infrared thermography (IRT) well reflects the thermal circumstance surrounding animal. The present study aimed to find out whether BST measurement is a useful method to detect thermal balance of livestock and eye BST was the least variable of all BST measured. The results indicated that BST may be used as an effective tool for precision cattle farming.

AN14282Ultrasonographic measurements of kidney fat thickness and Longissimus muscle area in predicting body composition of pregnant goats

Carla J. Härter, Herymá G. O. Silva, Lisiane D. Lima, Douglas S. Castagnino, Astrid R. Rivera, Oscar Boaventura Neto, Rafael A. Gomes, Júlio C. Canola, Kleber T. Resende and Izabelle A. M. A. Teixeira
pp. 1481-1485

Ultrasonography can be used as a non-invasive tool to estimate body composition during pregnancy. We estimated the body composition and fat depots of pregnant goats by indirect measurements and observed positive correlation with these measurements and fat depots and body fat and energy contents. These results allowed us to develop models that will aid in the monitoring of the nutritional status of pregnant goats.

AN14294Effect of intake of diets containing tannins and saponins on in vitro gas production and sheep performance

M. A. Barros-Rodríguez, F. J. Solorio-Sánchez, C. A. Sandoval-Castro, A. M. M. Ahmed, R. Rojas-Herrera, E. G. Briceño-Poot and J. C. Ku-Vera
pp. 1486-1489

The effect of leucaena, Enterolobium cyclocarpum, fruits and a mixture of both feeds on in vitro gas production and in vivo sheep productive performance was evaluated. Higher intake, digestibility and sheep performance were observed with diets containing grass + leucaena + E. cyclocarpum mixture. The results can be explained by their higher protein, lower cell walls and higher DM digestibility.

AN14198Changes in plasma oxidative stress biomarkers in dairy cows after oestrus synchronisation with controlled internal drug release (CIDR) and prostaglandinF (PGF)

Saranika Talukder, Kendra L. Kerrisk, Luke Ingenhoff, Gianfranco Gabai, Sergio C. Garcia and Pietro Celi
pp. 1490-1496

The aim of this study was to examine the changes in some plasma oxidative stress biomarkers in cows with ovulatory and an-ovulatory response in synchronized oestrus. A significant decrease in BAP and GSH were observed in ovulated cows which might be the consequence of OS caused by the luteolytic action of PGF and the subsequent ovulatory event. This type of study will provide an understanding of the physiological role of OS biomarkers on the ovulatory process.

AN14301Infrared thermal imaging as a method to study thermogenesis in the neonatal lamb

S. A. McCoard, H. V. Henderson, F. W. Knol, S. K. Dowling and J. R. Webster
pp. 1497-1501

The ability of a newborn lamb to maintain core body temperature is a key determinant of survival. This study demonstrated that thermo-imaging technology can be used to measure radiated heat loss in newborn lambs, providing a non-invasive tool for intensive animal measurement in confinement, and potentially under farming conditions. Such approaches are required to evaluate the success of strategies (e.g. feeding and/or management) that aim to improve the survival of lambs in the field.

AN14175Comparative growth performance of Kajli lambs suckling their dams or offered buffalo-milk, cow-milk or milk replacer during pre-weaning period

Musharraf Ahmad Anjum, Shaukat Ali Bhatti, Muhammad Sarwar, Ghulam Muhammad and Muhammad Jamil Basra
pp. 1502-1506

Rearing lambs without their mothers during pre-weaning is not a common practice in Pakistan. Kajli sheep were reared with or without their mothers for evaluating their growth performance and cost comparisons. In the absence of ewe’s milk, Kajli lambs performed better on buffalo-milk than on cow-milk or milk replacer during pre-weaning period.

As small ruminants are often used in basic research as models for the dairy cow, it is the aim of the present paper to give a summary of the similarities and differences between sheep and goats found in recent studies focusing on calcium homeostasis. Our results demonstrate that mineral homeostasis in herbivores is far too complex to be divided simply into ‘hindgut fermenter’ and ‘forestomach’ types.

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