bluuebunny/crossref_metadata_2025_split huggingface dataset:
The control of porcine adipose tissue metabolism by gut hormones before weaning
Authors: Oben J. , Morgan L. , Fletcher J. M. , Marks V. 
Published: June 2019

The period of growth from parturition to weaning is a time of rapid fat deposition in many species. In the pig, body fat increases from about 10 g/kg at birth to 150 to 200 g/kg by 21 days of age (Wood and Groves 1965; Whittemore, Aumaitre and Williams, 1978). An adequate reserve of adipose tissue may be crucial to ensure health and survival, for example during the period of low food intake frequently observed after weaning.It is likely that the nutrient composition of milk and the hormonal signals elicited by milk consumption play an important rôle in stimulating fat deposition. We have investigated the effects of milk ingestion on release of the gastrointestinal hormones GIP (gastric inhibitory peptide) and GLP-1 (glucagon-like peptide one). In addition, we have studied the effects of these hormones on fatty acid synthesis in vitro.Explants (0.4 to 0.6 mg) of adipose tissue were obtained from three anatomical sites of an 18-day-old pig fasted for 12 h. The explants were pre-incubated for 90 min and then incubated in the presence of hormones and [14C] acetate (0.2μCi/ml). Triacylglycerols were extracted from the explants and following saponification, fatty acids were separated and radioactivity counted.
3.1 The Nitrogen Supplied by and the Supplementation of Fresh or Grazed Forage
Authors: Thomson D.J. 
Published: June 2019

Forage contributes between 70 and 80% of the metabolizable energy (ME) and in excess of 70% of the protein consumed by ruminant livestock in the U.K. (Baker and Wilkins, 1975). The contribution from forage to the energy and protein consumed is highest for sheep and lowest for dairy cattle. For all classes of stock in the U.K., a major proportion of the nitrogen (N) or crude protein (CP) consumed is obtained from fresh or grazed forage.Research with fresh forage, both nutritional and production work, has been faced with the difficulty of measuring or estimating food intake by the animal while grazing. The measurement of protein supply from fresh or grazed forage is further made difficult as flow measurements throughout the alimentary tract are required. For forage, as with other foods given to ruminants, estimates of the supply of N or protein available to the animal are obtained from measurements of flow from the stomach or into the proximal duodenum and at the terminal ileum. The difference between these two flow rates, the disappearance of N, NAN (non-ammonia N) or AAN (amino acid N), is taken as the apparent absorption or supply of protein from the food. Values may be obtained for individual amino acids or for total amino acid N (TAAN).
Current and future developments in dairy cattle breeding: a research viewpoint
Authors: Hill W. G. , Brotherstone S. , Visscher P. M. 
Published: June 2019

AbstractRates of genetic improvement in dairy cattle breeding programmes have increased substantially in the last decade, not only in Europe where there has been substantial immigration of North American stock. More accurate statistical evaluation procedures, including the use of best linear unbiased prediction (BLUP) with the animal model, have been introduced; higher selection intensities have been achieved, particularly on production traits, through better organized and focused schemes; and developments in multiple ovulation and embryo transfer (MOET) have been both a stimulus and to some extent a cause. Continued rapid improvement can be expected as research and development enables more accurate and timely use to be made of recording data, because there is evidence that heritability values for milk production are rising, perhaps because of better cow management, and as competition among breeders internationally increases. There are a number of consequent challenges to geneticists and breeders. Attention will have to be given to maintaining the fitness of very high producing animals by recording health, fertility, longevity and parlour traits, and using the results of research to give them appropriate weight in selection decisions. Developments in molecular methods and in reproductive technologies present new opportunities, but are unlikely to do more for some time than complement progress from conventional selection on the important production traits.
Procedures of sire selection, sampling and application of new technology
Authors: Meland O. 
Published: June 2019

AbstractThe objective of any well designed progeny test programme is to identify those individuals that have inherited the favourable genes from his parents. Bulls that enter a progeny test programme have been highly selected on a set of selection criteria. The criteria vary among organizations based upon their breeding philosophy and their prediction of the future economic value of various traits. The accuracy of choosing among this highly selected group is quite low. Increasing the accuracy of selection before progeny testing is the greatest potential application of genetic marker technology. Markers associated with traits of importance can greatly enhance traditional selection methods by increasing the prospect of an individual having the desired characteristics. Genetic marker-assisted selection can greatly increase the actual genetic merit of traits of economic importance
Voluntary intake: a limiting factor to production in high-yielding dairy cows?
Authors: Forbes J. M. 
Published: June 2019

AbstractIn principle, food intake by lactating dairy cows might be limited by rate of eating, capacity to produce saliva, rumen or intestinal capacity, rates of digestion and passage of food residues, or by factors such as chemicals and osmolality in the rumen. It is likely that a combination of these is used by the central nervous system to control intake. In practice, the positive relationship between digestibility and intake of forages means that high-quality material must be offered to cows during lactation if a reduced level of concentrate supplementation is envisaged but undue mobilization of body reserves avoided. Better supplementation is possible, both in terms of more frequent, smaller allocations, and of more appropriate concentrate composition with regard to the composition of the basal forage. Intake of maize silage dry matter is usually greater than for grass silage and a mixture of the two, perhaps offered in free or restricted choice, is likely to become more widely practised. Changes in body reserves are difficult to monitor and this has made it difficult to resolve the question of the magnitude of diet/environment interactions, i.e. is the same breeding and selection programme appropriate for those animals which are intended to be pushed to high yields in intensive systems and those intended to be given principally forages in semi-extensive systems?
Protein requirements and responses: a United Kingdom perspective
Authors: Oldham J. D. 
Published: June 2019

AbstractOnly as recently as 1992 was the digestible crude protein approach to the calculation of protein requirements for ruminants abandoned in favour of a scheme in which metabolizable protein (MP) became the nutritional currency (Agricultural and Food Research Council, 1992). Application of this scheme requires reliable methods to characterize foods in a number of ways and whilst there are deficiencies in current methodology for this purpose there is now a sufficient body of information available to sustain use of the scheme. Evaluation of the MP approach shows it to be a considerable advancement on what went before but still with some inadequacies. More attention needs to be given to the impact of food constituents on digestive processes within the rumen. Tests of the relationship between predicted MP supply and dairy cow performance show that rules are needed to predict partition of available MP between alternative routes of use. With such rules it will become more likely that a useful response prediction system can be developed. Ideas are put forward as to how some progress might be made to develop frameworks which will bring together ideas about responses to protein and energy yielding nutrients. Clarification of partition rules will be important in promoting improved feeding strategies for cows of different genetic index for milk production. However, it is felt that, given adequate partition rules, the MP approach applies equally to high genetic index and low index cows as regards calculation of requirements. A concern is expressed, however, that the current UK research environment may not be conducive to the open sharing of information which will be important to make rapid progress towards the development of nutrient response frameworks. A technology transfer system is needed which will enable advances in knowledge to be organized for translation into practice.
Genotype X environment interactions in dairy cattle: a New Zealand perspective
Authors: Holmes C. W. 
Published: June 2019

AbstractIn recent genotype X environment studies between New Zealand and Canada, yields of fat and protein from Holstein Friesian (HF) cows were similar for daughters of sires from both countries, but Canadian daughters produced larger volumes of milk (6500 kg v. 3300 kg) and were taller. There was no interaction between the sire's national strain and the daughter's environment but there was a significant interaction between-individual sires within-strain and the daughter's environment so that the correlations between the sire proofs in the two countries were approximately half of the expected values.In New Zealand, milk production by cows of high or low genetic merit has been found to be affected similarly by differences in stocking rate, level of feeding and body condition at calving, providing no evidence of a large genotype X management interaction, although there is some evidence of an interaction between the effects of breed size and feeding, with smaller breeds being affected less severely by lower feeding level and clear evidence of genotype by milking management interactions. Over the past 40 years the need for pre-milking stimulation in New Zealand cows has been reduced or eliminated by inadvertent selection. Other recent evidence suggests that progress for genetic tolerance to once-daily milking may be possible.It can be concluded that interactions between group-average genotype and nutritional environment are not likely to have important effects on milk solid yields, at least within the HF breed, within the range of conditions normally found in temperate dairy systems, and provided that the environment is imposed from birth. However, there are likely to be significant interactions between the genotype of individual sires and environment and thus appropriate assessment and ranking of sires in each environment is essential.
The development, use and application of the gas production technique at Cornell University, USA
Authors: Pell A. N. , Pitt R. E. , Doane P. H. , Schofield P. 
Published: June 2019

AbstractSystems to measure gas production to study digestion kinetics have been developed at several locations. The system developed at Cornell University and the rationale behind its evolution are described with an emphasis on whether venting after each observation is necessary and on choice of sensors. Different non-linear-models used to fit gas production data are discussed with an emphasis on the dual-pool logistic model. The third section of the paper includes a theoretical discussion on how gas data can be integrated with data on passage to predict ruminal digestibility. The final section addresses the practical applications of these gas data and ways in which they can be used in models like the Cornell net carbohydrate and protein system. Also included are evaluations of ensiled and freeze-dried samples from the same source as an indication of how gas systems can be used to evaluate the soluble fractions of forages.
Can cell-free enzymes replace rumen micro-organisms to model energy and protein suppty?
Authors: Broderick G. A. 
Published: June 2019

AbstractNew ruminant feeding systems being developed in Europe and North America have greatly increased the need for rapid measurement of rate and extent of ruminal digestion of complex carbohydrates and proteins in individual foods. Application of these systems is lagging because of a lack of reliable kinetic digestion data. This has increased interest in using cell-free enzymes to assess ruminal breakdown of carbohydrates and proteins. The simplest kinetic model describing ruminal digestion divides carbohydrates and proteins into three fractions: A (that already digested and/ or that soluble), B (that digestible) and C (that completely indigestible). Fractions A, B and C sum to 1·0; proportion of digestible fraction B that is degraded is given by: [kd/ (kd+ kp], where kpand kdare, respectively, rates of ruminal passage and digestion. Some models divide fraction B into two or three subfractions while others include a digestion lag. Fully successful, cell-free enzyme systems would yield accurate estimates of digestion fractions and rates and, where appropriate, lag time. As a minimum, results with enzymes should be well correlated to in situ extents of digestion. In vivo total tract digestibility of organic matter (OM) and energy was predicted accurately when food samples were pre-treated with acid-pepsin or neutral-detergent solution, followed by treatment with cellulase from Trichoderma viride (T. reesei). Pepsin-cellulase and neutral detergent-cellulase methods have predicted in vivo digestibility more precisely than Tilley and Terry methods in some cases. Two-stage cellulase assays have given good results with many forages and, when including an amylase treatment, with mixed foods; OM digestibility of straws was not well predicted. Many different cell-free proteases have been tested to estimate ruminal protein degradability. Generally, effectiveness of proteases was assessed by correlating proportions of food nitrogen solubilized after specific incubation times with extents of in situ protein degradation. The broad specificity protease fromStreptomyces griseushas been used most extensively for this purpose in incubations at pH 8·0. However, somewhat better correlations have been reported for ficin, bromelain, papain and neutral proteases of fungal and bacterial origin in incubations at pH more similar to the rumen. Prior treatment with amylases improved correlations for concentrate foodstuffs. As yet, cell-free proteases have not accurately predicted rates and extents of protein degradation observed in ruminal in vitro and in situ systems.
Effect of malate on in vitro (RUSITEC) rumen fermentation
Authors: Carro M. D. , Lopez S. , Valdes C. , Ovejero F. J. 
Published: June 2019

In the last few years there has been an increasing concern regarding the use of antibiotics in ruminant feeding and the potential for selection of antibiotic-resistant pathogen micro-organisms. Some authors (Martin and Streeter, 1995; Callaway and Martin, 1996) suggested that organic acids (aspartate, fumarate, malate) potentially provide an alternative to currently used antimicrobial compounds. Several in vitro studies (Martin and Streeter, 1995; Callaway and Martin, 1996) showed that incorporation of DL-malate into fermentations with both Selenomonas ruminantium HD4 and with mixed ruminal micro-organisms resulted in changes in final pH, methane and volatile fatty acids (VFA) that are analogous to ionophore effects. Nisbet and Martin (1993) hypothesized that malate acted as an electron sink for hydrogen. However, the mechanism of action is not well known. Malate is a key intermediate in the succinate-propionate pathway and therefore could stimulate propionate production. The objective of this study was to study the effects of DL-malate and propionate on the in vitro rumen fermentation of a 50:50 foragexoncentrate diet.The study was carried out using the rumen simulation technique (RUSITEC) following the general incubation procedure described by Czerkawski and Breckenridge (1977). The complete unit consisted of eight vessels with an effective volume of 700 ml each. The vessels inocula (solid and liquid) were obtained from three ruminally fistulated ewes given a diet consisting of 700 g alfalfa hay and 300 g concentrate per kg dry matter (DM) (Table 1) and transferred to the RUSITEC system within 30 min of the 1st day of the experiment. The flow through the vessels was maintained by continuous infusion of artificial saliva at a rate of 533 ml/day. Each vessel received daily a nylon bag containing 7 g alfalfa hay, 7 g concentrate and 0·10 g vitaminsminerals mix. From the 1st day of incubation three vessels received daily 5·62 mmol DL-malate (disodium salt; Sigma-Aldrich Quimica, S.A., Spain), three vessels received 5·62 mmol of propionate (monosodium salt; Sigma-Aldrich Quimica, S.A., Spain) and two vessels received no addition (control). DL-malate and propionate were weighed into the nylon bags and carefully mixed with the food.
Effect of microbial isolates on microbial yield estimation in RUSITEC system
Authors: Carro M. D. , Miller E. L. 
Published: June 2019

The estimation of rumen microbial protein synthesis is one of the main points in the nitrogen (N)-rationing systems for ruminants, as microbial protein provides proportionately 0.4 to 0.9 of amino acids entering the small intestine in ruminants receiving conventional diets (Russell et al., 1992). Methods of estimating microbial protein synthesis rely on marker techniques in which a particular microbial constituent is related to the microbial N content. Marker : N values have generally been established in mixed bacteria isolated from the liquid fraction of rumen digesta and it has been assumed that the same relationship holds in the total population leaving the rumen (Merry and McAllan, 1983). However, several studies have demonstrated differences in composition between solid-associated (SAB) and fluid-associated bacteria in vivo (Legay-Carmier and Bauchart, 1989) and in vitro (Molina Alcaide et al, 1996), as well in marker : N values (Pérez et al., 1996). This problem could be more pronounced in the in vitro semi-continuous culture system RUSITEC, in which there are three well defined components (a free liquid phase, a liquid phase associated with the solid phase and a solid phase), each one having associated microbial populations.The objective of this experiment was to investigate the effect of using different bacterial isolates (BI) on the estimation of microbial production of four different diets in RUSITEC (Czerkawski and Breckenridge, 1977), using (15NH4)2 SO4 as microbial marker, and to assess what effects any differences would have on the comparison of microbial protein synthesis between diets.This study was conducted in conjunction with an in vitro experiment described by Carro and Miller (1997). Two 14-day incubation trials were carried out with the rumen simulation technique RUSITEC (Czerkawski and Breckenridge, 1977). The general incubation procedure was the one described by Czerkawski and Breckenridge (1977) and more details about the procedures of this experiment are given elsewhere (Carro and Miller, 1997).
The pig producer's perspective
Authors: Guise J. 
Published: June 2019

AbstractThis paper is designed to demonstrate that practical, applied research, which is popular with the farming community, is an important part of the decision-making process. Three recent or current projects are described in areas where strategic and basic science has made an important contribution to the debate but has not provided solutions. Confinement at farrowing, tail biting and fully slatted finishing systems are all areas of concern to producers and legislators alike and these concerns are not confined to the UK. The results of surveys of industrial practice have suggested that: (a) non-confined systems may perform as well as farrowing crates, (b) tail-docking appears an effective control measure for tail biting but more importantly, the relative influence of different management practices is measurable using the techniques described and could provide solutions to the tail-biting problem, and (c) experimental studies of finishing systems have produced ambivalent results and a new approach may be of value. The recent Scientific Veterinary Committee Report of the European Union is used extensively as the basis for the discussion.
Development of acceptable standards
Authors: Black W. J. M. 
Published: June 2019

AbstractUK welfare standards have evolved and are continuing to develop, as our knowledge increases and with the greater interest of a larger proportion of the general public. The government issues official ‘codes of practice’ on animal welfare, one for each of the major categories of farm livestock, addressed personally to every registered farmer in the country. UK legislation is continually updated, so that those with responsibility for keeping livestock have a basic set of rules which are relatively specific and which are enforced by random inspection, usually by the State Veterinary Service. The Farm Animal Welfare Council (FAWC) is responsible to the Minister and, with an element of independence, is asked to assist with the development of animal welfare standards in the UK FAWC is made up of 23 independent members, with a wide variety of skills, knowledge and experience, who, usually in working groups of about six people (with MAFF advisers and secretariat support), are commissioned to investigate and report on particular areas where farm animal welfare standards require attention or revision. The way in which FAWC operates is described using, as examples, recent reports on sheep and laying hens, to demonstrate how the government makes use of FAWC reports in revising codes of practice and legislation. Reference is also made to the way in which quality assurance schemes are being developed. These add a further dimension to the ‘rules’ which affect UK farm animal welfare standards
Framing legislation: a legislator's viewpoint
Authors: Milne J. C. 
Published: June 2019

AbstractWell balanced and effective legislation is required to protect animals and to address the concerns of organizations with interests in animal welfare. The principal aim of animal welfare legislation is the protection of animals by the prevention of suffering, pain and distress. This can be achieved by identifying animals’ needs and by the prohibition of procedures having a detrimental effect on welfare. Welfare policy and legislation are determined by many factors, including the results from government-funded research, advice from bodies such as the Farm Animal Welfare Council and other interested organizations and pressure groups, and compliance cost assessments. The mechanisms and processes of consultation and drafting legislation, and of the passage of a bill through parliament, are lengthy procedures and take a considerable time to complete. Although animal welfare issues in Scotland will be devolved to the Scottish Parliament, it is not envisaged that there will be a divergence of policy within the UK as a whole. The legislation itself is clearly important but it is also imperative that it is actively and effectively enforced by all the relevant authorities. All aspects of animal welfare legislation are continually reviewed on both a UK and an EU basis.