There is increasing interest in the use of higher levels of cereals in dairy cow rations. This reflects both die greater emphasis on milk protein concentration in milk pricing systems and the prospect of reductions in cereal prices as a result of reform of the Common Agricultural Policy. However, excessive processing of cereal grains results in rapid fermentation in the rumen which can lead to depressions in rumen pH and reductions in cellulose digestion and forage intake, particularly at high levels of feeding. Orskov et al (1978) have shown that treatment of whole cereal grain with sodium hydroxide (NaOH) reduced the rate of grain digestion in die rumen and enabled a higher forage intake compared to a similar level of ground cereal grain. However, inclusion of NaOH treated grain in die ration offered to dairy cows has produced varying effects on animal performance. The aim of the current study was to examine the effects of method of grain treatment on die performance of dairy cows offered a grass silage based diet and a range of concentrate intakes.

An increasing proportion of Agricultural Research funding is being directed to biotechnology and to cell and molecular biology. This shift in funding has two effects on animal production research. First it provides a certain amount of novel information and technology with which to improve current production systems. Second, it leaves less of the research budget for whole animal experiments. It behoves us therefore to keep abreast of the achievements and aspirations of the molecular and cellular biologists. The diverse interests and expertise of the BSAP membership in research, development, advisory work and teaching make the Society a unique forum for conducting the open and on-going debate that is needed to ensure that the results of modern biotechnology are examined critically and applied to the animal production industries in an efficient and acceptable manner.

Few people question the basis of their moral viewpoints, yet if science is to be applied ethically it is necessary to subject these viewpoints to rational analysis. The paper provides an overview of prominent ethical theories (deontological and consequentalist) and their impact on novel and prospective animal biotechnologies. These theories are applied to the principles of: autonomy, justice, nonmaleficence and beneficence in relation to the interests of animals, the environment and humans.

Deontological approaches include ‘rights’-based theories (often derived intuitively or from scriptural sources) and ‘contractualist’ theories, dependent on an ‘unwritten contract’ between rational beings to ensure fairness. For consequentialists (eg utilitarians), it is the outcome of actions that determines their ethical value. Few people, consciously or unconsciously, consistently employ a single ethical theory, but there is often much concordance between actions based on the different theories. Except for some intuitionists, ethicists emphasise the role of rationality in ethical theory; for even though intuition is an important element, many consider that universalizability of ethical theories entails the establishment of a ‘reflective equilibrium’

One of the principal restraints on the productivity of sheep in Less Favoured Areas of the EC is the small size of the native breeds which can only produce light finished carcases. The experiment reported here forms part of a collaborative study made between centres in Spain, Greece (Zygoyiannis, Stamataris and Katsaounis, 1993) and Great Britain (Friggens, Kyriazakis, Shanks and McClelland, 1993) aimed at assessing and comparing the potential and feed intake capacity of nine lesser known, small-sized European sheep breeds.

With links between saturated fat in the diet and health, consumers are increasingly favouring leaner meats. Increases in carcass lean weight and lean percentage can be achieved within breeds through selection. Yet fat may enhance post-slaughter processing and cooking of red meat and thus reductions in fat depots could detract from eating quality.

In the UK, selection decisions within terminal sire flocks are increasingly being based on a combination of liveweight and ultrasonic measures of fat and muscle depth. The underlying goal in these programmes is to increase the daily rate of lean tissue growth. In most pedigree flocks in terminal sire breeds ram lambs are reared on a high plane of nutrition. Yet most lambs in the UK are reared in extensive production systems. Thus it is important to know whether differences in performance of rams reared under feeding practices typical in pedigree flocks translate into detectable differences among their crossbred progeny in carcass composition and eating quality characteristics under grass finishing. In this study, the objective was to evaluate whether consumers could detect differences in the appearance and eating quality in shoulder joints from extensively reared crossbred lambs sired by Suffolk rams, with high or low lean growth index scores.

• 1. There are many ultrasonic machines using a range of techniques varying in sophistication to measure fat and muscle depths for predicting carcass composition. An evaluation of four techniques was conducted by the Meat and Livestock Commission (MLC) to enable potential users to select the most appropriate technique based on accuracy, practicality and cost.

• 2. A total of 150 commercial sheep comprising approximately equal numbers of castrates and ewes were evaluated in five batches of about equal size in lairage at one of two abattoirs. Live weight was recorded together with fat and muscle measurements from the Aloka, Dynamic Imaging, Dumatic and Velocity of Sound (VOS) ultrasonic techniques.

• 3. The Aloka is a B-Mode real-time medical scanner which is currently used on cattle in Australia. The Dynamic Imaging is also a B-Mode real-time medical scanner which is currently used in MLC's Sheepbreeder Service.

• 1. Increased leanness is an economic objective of nearly all breed improvement programmes. Predictions of lean concentration can be used in an index of performance or can be used to select animals for slaughter.

• 2. Predictions of carcass composition from ultrasonic measurements of fat and muscle depths are currently used to aid the selection of animals for breeding and slaughter. Recent developments allow muscle area to be measured using B-Mode pulse echo real-time ultrasonic scanning machines. These machines produce a two-dimensional image of a cross section through the animal, from which measurements may be taken.

• 3. There is a need to estimate for the live animal the benefits of including eye muscle area in the prediction of carcass composition but few data are available to estimate this directly. Therefore the potential benefit of including such measurements in the prediction of carcass composition has been evaluated using measurements taken on the cut surface of carcasses

In ruminants, pregastric ruminal digestion of a diet consisting exclusively of plant biomass is effected by a mixed but relatively stable population of anaerobic microorganisms comprising bacteria, fungi and protozoa. Together these organisms produce the enzymes necessary to hydrolyse each component of the plant cell, including the cell wall polysaccharides, cellulose and hemicellulose, which account for more than 50% of plant biomass, and are among the least degradable fractions of the ruminant diet. Although research has probably not yet revealed the full extent of the biochemical and genetic diversity of the rumen microbial ecosystem, it is nevertheless already apparent that microorganisms which inhabit the rumen are not only essential for normal digestion, but they are also a rich potential source of enzymes with applications in the field of biotechnology. This paper will explore two principal routes for exploiting the biodiversity within the rumen microflora, both of which are made possible by the application of recombinant DNA techniques. The first concerns the use of rumen enzymes in processes which are relevant not only to agriculture, but also to the pulp and paper, textile and food industries. The second involves the modification or selective amplification of existing biochemical events in the rumen as a means of enhancing digestive efficiency.

Many bacterial species are closely associated with epithelial surfaces of the gastrointestinal tract. The physicochemical interactions between bacteria and the intestinal surface are complex and include both stereospecific and chemotactic effects. Such mechanisms of interaction and attachment of bacteria to the gut have received considerable attention over the last decade as they have been recognised as an important initial event in colonisation and the pathogenesis of enteric infections. Many disease-causing bacteria possess surface fimbriae or fibrillae with lectin-like adhesins which interact with peptides or carbohydrates present on surface glycosphingolipids and/or glycoproteins. Research on the structural features of fimbrial receptors and on their expression on the surfaces of the mammalian intestine has led to new ideas for nutritional therapy and/or prophylaxis based on the prevention of adherence of pathogenic bacteria.

The major portal of entry for most pathogenic microorganisms is the mucosal surface. It seems reasonable therefore that the host in its turn should possess substantial immune defences at the mucosae to provide protection against these insults. Enteric infections usually result in at least some degree of specific protection against a subsequent infection with the same organism. However artificial induction of mucosal immunity has proved difficult. Clearly, as yet, we do not have a full understanding of the inductive events involved in the generation of mucosal immune responses or the immune mechanisms operating at mucosal surfaces. In this paper I will attempt to briefly review the main aspects of mucosal immunity concentrating on the gut as the model mucosal surface.

An optimum way of selecting animals is through a prediction of their genetic merit (estimated breeding value, EBV), which can be achieved using a best linear unbiased predictor (BLUP) (Henderson, 1975). Selection decisions in a commercial environment, however, are rarely made solely on genetic merit but also on additional factors, an important example of which is to limit the accumulation of inbreeding. Comparison of rates of inbreeding under BLUP for a range of hentabilities highlights a trend of increasing inbreeding with decreasing heritability. It is therefore proposed that selection using a heritability which is artificially raised would yield lower rates of inbreeding than would otherwise be the case.

Open nucleus systems (ONS) have been used in sheep breeding for a number of years, usually in group breeding schemes. In the simplest form the population is divided into two tiers, the nucleus flock composed of elite individuals, while the base, which forms the majority of the population, is usually sub-divided into a number of individual flocks. Animals born in the nucleus may be selected as replacements in the base, while superior animals born in the base may become part of the breeding population of the nucleus. The optimum structure and genetic benefits of using an ONS under Australasian conditions have been extensively studied using deterministic predictions (James, 1977; Mueller and James, 1983). However, subsequent advances in genetic evaluation (e.g. the application of Best Linear Unbiased Prediction (BLUP)) and the smaller flock sizes typical in Europe, are likely to impact on the outcome and optimum structure of such systems.

The SRY gene controls the presence of testes (i.e. maleness) in mammals. This has been demonstrated by Koopman et al (1991), who bred transgenic XX mice with a copy of the SRY gene on an autosome which were phenotypically male, albeit infertile. A fertile XY male with a copy of the SRY gene on an autosome should, theoretically, produce a greater proportion of offspring which are phenotypically male. This would be advantageous in, for example, breeding Terminal beef sires, where male calves are more valuable than females calves on commercial farms. The possible use of beef cattle transgenic for the SRY gene was investigated by Bishop and Woolliams (1991) who found that there were small genetic advantages in breeding schemes using these bulls, compared to traditional breeding schemes, although there may be practical problems in running such schemes. Their findings pertained to a restricted mating strategy (the "quota" system) and a restricted time horizon (15 years), however. This paper investigates the possible application of the SRY gene considering different mating strategies and a flexible time horizon.

Fat reserves are often perceived as essential to the hill ewe, so that they may be mobilised in adverse conditions to meet energy deficits. However, deer and some primitive breeds of sheep are remarkably lean animals which survive and thrive/reproduce in such conditions. The consequence of using genetically lean sheep in hill environments to meet the ultimate goal of reducing carcass fat is largely unknown. It is possible that the ewes' maternal ability, performance and welfare are in some way compromised. An SAC/IAPGR Hill Sheep Project was instigated: (1) to investigate if selection for differing fat levels under intensive concentrate feeding has any effect on progeny reared in extensive situations; (2) to determine the relationships between growth, carcass, reproduction, wool and survival traits, and to investigate which traits would be useful in an index of overall merit; and (3) to investigate if selection for improved carcass and growth characteristics affect maternal performance and survivability.

The agricultural industry in the UK is under increasing pressure to diversify its forms of production. One of the potentially most viable options suited to hill and upland farms is the production of cashmere, the fine undercoat produced by down bearing goats. Currently no breed of cashmere goat exists in the U.K. which meets market requirements, however, i.e. large quantities of fine, white cashmere. This paper presents results from a crossbreeding trial with Scottish Feral goats and several exotic lines of cashmere goats, the first step in improving production, and it considers future selection plans for improving cashmere production traits.

Cashmere fibre production was evaluated on Scottish Feral goats (F) and on goats imported from Iceland (I), Tasmania (T), New Zealand (N) and Siberia (S), and on two and three way crosses between the F and exotic lines. These goats are owned by a group of commercial farmers, along with the Macaulay Land Use Research Institute, forming a group known as Cashmere Breeders Limited.

Work at The Hannah Research Institute has demonstrated the effects of an inhibitory (autocrine) protein, within the whey fraction of milk, on the efficiency of milk secretion and responses to changes in milking frequency. The regulatory mechanism involves both the concentration of the inhibitor and the site of milk storage (relative to its site of action, the secretory tissue). Milk storage characteristics influence responses to a number of management practices, most notably changes in milking frequency (Dewhurst and Knight, 1992; Knight and Dewhurst, 1992). There is, therefore, a need to understand phenotypic sources of variation in the sites of milk storage in order to define standard conditions and procedures for making cistern measurements.

Recent experiments have shown consistent improvements in grass silage intake and milk yield by cows in response to increasing concentrations of crude protein (CP) in the concentrates. Such results have led to recommendations that a strategy for winter feeding of dairy cows should be based on relatively small amounts of high-protein concentrates with grass silage ad libitum. There is, however, little information about the possible effects of such a strategy on milk nitrogen fractions. The purpose of this experiment was to examine the effects of two approaches to increasing the CP concentration of the concentrates on milk yield and composition, particularly nitrogen fractions.

From calving, 44 muciparous Holstein-Friesian cows were given 3 weeks on a standard diet and then were allocated to one of five concentrate treatments with grass silage ad libitum from weeks 4 to 18 of lactation. Concentrates were formulated to contain 200, 300, 400 or 600g CP/kg DM (Table 1). The silage contained 312g DM/kg and, per kg DM, 483g neutral detergent fibre, 286g acid detergent fibre, 168g CP, 16lg lactic acid, 14g acetic acid and l.lg butyric acid. Ammonia-N was 69g/kg total N and pH was 3.9.

Recent studies have shown increased silage intake and improved milk fat concentration in dairy cows offered restricted compared to extensively fermented silages (Chamberlain et al., 1990; Mayne 1992). Changes in milk composition may be related to increased intake per se and/or alterations in rumen fermentation parameters. A study was therefore undertaken to examine the effects of silage fermentation type, dry matter intake and the addition of water soluble carbohydrate (WSC) or lactic acid on rumen fermentation parameters in dairy cows.

Two direct cut grass silages were prepared using either an inoculant (Ecosyl, 3 1/t, ICI. pic) or Maxgrass (BP Chemicals, 6 1/t). Five silage only treatments were offered to four ruminally fistulated dairy cows in a five period, partially balanced, changeover design experiment. Each period was of 4 weeks duration. Treatment 1: Inoculant treated silage (I), 2: Maxgrass silage (M), 3: Maxgrass ad-libitum (MAL), 4: Inoculant + sucrose (500 g/day) (IS), 5: Maxgrass + lactic acid (200 ml/day) (ML).

Recent work by Chiy and Phillips (1991, 1992) has shown that the application of sodium (Na) fertiliser can produce improvements in pasture growth, pasture composition and the performance of grazing dairy cattle. However other studies have shown much smaller or zero effects in terms of pasture production following Na application (Smith et al., 1983; O'Connor et al., 1989). The objective of the present series of studies was to examine the milk production response to Na fertilisation of pasture under a differing set of soil and climatic conditions and to establish if there was an optimum level of Na input. In addition it was important to pursue the mechanisms of any animal production responses recorded. A series of studies were therefore undertaken to examine: (a) the influence of Na fertilisation of pasture on dairy cattle performance in comparison with any effects obtained through dietary Na supplementation, and (b) the effects of Na on herbage production, composition and digestibility.

A mixed perennial ryegrass and white clover sward must be grazed to a short height to encourage clover growth. If high milk output is expected a supplement must be offered. A straw and concentrate mix (strawmix) utilizes surplus straw and enables nutrient intake to be controlled. Forage supplements also reduce the risk of bloat. In this experiment strawmix supplements of varying energy and protein content were compared.

Twenty Friesian dairy cows were allocated to a Latin Square design with five treatments: no supplement N, or pasture supplements of high or low energy (E and e) and high or low protein (P or p) in a factorial design (Table 1). Energy and protein contents were manipulated by changing the concentration of molasses and soyabean meal respectively.