Silage forms the basal diet during the winter months for the vast majority of beef cattle in the British Isles. There is currently a wide range of feedstuffs available as supplements to grass silage for beef cattle, many of these being by-products of the production of food for human consumption. The relative value of alternative feedstuffs as supplements to grass silage is dependent on the nature of the associative effects between each of the feedstuffs and the silage portion of the ration. Two experiments have been carried out to evaluate a range of by-product feedstuffs including maize gluten feed, citrus pulp, dark maize distillers grains and maize germ meal as supplements to grass silage and to compare their feeding values with those of barley and soyabean meal. As feeds such as maize gluten feed and citrus pulp have low tabulated metabolisable energy contents, the effects of adding protected fat to a low energy by-product feed to increase the energy content of the supplement was also examined.

Methionine and lysine have been shown to be the two amino acids most limiting for milk protein synthesis in lactating dairy cows. Many studies have shown positive effects of adding protected forms of methionine to cows on maize silage-based diets supplemented with soyabean meal. The aim of this study was to evaluate the effect on milk production and composition of adding protected methionine and lysine to cows fed a grass silage diet.

24 Autumn-calved cows (2nd lactation or greater) were blocked into groups of 4 based on calving date and milk yield in the immediate pre-experimental week. Cows within each group were subjected to each of the following 4 treatments in a latin square design: (1) 7 kg of by-product concentrate per day (C), (2) C plus 4.8 g digestible methionine per day (3) C plus 4.8 g digestible methionine and 6.2 g digestible lysine per day (4) 7 kg of barley-soya concentrate + 7.7 g digestible methionine per day. Each period lasted 4 weeks and data from weeks 3 and 4 were used to compare treatment effects. The amino acids were supplied in a rumen protected form (SmartamineTM, RPAN Technology) and all figures relate to estimated intestinally digestible amino acids based on the French system of calculating digestible lysine and methionine. The cows received primary growth unwilted grass silage ad libitum (Oven Dry Matter 189 g/kg, in-vitro DMD 714 g/kg DM, Crude protein 160 g/kg DM, pH 3.9).

With the current production targets and pricing structures prevailing within the UK dairy industry, the incentives for the dairy farmer are to maximise milk protein content whilst controlling the yield of milk and milk fat widiin individual farm quotas. Manipulation of milk fat content by nutritional means is relatively easy, but increasing die protein content of milk by similar means is more difficult and certainly less predictable. Increasing the crude protein content of the diet will invariably stimulate the synthesis of milk protein, but tiiese changes are often associated with a parallel increase in milk volume, such mat milk protein content shows little change. In contrast, several studies have shown mat changing the nature and amount of carbohydrate in the diet can substantially improve milk protein content; Krohn et al., (1985), Roberts & Martindale, (1990), Yan & Roberts (1992, 1993) and Phipps et al (1993). At the same time, the increased use of caustic treated wheat (soda grain) on U.K dairy farms has in part been associated with consistent improvements which have been observed in milk protein content. The primary aim of this study was to consider the effect of replacing part or all of the concentrate portion of grass silage fed cows with alternative carbohydrate rich feeds on me yield of milk and milk constituents. The second objective was to compare the use of soda grain with a 50:50 mixture of rolled wheat and sugarbeet feed on dairy cow performance.

In temperate countries, treatment of straw to improve digestibility is a a well established technique (Sundstol and Coxworth, 1984). In developing countries of the tropics, treatment of straw with ammonia generated from hydrolysis of urea (via urease action) has been the method generally promoted (Schiere and Ibrahim, 1989). Treatment of straw with urea has die advantage of being simple to apply on smallholder farms. However, there is evidence (e.g. in Tanzania) that the technology is not being widely adopted because of the increasing cost of urea due to the growing demand for its use as a fertilizer.

It is well known that transportation exposes livestock to stress which impairs welfare and affects productivity. Recent studies in pigs have investigated mortality during transport (Warriss & Brown 1994) and effects of loading density (Lambooy & Engel 1991) on welfare. Recent investigations in sheep have focused on the effects of handling and transport on bruising (Jarvis & Cockram 1994). Little attention has been focused on specific welfare guidelines which take into account the requirements of particular species. In the present study we compared the behavioural and physiological responses of pigs and sheep during road transport with a view to establishing whether guidelines of welfare should be species specific.

When farm animals are transported over long distances there is concern about their welfare. This has resulted in consumer pressure and additional legislation to control the transport of animals. However, information on the behavioural and physiological responses of sheep to transport is required to assess which aspects of transport can cause welfare problems. An optimal space allowance for long distance transport of sheep should ideally provide stability; allow normal posture (during standing and lying), and postural adjustments, without causing an increased risk of injury and psychological ‘stress’. Direct behavioural observations of potentially traumatic events related to vehicle movement and behavioural interactions (riding and trampling) were recorded during transport. Postures, orientation, rumination and eating were recorded to determine whether there was sufficient space to lie down during transport and to assess the relative priorities for resting and eating post-transport. Measurements of ‘stress’ (heart rate and plasma concentrations of Cortisol); injury (plasma activities of creatinine kinase and aspartate aminotransferase, and acceleration sensors), and dehydration (packed cell volume, plasma osmolality, plasma concentrations of total protein, vasopressin and sodium, water intake and live-weight change) were also made.

Reduced growth rates and calcium retention have been reported in poultry fed diets containing more than 20% rice bran (Warren and Farrell, 1990,1991). Rice bran contains significant quantities of phytate (approx 57.7g/kg) which binds to bivalent elements and may contribute to the adverse effects on growth performance in birds fed diets containing rice bran. Enzymatic degradation of phytate in rice bran may reduce the antinutitional effect of phytate and improve the availability of phosphorus and other bivalent elements. A study was conducted to examine the effects of phytase supplementation of rice bran based diets on broiler growth performance and bone mineralisation.

Reducing the protein content of commercial diets in Europe would reduce environmental nitrogen pollution. It has been demonstrated that this could be achieved by employing crystalline amino acid supplementation (e.g. Chavel and Granier, 1994; Fuller et al, 1979a, b). Accurate information on the true ileal digestible amino acid requirements of the modern lean genotype pig is necessary in order to ensure optimal production at low protein intakes. The objective of this study was to identify the optimum ileal digestible methionine:lysine (met:lys) ratio to achieve maximal growth and food conversion efficiency of the lean genotype pig given low protein diets.

Whole rapeseed can be used to provide energy economically in pig finishing diets. There has been concern that the unsaturated nature of the oil can give rise to adverse effects on fat firmness, visual appeal and eating quality of pork. Danish workers, for example, have recommended inclusion at no more than 4% of finishing rations (Madsen et al, 1992). MLC's Blueprint for Pork (MLC, 1992) limits whole rapeseed to between 4 and 5% of the diet due to its restriction on total oil content to 3.5%.

A trial was designed to establish whether any carcase or sensory quality differences result from inclusion of 5 or 10% whole rapeseed in pig diets.

There have been a number of trials with growing pigs where the digestibility of NSP for a few feeds of varying NSP content have been measured (Graham et al 1986, Longland and Low, 1988). However, there have been few systematic studies where the digestibility of many different types of NSP have been compared at different inclusion levels so that the animals response to each type of NSP can be evaluated, and the effects of NSP source and level on energy and nitrogen (N) digestibility can be assessed. Therefore in the current study the digestibility of NSP, energy and N of semi-purified diets each containing one of eight botanically diverse sources of NSP at a range of inclusion levels was measured.

In pigs, dietary fatty acids influence the composition of meat lipids. When diets high in unsaturated fatty acids are fed, meat quality may be adversely affected due to the susceptibility of unsaturated fatty acids to oxidation. Rapeseed oil is rich in C18:ln9, C18:2n6 and C18:3n3 (57.1, 21.4 and 12.5 g/100g fatty acid respectively) and the inclusion of full-fat rapeseed (FFR) in pig diets may be valuable in manipulating pig meat fatty acid profile in order to increase human dietary intake of n3-polyunsaturated fatty acids. However, increasing the levels of FFR in pig diets has been shown to lead to an increase in carcass fat softness and it is likely that the meat lipids may be more prone to oxidative instability than that from pigs fed diets containing more saturated fatty acids. Since the protective role of vitamin E in lipid peroxidation is well established (Asghar et al, 1991; Monahan et al, 1993), a study was conducted to examine the influence of FFR with or without supplemental vitamin E on growth performance, carcass characteristics and meat storage quality in pigs.

Litter size of commercial European sow lines, can be increased by the introduction of genes from the highly prolific, but obese Meishan. At present there is little information on the feed requirements of the “Meishan” during lactation. It is likely that these requirements are different to those of commercial lean white sows, due to differences in fat reserves. In European lean genotypes “thin” sows at parturition have lost significantly less backfat during lactation than sows which are fat at parturition (Yang et al, 1989). There may also be different relationships between nutrition, body composition change and performance in different breeds. It was predicted that the M might need a higher protein to energy ratio, to complement catabolism of their higher levels of body fat reserves.

The once bred gilt system of production has a number of benefits in terms of feed efficiency and welfare, however the system relies on the production of a quality carcass and acceptable reproductive performance. Previous studies have indicated that welfare might be improved if gilts were ad-libitum fed a diet containing 60% Sugar beet pulp (Stewart et al 1993). There was a suggestion however that reproductive physiology may be put at risk using such a diet. The objective of this experiment was to identify differences in reproductive performance using two different energy sources in gestation and to manipulate nutrition during lactation to study the effect on carcass quality.

The mechanisms by which the prolific Chinese Meishan pig achieves its reproductive advantage of greater Utter size at birth, when compared with control breeds, have not yet been identified. Breed differences in feed intake and/or metabolism might contribute to the enhanced embryo survival observed in the Meishan, however, little is known about the feed or energy requirements of this breed. This study was designed to monitor feed intake and metabolism in Meishan and control (Large White x Landrace) gilts, and to relate these to their reproductive characteristics.

The future abolition of stall and tether systems has meant that, increasingly, producers are opting for group housing systems. Generally sows are fed a restricted concentrate ration during pregnancy at levels which do not induce satiety, leading to increased feeding motivation and competition between penmates for food. Feed competition can lead to compromised production in less dominant individuals. A possible solution would be to feed ad libituma lower energy diet which would restrict voluntary food intake (VFI) so that large undesirable weight gains would not be encountered. Brouns.(1993) found that diets containing 60% unmolassed sugar beet pulp (SBP) were capable of restricting intake to match energy requirements. Recently there has been heightened interest in the use of prolific strains of Chinese pigs such as the Meishan to develop commercial crossbreeds. Chinese breeds are reported to be capable of utilising dietary fibre to a greater extent than European breeds which would make the Meishan a more suitable option for an ad libhigh fibre feed system.

Glucosinolates are a group of plant thioglucosides, found in a range of plant genera, notably the Brassicae. Glucosinolates assume agricultural importance because of their presence in rapeseed meal and forage brassica crops whose nutritional value they may limit. Glucosinolates are hydrolysed under the action of plant or microbial myrosinase to release a range of toxic metabolites (see Duncan, 1991). For example, sinigrin, a commonly found glucosinolate, breaks down to allyl isothiocyanate (AITC) and allyl cyanide as well as a number of lesser components. The course of hydrolysis is influenced by characteristics of the hydrolysis environment such as pH and the presence of metallic ions and enzymic co-factors. Because of the varied nature of the effects of different glucosinolate metabolites, the course of hydrolysis is a key influence on the ultimate toxicity of glucosinolates. Little is known, however, of the identity of metabolites arising in the digestive tract of livestock under different dietary circumstances. This is due, in part, to the technical difficulties associated with measuring concentrations of the compounds in the digestive tract. An alternative approach to the study of glucosinolate hydrolysis in vivo is to measure concentrations of ultimate excretory products and relate this to events earlier in the catabolic pathway. For example, isothiocyanates are excreted as their mercapturic acid derivatives in rats and thus provide potentially useful markers for estimating rates of release of isothiocyanates from sinigrin in vivo (Mennicke et al. 1983). In the experiment reported here, this approach was validated in rats and used to measure rates of release of AITC from sinigrin in animals consuming diets with or without added myrosinase.

Parturition and delivery are stressful situations for the mother as well as the neonate. In newborn human babies and lambs, high plasma β-endorphin (β-EP) concentrations have been found, especially in conjunction with foetal distress. Foetal anoxia during parturition causes decreased blood pH, increased pC02, decreased piglet viability and stillbirth. Since high opioid levels can cause respiratory and circulatory difficulties. Piglets born later in the litter during prolonged parturition are more likely to suffer from these problems. It was, therefore, of interest to us to investigate whether late birth order and anoxia were associated with elevated plasma β-EP concentrations in newborn piglets.

Previous studies of the porcine GH-IGF axis have demonstrated age related changes in liver, but not LD muscle, in expression of both GH-receptor (GHR) and IGF-I genes (Brameld et al, 1993; 1995), and also effects of energy availability on the expression of IGF-I in liver, but not in LD muscle (Weller et al, 1994). The work described here was carried out to study the expression of IGF-I and GHR mRNA in liver and skeletal muscle from different breeds of pig. The probes used were as described previously (Brameld et al, 1993; 1995; Weller et al, 1993; 1994), and were designed to monitor promoter usage for IGF-I expression, with the two promoters giving rise to class 1 and 2 transcripts, and also expression of the extra-cellular domain of the GH-receptor.

There is increasing evidence that foetal growth rate and birthweight have a major influence on subsequent offspring viability. Using reciprocal transfer of day 4 or 5 embryos between Meishan (MS) and Landrace x Large White (LxLW) gilts we have previously demonstrated that, regardless of the breed of the donor gilt, foetuses carried by MS mothers were significantly lighter, shorter and contained within smaller allantoic sacs on Day 30 after oestrus than foetuses carried by LxLW mothers (Ashworth et al., 1990). These results suggested that Meishan mothers may be able to limit foetal growth, although the mechanisms involved were unknown. In the present study, amniotic and allantoic fluids collected from these embryo transfer recipients were analysed to determine levels of insulin-like growth factor-one (IGF-1), which has been shown to be an endocrine regulator of foetal growth (Harding et al., 1994).

Blood cholesterol concentration is associated positively with the incidence of atherosclerosis. Dietary, genetic and environmental factors may play an important role in the development of high serum cholesterol level (Grundy, 1986), specially the quality and quantity of dietary fat. Human and porcine lipoprotein metabolism is very similar, then pig has been established as a suitable animal in which determine relationship between nutrition and atherogenesis (Pond, 1986).

The aim of this study was to determine the effect of an experimental diet supplemented with an 8% of added fat (27.67% saturated, 34.90% monounsaturated and 37.43% of polyunsaturated fatty acids) on lipoprotein composition in four different breeds of pigs.