Although there are numerous reports on the influence of dietary fats on milk yield and milk composition in the dairy cow (see review by Palmquist, 1984) little is known about the value of fat supplements in the diet of lactating ewes, a species which produces milk of a much higher fat content than the dairy cow. We now report the results of three experiments in which lactating ewes received diets supplemented with a lipid source that was protected from hydrolysis in the rumen.

Individually-penned Finnish Landrace x Dorset Horn ewes, each suckling two lambs by Suffolk rams were used in all three experiments. They were given a diet containing (per kg): 500 g hay (milled through a 4 cm screen), 300 g barley, 90 g white fish meal, 5 g dicalcium phosphate, 3 g salt and 2 g of a trace mineral/vitamin supplement. The crude protein and metabolizable energy contents per kg dry matter were 145 g and 10 MJ respectively. The source of the protected lipid was calcium palmitate (Megalac, Volac Ltd) with lipid and calcium contents (g/kg) of 850 and 90 g respectively.

Increasing public interest and more anti-pollution legislation sharpen the need to avoid pollution. Soil, water and air are at risk.

Apart from plant nutrient considerations, secondary effects of water-logging and oxygen depletion of the soil can occur. Slurry tankers can cause damage to the field surface by rutting. Some tankers exert pressures of 70 psi on the soil and then are often used on wet soils. Such malpractices create extra costs to rectify extra problems created.

Glucosinolate levels are thought to be the major factor limiting the use of rapeseed meals in pig diets. The greatest differences In glucoslnolate content between samples of rapeseed appear to be attributable to variety and site of cultivation. A growing pig feeding trial was set up to Investigate varietal and site differences in the nutritive value of different rapeseed meals.

Rapeseed of the double low varieties Tapidor, Cobra, Libravo and Ariana were obtained from each of two sites (High Mowthorpe EHF, North Yorkshire and Bridgets EHF, Hampshire) where agronomic practices at both sites were very similar. These materials were solvent extracted to yield eight rapeseed meals of commercial type.

Recent work in the United States (Reese, Moser, Peo, Lewis, Zimmerman, Kinder and Stroup 1982) and in Australia (King and Williams, 1984) has clearly shown that nutrition during lactation can affect the fertility of young sows. If first-litter sows are restricted in food intake during lactation, so that they lose body weight and backfat, they take longer to return to oestrus after weaning than their counterparts fed ad libitum. To reproduce successfully the sow must have some mechanism(s) of monitoring its nutritional status, preferably before conception takes place. It is difficult to imagine mechanisms capable of monitoring body reserves per se. It is more likely that the sow can monitor changes in its body reserves, for example, by measuring the rate of lipid mobilized from adipose tissue or the rate of protein breakdown from muscles, or both.

Crossbred gilts (Landrace x Large White) were selected at about 45 kg body weight (approx 3 months of age) and allocated to treatment according to litter and live weight. A total of 22 groups each of 24 animals was selected. Within each group gilts were fed (13.0 MJ DE/kg, 160 g/kg CP) either ad libitum (High), 2.0 kg/day (Medium) or 1.8 kg/day (Low) from selection through until mating.

A considerable amount is now known about the endocrine and neuro-endocrine control of parturition. Far less is understood however about the effect of events which may be considered stressful on the parturition process, despite its broad relevance to animal welfare and farm animal production. There is evidence that stress can have highly disruptive effects during parturition. For example, it has been suggested, that in pigs the behaviourally restricting farrowing crates used in commercial farming practice give rise to increased inter-piglet birth intervals and piglet mortality (Vestergaard and Hansen, 1984). Recent work on rodents has suggested that inhibtion of oxytocin secretion mediated by endogenous opioids, might be responsible for prolonged parturition following an acute stress such as a mid-partum change of environment. The aim of the present work was to extend the study of the effects of stress at parturition to a large animal model. We report two studies on the effects on parturition and oxytocin secretion of movement in mid-parturition to a novel environment (environmental disturbance). In Experiment 1 the effect of this disturbance on inter-piglet interval was investigated. In Experiment 2 a fuller investigation was made of the effects of environmental disturbance on a range of measures including inter-birth interval, behaviour of the sow and plasma oxytocin and Cortisol levels. The role of opioids was investigated in both experiments by administration of the opioid antagonist naloxone.

The British government is encouraging livestock diversification and the production of those animal products which are still being imported. Currently most farm animal fibres such as mohair, cashmere and alpaca are imported with the result that there is a potential for developing production in the U.K. South American camelids can all be farmed for their fibre and present few nutritional or managemental problems. The llama is the largest of the four species with the male weighing about 116 kg. It produces coarse fibre of various colours. The alpaca is smaller than the llama, has short ears, a woolly face and a rounded rump. It averages 1 m in height and the male weighs 64 kg. There are two types of alpaca with different characteristics, the Huacaya and the Suri. Yields of 2.00 kg of good quality 18-30 micron fibre are normal. In South America the vicuna and the guanaco exist only in the wild state. Guanacos have shaggy coats of fine texture, usually chestnut borwn.

The use of Automatic Control of Natural Ventilation (ACNV) has been shown to give good temperature control in a range of circumstances [2, 3]. Information on the performance of the system in wide, solid floored, pig finishing houses under extreme climatic conditions is sparse. A study was made of a commercial pig finishing house during the hot summer of 1983. Information collected allows an assessment of the climatic conditions encountered in relation to long term meteorological records.

The indigenous sheep breeds of Greece, which are used mainly for milk production, produce lambs which are killed at weaning to provide carcasses (including the head, pluck, liver, spleen and the omental and mesenteric fat) of 5 to 9 Kg. The production of heavier carcases could be of benefit if they are acceptable to consumers and if they could be economically produced. The purpose of this experiment was to characterise the growth and development of the entire males and females of three Greek breeds under conditions presumed to be non-limiting.

Animals. From each of three breeds, Boutsiko (B), Serres (S) and Karagouniko (K), 20 lambs of each sex were used in a serial slaughter experiment. Four animals of each breed/sex combination were killed at live weights which were 25, 35, 50, 70 and 100% of the estimated mature values. All sheep were weaned at 6 weeks of age and the males were entire.

The efficient production of lean beef suitable for current consumer demand necessitates effective rationing of beef cattle. Feeding standards for beef cattle given by ARC (1980) predict that a reduction in energy intake produces a large reduction in performance with little effect on the energy or fat contents of the gain. However previous studies have shown that diets containing a high proportion of grass silage may sustain lower levels of performance and result in a greater proportion of fat in the gain in both calves and finishing cattle, than when similar quantities of energy and protein are given in the form of high-concentrate diets. The effects of a change in energy intake on performance and carcass composition of beef cattle are therefore likely to depend on whether this change is achieved by restricting the quantity of food given or changing the forage: concentrate ratio of a diet given ad libitum.The present experiment was carried out to examine the effects of forage:concentrate ratio in the diet and ad libitum versus restricted dry matter intake on the performance, carcass composition and efficiency of lean meat production by steers.

The use of drinking water as a vehicle for the medication of early weaned pigs offers an advantage over infeed medication in that water intake postweaning is substantially higher than feed intake. A precondition for effective water medication is the accurate assessment of water intake. At present there is little published information on the water demand of early weaned piglets reared under contemporary conditions of housing and nutrition. The objective of this study was to establish whether the water intake of early weaned piglets could be predicted from easily measured variables such as feed intake and liveweight.

The primary aim of the calf rearer is to ensure a successful transition from non ruminant to ruminant status while achieving rapid growth and an early intake of solid food. Newbold, Blake and Hagges (1991), found that increasing the concentration of ME in either the starter or milk replacer will not promote more rapid growth, but will simply reduce the rate of starter consumption. This present study investigated the extent to which the energy density of a calf starter ration affected starter intake and liveweight gain in calves receiving a fixed allowance of a high energy milk replacer with ad libitum access to solid calf starter rations.

The continued genetic improvement for lean tissue growth rate and efficiency of pig production has allowed the liberal feeding of modern pigs without adverse effects on carcass quality or food conversion efficiency, even at heavy slaughter weights (Cole and Chadd, 1989; Webb, 1989). This genetic improvement has, however, been associated with a reduction in appetite so that the food intake of modern genotypes of pigs cannot be precisely assessed from the prediction equations established for the older and fatter genotype of pigs. The present experiment was designed to measure voluntary feed intake in order to facilitate the establishment of nutrient requirements and feeding strategies for modern pig genotypes.

Pigs are believed to posses a strong motivation to perform exploratory behaviour, which include a range of activities such as walking, orientation towards stimuli and direct investigation. Under free-ranging conditions these activities often occur in connection with foraging (Stolba and Wood-Gush, 1989). In ad libitum fed young growing pigs the provision of straw has been found to stimulate various behaviours involving direct investigation of the straw (e.g. Fraser et al., 1990; McKinnon et at., 1989). As it is assumed that growing pigs under such ad libitum conditions ingest sufficient nutrients, it is often assumed that the straw directed behaviour is unrelated to feeding motivation. However, individual pigs offered single diets may not be able to meet their nutritional requirements (Kyriazakis et al., 1990), and this may have behavioural consequences. For example, the straw directed behaviour observed in growing pigs may be a reflection of unfulfilled nutritional demands and in fact represent appetetive foraging. The aim of the present experiment was to assess the extent to which the exploratory activity of growing pigs is affected by limitations in nutrient intake (specifically the crude protein content of the food).

Although there is some understanding of the effects of immediate levels of nutrition on ovulation rate and embryo wastage, it is not yet possible to predict the reproductive performance of ewes at pasture in the autumn. In many situations sward height declines over the pre- and post-mating period but herbage intake and reproductive performance under these circumstances have not been described. Furthermore, responses in reproductive performance to supplementary feeding at pasture in the autumn have been variable. It may he possible to explain some of this variation in terms of sward height and the substitution rate of herbage by the supplement. This paper reports 2 experiments which were conducted to describe (1) the herbage intake by ewes grazing swards at different heights and when supplements were offered, and (2) the reproductive performance of ewes given supplements as sward height declined.

In general the energy supply is the main factor limiting the output of milk by the dairy cow from most food sources. Under Northern Ireland conditions grass produces a greater energy output per unit area than any of the other major crops grown there. Furthermore Lowe (1970) has estimated the relative production costs per unit of dry matter for cereals and root crops to be twice and eight times respectively those incurred with grass. Therefore it is apparent that both on a basis of energy output per unit area, and per unit cost input, grass must continue to provide the maximum possible proportion of the food supply for the dairy industry within Northern Ireland.

Artificial drying is undoubtedly the most efficient method of grass conservation. The nutrient losses incurred in the drying process are low and, in contrast to other conservation techniques, grass drying is consistently efficient throughout the season and between seasons. However, both capital and running costs of a drying plant are high and inevitably the cost of production of dried grass is also high. Where there is a large proportion of small farms, as is the case in Northern Ireland, it appears to be out of the question for a farm unit to have a grass dryer because of costs. It is more than likely that under these conditions grass drying will be either undertaken on a cooperative or commercial basis, in the latter case the grass so used being a cash crop.

Mating is one of the most critical processes influencing the success of any breeding pig enterprise since the efficiency of this process establishes the potential output of pigs. A study was conducted on 100 recently weaned sows during the mating process to determine potential sources of inefficiency.

The study was conducted in a large commercial herd with Large White (LW) x Landrace (LR) first cross sows. 4 genotypes of boar were in use, these being LW, LR, LW x LR and Duroc. The parity of the 100 sows involved in the study ranged from 1 to 9. Sows were housed in small groups of 5 to 6 following weaning at a mean of 18 days post partum and were taken daily to an oestrus detection area to test for standing oestrus (SO). Boars were housed around this area and SO was detected using the back pressure test Within 5 minutes of SO being confirmed, each sow was paired with a boar in a specialist 2.9 v 2.65 m mating pen. This pen had a 15 cm floor covering of sawdust-based deep litter which provided good foothold and comfort Boar-sow behavioural interactions, general behaviour of the mating partners and sow vocalisations were recorded from the first pairing in the pen to the dismounting of the boar following mating.

Methane production by ruminant animals is an important anthropogenic source of methane to the atmosphere and is considered an important source to more accurately estimate and to control. It has been known for some time that, in ruminants, diet type and composition can influence methane production, yet there is little quantitative information for contemporary diets used in the UK. Attempts to predict methane production from either diet chemical composition or digestibility have not been successful (Moss and Givens, 1990; Johnson et al., 1991). In order to estimate more accurately the amount of methane produced by a ruminant on a given diet, it is essential to establish whether there are interactions of various substrates with forage and to relate this to the rumen environment. Previous work showing interactions has used mainly hay-based diets (Blaxter and Wainman, 1964); as grass silage is now the major forage in the UK, work with this forage was undertaken.

The selection of lactic acid bacteria for use as silage additives is normally based upon their ability to dominate the silage fermentation and not upon benefits in animal performance. The object of this study was to investigate whether two lactic acid bacteria selected for fermentation characteristics would support the same animal performance as an established silage inoculant.

On 5 June 1989, first cut, predominantly perennial ryegrass (Lolium perenne) was ensiled direct with no wilting in plastolene silos of 2 tonne capacity. The herbage was harvested with a precision chop forage harvester and the following additive treatments were applied: None, control (C); Formic acid (Add-F, BP Nutrition, 850g/kg; 3 litres/tonne), (F); inoculant E. (Ecosyl, ICI Pic, 106Lactobacillus plantarum /g): inoculant A, (Pediococcus sp, 10 /g); inoculant B (L. plantarum 106 /g). The silages were fed to 6 wether sheep (Suffolk x Halfbred), initial live-weight, 40.1 kg (s.d. 2.22kg). Because the silages were unstable aerobically and restricted quantities of each silage were available, all sheep were fed the silages in the same (random) order.

The utilization of diets high in fibre (defined here as non-starch polysaccharide - NSP) is dependent on the extent to which the NSP is fermented by the gut microflora, and the subsequent utilization by the animal of the end-products of fermentation - the VFAs. It has frequently been assumed that fermentation of NSP in the pig occurs almost exclusively in the hind-gut. However, a number of studies using pigs fitted with ileal-cannulas have suggested that some fermentation of NSP may occur prior to the hind-gut (e.g. Graham et al., 1985). The aim of this study was to determine the relative roles of the small and large intestine in a) the digestion of feeds containing non-starch polysaccharides, and b) the subsequent utilization of energy by growing pigs. This was achieved by comparing the abilities of intact or ileo-rectomised pigs to digest and grow on cereal-based diets containing 0 or 300 g/kg sugar beet pulp.