Validation of a model based on energy metabolism equations given by ARC (1980) using data from experiments carried out in N Ireland and Denmark revealed major discrepancies (McCracken and Unsworth, 1989). While ARC predicted improvements in feed efficiency, and little change in carcase composition, of cattle with increasing plane of nutrition, there was some evidence that this was not the case when diets of constant forage:concentrate ratio were given. Apart from Danish studies (Andersen, 1975; Andersen et al.. 1984) relatively few data sets are available where plane of nutrition was a deliberate variable and carcase composition was determined at a series of weights. An experiment was therefore performed to examine the relationship between feed intake and slaughter weight on growth and feed efficiency of steers during the finishing period.

Protein is broken down by rumen microorganisms via peptides and amino acids to produce ammonia at rates which frequently exceed microbial requirements for N. Much of the ammonia-N formed in this way is eventually excreted as urea. If any of the steps in the degradation sequence could be inhibited, excessive ammonia production would be reduced. More protein, peptides or amino acids would escape fermentation in the rumen, thereby improving the protein nutrition of the host animal.

The breakdown of peptides to amino acids is a central part of the degradation sequence. The main enzymic mechanism by which peptides are hydrolysed in the rumen is a bacterial dipeptidyl aminopeptidase, which cleaves dipeptides from the N-terminus of the peptide chain (Wallace & McKain, 1990). Little carboxypeptidase activity appears to be present. The present experiments were undertaken to find out to what extent blocking the N-terminus of peptides enables them to survive degradation in rumen fluid, and to determine which peptides can be protected in this way.

Year round production of lamb Is constrained by the seasonal breeding of the ewe with a shortage of lambs onto the UK market In the first two quarters of the year leading to enhanced prices in this period. Lambs sold onto this market in the past have received little variable premium due to strong market prices. Transfer of support from variable premiums to headage payments in 1992 should encourage farmers to spread the marketing period of lamb into the period of shortage. New systems of storing lamb have been developed involving a housed store period from September to November on a straw based diet followed by turnout to swedes for finishing. Large liveweight loss on adjustment to the straw based diet has been a constraint In previous trials (Dingwall et al, 1989). Previous work on slimming diets for sheep (Vipond et al, 1989) suggests fishmeal supplementation during the changeover period could reduce weight loss and improve performance.

Little is known about the cobalt requirements of goats, or of ‘normal values’ for related diagnostic parameters. Consequently an experiment was set up, to define their minimum cobalt requirement and to establish critical levels of some diagnostic parameters.

24 wether goats were housed, fed a cobalt deficient diet of urea treated hay and cereal, and randomly allocated into 4 groups. Groups 2-4 received a cobalt supplement as detailed below in addition to the 0.04 mg Co/kg DM supplied by the diet. The goats were weighed weekly and blood sampled fortnightly.

When diets of concentrates and grass silage (70:30) were offered to cows to compare barley (B) and molassed sugar beet feed (SBF) as the major component of the concentrate, calorimelric studies revealed enhanced energy partition towards milk at the expense of tissue repletion on B, during lactation weeks 11-21, whilst heat production was unaffected (Beever et al., 1989). In contrast when Sutton el al. (1988) fed the same diets to early lactation cows SBF increased milk fat and energy yields particularly during weeks 4-10, but less so during weeks 11-14. One possible explanation for this difference in response may relate to the different stages of lactation examined. To investigate this further, energy partition was examined in cows between weeks 6 and 14 of lactation given barley or molassed sugar beet feed based concentrates with approximately equal proportions of grass silage.

Traditionally silage additives have increased silage intake and the performance of beef and dairy cattle through improvements in silage fermentation. In a series of studies undertaken at this Institute with feaef and dairy cattle an inoculant based on a single strain of lactobacillus planterum (Ecosyl) produced leBirable benefits in terms of silage intake and animal performance without any improvement in silage fermentation. Most of these benefits occurred in studies where the untreated silage was well preserved. Uherefore the present studies were designed to evaluate the same inoculant under difficult-to-ensile conditions.

With the trend in agriculture to more extensive systems of production it is likely that less productive grasslands with lower inputs of fertilizer nitrogen will be used. However, there is a need to marry conservation orientated policies with profitable farming. It is therefore necessary to study the nutritional quality of forage from extensive pastures which will be used for animal production. The objectives of this experiment were to measure the digestibility in vivo of silages made from extensive pastures containing grasses, clovers, wildflowers and herbs and to investigate the feeding value of big bale silage from these pastures for feeding dairy heifer replacements for calving at two years of age.

At least 25% of herbage grown in Britain contains Inadequate sodium (Na) for lactating cows (Baxter, 1968). The chances of defelcincy have been increased in recent years as more potassium (K) fertilizer has been applied which reduces herbage Na content. Voluntary DM intake of conserved feeds supplemented with Nacl is increased up to 5.5g Na/kgDM but thereafter declines (Shnelder et al., 1986). There is evidence that ruminants will select a high Na diet even when Na requirements are met (Michell and Moss, 1988). Milk yield responses to increased dietary sodium above ARC (1980) recommended allowances have been observed in some experiments (Mallonee, 1984; Schneider et al., 1988) but not in others (O'Connor et al, 1988). This experiment aimed to examine the effects of Nacl application to perennial ryegrass pasture on herbage and dairy cattle productivity, on the preference for Nacl fertilized pasture and to distinguish these effects from those of direct supplementation in concentrates.

Over recent years, the system of grazing management most commonly adopted by dairy producers has tended to oscillate between various forms of strip-grazing, on the one hand, and set-stocking, on the other. While arguments in favour of strip-grazing mainly revolve around the ease of grassland management, many of those for set-stocking are essentially behavioural -greater space for the cattle and, hence, less competition, aggression, and spoiling of localised areas of pasture. A current development in the southern hemisphere, ‘fast-rotation’ grazing, attempts to combine the merits of both systems. In this, the herd is given a fresh area each day, but a much larger one than in strip grazing, resulting in less close grazing and (given the same overall land allocation) a much quicker rotation over the total grassland.

This project, part of a larger one evaluating other aspects of the system, was designed to determine the effects a fast-rotation system, versus strip-grazing, on grazing, competition and aggression, and on the incidence and distribution of other basic activities.

Recently computerised pig feeding has attracted interest from pig breeding companies, to improve selection. Testing has in the past been carried out on Individually housed pigs, whereas on commercial farms pigs are group housed and correlations between these two environments can be poor. Practically this problem can be solved by group housing pigs with an electronic feeding station. This system allows one pig to feed at a time and records each pigs Identity and the amount of food consumed, making the selection environment similar to conditions found on commercial farms. This paper presents results showing the strong effect of social factors on the feeding behaviour of Individual growing pigs In such a system.

The subjects were 30 male and 30 female Large White X Landrace pigs (Cotswold Pig Development Co. Ltd, Lincoln UK), divided Into six groups of ten, balanced for sex and initially body weight (mean starting and finishing weight 32.1 vs 68.5kg) within a pen but not between pens. Measurements of feeding behaviour (see below) were continuously monitored for an average of 38 days, by one electronic feeding station (Feed Intake Recording Equipment, developed by Hunday Electronics Ltd.) In each pen. The pigs were fed on a standard pelleted grower diet.

Neonatal mortality represents a major loss of production efficiency for herds throughout the world and despite research and development work spanning many years the losses are still not tolerable either in economic terms or in terms of animal welfare. In the United Kingdom where producers are amongst the very best, the Meat and Livestock Commission estimate that pre-weaning mortality nationally is of the order of 12.8% of all piglets born alive (MLC, 1984).

The causes of death are well documented (Spicer et al 1986) but overlying, starvation, chilling and pathological problems are principal components. Central to all of these factors may be the events occurring within the first hours of a piglets life and those animals which are first born which suckle quickly and effectively have a high probability of survival.

Conversely, those piglets which are later born and which are also smaller than the average for the litter may be at a severe disadvantage because of the competitive environment around the udder of the sow after parturition. Modern hybrid sows also vary widely in their ability to produce colostrum (Varley,1984)

In the immediate days after weaning piglets reared under modern intensive conditions are subjected to a variety of stressors which are often, because of the management systems used, Imposed concurrently. The largest stress may stem from the weaning process itself and the sudden removal of the comfort and nurture provided by the sow. It is also possible that the stress of relocation to new accommodation is a principal stressor and piglets must adapt quickly to different environmental conditions to avoid problems of depressed growth or post-weaning enteric disease. The stress of mixing piglets after weaning into new social groups may be one of the most significant influences of all. Intense agonistic interactions occur for at least 48 hrs after mixing as a new dominancy hierarchy is established. The purpose of the present work therefore was to examine at 2 centres, individual and combined effects of weaning, moving and mixing on the performance and behavioural characteristics of weaned piglets.

Most people believe that it is highly probable that many animals are aware of both themselves and their surroundings. It may follow that a group of sows should not be reared as a homogenous mass because they are individuals each with their own distinguishable characteristics, or in other words each has a personality. It may also be the case that sows having different dispositions may be either more or less susceptible to certain environmental and psychological stressors and these in turn could affect reproductive performance. Hemsworth et al (1981) has found previously that on those farms where sows displayed a greater withdrawal response from a human investigator the number of piglets born per sow was significantly reduced. The purpose of the present experiment was to investigate the possibility that relationships may exist between the personality of multiparous sows, endocrine status and ultimately reproductive performances.

The dopamine systems In the brain are strongly involved in motor activity. Pharmacological stimulation of brain dopamine systems with dopamine agonists initially results in increased levels of motor activity that with increasing doses become more stereotyped in form. It has been suggested that in tethered sows, stereotypies develop because chronic environmental stress produces activation of brain dopamine systems (Dantzer, 1986). Furthermore, differences In the sensitivity of brain dopamine systems may form the basis of the large individual variation found in level of stereotypies (Segal and Kuczenski, 1987). Manipulation of the chain forms the major category of stereotypic behaviour during long term tethering. In addition, many pigs develop excessive drinking (Terlouw et al., in press). The present study investigated whether female nulliparous pigs differed in their response to a standard dose of amphetamine and whether this response is correlated to the amount of chain activity and drinking that developed during subsequent long term tethering.

Feed barriers and mangers form an integral part of a cattle housing system. Their role is to prevent the animals’ wasting feed by scattering it or by walking and defecating over it. Feed barriers generally effect a better distribution of feed and should allow individuals adequate and ready access. Often they have a dual role and act as the side of a pen. These functions are often achieved with some regard to several managerial objectives; simplicity of feed distribution, labour economy, the regulation of excessive animal activity, minimal feed wastage and promotion of animal comfort.

Time spent at the feed barrier depends on the feedstuff, the rate of eating by the animal, space allocation, and the accessibility of the feed. Depending on the feed barrier design the animal may need to exert some force to reach the food. Injuries arise in those situations where large forces are exerted against the barrier and/or accommodating postures (ie kneeling or other) are adopted to reach the food. In extreme cases intake may be restricted. Thus, to assure maximum intake and minimise injuries the feed must be within the easy reach of the animal. Two trials with Friesian heifers compared the performance of 4 types of feed barrier.

Feed spillage is a major cause of inefficiency when non-pelleted diets are fed ad libitum especially when large groups of pigs have access to only one feeding space (Patterson and Walker, 1989; Walker, 1990). Competition for access to the feeder may contribute to spillage (Hansen, Hagelso and Madsen, 1982) although Albar and Granier (1989) showed no reduction in feed efficiency with 8 to 12 pigs per feeding place. The objectives of the present study were to investigate the performance and feeding behaviour of pigs fed ad libitum in groups of 20 when given an extra single-space feeder or an additional drinker or ‘toy’.

Six hundred and forty cross-bred pigs from Landrace and Large White origins were used from 37 kg to slaughter at 91 kg live weight. They were penned in groups of 20 with a floor space allowance of 0.66 m2 /pig on fully slatted floors.

In commercial farrowing pens, creep areas for the piglets are often provided only at the front or on one side of the pen. Because of the strong bonding which newborn piglets have to the udder, such arrangements are often inadequate to attract piglets into the creep area where danger from hypothermia increase the suitability for the newborn piglet of farrowing pens with a typical commercial side creep design.

The experiment was carried out in a commercial farrowing house with partially slatted, unbedded pens. These pens were of typical commercial ‘side creep’ design with a wide creep area on one side of the crate, and a narrow unheated area on the other. The wide creep area contained a tray with a bedding of shavings and was heated by a heat lamp. Experimental pens were adapted by placing diagonally the pen division separating the narrow creeps in two adjacent pens. This created a wider area at the front of one pen and at the rear of the adjacent pen (Fig 1). These areas were provided with a bedding of shavings and a heat lamp for the first 48 hours of life.

To satisfy stringent welfare criteria a farrowing pen must meet the sows’ needs for freedom of movement and allow her to exhibit most normal behaviours.

Pens must be designed which provide adequate space for the loose housed farrowing sow but which have additional features to promote high standards of pig care. The sow should not be left to farrow indiscriminately within the pen but must be provided with an enriched environment to satisfy both her needs and those of the piglets. Within the pen the sow requires a suitable nest site and material to manipulate immediately pre-farrowing. These features can only be provided when it becomes known what the sows’ find desirable. In previous work it was shown that sows’ preferred to build their nests and farrow within a cubicle rather than in a corner or against a straight but open wall and that sows exhibit intensive nest building activity in the 14 hours before farrowing. In this trial the objective was to determine the farrowing sows’ response to an arrangement of parallel walls spaced 0.55, 0.95 and 1.35 m apart. The rationale behind the measurements was that they approximated to the body width, height and length of a generalised sow. Information about the sows’ response to such a wall arrangement would be useful if pens with walk-through nests were being designed.

On many farms in Britain, the housing of pregnant sows in groups, principally in electronic sow feeder systems, is becoming an increasingly popular alternative to housing them individually in stalls or tethers. When sows are housed in large groups, particularly in "dynamic groups" where individuals are continually leaving the group to farrow and re-joining it after lactation, aggression between group members may become a problem. Aggression may give rise to social stress and injuries and may also have detrimental effects on production. In order to ensure good welfare and high production in group housing systems, it is essential to gain some fundamental knowledge as to how individual sows are affected by the social environment in which they live. This paper examines how a group of gilts responded to being introduced into an electronic sow feeder system and mixed with unfamiliar animals. Detailed data on behaviour, physiology and reproduction were collected for each individual in the group /in an attempt to examine whether the way in which individuals responded to the social environment had consequences for measures of their welfare and productivity.

It is traditional in the British Isles to house the working boar as an individual and this practice was the sensible policy when breeding pig herds were small and replacement boars were purchased singly. However in large herds today several boars are often purchased simultaneously, creating the possibility for group housing during their working life. Important beneficial effects of social contact of young boars up to puberty in terms of sexual behaviour and socialisation have been demonstrated. D'Arcy (1984) found that boars penned singly relative to those in groups of 8 from 30 to 240 kg liveweight took 11 days longer to first successful mount and ejaculation, had a higher number of incorrect mounts and did much more fighting with oestrus gilts. Thus group housed boars were less aggressive to oestrus gilts, had better mating dexterity and had higher mating scores at an earlier age. In addition there may be benefits in terms of comfort and welfare including leg soundness in boars by group relative to individual housing (Tonn et al, 1985; Hemsworth and Findlay, 1978) because of the increased exercise in a group due to the larger area to move in the physical interactions occurring within the group. However, there are concerns about aggressive and sodomy behaviour of mature boars kept in groups as well as the possiblitiy of increased handling difficulties. These latter aspects were studied in group housed boars in this investigation.