Oestrous synchronisation involves synchronisation of ovarian follicular turnover, new wave emergence, and finally induction of ovulation which can be achieved with an injection of either GnRH (Pursley et al. 1997)or oestradiol benzoate (ODB) (Day et al. 2000). A comparative study investigating corpus luteum (CL) and follicular emergence after the administration of either GnRH or ODB at pro-oestrus has not been reported. It was hypothesised that the injection of ODB at pro-oestrus would delay emergence of the first post-ovulatory follicular wave, but that CL development and plasma progesterone concentrations would be similar in cows induced to ovulate with either GnRH or ODB.

The insulin receptor (IR) is one participant in the partitioning of absorbed nutrients to, and between, the insulin-responsive tissues of animals. We previously reported the alternative splicing of a 36 base pair exon 11 segment of the sheep IR gene and found differences in the ratio of the resultant 11 m-RNA and 11+m-RNA isoforms between muscle and fat depots in crossbred, but not purebred, Texel lambs (McGrattan et al., 1998). Because the IR isoforms, when expressed in cultured cell lines, differ in affinity for insulin by two fold or more (McClain, 1991), variations in the ratio of IR isoform expression may have practical significance for the partitioning of nutrients between tissues and thus for differences in lean and fat gain between the purebred and crossbred lambs. Similarly, variation in IR m-RNA isoform ratios amongst the adipose depots in different breeds of dairy cow could have practical significance for differences in the ability of the breeds to store and mobilise energy and thus for differences in lactational performance between dairy breeds. This study is a preliminary investigation of this hypothesis.

Nutrition during the rearing period has significant effects on subsequent milk production and reproductive performance of dairy herd replacements. Carson et al. (2002) reported that heifers reared to calve down at 620 kg, in contrast to 540 kg live weight, produced 11% more milk, lost more weight and body condition score (BCS) post-calving and had a 30 day longer calving interval. This suggests that a higher BCS at calving and/or a greater rate of BCS loss during lactation appear to be correlated with poorer fertility. The objectives of this experiment were to investigate the effect of (1) diet composition during the rearing period and (2) live weight at first calving on body size and condition score changes during the first lactation and to assess linkages with metabolic hormone concentrations.

A previous study using X-ray computed tomography (CT) of Scottish Blackface hill ewes found that carcass fat, internal fat and muscle are depleted during pregnancy and early lactation and deposited during late lactation and the dry period. Relationships were also found between fat and muscle levels and lamb production traits (Lambe et al., 2002a). Changes in tissue levels over multiple production cycles of the hill ewe, and how these changes relate to lamb production are also of interest. The aims of this study were to model changes in carcass fat, internal fat and muscle through three production cycles and to compare patterns of tissue change in ewes producing different numbers of lambs.

Lamb vigour at birth (i.e. time to stand after delivery) is known to be affected by a number of maternal factors, such as parity and litter size (Dwyer, 2002), as well as lamb breed (Dwyer et al., 1996), and is related to subsequent lamb survival (Dwyer et al., 2001). It is likely that these factors act before birth to influence lamb development and may exert their effects through differences in placental development and function. The purpose of this experiment was to examine the effects of ewe parity, litter size and ewe breed on placental components, and relate these to lamb behavioural development at birth.

When cows are offered a choice of foods they are able to select a consistent combination of these foods over long periods of time. Consistent long-term diet choice (DC) is the result of feeding behaviour, which may be regulated in the short-term. The shortest unit of feeding that can be measured is often a visit to a feeder supplying one food type only. These visits are usually clustered into meals, which are the shortest biological unit in which DC can be expressed. Previous work led us to hypothesise that animals may select a consistent diet within meals, thus ensuring nutrient synchronisation in the short-term. Therefore, the aim of this study was to investigate whether long-term average DC was a direct result of cows selecting a consistent diet within meals.

The analysis of short-term feeding behaviour may give insights into how food intake is regulated in farm animals. Food intake is often recorded in terms of feeding events, e.g. visits to feeders, which can be clustered into meals. This enables calculation of the probability of cows starting a meal in relation to time since the last meal, which is thought to give insight into intake regulation. Starting probabilities are often calculated after data have been pooled, e.g. across day and night or across individuals. Recent work suggested that such pooling might have strongly affected previously published conclusions. We therefore constructed simulation models to investigate how such pooling affects interpretation of feeding behaviour and consequently the biological significance attached to results.

Food intake (FI) can be predicted on the basis of variables that describe food quality, the environment and the animal. Live weight (LW), in some form or other, is usually the only variable used to describe the animal. Animal fatness, estimated by condition score (CS), can affect intake at a given LW. A simple model to account for that is FI= a.LW.(1-b.CS) with FI in g/day, LW in kg and CS in units of a scale up to 5. It is evident that food quality will affect parameter a. Here we test the hypothesis that the parameter b in this model is significant but not affected by food quality. To that end, we measured LW, CS and intake of three different foods with ewe lambs that showed a large variation in LW and CS as a result of different nutritional histories.

A significant proportion of the grass silage fed to lactating dairy cows may be of only modest quality due either to delayed harvesting and/or poor ensiling conditions. In such situations, both total feed intake and milk production are likely to be compromised with the consequent need to feed more concentrates. Part of this effect is considered to be due to the development of a solid mass of digesta in the rumen, with loss of the normal layered or biphasic stratification of rumen contents. Under such conditions, rumen motility, rate of forage digestion and hence voluntary feed intake will be compromised. Mertens (1997) stressed that chemical definition of dietary fibre such as neutral- (NDF) or acid-detergent (ADF) fibre content was an inadequate description of the fibre content of a diet as it affects rumen function and animal performance. Consequently he proposed both effective NDF (eNDF; ability of a feed to replace a roughage with no negative effect on milk fat content) and physically effective NDF (peNDF; a measure of the physical properties of fibre as it stimulates chewing activity and development of the biphasic stratification of rumen contents) as additional descriptors of the physical characteristics of dietary fibre but to date these concepts have attracted limited attention in the UK. This study examined the effect of replacing increasing amounts of grass silage (GS) on a dry matter (DM) basis in a silage:concentrate ration with pressed sugar beet pulp (PP) on various processes of digestion in the rumen of lactating dairy cows, specifically in relation to chewing activity and rumen mat density.

A preliminary study at this Institute indicated that inclusion of high quality maize silage in a grass silage-based diet could promote higher forage intakes in beef cattle, but the response to inclusion of maize silage was affected by the quality of grass silage. The objective of this study was to further examine the effects of grass (GS) and maize (MS) silage qualities on intake characteristics, and to evaluate the influence of forage offered on animal performance.

Enhanced economic sustainability may be achievable by upland beef farmers if they could finish weaned suckled calves on-farm using purchased feeds, rather than selling store animals. The objectives of this study were to examine voluntary feed intake, growth rate and carcass slaughter parameters of weaned bulls from an upland suckler herd finished intensively from approximately 9 months of age using a cereal-based ration.

Behavioural responses to pain are highly species specific and reflect varying strategies for survival. As prey animals, horses may fail to show obvious pain responses, instead masking pain to reduce predation through selection as the weakest of a group (Anil et al., 2002). Price et al. (2002) identified disagreement amongst vets regarding pain assessment and management in horses. This was highlighted by recent debate concerning the existence of post-castration pain and the necessity for analgesia in equines (e.g., Capner 2001; Green 2001). While optimal assessment and management of pain is an important equine welfare issue, the behaviours of horses in response to pain are poorly defined (Raekallio et al. 1997) and the relevance of physiological indicators not confirmed. Palpation or human interaction tests, used in other species (e.g. Holton et al 1998), have yet to be validated in horses. This study aimed to identify and quantify potential behavioural indicators of post-castration pain in horses.

Behaviours such as weaving, box-walking and wind-sucking have traditionally been regarded as undesirable behaviours or ‘vices’ by horse owners, which has led to ‘treatment’ regimes that aimed to physically prevent the performance of the behaviour rather than understand the underlying causes for it. In recent years, however, a number of studies have shed light on the epidemiology of these behaviours (e.g. Luescher et al 1998), leading to the development of more welfare compatible treatment options. In this study, a clinical population of horses presented with stereotypical behaviours is examined for relationships between presenting signs and historical and observational findings.

It is generally recommended that female laboratory rabbits are housed socially, although this may not always be possible for experimental reasons. Some newer cage designs allow rabbits in adjacent cages to have visual and minimal tactile contact through a mesh panel. However, it is not known whether rabbits find such limited contact rewarding. It is becoming increasingly common for rabbit cages to be fitted with a platform, which provides a raised area as well as a darkened and often enclosed area underneath, which can act as a bolt-hole. Rabbits may be able to see into adjacent cages from on top of platforms, and it is not known whether they use the platform primarily to rest on or as a means of gaining social contact, or both. The aim of this experiment was to investigate the motivation of rabbits for visual and minimal tactile contact with a conspecific and a raised platform/bolt-hole.

It is often claimed that certain dominance-related problems in dogs can be triggered by the games played by dog and owner. In particular it is thought that allowing a dog to win uncontrolled games such as Tug-of-War will increase the likelihood of it attempting to become dominant over its owner. However questionnaires (Goodloe & Borchelt, 1998) and experimental studies of Labrador and Golden Retrievers (Rooney & Bradshaw, 2002) have found no evidence for these postulated effects. In this paper we further investigate possible links between the types of games played in the domestic environment and both dominance and attachment dimensions of the dog-owner relationship.

In the diagnosis and treatment of behavioural disorders in multi-cat households, it is often assumed that a dominance hierarchy exists between the cats (e.g. Crowell-Davis, 2002). While such hierarchies are probably commonplace among dogs, what evidence there is to support the existence of social hierarchies in groups of domestic cats has mainly been gathered from reproductively entire animals, such as single sex laboratory colonies, and free-ranging aggregations of ferals. For example, Natoli et al. (2001) used receipt of “submissive” (defensive) behaviour to construct a weakly linear hierarchy in a group of 14 farm cats, but this did not correspond to the hierarchy derived from receipt of affiliative behaviour. We have investigated the alternative hypotheses that apparent dominance hierarchies in multi-cat households may actually be based upon territorial behaviour, or some other undetermined social system.

It is now accepted that the microbial communities living within the gastro-intestinal tract (GIT) can influence pig health, especially at stressful times such as weaning. Careful design of the animal diet is considered to be an easy way to influence the microflora positively. In this work, fermentable carbohydrates were selected after an in vitro test (cumulative gas production- Bosch et al., 2002) for both rate and extent of fermentability. The ingredients were chosen both for their end-products and in terms of their fementation kinetics so as to stimulate fermentation along the entire GIT. They were incorporated into a test diet (TEST), and compared with a control diet (CONT) which contained minimal fermentable carbohydrates. Digesta were analyzed both in terms of microbial species (molecular techniques) and their end-products (e.g. lactic acid), to determine whether fermentation had, in fact, been stimulated by the TEST diet.

Variability in the nutritive value of wheat is established particularly with young poultry and pigs. However, underlying causes have yet to be established unequivocally. Numerous reports attempting to relate variability to varieties have not proved convincing due to interactions with environmental factors. Furthermore reliance on name alone is not appropriate in attempting to differentiate between varieties as it would give no indication of genetic relationships. One promising approach, is the use of near-isogenic lines, which differ in only one key characteristic whose nutritional significance can thus be examined. This was the basis for establishing the negative effects of the IBIR rye translocation and hard endosperm texture, together with interactions, with poultry (Short et al., 2000). Crucially it was confirmed that investigating the IBIR translocation should not proceed without knowledge of endosperm texture, a requirement overlooked by Lewis et al. (1999). The current programme sought to examine the IBIR translocation and endosperm texture in terms of performance of piglets from 15kg fed diets based on identical formulations but containing wheats of known background; presence of xylanase was the second variable.

The amount of a bulky food that an animal can eat depends on its capacity for bulk and the bulk content of the food. For pigs between 12 and 40kg the capacity for food bulk was found to be directly proportional to liveweight (Kyriazakis and Emmans, 1995). The way in which the capacity for bulky foods changes with weight above 40 kg is not clear; there is no a priori reason to assume that the scaling rule proposed for young pigs will hold in heavier pigs. The applicability of the work in young pigs for use in more mature pigs needs investigation, to develop predictive equations for the whole relevant weight range. An experiment was designed to determine how the capacity for bulk changed with weight; the objective was to develop a relationship between the capacity for food bulk and liveweight.