An in vivo procedure to determine nutrient requirements for growing pigs would have substantial cost advantages over serial slaughter and furthermore repeated measurements would allow estimation of protein requirements at each stage of growth. Serum urea concentration (Urea) has been proposed as a candidate indicator of protein requirement as over-supply of protein will increase Urea (Chen et al., 1995). The study estimated genetic variation in Urea at different stages of performance test and the relationships between Urea and performance traits.

Scottish Blackface sheep have a multi-purpose role in the UK to produce breeding females and lambs for meat consumption. Over the last fifty years, wool has accounted for a very low proportion of economical return from hill sheep production in the UK. In recent years, the ratio of the value of lamb meat to wool clip has altered, with wool becoming relatively more important in particular for hill breeds. The consequence of direct selection for improved carcass traits in these breeds on wool quality is unknown. With other sheep breeds such as Merino, selection for improved wool traits has largely been undertaken with little regard to the impact on meat production. The objectives of this study are to quantify wool quality traits and examine genetic relationships between wool quality and carcass traits in Scottish Blackface sheep.

Genomic research and the detection of quantitative trait loci (QTL) provide tools to enhance genetic progress and improve understanding of the biology of commercially important traits. The large sire reference schemes in UK terminal sire sheep breeds provide a unique opportunity to investigate QTL segregation within commercial populations. This study aims to identify QTL for performance traits in commercial Suffolk and Texel sheep.

Sow lactation performance is critical to piglet survival and pre-weaning growth. Effective lactogenesis combined with strong piglet vigour at birth will help prevent hypoglycaemia and mortality. In addition, immune protection of the sucking pig is dependant on the acquisition of immunoglobulins from the colostrum of the sow. High milk output in late lactation will ensure greater weaning weights, since piglet growth potential exceeds milk supply by day 10 of lactation (Harrell et al, 1993). Maximising sow feed intake ensures maximum milk production. A variety of plant extracts are recognised for their health and growth promoting properties which include stimulation of the digestive and immune systems (Platel and Srinvansan, 1996). The objective of this study was to evaluate the ability of various plant extracts to stimulate piglet and sow performance when used as supplements in the diets of lactating sows. Three extracts were selected for their potential benefits to health, appetite and digestion, these being Yucca Shidigera, Quillaja Saponaria and Combination (a blend of the spices capsicum 1.0%, cinnamaldehyde 1.25 % and oregano oil 0.85 %).

Avilamycin (antibiotic growth promoter) and zinc oxide are both included in the diets of newly weaned piglets to enhance growth performance and reduce the incidence of diarrhoea (MLC, 2000). It is thought that both compounds positively influence the bacterial populations residing in the gastrointestinal tract. However, growing concerns regarding antibiotic resistance and environmental pollution are likely to result in the banning of these dietary additives within the EU. This experiment, therefore, aimed to investigate what effect removing both avilamycin and zinc oxide from the post-weaning diet would have on the growth performance of weaned piglets.

Current models that predict food intake over time assume that the animal is always fully adapted to the food that it is on. This approach does not account for the immediate effects of a change in food type upon intake. Such a change may have large effects on intake and performance particularly when the change is to a food of higher bulk content. Such a change initially causes a reduction in intake. Over time, with adaptation, intake gradually increases until a new equilibrium intake is reached. The ability to predict intake and performance during the period of adaptation will allow models to predict food intake on high bulk foods more accurately. Data recorded during the period of adaptation are frequently excluded, perhaps to make the prediction of intake on high bulk foods easier. This work is an attempt to develop a model to predict intake and performance during the adaptation period when an animal is changed to a food of higher bulk content.

The proposed model may be considered as an advance upon previous models; giving a synthesis of the contemporary information base and having a structure with maximum flexibility and minimum usage of fixed coefficients. It is distinctive in that it includes: (1) linkage from dietary nutrients to tissue retention via algorithms for main-stream biochemical processes; (2) a unified driver allowing compatible calculation of (i) the nutrient costs of energy and of protein cycling, (ii) the nutrient costs of maintenance and protein retention, and (iii) the interactions between energy and protein usage; (3) prediction of the rate and composition of tissue retention during growth, and of the cost of thermoregulation; (4) reversal of the role of conventional model parameters such that they become out-turns, rather than inputs, of the model, including (i) the metabolisability of energy, (ii) the ideality of protein and the efficiency of use of ileal digested ideal protein, (iii) the efficiency of utilisation of energy (k) for maintenance (kM), for protein (kPr) and lipid (kLr) retention, which are accepted as variables derived from calculation of efficiencies of production of ATP.

We need to improve our understanding of the factors that are important for the control of food intake on high bulk foods. The study of short term feeding behaviour (STFB) may help to do this. The objective of this experiment was to study the effects of giving foods differing in bulk content on the STFB of growing pigs. It was expected that the foods would result in different levels of daily intake and that this would be reflected as differences in STFB between the foods. Two hypotheses were developed based on ideas about the way in which a physical constraint to intake could arise. H1; there would be less diurnal variation in feeding on high bulk foods that limit intake. H2; feeding patterns on bulky foods would be less flexible than those on a control food when feeding time is limited by reducing time of access to the feeder.

The management and maintenance of swards grazed by horses is known to be a difficult task. In a short period of time (2 to 3 weeks) pastures used for horse grazing develop patches of bare ground, short grass and areas which horses refuse to graze because of faecal contamination. Bite depth and bite area are important in determining the effects of grazing on the vegetation. The dimensions of the bite have been investigated in cattle (Ungar et al., 1999), sheep and goats (Concha, 2000), but not horses. The interaction of the horse with the pasture surface is poorly understood but important to improve management and maintenance of areas grazed by horses. The study reported examines the influence of grass height on bite dimensions, i.e. bite depth, bite volume and bite area of the horse at grazing.

Feeding horses high levels of cereal starch can result in diet-related azoturia, laminitis and colic, whereas high fibre, forage-based diets do not generally elicit these conditions. Therefore, it would be advantageous to develop fibrous feeds with increased digestibilities, permitting horses with high energy demands to be sustained on greater forage: cereal starch ratios. High temperature dried (HT) alfalfa has been fed to horses for a number of years and it is common practise to combine this with sugar beet pulp (SB) another nutritious fibrous feed for horses. Synergistic effects of SB when added to fibre-based diets have been observed in other species in vivo (Longland et al., 1994) whereby the digestibility of graminaceous feeds has been increased. However, such effects have been little examined in horses fed a leguminous-forage diet. The aim of this study therefore, was to determine if SB enhanced the digestibility of alfalfa, a forage legume that is increasingly being fed to equines in the UK.

Lucerne and chalk are sources of calcium used to supplement horses diets. The voluntary ingestion of lucerne varies with its form (Cuddeford, 1994). The objectives of this study were to compare the appetency for different sources of calcium, measured by kinetic of ingestion and selection behaviour (sorting, refusal) and to evaluate the effect of those different sources of calcium supplements on the preference of diets offered as a simultaneous choice. The sources of calcium studied were chalk and dehydrated lucerne presented in three forms: 6 mm diameter pellets, 18 mm diameter pellets and ground.

When horses are on diets that are predominant in cereals, the combination of low concentrations of calcium in the diet and the binding of calcium by phytates may result in inadequate calcium intake (Rose, 1990). Chalk and dehydrated lucerne are rich in calcium. It has been shown that the voluntary ingestion of lucerne varies with its form (Cuddeford, 1994). The aim of this study was to evaluate the effect of different sources of calcium (chalk vs dehydrated lucerne) and lucerne forms (6 mm diameter pellets, 18 mm diameter pellets and ground lucerne) on the ingestion and on the metabolic profile in horses offered a cereal-based diet.

Previous work has indicated that unmolassed sugar beet pulp (USBP) may suppress voluntary feed intake (VFI) in ponies when offered as the major component; but not when offered as a relatively minor component of the diet (Hyslop et al, 1998, 1999). However, critical levels of USBP inclusion in equine diets remain to be established. This study examines VFI, in vivo apparent digestibilities and nutritive values in ponies offered pelleted complete diets containing USBP at inclusion levels between 0 – 800 g/kg dry matter (DM).

The performance of tail biting and other harmful social behaviours is a common problem on pig farms. Many risk factors relating to tail biting have been identified, but the problem remains intractable. One contributory factor may be the genetic makeup of pigs but, as with most pig behaviour, there has been little research into the genetic basis of its expression. The aim of the current experiment was to investigate the genetic component of harmful social behaviours, such as tail biting, by assessing breed differences in the predisposition to perform these behaviours.

Previous work (McIntyre and Edwards, 2001) revealed a significant correlation between plasma tryptophan (TRP) concentration and blood preference scores when pigs were fed a low CP diet. Increasing dietary TRP in rats causes increases in plasma and brain TRP, and brain serotonin concentration (Fernstrom and Wurtman, 1971), which appear to be highly localised to serotonin-containing neurones that may monitor the metabolic state and control behaviour. Uptake of TRP at the blood-brain barrier and serotonin level may also be increased by a higher TRP: LNAA (large neutral amino acids) ratio and level of dietary carbohydrate. This study aimed to determine if pigs fed diets differing in TRP and TRP: LNAA ratios differed in their behaviour or in their preference for blood during a model tail test.

Pre-weaning mortality (11.9% as estimated by M.L.C., 2000) continues to be a major economic and welfare problem in commercial indoor pig production. The main causes of mortality are crushing by the sow and low viability/starvation. Both of these causes of death may be as a result of increasing sow body size and smaller piglet body size as a result of intense genetic selection for increasing litter size. However it is unclear whether sows are consistent across parities in their level of pre-weaning mortality. Therefore this study aimed to examine individual differences in piglet mortality of sows throughout their reproductive life, investigate factors likely to affect piglet mortality, and to assess whether piglet mortality may be a candidate trait for genetic selection.

The stress caused by weaning piglets is known to have a serious detrimental effect causing a growth check, increased aggression leading to skin lesions and reducing future performance potential. Previous work (Allen et al., 2000) has shown that mixing piglets pre-weaning can improve post-weaning performance and reduce skin lesions caused by fighting without detrimental affects on pre-weaning performance and behaviour. The aim of this experiment was to assess the effect of changing the post-weaning environment on piglet performance.

Reduced welfare and productivity during the post weaning period continues to pose a problem for producers. It may be possible to reduce these problems by altering management practices. The objective of the present study was to investigate the effect of weaning age, mixing strategy and group size on the welfare and productivity of weaned pigs.

Nose-ringing is commonly used in outdoor pig production to prevent pasture damage. However, nose-ringing causes acute stress at the time of ringing and inhibition of normal rooting behaviour (Horrell et al. 2001). Therefore alternatives to nose-ringing need to be investigated. Previous studies have focused on dietary modification as a way of reducing rooting behaviour and pasture damage (e.g. Braund et al. 1998). Although these methods helped to reduce rooting behaviour they were ineffective at decreasing long-term pasture damage. This experiment examined the effectiveness of providing a special, enriched rooting area in an attempt to reduce pasture directed rooting behaviour and consequently reduce overall pasture damage.

The energy feeding systems currently adopted for dairy cows in Western Europe and North America were developed from calorimetric data published 30 years ago. However, the calorimetric measurements were usually undertaken with a small number of trained animals, housed for a short period in respiration chambers. The objective of the present study was to use production data to develop the metabolisable energy (ME) requirement for maintenance (MEm) and the efficiency of ME use for lactation (kl) for dairy cows.