Individual piglet birthweight is a major determinant of subsequent survival and weaning weight of the litter. Low birthweight piglets are more likely to die from starvation and thermoregulatory stress than their heavier littermates, while those that do survive grow more slowly and reach a lower mature body weight with a higher body fat to muscle ratio. Inadequately grown porcine fetuses are often characterised by assymetrical organ development although it is not clear when this difference in relative organ size arises and whether this is a consequence of changes in cell size or cell number. The objectives of this study were to assess a range of determinants of fetal growth at stages of gestation and to determine when changes in the relationship between fetal size and organ development occur.

There are now a range of new reproductive technologies which are actually or potentially available for use in commercial dairy cows. To obtain an economic assessment of adopting the use of such new technologies, the effects of the technology adoption on milk production resulting from genetic lift, generic gain and the conception rate have to be estimated. This paper demonstrates a Markov chain model which allows die estimation of these effects by considering the change in physiological state of individual cows and the genetic improvement through me use of embryo transfer to produce replacement heifers.

Grass is the main energy feed for cattle but it declines in digestibility and intake during the summer months and loses about 20% nutrients during ensiling and feeding in winter. Grass is also low in minerals and this has implications for cattle health and performance. It is thus essential to use supplements to boost digestibility and intake of grass and subsequently the performance of cattle. This study compared the effect of two supplements which are marketed as molasses based feed blocks (Booster with 12% crude protein or CP and HIPRO with 28%: CRYSTALYX) on the in vitro dry matter (DM) degradation of barley straw (Straw) and grass nuts (Grass). These blocks contained same energy (13MJ ME/kg DM) but different amounts of sugars (33-35%), oil (6-8%) and minerals (20 to 28%) and thus were considered appropriate for use as feed supplements to compensate for the deficits of nutrients that the cattle can face when consuming grass or straw. These forages represent a range of forage quality that can be found in the UK.

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.

In previous studies where sheep were subjected to experimental subclinical Trichostrongylus colubriformis infections, protein metabolism was seriously impaired during both the initial infection (5-7 weeks at early dosing) and the subsequent immune response (11-13 weeks of dosing) periods (see MacRae, 1993). Symonds and Jones (1983) reported that T. colubriformis infection increased the rates of protein synthesis in the small and large intestines of guinea pigs by 24 and 70% respectively, however there are no equivalent data in farm animals. In the present study trans-organ catheterisation procedures have been coupled with mass isotope tracer kinetics to examine leucine metabolism across the gastrointestinal (g.i.) tract of lambs subjected to subclinical T. colubriformis infection.

Many mature, non-pregnant, non-lactating equids are often kept in circumstances where they are expected to perform only light physical work or activity eg: a childs pony. Consequently their maintenance energy and protein needs can often be met at very restricted feed intake levels. Conversely, when they are housed during the winter months it is believed desirable to manage such animals on unrestricted ad libitum feeding regimes in order to allow the animals to exhibit their natural feed intake pattern and consume forage on a little and often basis throughout the daily feeding period. However, ad libitum access to the diet may lead to such animals becoming excessively fat. These conflicting needs of low energy and protein requirement coupled with the desirability of unrestricted access to the diet could both be met, at least in part, if a low quality forage is available ad libitum. This study examines the voluntary feed intake and apparent digestibility in vivo of a mature threshed grass hay offered ad libitum and determines its ability to meet the predicted energy and protein needs of mature ponies.

Preferably, a crop for silage should be immediately ensiled after harvesting. However, this is not always possible in research situations when a large number of laboratory-scale silos have to be prepared. Thus, in many cases the chopped material is frozen and ensiled at a later date after defrosting. Richard and Allen (1992) and Nelson and Bozich (1996) have shown that freezing vegetative material may increase cell-wall contents, which in turn, may affect nutritive value. The current study was conducted to determine changes in the composition of fresh and frozen stover, ensiled with and without a cell-wall degrading enzyme solution.

Reducing the time available for grazing from 20h to 5h daily, and replacing this with access to a maize silage/soyabean meal diet indoors had no significant effect on milk yield in spring (Hernandez-Mendo and Leaver, 1999). Grazing conditions in autumn present additional problems of shorter daylength and accumulated herbage contamination. The objectives were to examine the production and behavioural responses of grazing dairy cows to reducing access to grazing and increasing access to a maize silage/soyabean meal diet offered indoors.

During winter, voluntary food intake (VFI) and growth decreased in light horse weanlings given ad libitum access to a forage/concentrate diet (Cymbaluk et al, 1989). These changes were attributed to decreased ambient temperatures. However, photoperiodically entrained seasonal changes in VFI and growth are documented in other Northern ungulates (Moen, 1978) and may comprise an adaptation to changes in forage availability. Throughout their evolution, horses experienced similar environmental pressures and may demonstrate similar photoperiodic adaptations. This study characterised changes in VFI and growth in pony colts maintained under an artificial photoperiodic regime.

Seven, 2 year-old pony colts of Welsh Mountain type (182.4 ± 5.4 kg), were obtained from pasture (53°N). Animals were individually housed in loose-boxes, within a light-proof building. Measured quantities of a complete pelleted diet (gross energy = 16.7 MJ.kgDM-1), calculated to exceed appetite by at least 1 kg, were offered daily.

The behavioural development of precocious mammals contributes to their survival in the neonatal period. In the sheep, neonatal behavioural progress is known to be affected by breed and birthweight (Dwyer, 2001), and is related to lamb survival (Dwyer et al., 2001). Lambs that are slow to stand and suck may be less mature at birth than lambs that stand quickly. Foetal cortisol plays an important role in the preparation of the lamb for postnatal life (Liggins, 1994) and may also play a role in the development of behavioural competency at birth. In this study differences in behavioural develoment and plasma cortisol were measured in two breeds of sheep known to differ in behavioural competency at birth. In addition, ability to maintain body temperature was also investigated.

Wahed et al. (1990) showed that the intakes of barley straw in untreated, long form, were increased by 0.35 and 0.57 when the ad libitum amounts offered to sheep were increased from 18 to 54 and 90 g dry matter (DM)/kg live weight (M) daily, respectively. The quality (in vitro digestibility) of straw consumed also improved with offer rate. There is no such information available for oat straw. In view of the latter, and the increasing use of oats in human foods and the greater availability of oat straw for feeding, the present experiment investigated whether the intake of oat straw by sheep could be increased by increasing the amount offered.

It was the purpose of this study to ascertain whether concentrations of glucose (GLU), urea and non-esterified fatty acids (NEFA) in blood collected from the umbilical cords of newborn piglets vary according to the position of the piglet in the birth order of a litter. Umbilical cord blood is representative of the piglets status at the time of birth. It would therefore be advantageous to know whether blood withdrawn from the umbilical cord of one piglet is representative of the litter in terms of these metabolites. This study was therefore designed to test the hypotheses that position in the birth order, and time of birth relative to delivery of the first piglet in a litter, will influence GLU, urea and NEFA concentrations in umbilical cord blood.

The in sacco technique (e.g. Ørskov et al., 1980) remains the methodology with which the majority of rumen degradability estimates are made. However ethical, animal welfare and cost issues regarding the use of surgically modified animals plus the relatively slow rate at which samples can be examined (two samples per week using three sheep) have combined to compel researchers into developing alternative techniques. Precise, high capacity in vitro systems now exist. However the feed industry is unwilling to adopt these “new” values, partly due to having spent considerable time and effort creating databases of in sacco values which can be used directly in current feed evaluation systems. This paper describes modifications to an in vitro system that provides values similar to that obtained in sacco.

A significant relationship between the ESR gene and litter size has been reported for a range of Meishan synthetic and Large White lines (Rothschild et al., 1995). The effect of one copy of the positive (B) allele in a European 50% Chinese Meishan synthetic (L93) was estimated as +0.79 pigs born alive per litter in the first parity (Southwood et al, 1995). It is therefore of interest to incorporate the positive allele into a comercial parent gilt, the growing performance and soundness of these animals also being of importance. The objective of this trial was to evaluate the effect of the ESR gene on growth and performance traits in a commercial type background.

The health benefits of n -3 polyunsaturated fatty acids (PUFA) and conjugated linoleic acid (CLA) to humans are now widely recognised. Polyunsaturated fatty acids of the n -3 series such as a-linolenic acid (C18:3n -3), eicosapentaenoic acid (C20:5n -3; EPA) and docosahexaenoic acid (C22:6n -3; DHA) reduce the risk of coronary heart diseases (Department of Health, 1994). CLA has a diverse array of potential beneficial health effects which include anticarcinogenesis, antiatherogenesis, immune system modulation, antidiabetic effects and reduction of body fat accretion (Bessa et al., 2000). However, the consumption of both n -3 PUFA and CLA by humans is currently less than optimal. The current study investigates the extent to which n -3 PUFA and CLA in milk fat of lactating ewes may be enhanced by feeding diets rich in EPA and DHA.

Belgian beef production is mainly using double-muscled Belgian Blue animals finished indoors on all-concentrate diets or high-concentrate/maize silage diets. In relation to consumer health and in order to improve the “functional food” value of beef, it is attempted to increase its n-3 PUFA content using linseed or grass and grass silage in the fattening diet. The aim of this study was to investigate the effect of feeding grass or linseed at different stages of the production period on the intramuscular PUFA content of Belgian double-muscled beef.

Lewis et al (1998) observed differences in overall and ileal apparent digestibility of wheat varieties using a wheat / casein diet but no significant relationships with in vitro viscosity of wheat. In the present study six of the varieties used previously were selected to examine if the variety differences would be repeatable using a more commercial diet and the extent of correlation between overall digestibility (OD) and performance parameters. The wheats chosen were Abbott, Caxton, Crofter, Encore, Hussar, Riband (in vitro viscosity range 6.8 - 19.2 cps). Three contained the 1B1R gene (Crofter, Encore, Hussar) and three were soft wheats (Crofter, Encore, Riband). All wheats were harvested in Northern Ireland in 1997.

Endocrine disrupting compounds (EDC) include a diverse range of chemicals derived from industrial, agricultural and domestic processes (IEH, 1999). They include phthalates (used in the manufacture of plastics), alkyl phenols (present in detergents and surfactants), polychlorinated biphenyls (PCB; formerly used in electrical equipment), dioxins (released from incinerators), organochlorine pesticides and organohalogens (used as flame retardants).

The compounds have a wide range of chemical structures but all of them have the capacity to disrupt normal hormonal actions. In some cases they bind to steroid hormone receptors and so they can have weak oestrogenic or androgenic effects while others disrupt thyroid hormones or other physiological functions. Consequently, they may disrupt reproductive or immune function and can be carcinogenic.

Evidence of adverse effects on animal physiology is partly circumstantial and partly based on empirical studies, mostly involving laboratory rodents. Many reports in the literature indicate that reproductive disorders in wildlife species such as pelicans, birds of prey and polar bears are associated with abnormally high concentrations of EDC in their tissues. Furthermore, controlled studies involving the administration of large, arguably pharmacological, doses of EDC to laboratory rodents have demonstrated adverse effects on their reproductive or immune systems. Relatively little work has yet been done to determine the pattern of uptake and bioaccumulation of EDC in domestic species or the effects of EDC on the physiology of these species.

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.

Declining reproductive performance is a major problem for the global dairy industry (Lucy 2001) whereas magnitude and duration of postpartum negative energy balance of dairy cows are considered as the main reasons (de Vries and Veerkamp 2000). Moreover, various energy balance indicators, such as body condition score (BCS) and plasma βhydroxybutyrate (BHB) concentration, have been correlated with reduced reproductive performance (Pryce et al 2001, Taylor et al 2003, Patton et al 2007, Walsh et al 2007). Such information has been already used to adjust herd management practices in order to prevent negative effects on reproduction. Furthermore, the ability to predict reproductive performance of cows with reasonable accuracy would also be very useful to dairy farmers. In such case, important management decisions (e.g. length of voluntary waiting period, starting dates of synchronisation programs and price of semen used), could be made for each individual cow. The aim of this study was to investigate whether combining certain energy balance indicators would yield useful predictions of cow reproductive performance at 1st artificial insemination (AI).