Not all commercial lines and breeds contain the best alleles for genes of economic importance. Introgression strategies transfer a gene from a non-commercial source to a commercial line by incorporating the favourable allele of a gene from the donor animals whilst retaining beneficial alleles affecting commercial traits in the recipient animals. This is achieved through generations of backcrossing and the resulting heterozygotes are selected and intercrossed to produce animals homozygous for the gene of interest. Animals produced from an introgression program can be inferior to commercial animals because of the contribution from the donor genome at loci not under selection. This genetic lag experienced in an introgression program can be partly attributed to the intercross as a higher number of animals are selected primarily upon genotype thereby reducing the selection intensity for other traits (Visscher and Haley, 1999). The chromosome segment containing the desired introgressed gene (linkage drag) can be quite large, e.g., 32 cM for a 100 cM chromosome in backcross 6 (Stam and Zeven, 1981). The aim of this study is to examine the genomic contribution of each generation to animals produced after the intercross and the level of homozygosity.

Cattle have an innate fear of humans that may be reinforced during the potentially painful routine husbandry procedures performed by humans during the rearing of young calves. This fear may be reduced by positive handling of calves early in the rearing period (Krohn et al., 2001) and by use of calming devices such as blindfolds (Mitchell et al., 2004). Mitchell et al, (2004) found that blindfolding cattle during restraint and simulated husbandry procedures reduced struggling by 44% and decreased heart rate compared to control cattle with unrestricted vision. However, this study did not test the effectiveness of the blindfold during actual invasive procedures. The aim of the present study was to investigate whether blindfolding during disbudding and positive handling of dairy calves would influence the response of calves to human interactions.

In vitro and in situ techniques for research on ruminants are currently much in focus. Since they have good correlations with in vivo data, they are feasible alternatives to predict the nutrition rates of feeds and may be applied in equine research on in vivo apparent digestibility. On the other hand, the disadvantage of these methods is due to the fact that fistulated animals are required to obtain the inoculum. Theodorou et al., (1994) developed an extremely promising gas production technique to assess feeds for ruminants, but still require rumen inoculum obtained from operated animals. Faecal microorganisms function similarly to those in the rumen and in the large intestine of equines. The objective this experiment was to compare rumen liquor and equine faeces as inoculum to determine in vitro digestibility of equine feeds.

A recent study carried out by Houdijk et al (2005), used a rodent model to assess whether a reduction in protein scarcity during lactation resulted in a reduced degree of parasitism. Feeding high protein foods resulted in a reduced worm burden, but was confounded with increased food intake per se. Therefore, effects observed on parasitism may not necessarily have been associated with an increased protein supply, but with changes in the gut environment due to the increased food intake. Before this model can be used to assess the underlying immune responses, further work is needed to verify that the effects observed are indeed related to changes in nutrient supply. This experiment aimed to provide further evidence on the nutritional control of parasitism during lactation by manipulating nutrient demand. It was expected that the latter would not be associated with changes in food intake per se and results could therefore be used to exclude the influence of non-immunological changes in the gut environment as a contributing factor of reduced parasitism.

X-ray computed tomography (CT) can be used to accurately assess carcass composition in sheep (Sehested, 1984; Young et al., 2001) both in research and commercially, as part of a breed selection programme. Two different CT scanning methods have been used: a) the reference scan method where tissue weights are predicted from tissue areas in a small set of cross-sectional scans at ‘anatomical landmarks’, and b) the Cavalieri method where a larger number of scans are taken along the body. It is of interest to examine the accuracy of evaluations made using these two methods and the individual merits of the two methods depending on their application.

Variety and location of production affect the chemical composition of cereal grain (Valaja et al 1997). There are several varieties of Spring barley produced in Northern Ireland (NI) and in the Republic of Ireland (ROI). However, there is no information in the literature concerning the chemical composition of these varieties nor is there any information regarding location of production. The main aim of this study was to examine the effect of variety and location of production on the chemical composition of barley grown in these countries. Specific weight is traditionally used to predict nutritive value. However, a number of research reports including that of Stewart et al (1997) have not found a strong relationship between specific weight and chemical composition or nutritive value. For this reason the use of specific weight as a predictor of chemical composition was studied.

It has been suggested that the anterior glands may be larger, produce more milk or provide a more comfortable position for piglets (Donald, 1937; Gill and Thomson, 1956) while others have suggested that there is no difference in milk yield among teats (Hartman et al., 1962; Pond et al., 1962). The real advantage of the anterior mammary glands of sows for the suckling pig remains unclear. We have demonstrated that substantial mammary growth occurs during lactation in the sows (Kim et al., 1999). This study was designed to relate teat preference and piglet growth with gland size and composition. Our hypothesis is that there are differences between anterior and posterior glands in size and composition and that these differences may be related to piglet growth during lactation.

The increasing prevalence of PMWS /PDNS within global pig production since 1995 has steadily increased, UK first affected in 1999. Impact on post weaning mortality is variable with rates exceeding 30% commonly reported, no medication or treatments have proved effective or successful, vaccination is still unavailable and the industry is still striving to find the scientific answers and solutions behind this economically damaging disease. Porcine Circovirus 2 (PCV2) is widely acknowledged as the probable causal agent but still not confirmed, if so has it changed or is it a new PCV? With enhanced virulence, a definitive identification and test is urgently required. The objective is to demonstrate how successful specialised management techniques alongside a batch system is capable of reducing post-weaning mortality to pre PMWS levels and to further improve overall herd health, productivity and economic performance.

Bacteria belonging to the family Enterobacteriaceae enter the animal feed chain as normal contaminants of raw materials used in the manufacture of animal feeds. The family Enterobacteriaceae encompasses 30 established genera, including Salmonella spp, Escherichia spp, Shigella spp and Yersinia spp. Many of the genera exhibit pathogenicity towards man, animals, insects and plants and many of the pathogenic forms produce toxins. A number of the genera in this family occur regularly in association with animals; they are found as indigenous members of the gut microflora where they may either produce no harmful effects, or are capable of causing disease in both endothermic and ectothermic animals. There is a recognised association between the risk of isolation of salmonella and degree of Enterobacteriaceae contamination (Veldman et al. 1995). This has led to the consideration of recording Enterobacteriaceae contamination levels in feed stuffs as an indicator of feed hygiene and potential limits to the degree of contamination being set by the major retailers. This paper sets out data gathered from the routine analysis of feed raw materials examined for Enterobacteriaceae contamination.

Poultry diets and production Poultry diets in northern Europe are composed of relatively high quality ingredients, consisting primarily of wheat and soyabean meal with smaller quantities of barley, peas, beans, rapeseed meal and sunflower meals. The cereal component is usually from the less expensive residual material from human use and as a result the quality of the ingredients tend to vary in nutritional value. The major cost of production of poultry resides with the diet (around 60-70%). Thus, strategies that reduce dietary costs, and increase the efficiency of utilisation of nutrients have important implications in the production of poultry. The major types of poultry production in Europe consists of chicken, turkey and laying hens (6.2Mt chicken meat, 1.8Mt turkey meat, 5.1Mt eggs, from a total of 33.9Mt of meat). Thus poultry products, including eggs, accounts for about 39% of meat products and therefore assumes significant financial importance (FAO, 2002).

There is an increasing body of evidence to support the view that the periparturient breakdown of immunity to parasites has a nutritional basis; an increased supply of metabolizable protein (MP), at times of MP scarcity, would reduce gastrointestinal nematode egg excretion and worm burdens in periparturient ewes (Houdijk et al., 2001). However, the rate at which MP supply can improve expression of immunity to gastrointestinal nematodes is not known. The objective of this experiment is to assess this rate, which will be studied through reducing the degree of MP scarcity.

Liquid feeding of growing pigs is believed to increase feed intake and growth performance compared to a dry diet. There is little information on the comparative feed conversion efficiency of pigs on the two forms of diet or the underlying physiological basis for the differences and how liquid diets affect the absorptive mucosa of the small intestine. This study was designed to investigate differences in feed utilisation and mucosal structure in modern genotype pigs offered equal amounts of feed in dry and liquid form. Additionally, the effect of reducing the pH of the liquid diet was considered.

The development of grazing management strategies to optimise nutrient intake from grazed herbage requires an understanding of the factors influencing the dietary preference of grazing domestic ruminants. Although there has been considerable progress in understanding the factors influencing the dietary preference of grazing sheep, there has been comparatively little research with lactating dairy cows (Rutter et al., 1997). The aim of the experiment reported here was to study the dietary preference of lactating dairy cows grazing grass and clover.

Particle size (PS) may be reduced when feeds are ground through small screen sizes leading to increased losses from artificial fibre bags during in situ or mobile bag experiments in equines. Smaller PS may also alter the water holding capacity (WHC) of feeds which in turn may alter bag transit times during mobile bag experiments. This study examines PS and WHC in a range of starch based equine feedstuffs ground through two screen sizes.

Five feedstuffs (F) were used ie: barley (B), maize (M), peas (P), wheat (W) and naked oats (NO). Feedstuffs were subjected to three types of physical pre-processing (Pr) ie: unprocessed (Un), micronised (Mi) or extruded (Ex) and then ground through either a 1.0 or 0.5 mm screen size (SS). For PS analysis a 25g sample of each feedstuff was sieved through a stack of 11 sieves ranging in pore diameter between 45 μm and 2 mm using a mechanical shaker for 20 min.

Forage trees are commonly use for livestock feeding in the tropics. It is known that some species can affect the rumen protozoa population (Odenyo et al., 1997). However, little is known about the potential effect upon rumen protozoa of several species which are also use as feed in tropical systems. The objective of the experiment was to assess the defaunating capacity of forage trees. In companion reports (Monforte et al., 2005) we reported plants with a potential defaunating effect as evaluated under an in vitro batch culture system (Sandoval et al., 2005). Here we present those plants which did not have or had low effect on protozoa population in an in vitro culture.

Livestock production is inherently ‘leaky’ with materials moving from the farming system into waters and the atmosphere as part of the biogeochemical cycling processes that occur in all ecosystems. Increasingly, there are national and international legislative pressures to minimise fluxes of environmentally active materials into waters and the atmosphere. Public opinion is also demanding that the husbandry and management of livestock production is adjusted to take account of the short and the long term impacts on environmental quality. Although livestock farms may be responsible for point source effects these have diminished over recent years and the greater concern is with diffuse pollution effects.

During growth period of 6 to 7 weeks, broiler chickens are exposed to different stressors, the effects of which are dependent on the type, duration and intensity of stress that affects the bird. Stress-induced changes in muscular metabolism alter the physico-chemical traits of meat, thus affecting its quality (Ali et al., 1999). The negative effect of ante-mortem thermal stress on the quality of broiler meat has been the object of many studies and is relatively well documented (Warriss et al., 1999). There is a scarcity of data on whether and to what degree hyperthermia in growing chickens affects the technological parameters of poultry meat. Therefore we carried out an experiment to determine the effect of 5-day heat stress in 4-week-old broiler chickens on their later meat quality.

Wheat and wheat by-products vary in their available energy and protein content (Batterham et al., 1980) leading to unpredictable growth rate and feed use efficiency. Carbohydrase enzymes, targeting the non-starch polysaccharides in these raw materials, may improve their nutrient availability. However, questions remain over the relationship between the quality of the dietary raw materials and the level of exogenous enzyme activity required in the feed to elicit a response from pigs. Hence, the response of pigs to the use of a fungal xylanase, produced by Trichoderma longibrachiatum, was studied in diets containing wheat and wheat by-products.

There is increased interest, in using sugar beet pulp (SBP) products in equine diets as a major source of fibre in place of traditional forages. It has been observed that voluntary feed intake (VFI) was lower when SBP products were included in the diet of dry sows compared to other fibrous foodstuffs (Brouns, et al 1995). Equids are similar to pigs in respect that fibrous feed components must pass through the stomach and small intestine before reaching the hindgut; the primary site of fibre fermentation. This study examines the VFI and apparent digestibility in vivo of two SBP based diets and determines their ability to meet the predicted energy and protein needs of mature ponies.

Five mature Welsh-cross and three mature Shetland pony geldings with a mean liveweight (LW) of 219 kg (s.e.d. 2.2) were individually housed and offered 2 kg/d dry matter (DM) of a mature threshed grass hay (THAY), 60 g/h/d minerals and ad libitum access to either soaked molassed sugar beet pulp (MSBP) or soaked unmolassed sugar beet pulp (USBP).

Analysis of environmental factors within equine sporting competition is critical to understanding potential effects on performance. If such effects are occurring they need careful consideration within any performance assessment mechanisms that are subsequently undertaken on the data. Such effects may have implications for competitor’s selectors and trainers. Additionally and importantly if the performance data is being related to breeding information, these environmental effects may be playing a significant role in our subsequent judgements and predictions within breed improvement models.