Increasing the n-3 polyunsaturated fatty acid (PUFA) content of ruminant products may be important in reducing the incidence of cardiovascular diseases in man. Previous experiments suggest that a-linolenic acid (C18:3n -3) in the form of whole linseed is extensively biohydrogenated both in vitro (Cooper et al., 2001) and in vivo (Wachira et al., 2000) and that some form of protection is required. By contrast the long chain PUFA’s in fish oils appear less susceptible to biohydrogenation (Wachira et al., 2000). The objective of the present study was to quantify the extent to which n-3 PUFA from different sources were biohydrogenated in the rumen and to determine the degree to which they were incorporated into plasma lipids.

Selection for carcass leanness in pig breeding schemes has promoted lean tissue growth rate whilst reducing body fat stores and appetite. Dietary protein restriction has been proposed as a way to enhance body fat reserves in the breeding animal. However, protein restriction during gilt rearing has been shown to adversely affect reproductive performance (Cia et al., 1996). The aim of this study was to test the effect of short term elevation of dietary protein prior to ovulation in gilts reared on restricted protein, to determine whether short term improvement in metabolic state could reverse these detrimental effects.

Automatic milking systems have the option to feed cows as they are being milked. This would be beneficial if it were to keep cows quieter during the teat cup attachment and milking process, and improve yield, flow rate and time taken to milk out via its action on oxytocin as shown by Svennersten and Samuelsson, 1994. Potentially feeding may create dust and encourage vermin, defecation and urination. It may also make the cows more restless (Whipp, 1992). The aim of this experiment was to assess the effects of feeding cows in the milking stall of an automatic milking system on their behaviour and milking characteristics.

There is increased interest in using forages other than grass hay as the basal diet for equines in the UK. Whilst a range of short-chopped dehydrated alfalfa based forages may be used as alternatives to grass hay in equine diets, there is very little information available on their likely intake characteristics, apparent digestibilities or their nutritive values. The objectives of the current experiment were:- 1) to determine the voluntary feed intake (VFI) characteristics of three alfalfa based forages when offered ad libitum to ponies, 2) to determine the in vivo apparent digestibility, digestible energy (DE) and digestible crude protein (DCP) contents of these forages and 3) to compare the actual energy and protein intakes with theoretical energy and protein requirements.

The Thoka gene for fecundity, a gene which originally occurred in Icelandic sheep, was introduced to the UK in 1985 and through a programme of crossbreeding was established in Cheviot sheep (Russel et al, 1997). Ewes are now retained as "Thoka carriers" only if they have lambed in each of the first three years and had at least two sets of twins. The gene has been introduced into separate North and South Country Cheviot (NCC and SCC) lines which are now phenotypically indistinguishable from purebred animals and contain proportionately less that 0.2 of the Icelandic genotype. The purpose of this analysis was to determine the increase in fecundity in the two breeds and whether or not the reproductive response to the incorporation of the Thoka gene differs between NCC and SCC breed types.

Weaning pigs from the sow at an older age, when their digestive systems are more mature, has been suggested as an approach to reduce the potentially negative effect of the in-feed antibiotic growth promoter (AGP) ban on the national pig herd. Whilst this approach has been shown to improve feed intake and piglet growth rate during the early postweaning period (Edge et al. 2006) it is also important to consider how changes in weaning age may influence sow productivity and longevity in the herd. The AGEWEAN programme of research followed 570 gilts whose piglets were weaned at either 4, 6 or 8 weeks of age through four successive parities; reproductive performance, litter data and the timing and reasons for any sow being culled from the herd were recorded.

Formulation of diets that are synchronous for hourly energy and nitrogen (N) release in the rumen has been shown to increase the efficiency of microbial protein synthesis (MPS) in the rumen (Sinclair et al. 1995). However diets formulated to be synchronous for hourly release of energy and N did not improve the whole body N efficiency of male lambs (Witt et al. 19%) but there were indications of possible differences in energy metabolism between animals offered synchronous or asynchronous diets. The objectives of the experiment were to measure the effects of synchronising hourly energy and N release in the rumen in diets with two rates of energy release on growth, aspects of whole body metabolism and carcass traits in male lambs.

Pea-wheat bi-crop silages were reported to have moderate nutritive value when the proportion of peas in the sward was less than 200 g/kg (Adesogan et al., 1999). These authors also suggested that improvements in the digestibility, intake and nitrogen (N) balance of the forages may result from increasing the proportion of peas in the sward. This experiment was designed to examine this theory by determining the in vivo apparent digestibility, N retention and voluntary feed intake (VFI) in sheep of pea-wheat bi-crop silages containing different ratios of peas to wheat and harvested at two stages of growth.

Major psychological stress occurs when piglets are weaned and in particular the stress of mixing piglets into new social groups may be one of the most significant of all (Musgrave et al, 1991). The objective of the experiment was to determine whether the practice of mixing litters prior to weaning and at weaning had any effect on performance both before and after weaning.

Nutritional manipulation during the dry period can alter subsequent animal responses to feeding in terms of milk yield and composition. Previous research has shown interesting differences in milk production and composition due to energy or protein supply in the dry period (Moorby et al., 1996). The objective of this experiment was to test the interaction between energy and protein supplies during the dry period on subsequent milk production and composition. Effects on live weight gains and condition scores are reported in a separate summary (Jaurena et al., 2001).

Recent studies at this centre (Flanagan 2003, Keady et al. 2006) have shown that grazing swards in the winter (extended grazing), either in mid, late or throughout pregnancy, provides a low-cost system for wintering ewes. With decoupling of subsidy from production post Mid Term Review of the Common Agricultural Policy it is essential to improve efficiency and reduce costs of production. One of the major costs in sheep production is the cost of rearing replacements. The aim of the present study was to evaluate the effect of herbage allowance and concentrate supplementation on animal performance during extended grazing and on compensatory growth during the subsequent grazing season. Furthermore the potential herbage allowance sparing effect of concentrate supplementation was also determined.

As a result of the Agenda 2000 increase in the Special Beef Premium and introduction of a slaughter premium for bulls, there is renewed interest in bull beef production especially from low value Holstein-Friesian calves. To evaluate the economics of such a production system further information is required on responses to supplementary concentrates with silage and duration of the finishing period.

Calliandra is a proteinaceous leguminous browse for ruminants. Its PA content may however reduce its nutritive value. The negative effects of PA can be reduced by treatment with polyethylene glycol (PEG). Tannin-protein complexes are stable at pH values up to the isoelectric point of the individual protein, and may dissociate at lower or higher pH values. The aim of the study was to determine the PA concentration of Calliandra, and to evaluate the effect of PEG and pH on the formation of complexes between BSA and compounds from Calliandra extracted with aqueous methanol.

Leaves (containing the leaflets and petioles) were harvested from Kenya Agricultural Research Institute regional research center, Embu, in the central highlands of Kenya. Leaves were oven dried (50 °C for 48 h) and were milled (1 mm aperture). The top 30 and lower 30 cm leaves were harvested from 2.5 year old plants.

Considerable research efforts have been directed towards the use of cell wall degrading enzymes as feed additives. However, the factors affecting the response to a certain enzyme preparation are not well understood. A better knowledge of the enzymatic activities present in the preparations and their interaction with a substrate in presence of rumen fluid is needed. The objectives of this study were to characterise the main enzymatic activities of six enzyme preparations and to evaluate them in the presence of rumen fluid, using the in vitro Reading Pressure Technique (RPT).

Accurate estimates of carcass composition and eating quality are critical to the introduction and the success of a value-based marketing system (VBMS) and to help address increased consumer demands for leaner meat with higher quality. Currently in the UK, carcass composition is assessed by a subjective carcass classification system based on the EUROP conformation system, and a visual assessment of fat cover using a numeric fat score (“MLC Scoring”) (Anderson, 2003). Objective, image analysis based systems to classify carcasses into current classification categories have been studied (Allen and Finnery, 2000) and are in use in the beef industry in the EU. However, the introduction of automatic technologies such as VIA may also have considerable potential for prediction of lean meat yield of the carcass. There is growing interest in the possibility of developing payment criteria which are based on carcass meat yield. Therefore, the present research project investigated the potential of VIA technology to predict meat yield in terms of saleable meat yield (SMY), saleable primal meat yield (SPMY) and the carcass components leg, chump, loin and shoulder in lamb.

The Breeding Center of Raeini (BCR) cashmere goats was established in 1965 in Kerman province, with a base population of 120, 8 and 42 does, bucks, and kids respectively. Some new animals have been introduced to the BCR population in some periods of time, and selected males have been sold out to the local breeders each year. Animals have been selected based on their phenotypic performance for fleece weight (FW) and fleece color (FC-white), and body weight (BW). Mating system has been planned based on non-relative mating, but some relative mating has been occurred. Inbreeding depression is one of the most important empact of having inbreeding in a population (Miglior and Burnside 1995). A decrease of 0.8% in fiber length and 6.3% in longevity per 10% increase of inbreeding coefficient in cashmere goats has been reported (Deb 1998). The objective of this study was to estimate the animals inbreeding coefficient and to explore the impact of inbreeding on some economic traits in Raeini cashmere goats.

Newly weaned pigs are at least partially protected against sub-clinical gastrointestinal disorders through the provision of in-feed antimicrobials. Possible associations with antibiotic resistance to life threatening bacterial infections in humans and environmental pollution will result in their ban. As a consequence, gut health and pig performance will be compromised. Current research is aimed at reducing, and eventually overcoming, such consequences through novel nutritional strategies. Effects of the latter on the consequences of sub-clinical infection may be assessed in an infection model, since the absence of in-feed antimicrobials does not always lead to gastrointestinal disorders, due to e.g. variation in infectious environmental conditions. A common gastrointestinal disorder is post-weaning colibacillosis (PWC), which is caused by enterotoxigenic E. coli (ETEC), and is associated with diarrhoea and reduced food intake, and hence reduced performance. Existing ETEC infection models, which have yielded variable results and employed relatively large infective doses of ETEC, have focused on clinical PWC (Madec et al., 2000). The objective of our experiment was to assess whether sub-clinical PWC can be induced through experimental infection with ETEC, and whether such sub-clinical PWC is sensitive to the level of infection used.

The distinctive (phospholipid or total) fatty acid profiles of the major classes of micro-organism have been used in microbial taxonomy as well as to act as microbial markers in soils. Our studies seek to identify the potential of this approach in rumen studies. One of the main distinctions is between solid- and liquid-associated bacteria (SAB and LAB) in the rumen, though it is not clear what relative contributions these make to microbial yield from the rumen. The objective of this work was to determine whether SAB and LAB have distinctive fatty acid profiles and if differences are affected by dietary fat supplementation.

Currently 53 and 47% of prime beef production in Northern Ireland originates from beef and dairy herds, respectively. The beef herd comprises of a diverse range of genotypes which result in major variability in carcass weights, conformation and fat classification. The present study was undertaken to investigate the effect of genotype, carcass weight and fat classification, and pelvic hanging technique on meat quality.

Wray and Thompson (1990) described the relationship between genetic contributions and the rate of inbreeding and this work was extended by Woolliams and Thompson (1994) to interpret genetic response in terms of genetic contributions. By using these relationships Meuwissen (1997) developed an algorithm for obtaining optimum selection decisions at a given (discrete) generation and level of inbreeding by maximising a function of accumulated gain corrected for squared contributions. Here we extend this method for optimising populations with overlapping generation structure and maximising response at a given rate rather than level of inbreeding. Three modifications to the afore mentioned model are presented: an augmented numerator relationship matrix which has not been corrected for reduced Mendelian variance with inbreeding, the consideration of committed future contributions beyond the next cohort derived from the lifetime breeding profile of the population, and a constraint to achieve the desired rate of inbreeding.