Traditionally fed outdoor sows at commercial stocking rates can deposit onto soil in excess of 500 kg of nitrogen per hectare per annum from unused dietary nutrients. This has the potential to give rise to serious environmental pollution problems, and it is therefore important to seek methods to reduce this amount or to influence its pollution potential. One major determinant will be the extent to which it can be captured and utilised in grass growth, but this will be dependant on the extent to which the rooting activity of the pigs has destroyed the vegetation cover. This experiment was therefore designed to measure the impact of reducing dietary nitrogen inputs and maintaining grass cover by nose-ringing of sows on the long term changes in soil nitrogen content.

A number of experiments have examined the milk production responses to feeding concentrates and forages in total mixed rations (TMR) compared with being fed separately. Grass and maize silages have very different energy and protein levels/sources, but the responses to feeding them mixed as opposed to separately has not been examined. This experiment compared grass and maize silages mixed, or fed separately within days or fed on alternate days. Two levels of protein were offered in the concentrate supplement to examine possible interactions between feeding method and protein content of the diet.

The CAMDA group breeding scheme was established in 1976. Its objective is to increase lamb growth rate, mature size and maternal ability of the Welsh Mountain sheep while retaining their hardiness and breed type. The opportunity to achieve this goal depends on the extent of genetic variation within the breed for these traits. The objective of this study was to estimate the amount of variation in 18-week live weight attributable to the lamb genotype (direct) and dam maternal ability, both genetic and environmental, in Welsh Mountain sheep within this scheme.

A total of 12954 records of 18-week live weight of Welsh Mountain lambs collected between 1976 and 1995 from 4 flocks of the CAMDA scheme were considered. The data were edited for small contemporary groups and for incomplete performance or pedigree recording.

The metabolisable energy (ME) requirement for maintenance (MEm) has been derived from measurements of fasting heat production (FHP) with non-lactating cattle, with, for example, ARC (1980) using published data on steers to develop equations to calculate the MEm of dairy cattle. Recent studies at this Institute (Yan et al. 1997 a&b) have produced estimates of MEm, through either direct measurement of FHP, or the use of regression techniques for producing animals and concluded that MEm was higher than those in published feeding standards (ARC, 1980; AFRC, 1993). The objective of the present experiments was to explore possible reasons for the differences, such as the effect of cow body condition score (CS) on FHP and the effect of level and type of diet given during the pre-fasting period on FHP.

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.

Laminitis is often recognised as one of the most common causes of lameness in horses. This painful condition has obvious far-reaching implications for the welfare of affected animals, yet, despite the prevalence and seriousness of laminitis, the exact aetiology of the disease has still to be unanimously identified. It is generally accepted that acidosis within the hind gut of the horse is a predisposing factor to the onset of laminitis (Bailey et al., 2003). Fast digestive transit times and low production rates of α-amylase, result in the horse being relatively inefficient at the breakdown of starch within the small intestine. Rapid fermentation of cereal starch in the caecum and dorsal colon will ultimately yield lactic acid and can culminate in changes to the caecal bacterial populations (Bailey et al, 2003). Rising lactic acid levels, coupled with a drop in pH will result in the development of acidosis. It is believed that a window of opportunity exists between the occurrence of acidosis and the development of the symptoms associated with laminitis (Al Jassim, 2005) in which changes to diet could be made, thus preventing the eventual onset of the disease. It has been established that faecal pH is intrinsically linked to caecal pH, and studies reporting diet-induced pH changes in both horses (McLean et al., 2000) and pigs (Cahn et al., 1998), have shown close correlation between faecal and caecal pH. It is therefore postulated that faecal pH may be an indication of acidotic conditions within the hindgut of the horse and a faecal test to indicate acidotic status would obviously be of benefit. The aim of this study was to investigate optimal collection times of faecal samples destined for pH analysis, and to establish whether time of feeding significantly altered faecal pH, thus enabling further work to be carried out on the development of a faecal test for acidosis.

Dairy sheep production is an important industry in Greece and other Mediterranean countries. The traditional system of lambing once a year, as well as the size of the flocks and the extended lactation period has been an obstacle to implement accelerated breeding systems that could capitalise on the full potential of the ewe (Fahmy and Lavallee, 1990). The objective of this study was to develop a management system which combines an accelerated breeding scheme and grouping of ewes in relation to their milk yield, for large, intensively reared, dairy flocks.

Previous results have shown that during late gestation even under conditions of live weight (LW) gain, maternal body protein can be in negative balance due to the highly demanding gravid uterus and udder. It has also been claimed that current feeding standards underpredict dry cow nitrogen (N) requirement. Considering that it is not possible to measure maternal body N status independently of the requirements of the conceptus and the udder, estimation of conceptus and udder N requirements by mathematical models can help to predict maternal N requirement. The aim of this study was to assess cow N requirement during late gestation by predicting maternal N balance through a mathematical model. Previous results related with this study were presented in Jaurena et al, (2001).

The few days before and after hatch is a critical period for the development and survival of commercial broilers. Glycogen reserves in the chick embryo are significantly depleted during the perihatch period in order to meet the high energy demands during the process of emergence (Uni and Ferket, 2004). The immediate posthatch period is characterized by a transition from the use of lipid-rich yolk as the nutrient source to exogenous feed rich in carbohydrates and proteins. This transition is accompanied by rapid physical and functional development of the gastrointestinal tract (Sklan, 2001). The accelerated rate of development posthatch is reflected in the several-fold improvement in the development of the gastrointestinal tract and organ growth which will allow for a more efficient uptake of nutrients for muscle development. During late embryogenesis, solutions administered into the amniontic fluid (in ovo feeding) are consumed by the embryo, digested, and absorbed by the embryonic intestine prior to pipping (Uni et al., 2005). In ovo feeding of supplemental nutrients may help to overcome the constraint of limited egg nutrients (Foye et al., 2006). The objective of this experiment was to evaluate the effects of in ovo feeding of carbohydrates and threonine, alone or in combination, on growth performance of broiler chicks from 1 to 42 d of age.

The term biotechnology has been defined as the application of biological organisms, systems or processes to manufacture and service industries (Anon, 1980) and is, therefore, more than the application of ‘genetic engineering’ techniques alone. The potential application of biotechnology to the agricultural livestock industry includes many wide ranging areas: animal health; breeding; livestock production; livestock nutrition and the nutritive value of feeds. The role of biotechnology in animal nutrition and feeding is of particular importance since feed costs account for a significant proportion of the total variable costs in any livestock production system (e.g. milk, meat). The potential implications of biotechnology in animal nutrition has been reviewed by Armstrong (1986) and includes references to the improvement of the nutritive value of feeds through, for example, genetic manipulation of feed sources (cereals), appropriate supplementation and the use of biological inoculants with or without enzymes as silage additives and to improvements in the ability of the animal to obtain nutrients from feeds through the addition of enzymes to feeds and modification of rumen microbes through genetic engineering.

Rusitec has become the method of choice when studying the in vitro ruminal effects of the gram-positive ionophore monensin. The objective of the current study was to determine the in vitro effects of monensin treatment on volatile fatty acid (VFA) molar production and methane production from two complete diets which varied in maize silage:grass silage ratio and NaOH treated wheat grain:molassed sugar beet feed (MSBF) ratio.

The effects of high milk yields on the behaviour and welfare of the dairy cow are unclear. A high milk yield increases the need to consume sufficient fodder in an attempt to meet high nutrient demands. The failure to meet the demands may result in persistent hunger in the dairy cow having to modify her behaviour by employing various coping strategies. These modifications may help the cow overcome a state of hunger but at the expense of being unable to express other important behaviours. The objective of this study was therefore to determine whether the behaviour and welfare of the genetically high yielding dairy cow is being compromised by the increased nutritional demands of milk production, and to investigate the possibility that an increased amount of time spent in food-directed behaviours may have a detrimental effect on the time available to perform other important behaviours.

Previous research has demonstrated that dietary supplementation with high levels of die antioxidant vitamin E is effective in improving beef quality and shelf-life (Arnold et al., 1993). However, these animals did not have access to fresh forage which contains high levels of endogenous vitamin E and also higher concentrations of readily-oxidisable n-3 unsaturated fatty acids (Marmer et al, 1984). This study investigated the effectiveness of vitamin E in improving meat quality of grass finished cattle compared with those fed concentrates.

The value of a pig carcass is largely based on its lean meat percentage (LM%). The ultimate method of accurately measuring the lean meat percentage is a full dissection of the carcass. However, this is both time consuming and expensive. Lean meat percentage prediction equations have been established for various ‘probes’ and indicator cuts. Although these prediction equations have low (less than 2.5) Root Mean Square Errors of Prediction (RMSEP) and high R_a2 values, research continues to investigate other methods to produce equations with greater accuracy and to identify alternative techniques to full dissection. The aim of this experiment was to investigate the accuracy of lean meat percentage prediction equations using data gathered from 1) grading probes, 2) primal cuts and 3) photographs from cross sections of the loin.

The overall objective of our work is to assess the relative contributions of plant enzymes and rumen microbes to rumen degradation of freshly-ingested herbage. In situ techniques have been used extensively to compare rumen degradation characteristics of feeds, though there remain technical problems associated with microbial contamination of residues after incubation. We hypothesised that techniques to study microbial contamination might also provide insights into microbial colonisation. Our earlier studies (Lee et al., 1999) identified distinctive odd-chain fatty acids that could be used as microbial markers. A dacron bag study was conducted to examine the influence of dacron bag rinsing techniques on DM disappearance and microbial contamination in residues from fresh grass, assessed using odd-chain fatty acids as markers.

The success of any farm business relies on allocating resources optimally across all farming activities. This is particularly important for disease prevention activities because of their potential impact on farm business viability, the temptation to reduce such activity when funds are scarce and the possible implications for animal welfare and food safety. The objective of the current study was therefore to explore the relative impact of alternative disease prevention strategies under a range of different circumstances. This was done by example, using the case of BVD in a typical Scottish beef herd.

It is well established that the intake and digestibility of roughages by ruminants is positively correlated with rate of passage (ARC, 1980), presumably to enable as complete a microbial degradation of the poorer roughages as possible. On the other hand hind gut fermenters such as horses have been thought to have adopted the alternative strategy of using a high rate of passage to ‘cream’ off the rapidly degradable material of poor quality roughages so as to maintain adequate nutrient intakes. Surprisingly, there are remarkably few actual comparisons between ruminants and hindgut fermenters in the literature. Traditionally dried roughages (hay) and cereal and ‘by-product concentrates’ have been used as horse feeds (grains, brans sugar beet pulp). Recently there has been more interest in the use of silages with horses (eg Smoulders and Hobiers, 1988). However the information as to the utilisation of silages by horses is limited.

Any method to increase the utilisation of nutrients from feeds given to horses exercised on a regular basis is important. Commercially-available dried yeast cultures, used as supplements to equine diets have been shown to increase the digestibility of gross energy and enhance the retention of N in yearling horses (Glade and Biesik, 1986). There is however, limited information on whether the increase in digestibility of GE or enhancement in retention of N occurs in mature horses (Glade and Campbell-Taylor, 1990). The aim of the research reported here was to determine the effect of a dried live yeast culture on the digestibility of nutrients from a mixed diet given to riding school horses.

Six 2 and 3 year old riding school horses (mean live-weight 433 (s.e. 11.1) kg) were allocated to three balanced 2 x 2 Latin squares with two treatments and two periods of 3 weeks. The first 14 days of each period was a preliminary and the last 7 days was for measurement. The horses were housed individually (bedded on saw dust) and given 13.5 kg DM hay and 3.0 kg DM concentrate mix as a base diet. The base diet was either supplemented with 10 g dried yeast culture (S) or not supplemented (N).

A widely adopted procedure to characterize degradation in the rumen is the in situ incubation technique (IS), that assumes the washout fraction of feeds (W) to be equal to the soluble (S) fraction and that both are rapidly and completely degraded which may not be the case. Because IS technique is unable to measure the rate at which the W fraction is actually degraded; therefore, alternative washing procedures need to be developed to recover and fractionate the W fraction. Recently, simple washing procedure have been developed at Lelystad (method M) (Melin et al, unpublished results) and at Wageningen (method AA, SM and Y) (Azarfar et al., 2004; Yang et al., unpublished results), by which the feeds can be fractionated in a non-washout (NWF), an insoluble washout (ISWF) and a soluble washout fraction (SWF). The aims of this study were: 1-To study the effect of different washing procedures on the size of NWF, ISWF and SWF in some concentrate ingredients. 2- To study the effect of different dilution ratios (5, 10, 20, 30 and 40) on the size of SWF, and soluble true protein (STP) in some concentrates ingredients.

The in vivo digestibility of compound foodstuffs and ingredients can be predicted from laboratory techniques such as the in vitro rumen fluid (RF), the pepsin cellulase gammanase (PCG) and the neutral cellulase gammanase (NCG). There have been few comparative studies of these techniques using concentrate feed ingredients, especially since the addition of gammanase to the cellulase based techniques. Young et al. (1996) reported little difference between the cellulase based techniques in the accuracy of predicting in vivo organic matter digestibility (OMD) of concentrate ingredients, but both were superior to the rumen fluid technique. The objective of this study was to evaluate these techniques with a different set of foodstuffs which included less cereal and pulp samples but more maize by-products and oilseed meals.