Over the last twenty years, pig breeding has been very successful in the selection for improved lean meat production and reduced fat level. In order to meet increasing pressure to reduce fatness and increase muscularity in fatteners different types of meat boars are used by pig producers instead of traditional sires (Landrace, Large White or Duroc). There is some concern that meat and eating quality have suffered as a result of this strong use of meat boars. According to Warriss (2000), specifically the presence of Pietrain genes in many meat-line boars could potentially make their offspring more prone to the production PSE meat. Colour is the major determinant of appearance of raw meat. It can be determined by two main factors – the first is the concentration of the haem pigments, myoglobin and haemoglobin - the second is the muscle microstructure. Heavier slaughter weights have become a feature of a number of markets. Therefore, the objective of this work was to study the effect of sire genotype on the histochemical profile of the M. longissimus dorsi from pigs slaughtered at a relatively heavy weight the 129.3 kg.

β-agonists are known to enhance muscle growth in livestock species, although sometimes at the expense of increased meat toughness. In pigs, administration of porcine somatotropin (pST) produces muscle hypertrophy without detrimental effects on toughness. Calpastatin, a specific inhibitor that regulates the calpain proteinases responsible for cleavage of myofibrillar proteins, has a key role in growth and the rate at which meat tenderises postmortem. In the porcine calpastatin gene there are at least three calpastatin promoters (upstream of exons 1xa, 1xb and 1u respectively), of which 1u is used predominantly in skeletal muscle. All three promoters contain transcription factor binding motifs suggesting sensitivity to β-agonist/cyclic AMP (cAMP)/protein kinase A (PKA) and IGF-1/Ca2+/calcineurin-mediated signalling pathways (Parr et al., 2004). It was previously shown that expression of calpastatin mRNA from all three promoters can be increased in pigs treated with clenbuterol and suppressed in pST-treated animals (Sensky et al., 2004), suggesting differential regulation by the two pathways. In this study, the effect of manipulating these pathways is evaluated in vitro in order to determine if there is a specific element within the porcine 1u promoter that is responsive to both pathways, using rat muscle cells transfected with a series of 5’-deleted porcine 1u promoter constructs and treated with cAMP analogues and the calcium ionophore calcimycin.

Upland livestock systems dominate land use on upland semi-natural habitats of high conservation value. The future is unclear. CAP reform is likely to highlight the poor financial performance of hill livestock, cross compliance may be very light and agri-environmental support for positive management is likely to be limited. There is much debate about management for different objectives. Trends of abandonment of livestock grazing may continue. This paper highlights alternative outcomes of management of semi-natural grasslands and the linked impacts on livestock production.

In heterogeneous environments, such as complex vegetation mosaics, there is likely to be a dynamic interaction between the spatial pattern of the vegetation and the distribution of the animals grazing there. Preferences for particular vegetation types will influence where animals choose to feed and, in turn, changes to the vegetation caused by damage from grazing and trampling will affect the dynamics of the mosaic. Social interactions, amongst highly social grazers such as sheep, can also affect the distribution of the animals, depending on the relationship between the dimensions of vegetation patches and the characteristic spacing of the animals. The aim of this study was to investigate the relationship between patch utilization and patch size for small groups of Scottish Blackface sheep foraging in a natural heather (Calluna vulgaris ) and grass mosaic.

Developments in UK agriculture and nature conservation provide promising prospects for native breeds of farm livestock, and hence for the conservation of their genetic resource, but only if certain difficulties can be overcome. This analysis explores the opportunities provided by those developments, the strengths and weaknesses of the use of native breeds in conservation management, and threats posed to native breeds by extraneous factors.

Invertebrates are of particular interest on heather moorlands because of their rapid response to small scale habitat changes. Spiders constitute a variable proportion of the diet of heather moorland bird, mammal and reptile species. Furthermore, spiders may be an important indicator of habitat change resulting from management practices, especially those that exert a large- scale spatial impact, e.g. grazing. The component families and species of spider assemblages indicate, through their differing preference for web attachments and web structure, the vegetation density, height and structure (Marc et al., 1999). This effect may be especially pronounced where continued grazing at a particular stocking rate results in characteristic patterns in the vegetation structure. Species and family specific hunting strategies determine prey type and so the presence of some spider species may indicate the presence of a preferred prey species. This study aims to investigate the effect of grazing with sheep alone or in combination with cattle grazing on an upland heather moorland in the north of England.

Most agricultural grassland in lowland UK is species-poor and structurally uniform. Management intensification has had a deleterious affect on the biodiversity of invertebrates and the suitability of grassland as feeding and breeding habitat for birds (Vickery et al. 20001). The PEBIL project (Defra BD 1444: Potential for Enhancing Biodiversity in Intensive Livestock Farms) is investigating the effects of structural and plant species manipulation on the invertebrate communities of field margins. The different treatments are designed to test the effects of increasing amounts of sward structural heterogeneity, in terms of canopy height, architectural complexity & botanical composition, on faunal abundance and diversity as well as improving food resources for birds.

Sheep and cattle interact with arthropods (e.g., insects and spiders) and small vertebrates (e.g., passerine birds and small mammals) directly and indirectly by the removal of vegetation during grazing, the trampling of vegetation and soil, and the deposition of excreta, associated with the redistribution of nutrients. The cold and wet upland and montane biotopes have low productivity, and grazing by free-ranging domestic livestock alters structure more than botanical composition of the vegetation in these biotopes over short periods (one to three years). In contrast to productive lowland or intensified upland pastures, upland and montane biotopes include patches of vegetation with a high proportion of leaf litter associated with plant species that are unpalatable or of poor nutritional value for grazers.

Habitats associated with livestock production systems are important in terms of avian biodiversity in the UK and across Europe. Livestock play an integral role in structuring grassland habitats, which in turn affects their suitability for different ground-nesting bird species. Such habitat engineering is driven mainly by the effect of grazing on plant species composition and vegetation structure. However, ground-nesting birds are also negatively affected by the presence of grazing animals since livestock destroy nests mainly through trampling.

Field studies of grazing management have frequently concluded that the magnitude and direction of vegetation response is dependent on initial vegetation condition. On upland heath, this dependence reflects the importance of small-scale ecological processes (e.g. plant competition), and local neighbourhood effects (e.g. spatial distribution of plant species), in driving the vegetation dynamics. These small-scale effects, together with variation in grazing patterns, increase the difficulty of deriving general rules about the effect of grazing on vegetation change from field studies. However, we need to determine the impacts of such grazing-related vegetation change upon biodiversity, (e.g. birds). For many bird species it is impractical to use experimental approaches due to low breeding densities, and the influence of other site and management effects (e.g. predator control). To predict the effect of management changes on them requires an accurate assessment of the large-scale effects of grazing management on the ecological landscape using data from small-scale field studies. This paper sets out an approach that integrates field studies with theoretical models to investigate the large-scale effects of grazing management on plant and bird communities on upland heath.

Microbial protein contributes about two-thirds of the amino acids absorbed by ruminants. Information on the proportion of bacterial and protozoal N passing to the duodenum would enhance our understanding of the effect of diet not only on microbial protein synthesis but also on the contribution of bacteria and protozoa to duodenal flow of others metabolites of interest. However, differentiation of the duodenal fractions has proven to be difficult because routine procedures cannot separate microbial protein at the duodenum into bacteria and protozoa (Punia et al., 1992). Molecular techniques that use group-specific rRNA-targeted probes may help overcome these problems. The objective of this experiment was to quantify the flow of protozoal N at the duodenum in steers, fed two silage diets differing in water soluble carbohydrates (WSC) content, by real-time PCR using protozoa specific primers.

Data on ruminal metabolism of lipids from forages have shown extensive biohydrogenation of C18 polyunsaturated fatty acids (Lee et al. 2003). Recent studies have noted a reduction in biohydrogenation an increase in duodenal flow of C18:1 trans- 11 and a shift in the ruminal production of CLA from cis- 9 trans- 11 CLA towards trans- 10 cis- 12 CLA with increasing amounts of concentrate in the diet (Kucuk et al. 2001, Loor et al. 2004). The study assessed the effect of feeding steers on isonitrogenous and isolipid diets differing in forage concentration and supplemented with linseed oil on ruminal lipid metabolism.

This review surveys the nutritional and veterinary effects of tannins on ruminants and provides comparisons with non-ruminants. Tannins are a diverse group of naturally occurring compounds with useful biological effects. However, currently there are difficulties in predicting which tannins produce what effects.

Milk fat conjugated linoleic acid (CLA) concentrations are higher for milk produced from cows grazing fresh pastures than for milk when conserved forages are fed (Jahreis et al., 1997). This experiment investigated the hypothesis that this increased CLA production results from the action of volatile compounds (hydroperoxides, alcohols, aldehydes and ketones) released during the cutting of grass (De Gouw et al., 1999).These compounds have antimicrobial activities (Kubo et al., 1995) and may have an effect on rumen microbial populations.

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 ability of a ration to meet the nutritional needs of a high yielding dairy cow requires understanding of both the chemical and physical characteristics of the ration (NRC, 2001). Having the proper particle size distribution (2 to 8 percent of the particles on the upper sieve, 30 to 50 percent on the middle and lower sieves, and no more than 20 percent on the bottom pan) of feeds is an important part of ration formulation. Chopping the crop at the proper length produces forages that can be combined to achieve the desired particle length in a TMR. The dairy cow’s need for increasingly higher levels of energy have led to diets relatively high in concentrates. However, cows still require adequate fibre in the ration to function properly (Allen, 2000). Adequate forage particle length is necessary for proper rumen function and reduced forage particle size has been shown to decrease the time spent chewing and cause a trend toward decreased rumen pH. When cows spend less time chewing, they produce less saliva, which is needed to buffer the rumen. The objective of this study was to evaluate the effects of reducing alfalfa hay length of cut on TMR particle size distribution, rumen pH and chewing activity using penn state particles separator.

Rapeseed meal (RSM) is the richest source of commercially available home grown protein in the UK, but its inclusion in livestock diets is approximately half that of soyabean meal (SBM, DEFRA, 2004). RSM has a lower protein and available lysine content than SBM but increased nutrient digestibility was observed when pigs were fed RSM supplemented with non-starch polysaccharide degrading enzymes (Hoare et al., 2003). The objective of this experiment was to determine the effect of adding different amounts of a cell wall degrading enzyme on the available amino acid content of RSM as estimated in poultry.

By-product-based diets generally contain lower levels of energy than cereal-based diets due to higher levels of fibre (Bakker et al., 1995). Supplementation with oil is a common method of improving the digestible energy content of by-product-based diets and it has been reported that this practice may also improve energy digestibility. However, the results of McCann et al., (2004) suggested that the method of oil application to finishing pig diets may affect the digestibility of dietary nutrients. The aim of this experiment was to compare apparent digestibility coefficients determined in finishing pigs offered either by-product based diets or cereal-based diets, with and without vegetable oil blend supplementation applied using two different methods (either directly incorporated into the pellet (IN) or sprayed (SP) on after pelleting).

Oil supplementation of by-product based diets is a common method of increasing the energy content of pig diets to levels equivalent to those of cereal-based diets (Overland et al 1999). However, by-product based diets supplemented with oil have been reported to reduce feed intake and digestible energy intake when compared with cereal-based diets (Magowan et al 2004). It is not known whether this effect occurs as a result of the higher levels of fibre in by-product-based diets or as a result of a reduction in palatability arising from the inclusion of oil in the pellet. The aim of this experiment was to investigate the effect of method of vegetable oil blend application (either incorporated directly into the pellet (IN), or sprayed on after pelleting (SP)) on the performance and carcass characteristics of commercially housed finishing pigs.

The nutritional benefits of consuming long chain n-3 polyunsaturated fatty acids (PUFA), which are predominantly found in oily fish, are well known but consumption of oily fish is declining. Poultry consumption, on the other hand, is increasing, but poultry meat is generally a poor source of long chain n-3 PUFA. The concentrations of the n-3 PUFA α-linolenic acid (LNA), EPA and DHA in poultry meat may be increased by feeding birds diets that are themselves rich in these acids. The objective of this study was to review the literature to determine what relationship if any there was between n-3 PUFA content in the diet and edible tissues of poultry.