Feedlot management systems for beef cattle are becoming a more common practice in Australia reflecting opportunities to ensure quality of product whilst maintaining cost efficiencies within production. However, feedlot systems have been identified as point sources of greenhouse gases emissions (GGE: methane, nitrous oxide and the indirect greenhouse gas ammonia). It has been estimated that feedlot systems contribute 3.5% of total direct methane emissions (Alford et al. 2006), and 30% of total emissions from livestock wastes. Furthermore, approximately 1% of total N2O emissions from agriculture are attributed to livestock. This paper reports methane, N2O and NH3 emissions from an Australian feedlot system managed under summer climatic conditions. It compares actual measured emissions with estimated from three recognised models used by national governments to estimate total GGE per annum from livestock agriculture.

Because ruminants make a significant contribution to greenhouse gas emissions, attempts are being made by dietary manipulation, to mitigate methane emissions without altering animal performance. Dietary fat supply may be a promising solution (Martin et al., 2008a). A first experiment has shown that increasing extruded linseed supply in a hay-based diet resulted in a decrease in methane production (Martin et al., 2007). A second experiment has been carried out using a maize silage-based diet and the same linseed supply. The present abstract summarises the results of both experiments.

Mitigating, or abating, greenhouse gases (GHG) from livestock systems can play a vital role in providing solutions to the UK’s climate change obligations. The main abatement options from the livestock sector, independent of grazing/pasture management, are through the efficiencies with which ruminant animals utilise their diet and manure management. Options include breed selection, through manipulation of dietary regimes or manure storage strategies. Attempts to abate GHG emissions should first target those abatement options that are cost efficient and this study estimates the cost effectiveness of selected options for the UK livestock sector.

The economic appraisal of greenhouse gases (GHG) emissions is complex. The shadow price of carbon (SPC) is derived from the best estimate of the present value of damages associated with a tonne of GHG emission in carbon dioxide equivalents (CO2 eq). The SPC rises with time, reflecting the increasing marginal damage of a tonne of GHG when added to a growing stock of atmospheric GHGs. There are many possible technical mitigation options for livestock systems, one of which includes harnessing selection tools. The study of Stott et al. (2005) describes how relative economic values (REVs) are calculated for traits included in the UK dairy profit index (£PLI) using dynamic programming tools to model a whole farm system. The REV for each trait is calculated by examining the consequence of a unit change in a trait of interest on net farm revenue, while keeping all other traits in the index fixed. The SPC provides a useful mechanism of considering the costs of GHG emissions in an economic index framework, such as £PLI. This study outlines methods for incorporating the environmental value of emissions mitigation into breeding goals.

A series of studies have been undertaken to examine effects of dietary protein source and concentration on milk production, energy and nitrogen (N) utilisation efficiencies and fertility in dairy cows. The present study evaluated effects of dietary crude protein (CP) concentration on energetic efficiency and methane emission in lactating dairy cows.

Irish livestock account for 0.55 million tonnes of methane (CH4) annually from enteric fermentation and manure management (EPA, 2006). However, recent studies have shown the potential to reduce ruminal methanogenesis through strategic dietary supplementation with polyunsaturated fatty acids (PUFA; Jordan et al. 2006). This is likely to be mediated, in part, through the unsaturated double bonds of PUFA acting as sinks for free hydrogen during ruminal biohydrogenation. Fish oil is acknowledged as the richest natural source of long chain n-3 PUFA such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids (Ruxton et al., 2004). Despite this, there is little published information on the effect of dietary fish oil supplementation on in vivo ruminal methanogenesis in cattle. The aim of this study was to assess the effect of a novel concentrated n-3 PUFA fish oil, on the intake and CH4 emissions of beef steers.

Enteric fermentation in ruminants is an important source of methane (CH4) production. In the UK, ruminants contribute approximately 20% of all CH4 emission, with most arising from cattle. This presents a considerable challenge for the dairy industry in the battle against global warming, and reduced CH4 emission is likely to be a major target for government policy within the next few years. The objectives of the present study were to evaluate the effects of level of concentrate supplementation and cross-breeding of Holstein cows with Jersey sires on CH4 production.

Ruminants lose about 8 to 12 % of their food energy as methane (CH4). Eructation of CH4 from ruminants may contribute to the climatic change and global warming. Reducing CH4 production can be of direct economic benefit because it coincides with greater energy-use efficiency of feeds by the animal. To reduce CH4, antibiotics have been used in addition to their use for growth and disease prevention. However, the European Union has banned the use of antibiotics in animal feeds from January 2006, so there is a need to find alternative methods to reduce CH4 production. It has been shown that tannin and unsaturated fatty acid can play important roles to reduce CH4 production in ruminants (Patra et al., 2006; Giger-Reverdin et al. 2003). Some spices are high in tannin and others are high in fatty acids. In the present study, the chemical composition of five spices and their role in reducing in vitro CH4 production were assessed. Ground wheat (wheat) is a highly fermentable feed as it can produce large amount of gas, and it was therefore used as a substrate to compare the effects of spices on in vitro rumen fermentation in this study.

The extent of periparturient relaxation of immunity (PPRI) to gastrointestinal nematode parasites is sensitive to metabolisable protein (MP) scarcity but also varies between breeds of sheep (Houdijk, 2008). For example, under ad libitum feeding, Scottish Blackface ewes had a lower extent of PPRI than Greyface ewes (Zaralis et al., 2008). Such between-breed variation in PPRI may not necessarily be associated with genetic resistance per se but could arise from a higher nutrient demand of the more productive Greyface ewes (Houdijk, 2008). This experiment was designed to test the hypothesis that if the extent of PPRI has only a nutritional basis, then the sensitivity of PPRI to MP scarcity will not differ between the breeds when MP feeding is adjusted for between-breed differences in MP demand.

Scouring (diarrhoea) is a major concern for sheep producers as the accumulation of faecal material (dags) around the breech pre-disposes sheep to flystrike. Scouring occurs when the consistency of faeces is fluid with a low percentage of dry matter. In temperate areas such as the southern half of Australia, New Zealand and the United Kingdom, scouring is associated with ingestion of parasitic nematode larvae, mainly Teladorsagia circumcincta and Trichostrongylus colubriformis (Larsen et al., 1994). Breeding sheep to be resistant to these nematodes is a sustainable parasite-control strategy due to reduced reliance on chemical treatment. However, in adult sheep, scouring appears equally prevalent in resistant animals and, in some environments, is even more severe than in susceptible sheep (Karlsson et al., 2004). In this experiment, we investigated how faecal dry matter (FDM) in sheep from a flock bred for resistance to parasitic nematodes changed when challenged with infective larvae. We expected that FDM would be lower in challenged sheep compared to unchallenged controls, and FDM would also be lower in sheep with high dag scores compared to sheep with low dag scores.

Porcine reproductive and respiratory syndrome (PRRS) is an endemic pig disease in most European countries, causing respiratory distress, fever and growth reductions in growing pigs and increased litter mortality in sows. The disease is characterised by exceptionally long-term viral persistence within the host, a weak innate host immune response and delayed adaptive host immune response, and large between animal variation in the immune response (Murtaugh et al., 2004). Although numerous in-vitro and in-vivo studies produced valid insight into the fine details of the virus dynamics and its interaction with the host’s immune response, several fundamental questions concerning the role of diverse immune components and host genetics remain unanswered. In this study mathematical models were developed to investigate the role of diverse processes caused by the virus or the immune response on the infection characteristics.

The bacterial populations present in the porcine gut play an important role in pig health. A number of factors may influence these populations including diet, medication and environment. To identify what effects rearing environments have on the gut microbiota, this study compares the numbers of four common groups of gut organisms – enterococci, Bacteroides spp., lactobacilli and coliforms – in faecal samples taken from pigs reared either indoors or outdoors. The presence of three zoonotic bacteria – Campylobacter jejuni, Clostridium difficile, and Verocytotoxigenic Escherichia coli O157 -was also assessed to determine whether rearing environment might influence the threat of zoonotic infections.

Pharmacological levels of zinc oxide in the post-weaning piglet diet reduce the incidence and severity of diarrhoea, in particular that caused by enterotoxigenic Escherichia coli (ETEC) K88 (Owusu-Asiedu et al. 2003). A previous in vivo genomic study (Sargeant et al, 2008) identified several genes differentially expressed in the small intestine of ETEC-challenged piglets when fed a zinc oxide-supplemented diet. This included decreased expression of several genes involved in the inflammatory and innate immune response. It has been reported that ZnO reduces adhesion and internalisation of K88 to cultured human enterocytes, counteracting the up-regulation of inflammatory cytokines caused by ETEC infection. However, this effect was not due to growth inhibition of ETEC K88 in ZnO (Roselli et al, 2003). The objective of this study was to determine whether zinc oxide shows the same mode of action in protecting porcine intestinal cells against ETEC K88 as has been demonstrated in human cells, providing an explanation for in vivo findings.

Crossbreeding is common practice in commercial pig production as one way to increase lean growth and improve meat quality (Visscher et al., 2000). Reducing disease is another way to help improve growth rate in pigs. Porcine circovirus type 2 (PCV2) has devastated the pig industry in recent years. PCV2 infection increases mortality and reduces growth rate as it acts as an immunosuppressant thereby making pigs more susceptible to co-infections (Kixmöller et al 2008). Keeping disease at low levels has been achieved by improving husbandry standards, biosecurity, minimising presence of other pathogens and use of antibiotics. However vaccines against PVC2 are now available. The aim of this study was to investigate the effects of sire genotype and PCV2 vaccine on growth performance and body composition of pigs.

Farmers have become heavily reliant on anthelmintics for the control of nematode parasites Due to the widespread development of anthelmintic resistance, alternative approaches for control of nematode parasites are needed. Cruden and Hovell (2008) reported that commercial lambs treated with quebracho tannin had reduced faecal egg counts and improved lamb growth. This paper reports a second in vivo study with quebracho tannins at higher dose rates in lambs.

The consumption of plants rich in plant secondary metabolites has been associated with improved resilience of parasitised hosts, i.e. their ability to perform under parasitic infection, compared to animals fed conventional feeds (Athanasiadou et al., 2007). Furthermore, such bio-active plants can improve host resistance, which refers to the host ability to regulate gastrointestinal nematode establishment, development, fecundity and survival (Athanasiadou et. al. 2008). Chichorium intybus L. (chicory) is such a bio-active forage and its potential anthelmintic activity is currently investigated as an alternative means to control parasitism in sheep production systems. In the present study we employed an in vitro assay to study a possible mechanism of anti-parasitic action arising from chicory, and to test whether this anthelmintic activity is affected by the vegetative stage of the plant.

The overall trend of the reproduction performance is a reduction since at least 20 years. In Belgium, the pregnancy rate at artificial insemination decreases about 1% per year (Opsomer et al, 2006). To obtain good reproduction performance, many requisite factors are necessary. Health status, nutritional status or production level are some well-known examples. Many studies review these factors and their impact on the reproduction performance. The aim of this work was to describe the impact of health status, production and management on the reproduction performance in Walloon farms.

The significant contribution of pig production in the supply of high quality protein in Nigeria is evident in the rapid increase in number of pig farms witnessed recently. However, African Swine Fever (ASF) has since ravaged pig farms and consequently resulted in loss of farmers’ investments especially in some parts of the Southwest Agro-ecological zone of Nigeria (Majiyagbe et al., 2004; Otesile et al., 2005; Olugasa and Ijagbone, 2007). Putting the growth of the enterprise back on track requires proper assessment of the socio-economic environment surrounding the spread of the disease with the aim of determining the extent of infection, the consequences in terms of mortality of animals and loss of revenue alongside identifying farm specific factors that could have contributed to the spread. This study thus investigated the incidence of ASF and its socio-economic implications on pig enterprise in the zone.

Technological meat quality has a significant economic impact and many publications have shown that pig meat quality is strongly influenced by the effect of genetic type (especially Hal and RN genes) and by rearing and slaughter conditions (Sellier and Monin, 1994). The quality of meat is generally assessed by measuring meat pH at different times post mortem, colour or drip loss. Our study consists on a meta-analysis based on 11 publications in order to assess the possibility of predicting the effects of halothane gene, sex, breed and slaughter weight of animals on three selected parameters: pH at 45 minutes post mortem (pH45), ultimate pH (pHu) and reflectance (L*-value).

Most quantitative trait loci (QTL) studies have focussed on the identification of individual QTL effects (additive, dominance and imprinting) in the absence of interactions (epistasis). There are numerous reports in the literature for QTL associated with growth and body composition of pigs, however much less effort has focussed around the identification of epistatic QTL for these traits. Growth and body composition of pigs are probably influenced by numerous QTL located throughout the genome as well as interactions between QTL. Therefore the objective of this study was to investigate the contribution of epistasis to the genomic regulation of growth and body composition of pigs.