It is recommended that the n-3 fatty acids intakes and the polyunsaturated/saturated fatty acids ratio be increased and the n-6/n-3 ratio reduced below 5 to reduce the incidence of cardiovascular diseases and cancers in humans. Linseeds are commonly used to increase the n-3 content in meat as they are an important source of C18:3 n-3 fatty acids. Owing to their small size, linseeds must be processed before being offered to cattle. The aim of this study was to compare the inclusion of crushed, flaked and extruded linseeds in a fattening diet of Belgian Blue cattle.

Toughness is a determinant of meat quality, a common cause of unacceptability in meat products and consumers are willing to pay higher prices for meat which is guaranteed to be tender. The calpain proteolytic enzymes are involved in the process of meat tenderisation through their degradation of muscle proteins postmortem (Sensky et al., 2001) and their activity is influenced by fluctuating levels of Ca2+, pH and temperature, all of which change rapidly in the immediate postmortem period. As vitamin D (vit D3) is responsible for Ca2+ homeostasis, we hypothesised that supplementing feed with vitamin D or vitamin D plus calcium propionate (CaPr) before slaughter would result in more tender meat through enhanced postmortem calpain system activity.

In line with international treaties, UK Government policy seeks to diminish the Global Warming Potential (GWP) of agricultural activities through reductions in Greenhouse Gas (GHG) emissions associated with livestock production. For suckler beef production systems these GHGs are principally methane (CH4) and nitrous oxide (N2O) associated with rumen fermentation of feeds consumed and management of manure produced by animals and spread on land. The objective of this simulation exercise was to simulate the GHG emissions and therefore GWP associated with a range of suckler beef production systems potentially available to current and future UK beef producers.

In line with international treaty obligations, UK Government policy seeks to reduce ammonia (NH3) emissions from livestock production systems. For suckler beef production systems NH3 release is principally associated with cattle grazing, emissions during winter housing, storage and management of animal manures and spreading of both animal manures and artificial fertilisers on land. The objective of this simulation exercise was to simulate the NH3 emissions associated with a range of suckler beef production systems potentially available to current and future UK beef producers.

Organic acids, most commonly fumarate and malate, when offered to ruminants have been shown to produce a decrease in methane emissions along with an increase in in vitro DM digestibility in rumen fluid taken from sheep (López et al., 1999). They are classed as ‘preservatives’ in the list of feed additives authorised by EU legislation, and as such are permitted for use in livestock (Castillo et al., 2004). However, the addition of fumaric acid to the diet has been associated with inappetance and problems of reduced rumen pH. Fumaric acid encapsulated in a soya oil capsule enables a slow release of fumaric acid in the rumen, which should overcome these problems. Encapsulated fumaric acid (EFA), when offered to lambs as 10% of the diet, reduced methane emissions by 75% and increased feed conversion efficiency by 20% (Wallace et al., 2006). To date, no in vivo studies have been carried out on dairy cattle. Therefore, the objective of this study was to determine the effect of addition of EFA on animal performance and methane production from grazing dairy cows.

Methane from enteric fermentation is a large component of livestock related greenhouse gas emissions. Typically, methane emissions from enteric fermentation represent on average 6% of dietary gross energy, but this varies greatly with diet (Johnson and Johnson, 1995). In order to mitigate methane emissions in a way that is acceptable for both the environment and animal welfare, it is important to quantify the effects of different diets on methane emissions. The objective of the current study was to determine the effect of different silages on methane emissions from dairy cows.

Livestock selection programmes have progressed from visual assessments to the use of quantitative information from multiple sources. More recently genetic markers have been used to incorporate information from quantitative trait loci (QTL) into selection decisions. The uptake this technology has been slow due to the cost and difficulty of discovering and using QTL. For a number of livestock species single nucleotide polymorphism (SNP)-chips are becoming available. These have the ability to genotype 10,000s of SNP markers in a single assay. This opens up the possibility of ‘genome wide selection’ (GWS) to ‘tag’ most of the genetic variants contributing to trait differences. This paper discusses what impact GWS might have in the main NZ livestock breeding industries (dairy, beef, sheep and deer).

Identification of quantitative trait loci (QTL) provides insight into the genetic control of growth and body composition in pigs. The majority of QTL have been identified on autosomes with less QTL reported on the sex chromosomes. A reason may be that the genomic analysis of the X chromosome is more statistically challenging. Computer programmes accounting for the unique features of chromosome X have been unavailable until recently. Most studies have adopted a regression-based approach analysing males and females separately, which results in a decrease in power to detect QTL. In the present study, a QTL analysis of pig chromosome X (SSCX) was carried out using a method which accounts for the unique features associated with chromosome X, including the pseudoautosomal region of the Y chromosome.

In 2006, myostatin single nucleotide polymorphisms (SNPs) were identified on ovine chromosome 2 (OAR2), with two SNPs (g-2449C-G and g+6723G-A) having significantly higher frequency in hyper-muscled Belgian Texel than in control animals (Clop et al., 2006). In particular, the A allele of the g+6723G-A SNP was proposed to be a causative mutation for increased muscularity in Texel rams (Clop et al., 2006). We aimed to assess whether the above two SNPs were present in UK commercial Texel, Suffolk and Charollais breeds. Moreover, we performed association analysis of the SNP effects on phenotypes in an extended UK commercial population of Charollais sheep in order to further evaluate the SNP contribution to muscle and fat tissue composition, and to quantify and fully characterise the SNP effects in this breed.

A QTL (TM-QTL) identified on ovine chromosome 18 (Walling et al., 2004), which increases loin muscle depth by 4-8% in UK Texel sheep, is of interest for the sheep industry as a potential means to increase carcass value. Since the contribution of Texel genes to the UK slaughter generation is generally through use of Texel sires to produce crossbred slaughter lambs (e.g. Texel x Mule lambs), it is necessary to verify the effects of the TM-QTL on loin muscularity and other carcass traits in such crossbred progeny of Texel sires before explotiation of the TM-QTL in commercial sheep populations.

The third build of the bovine genome comprises about 3 billion base pairs (bp; Ensembl, 2007). Locating functional DNA (fDNA) within this vast array of sequence is therefore a massive job. A method which can reduce the search space for this task may well have a wide application. It has been shown previously that the Neutral Indel Model (NIM; Lunter et al., 2006) can be used to locate a high proportion of human (Lunter et al., 2006) and bovine (Pollott, 2007) exonic DNA within a known 4% of the respective genomes. The NIM uses a mixture of methods from molecular evolution and comparative genomics to identify indel-purified segments (IPS) which should contain conserved fDNA. An IPS is the sequence located between two successive indels (insertions/deletions) and greater in length than a given threshold, as determined by input to the NIM method. Pollott (2007) found 64% of exonic DNA located in 233,715 IPS generated at a 0.1 false discovery rate (FDR) and these IPS overlapped with 87% of bovine genes. This increased to 81%, and 95%, respectively at a 0.5 FDR but the proportion of the genome searched increased from 3.3 to 10.7%. The objective of this work was to test some methods which may improve on the proportion of exonic DNA ‘found’ by the NIM without increasing the proportion of the genome searched by too much.

A microarray is an orderly arrangement of spots printed on an impermeable solid support, usually glass, silicon chips or nylon membrane. Each gene is represented by multiple spots and a single microarray chip can detect thousands of expressed genes simultaneously and in some cases the entire genome of an organism. Microarrays therefore allow high-throughput determination of changes in expression of thousands of genes of both known and unknown function in response to experimental treatment and so aids in the identification of novel genes associated with physiological pathways. For most mammalian species there is currently either a lack of a specific microarray or a limited coverage of the genome, both of which limit the use of microarrays in those species. For humans and rodents, however, there is complete coverage of the expressed genome. The aim of this study was therefore to determine whether the human Affymetrix GeneChip could be used to measure gene expression in a ruminant species and whether this is a viable alternative to species specific microarrays.

DNA polymorphisms have been well established for the diacylglycerol acyltransferase 1 (DGAT1), leptin and growth hormone receptor (GHR) genes, and they seem to correlate with several economically important traits in dairy cattle. In particular, a lysine-to-alanine substitution (K232A) and a phenylalanine-to-tyrosine substitution have been described for the DGAT1 (Kaupe et al., 2004) and GHR genes (Aggrey et al., 1999, Blott et al., 2003), respectively. Polymorphisms have also been identified within the leptin gene; for example, one has been found in an intronic sequence (RFLP1) and another inside exon 3 (Liefers et al., 2002). The objective of the present study was to determine the polymorphism status of these three gene loci in Holstein cows raised in Greece.

Beta-lactoglobulin (LGB) is the best studies protein and found in whey protein milk of ruminants. It has been observed that the heterozygous cows produce LGB-A much more then LGB-B (Wagnet et al. 1994, Gustafson et al. 2003). The differential expression of LGB-A and LGB-B has been suggested to be because of polymorphisms in the regulatory region of LGB, and where these promoter alleles occur in linkage distinct with the alleles in the coding part of the gene (Gustafson et al. 2003). In this study pyrosequencing and PCR-RFLP were utilized to estimate allele frequencies at positions -435(R10), -424(R9), -422(R8) and coding region at codon 64, and also linkage disequilibrium in three native breeds (Mazandarani, Sarabi and Golpaygani) and Holstein cattle of Iran.

Increasing scientific awareness of health and production promoting intestinal bacteria has enhanced the use of probiotic bacteria as active functional ingredients in animal and human nutrition. Strict selection criteria, suggested by Edens (2003), for potential probiotics in order to achieve well established and positive probiotic effects have been engaged, including the safety for the host and the capacity of the strains to be viable as well as metabolically active within the gastrointestinal tract (GI). In vitro methods have been used for screening potential probiotic strains using a dynamic model that mimics in vivo GI conditions as closely as possible. The objective of this study was to isolate, characterise and further select beneficial lactobacillus strains in an attempt to predict candidates that could be used in vivo as chicken probiotic adjuncts.

Native chickens are important in some rural areas. They usually produce meat and eggs without extra feed using only picked food. Improving their economical traits, such production efficiency would save these genetic resources. Kianimanesh (2002) showed that age at sexual maturity, number of eggs, egg weight and body weight at 8th week of age are among most important traits for improving economical efficiency of Iranian native fowl. Although, natural selection is the great evolutionary force that fuels genetic change in all living things, selection at the long term has important responses such as increase of inbreeding and decrease genetic variation. However, changes in average of production traits and population response in breeding programs after a few generations of selections depended on accuracy and intensity of selection, effective size of population and the rate of inbreeding. The aim of this research was to study the rate of additive inbreeding on some of the economical traits in Fars native chickens in Iran.

Iranian native fowls are raised for both meat and egg yield. Growth rate and egg production under conventional rearing systems in the villages are very low, Also, in past several decades imports of exotic breeds have increased the risk of extinction native fowl species. Evidence shows that there is good and useful variation in native fowl species for different traits, especially for those of economic importance. The objective of the current study is to estimate genetic parameters for economic traits of Iranian native fowl, so that efficient multi-trait selection programmes can be developed which will maximise economic return and secure genetic diversity.

High environmental temperature is one of the important stressors faced by laying hens usually in summer months. In a hot environment, hens exert extra effort to maintain their body temperature within a normal range. This challenge is associated with behavioural, physiological, hormonal and molecular responses. Hens in stressful environments decrease their rate of ovulation and also produce lower antibody response to a variety of antigens. Vitamin E and selenium have important roles in the antioxidant system and they have an influence on the immune system. Dietary supplementation with Vitamin E facilitates release of vitellogenine necessary for yolk formation which reduces its release in heat stress (Bollengier-Lee et al., 1998). Also, Chickens provided with organic selenium are more resistant to thermal stress than chickens fed inorganic sodium selenite (Mahmoud and Edens, 2003).

This study was conducted to determine the effect of dietary vitamin E and selenium, as well as comparison of organic and inorganic selenium, on performance, egg quality and antibody response to sheep red blood cells (SRBC) in laying hens exposed to high environmental temperature.

Broilers are unable to utilize palm kernel cake (PKC) efficiently because it contains high amounts of non starch polysaccharides (NSPs) and broilers do not have the full complement of the endogenous enzymes required to break down the NSPs to soluble carbohydrates. Microbial enzymes have been reported (Bachtar, 2005) to be able to act on both the endo and exo sites of NSPs, breaking both the ß-1,4 and ß-1,6 linkages with the production of soluble carbohydrates. Multi enzyme complexes from fungi have the potential to breakdown the NSPs in PKC thereby enhancing its nutritive value for broiler feeding. It was the aim of this study to apply enzyme extracts from Aspergillus niger, Trichoderma viride, Rhizopus stolonifer and Mucor mucedo on PKC and to investigate the effect of the biodegraded PKC on performance of broilers.

Aflatoxins (AFs), potent mycotoxins produced by the fungi Aspergillus flavus and Aspergillus parasiticus, are a major concern in poultry production. AF contamination causes reduced animal efficiency, increased susceptibility to environmental and microbial stresses and reduction of immune function (Miazzo et al., 2000). Different approaches such as the use of mold inhibitors, fermentation, physical separation, irradiation, ammoniation and ozone degradation have been used to prevent food contamination by AFs. Unfortunately, most of these procedures are expensive, time-consuming and only partially effective. Currently, the most promising and practical approach has been the addition of adsorbents (Mycozorb and aluminosilicates) to contaminated feeds to selectively bind the aflatoxin molecule. So far, the effects of aflatoxin adsorbents have not been evaluated on antibody titres of chickens. The purpose of this study was to evaluate the effects of sodium bentonite and a commercial yeast cell wall product (MycosorbTM) on antibody titres against Newcastle and Infectious bursal diseases of chickens fed rations containing AF.