Various studies in dairy cows have shown that their Body Condition Score (BCS) effectively reflects their nutritional status and energy content (Ferguson et al. 1994). Extremes in BCS and BCS losses have been identified as a risk factor for health problems and reduced reproductive efficiency (Markusfeld et al. 1997, Lopez-Gatius et al. 2003). Body condition scoring is easy and inexpensive to perform and gives a reliable estimate of body energy reserves. Hence, in practice, BCS can be used as a tool for ration formulation and management decisions concerning reproduction of dairy cows (Banos et al. 2004). The objective of this study was to determine and quantify the impact of BCS in the reproductive performance of primiparous Holstein cows.

Competition data is widely used in the genetic evaluation of racing (Belhajyahia et al., 2003) and showjumping horses (Reilly et al., 1998). However, its use in the evaluation of eventing horses is rare. In a previous study, we investigated the use of competition results for the evaluation of eventing horses by examining the component parts of eventing competition – dressage, showjumping and cross country (Kearsley, unpublished). The aim of this study is to estimate genetic correlations between the different phases of eventing competition at pre novice and novice level as part of a project to predict breeding values for British sport horses.

Recently, Pollott (2000, 2004) has proposed a biological model of lactation which mimics the three processes of cell proliferation, apoptosis and milk secretion rate per cell during lactation. This model has been used on dairy sheep and cattle to investigate several aspects of its utility to account for the factors which influence the milk production during lactation. Pollott and Gootwine (2001) and Pollott (2002) reported genetic parameters of the biological model for a single flock/herd sheep respectively. Here we report an extensive genetic study of over 400 UK dairy herds using the biological model of lactation.

Inbreeding occurs when related individuals are mated to each other. Inbreeding reduces milk production, and impairs health, fertility and survival; a phenomenon known as inbreeding depression. Smith et al. (1998) reported losses in milk yield of 27 kg per 1% increase in inbreeding in US Holsteins. The objective of this study was to investigate the level of inbreeding in Irish Holstein-Friesian cattle and to quantify its effect on milk, fat and protein production and somatic cell count.

In January 2006, ANAFI (Italian Holstein Breeders Association) introduced a genetic evaluation for fertility based on a multiple-trait animal model (Biffani et al., 2005), which included the following traits: days from calving to first insemination (DTFS), calving interval (CI), first-service non return rate to 56 d (NR56), angularity (ANG) and mature equivalent milk yield at 305 d (ME305). Breeding values have been subsequently combined in an aggregate index (T), with the breeding goal to increase conception rate (CR). This paper will show how the breeding values have been combined into an aggregate index. At the same time the efficiency of selecting on alternative aggregate indexes versus the official aggregate index is presented.

Peri- and postnatal mortality of piglets is reported to be around 20% and genetic improvement in piglet survival has great potential benefits in terms of animal welfare, economics and the environment. The indication of an unfavourable genetic correlation between litter size and survival in particular points to the importance of including piglet survival in those pig breeding programmes that currently only aim to increase litter size. Phenotypically, individual birth weight is closely associated with piglet survival (Roehe and Kalm, 2000). Genetic parameters for piglet survival traits and individual birth weight therefore need to be estimated in order to genetically improve piglet survival efficiency

The reproductive performance of ewes is a major factor influencing the economic success of lowland flocks. Even so reproductive traits have not often been included in sheep genetic improvement programs because of their low heritabilities compared with other performance traits like body weight and carcass merit. Litter size is one of the most important traits affecting reproductive performance. There are two important factors to be considered in the genetic analysis of litter size. First, several authors have suggested that litter size in different parities is controlled in part by different genes, and therefore should be treated as different traits. Second, ignoring the categorical nature of litter size and analysing it using a linear model does not account for its non-normal distribution. As a consequence, threshold models are likely to be more appropriate for the analysis of categorical traits (Gianola and Foulley, 1983). Therefore, the objective of the current study was to estimate the genetic parameters for litter size of Mule ewes using both repeatability and a multiple trait threshold models for repeated observations of litter size across four different parities.

Genetic selection has dramatically increased the potential for growth, feed efficiency and yield in meat type broilers. It is a widely held belief that these improvements in genetic potential have produced a broiler that is lower in fat content. However, some recent work has implied that the Modern broiler is actually fatter than its counterpart of 30 years ago (Wang et al., 2004). The objective of this study was to explore the impact that selection for growth rate and yield has had on broiler body composition.

The general aim of selection in animal breeding is to acquire new generation of animals, which under future economic conditions of production system are more efficient than the present generation. In selection index method, genetic trend of important traits is directed based on their weights in economic efficiency of production system to acquire maximum improvement in economic merit (Mirhosseini et al., 2005). Silkworm commercial egg is produced by crossing between Japanese and Chinese origin parent stocks. There are three steps in the cycle of egg production including GGP (great grand parent), GP (grand parent) and P (parent stock). Breeding programs along with high selection pressure are used only in GGP lines which are typically much smaller in size than other stocks. The objective of this study was to evaluate effect of six generations of index selection in the GGP lines on performance of commercial silkworm hybrids.

The primary emphasis of the long-term Sahiwal cattle breeding programme is to increase milk yield by selecting cows based on their performance in first three lactations. It is therefore important to have knowledge on the extend of additive genetic variance and genetic parameters for these traits. Genetic and phenotypic parameter estimates normally apply directly to the specific population and environment from which the data were collected. In the Sahiwal cattle in Kenya, very little is known about the genetic variation of milk production traits and their genetic relationships. Furthermore, genetic and phenotypic parameter estimates for the Sahiwal cattle based on multivariate animal model are scarce. This paper presents estimates of variance components and genetic parameters for milk production traits using trivariate animal model.

Performance of one genotype in similar climates is approximately the same but if this genotype is introduced into a different climate, its performance will be affected, based on Nizamani and Berger (1996). The function that relates phenotype to environment is unique for each genotype. Hence, the response to changes in environment may vary from one genotype to the other, based on Mulder et al. (2004). Different selection responses between environments are generally attributed to two types of genotype by environment interaction. The first type occurs when the genetic correlation between performances in two environments is substantially less than 1.0, indicating a genetic difference basis for the trait in the two environments. The second type of genotype by environment interaction results from heterogeneous variances, based on Ojango and Pollott (2002). The goal of this study was to estimate genetic (co)variances, environmental variances, and genetic parameters of milk production and fat yield among different environments in Iran to determine variables that are useful indicators of genotype by environment interaction.

Baluchi is the most common native breed of sheep in Iran, comprising 30% of the sheep population. This breed is native to the eastern part of the country, which has a dry and hot climate. The animals have had to adapt to the harsh environment. In order to improve efficiency, the performance of the animals for economic traits is used to estimate genetic parameters and selection in some nucleus flocks. The genetic and phenotypic correlations between weight traits have been reported for different breeds. The objective of this investigation is to estimate the genetic parameter and genetic and phenotypic correlations between weight traits.

Index selection is the most effective selection strategy to improve total merit. Index selection requires the economic values (EVs) of the traits in the breeding goal and the genetic parameters of the traits in the breeding goal and in the index (Hazel and Lush, 1942). According to this theory, in most countries a national selection index has been developed for dairy cattle (Miglior et al., 2005). In Iran a national selection index has not yet been developed. The first objective of this study was, therefore, to estimate economic values for production traits (milk, fat and protein yield) and longevity for Holsteins in Iran. The second objective was to compare the proposed Iranian selection index with selection indices of other countries in the world.

Outdoor reared pigs are said to suffer from less of a growth check post weaning than their indoor reared counterparts, Payne et.al (2003). Zinc oxide (ZnO) is often used to reduce the incidence of post weaning scours and the use of sodium butyrate as an additive in weaner pig diets has been shown to improve some aspects of small intestine structure (Miller et.al, 2006). The purpose of this experiment was to investigate the effects of butyrate supplemented weaner diets with or without a ZnO background (3.1 or 0g/kg ZnO) upon gut structure immediately post weaning in both indoor and outdoor reared pigs. We hypothesised that piglets reared outside would have a more developed gut than indoor reared pigs when weaned at 4 weeks and that the presence of ZnO and butyrate would further enhance gut development.

The current estimate of live-born piglet pre-weaning mortality in UK outdoor systems is 11% (MLC, 2006), representing a major welfare and economic concern. The majority of deaths occur in the first few days of life when the piglets are at their most vulnerable. Selecting for high survival in piglets, may allow breeding of animals better able to survive and better suited to alternative and less restrictive systems than the farrowing crate. The aim was to develop and measure behavioural and physiological indicators of neonatal survival, and to determine treatment effects in populations of piglets selected for high survival and control lines farrowing in an outdoor system.

Outdoor piglets are reported to eat more readily post-weaning than indoor pigs and show improved post weaning performance (Cox and Cooper, 2001). They are therefore likely to be less reliant on the inclusion of antimicrobial agents in the diet post weaning to enhance performance. Similarly piglets which are older at weaning should also be more resilient and less likely to benefit from antimicrobial agents in the feed. In this experiment we compared piglets reared indoors with those reared outdoors at two different weaning ages to determine whether performance was less dependent on dietary antimicrobial additives in the outdoor-reared older pig.

Starch is of major importance to the young piglet, since by weight it constitutes the largest portion of the diet and is the major energy-yielding component. Usually provided in the form of cereals, the digestibility of starch is fundamental in contributing to the dietary energy requirements of the animal. Two trials were designed in order to examine the effect of variability between raw cereals on the digestibility of starch in the newly-weaned piglet.

The prophylactic use of in-feed antimicrobial growth promoters (AGP) in weaner pig diets has been banned within the EU and emphasis must therefore be placed on the development of effective nutritional strategies for disease prevention. Manipulating dietary protein supply (Wellock et al., 2006) and the heat treatment of cereals (Doucet et al., 2006) have been shown to improve gut health, decrease the risk of enteric disease and minimise the post-weaning growth check under experimental conditions, by decreasing substrate availability to potential pathogens, such as enterotoxigenic E. coli (ETEC). The aim was to investigate the combined effects of protein level and diet quality on the health and performance of weaned pigs in the absence of AGP and therapeutic levels of ZnO and CuSO4 in a large-scale facility.

Although dietary composition for weaned pigs can be altered to promote a beneficial microflora which resists proliferation of pathogenic bacteria, this concept has yet to be applied to the pre-weaning phase. Commercial creep feeds typically are highly digestible and based on milk products and cooked cereals which, in the presence of lactase enzyme activity in the suckling piglet, promote relatively limited microbial fermentation in the gut. The gut flora therefore remains relatively immature and less able to deal with the challenges of weaning and transition to a non-milk diet. Recent studies in weaned piglets have shown how dietary ingredients such as inulin can enhance the proportion of beneficial bacteria in the gut (Wellock et al., 2006), and thus may provide a more stable gut pH and microflora over the weaning transition. Similarly, addition of sodium butyrate to the diet can enhance gut architecture (Miller and Slade, 2006), which could promote development of a more mature gut at weaning if fed prior to this time. The aim of this experiment was to test whether manipulations which have had beneficial effects on enteric conditions in weaned pigs can be used prior to weaning, to promote more favourable gut conditions and thereby reduce the feed intake deficit and growth check associated with the weaning process.

The animal feed industry produces various complementary feedstuffs with high levels of crude protein (CP) and synthetic amino acids designed to provide optimum nutrition to the post weaned pig. The use of synthetic amino acids has both advantages and disadvantages and other ways of delivering amino acids are of interest to the feed industry. One possible way of delivering amino acids is through the Maillard reaction; this is the chemical catalysis of the amine group of an amino acid to the carboxyl group of a sugar giving Maillard reaction products (MRP). These molecules occur during cooking, but have been shown to have a variety of other applications (Namiki, 1996) In this study, lysine (Lys), methionine (Met) and threonine (Thr) where chemically reacted with sugar molecules to give in vitro early Maillard Reaction Products (MRP). The aim of this study was to assess the effect of a solution of these MRPs with particle sizes of cereal base in a complementary feedingstuff (Matan XL, Devenish Nutrition) on overall diet performance.