In addition to work showing a detrimental effect of low postovulatory progesterone on embryo development (Mann and Lamming, 2001), a number of studies have demonstrated reduced fertility in animals in which plasma progesterone concentrations were low during the cycle preceding insemination (Holness et al., 1981; Folman et al., 1990). In this study we investigated the effect of reduced progesterone concentrations during oestrus synchronisation on the timing of ovulation and on progesterone concentrations during the ensuing cycle.

Reproductive wastage in cattle is largely the result of fertilisation failure and early embryo loss (Sreenan et al., 2001). Oviduct fluid forms the environment in which the oocyte and spermatozoa undergo final changes before fertilization and the early embryo develops. However, while oviduct fluid is partly a transudate of blood plasma little is known of its biochemical composition and especially the concentration of energy substrates essential for early embryo development. The objective of this study was to measure the comparative concentrations of glucose, lactate and pyruvate in cattle oviduct fluid and blood plasma on different days of the oestrous cycle.

Poor reproductive performance is a major problem on dairy farms throughout the United Kingdom and has been identified as the single most important problem in two recent farm surveys in Northern Ireland (AgriSearch, personal communication). The decline in reproductive performance is often attributed to increased genetic merit for milk production, but is also influenced by a large number of factors including changes in management practices and nutritional factors. The aim of this study was to examine reproductive performance in a range of dairy herds in Northern Ireland to identify the key factors influencing reproductive performance at farm level. This paper presents the findings of three years of study.

Livestock play an important role in sustaining rural livelihoods in the mid-hills of Nepal. Farmers in this region have an indigenous knowledge system for describing the nutritive value of tree fodders (Thapa et al., 1997) that they use in the management of fodder resources to cope with feed scarcity during the winter. Previous studies of farmers’ knowledge revealed two descriptors for fodder: posilopan, meaning literally nutritiousness and related to protein supply, and, obhanopan literally meaning ‘dryness and warmness’, as opposed to ‘chiso’ which means ‘wet and cold’ but relating to how voraciously fodders are consumed and their overall dry matter digestibility (Thorne et al., 1999). These descriptors are widely and consistently used by Nepalese farmers (Walker et al., 1999). Further investigation has led to the discovery of a third descriptor, ‘adilopan ‘, (literal meaning ‘duration of appetite satisfaction’ used in association with the term ‘obhanopan’. This study investigates the biological interpretation of the term adilopan, revealing the importance to farmers of the extent to which tree fodders satisfy animal appetite.

There is considerable interest in the use of alternative dairy breeds and cross breeding in the dairy industry as a method of improving herd fertility and longevity. Currently in Northern Ireland 47% of prime beef production is sourced from the dairy herd, and this proportion is likely to increase post implementation of the Mid Term Review of the Common Agricultural Policy. The present study was therefore undertaken to investigate the effects of two pure dairy breeds and their reciprocal crosses on carcass characteristics and meat quality.

Concentrate supplements for finishing beef cattle are normally offered either as coarse or pelleted rations. Currently in Northern Ireland the majority of beef farmers are part time and consequently feeding concentrates in one feed per day is a practical option on many units to reduce labour requirement. The effects of method of processing concentrate supplement and number of feeds per day on carcass characteristics and meat quality were also evaluated in this study.

Recent developments in maize breeding and in agronomic practices, particularly the development of complete cover plastic mulch, have resulted in the possibility of consistently producing high yields of high starch maize silage in Northern Ireland. Recent studies (Keady et al., 2002, 2003) at this Institute have clearly illustrated that inclusion of maize silage, varying in maturity, consistently increases the performance of lactating dairy cows. Keady et al. (2002, 2003) concluded that the inclusion of maize silage in the diet of dairy cows had a potential concentrate sparing effect of up to 3 kg/cow/day. Currently there is considerable interest from beef producers of the potential effects of the inclusion of either maize or whole crop wheat (WCW) silages on the performance of beef cattle. The objective of the present study was to evaluate the effects of including maize and WCW silages in grass silage-based diets on food intake and animal performance of beef cattle offered two levels of concentrate.

Forage lipids contain a high proportion of the polyunsaturated fatty acids (PUFA) C18:2n-6 and C18:3n-3. However, microbial biohydrogenation in the rumen results in extensive loss of these beneficial fatty acids. This experiment investigated the duodenal flow of fatty acids in beef steers offered grass or red clover silage, the latter of which has been shown to reduce biohydrogenation of C18:3n-3 (Lee et al. 2003a). In addition the effect of silage prepared from a ryegrass with high water soluble carbohydrate (WSC) content was investigated, as previous research (Lee et al. 2003b) has shown that increasing the availability of WSC lowered rumen pH and increased the proportion of propionate, relative to other volatile fatty acids, conditions which have been linked to reduced biohydrogenation (Jenkins, 1993).

Biohydrogenation of polyunsaturated fatty acids (PUFA) such as C18:2n-6 and C18:3n-3 results in the formation of C18:0 and numerous intermediary products such as the C18:1 cis and trans isomers and conjugated and non-conjugated C18:2 cis and trans isomers. Interest in these isomers has grown with the identification of biologically active isomers of conjugated linoleic acid (CLA cis 9 trans 11 and CLA trans 10 cis 12) and enzymatic pathways for CLA cis 9 trans 11 formation from C18:1 trans 11, both in the mammary gland and muscle. This abstract reports on the duodenal flow of biohydrogenation intermediates, with the objective of explaining the reduced biohydrogenation with red clover silage (Lee et al. 2004).

Growth rate of beef cattle is influenced by gender and can also be manipulated through changes in the plane of nutrition offered throughout the lifetime of the animal. Due to the low profitability of calf production at present it is essential to achieve optimum carcass weight as cheaply and efficiently as possible. Compensatory growth, whereby a restriction in growth during a period in life is compensated by higher growth rates later in life, may have the potential for achieving cost effective animal performance from beef cattle. The aim of the present study was to evaluate the effects of plane of nutrition during the first winter growth and final winter finishing phases on carcass characteristics and meat quality of steers and heifers. Furthermore the effects of ad libitum concentrate systems during the finishing phase were also evaluated.

Polyunsaturated fatty acids (PUFA), especially the n-3 and n-6 families are dietary compounds with significant immunomodulatory potential. Mechanisms proposed to explain their impact on immune function include (1) direct effects on leukocyte and epithelial cell membrane function, (2) the regulation of expression of immune genes and their products and (3) eicosanoid-mediated mechanisms (Hwang, 2000). Eicosanoids are immune effector molecules which have important roles in the regulation of immune and inflammatory responses (Calder, 2001). The aim of this experiment was to establish the extent to which supplementation of pre-ruminant calves with an n-6 or n-3 PUFA source may influence mucosal mast cell numbers in the abomasum (ABO), duodenum (DD) and terminal ileum (TI).

Dynamic grouping systems for sows involve the regular replacement of sows which are due to farrow with those that have just been mated. Evidence suggests that newly-introduced sows are often subjected to high levels of aggression from ‘resident’ sows in dynamic groups (O’Connell et al., 2003). In addition, newly-introduced sows often appear intimidated from using kennel areas and are forced to lie on less-preferred slatted dunging areas (Moore et al., 1993). The aim of the present study was to assess the effect of replacing 10, 20, 30 or 40 percent of a group of forty sows on the welfare of sows newly-introduced to the group.

Providing environmental enrichment to farmed animals such as pigs is very important to safeguard their welfare. Current legislation specifies that all pigs must have permanent access to a sufficient quantity of material to enable proper investigation and manipulation activities. Straw has always been regarded as a functional form of enrichment for pigs, but can be difficult to use in slatted housing systems. Alternative enrichment objects might be acceptable substitutes, provided they are designed according to characteristics which pigs find important (Van de Weerd et al., 2003), as pigs may lose interest in simple devices. Most enrichment studies have focussed on immediate effects on behaviour, but it is also important to find out whether there are critical periods where providing enrichment will have effects later in life. The aim of the present study was to investigate whether early life enrichment had an effect on the behavioural development of pigs. To assess this, pigs were tested on an Elevated Plus Maze (EPM) at 10 weeks of age. The EPM is a well-validated anxiety model in rodents, which has more recently been used in pigs. It provides a way to separate fear of novelty (avoidance of open arms) and activity-related elements (entries into closed arms) (Anderson et al., 2000).

Previously reported results indicate that milk production and somatic cell counts were improved by the habituation of replacement heifers to the milking parlour prior to calving (Wicks, et al 2003). Rushen, et al. (2001) reported that when mature cows were milked in unfamiliar surroundings, milk yield, milk flow rate and milking duration were affected due to increased stress (Rushen, et al. 2001). The objective of the current study was to investigate the effects of habituating Holstein-Friesian and Norwegian heifers to the milking parlour pre-calving on subsequent milking parlour behaviour.

Browsing herbivores tend to feed selectively, focussing on nutritious species and plant parts and avoiding toxic components. Recent research suggests that this selective browsing is substantially dependent on learning about post-ingestive consequences. Thus, animals come to associate particular foods with particular effects through experience and subsequently adjust their preference accordingly. Most previous experiments have involved simple training tasks (e.g. Burritt and Provenza, 1992) which do not reflect the complexity of the diet choice problem for free-ranging herbivores. A series of experiments was conducted testing the following more realistic food choice scenarios: (1) simultaneous vs temporally separated presentation of food options during the learning phase (2) seasonal change in post-ingestive consequences and (3) trade-offs between positive and negative consequences arising from single feeds.

There have been numerous studies of laterality (handedness, sidedness or lateralised motor behaviour) involving several species including humans, primates, dogs, cats, rodents, whales and horses. In humans for example, population bias of the order of 93% for right-handedness has been reported from studies of more than 5000 years of art work, which appears to be unaffected by culture or geographic location. It has long been accepted that the majority of horses are lateralised (to varying degrees) and training programmes have been designed to ‘straighten’ the lateralised competition horse, (Klimke, 2003). The specific cause of laterality in any species still remains open to some degree of debate and theories of genetic predisposition, environmental influences and combinations of both have been proposed. While both environmental and genetic models have been suggested with regard to the aetiology of lateralised behaviour, mapping of any specific locus, which could be unequivocally attributed to lateralised behaviour is as of yet incomplete. There is evidence suggesting a relationship between facial hair whorls and side preferences from studies in cattle, Tanner et al., (1994). Dalin et al., (1985) reported that laterality and asymmetry in equine motor behaviour may negatively affect locomotion and subsequently compromise competitive performance. The objective of this study was to explore the possibility of predicting the direction of lateral bias in the horse from observations of the direction of facial hair whorl rotation.

Elephants are long lived, apparently highly intelligent mammals with complex social structures and large home ranges (e.g. median 113km2 for Asian elephants). There are over 1700 elephants housed in captivity world-wide, of which over 1000 are kept in Zoos as part of an actively managed conservation breeding programme, associated educational activities and benign scientific research aimed at improving breeding and welfare (Stevenson 2002). However, a recent RSPCA report (Clubb and Mason 2002) has suggested that there are serious welfare issues associated with keeping these large essentially herbivorous mammals in captivity. For instance, wild elephants spend between 60-80% of their waking hours feeding and foraging and will migrate in pursuit of food but in Zoos foraging accounts for only 30-40% of an elephant’s waking time budget. Animals that are prevented from performing highly motivated behaviours, such as feeding, may be prone to develop stereotypic (repetitive, apparently functionless) behaviour. The objective of this study was to evaluate the efficacy of a specially designed elephant feeding device, the peanut shuttle, in increasing foraging time and decreasing stereotypy in a group of Asian elephants, Elephas maximus, housed within Blackpool Zoological Gardens.

Breeding for increased intestinal worm resistance using faecal egg count (FEC) as an indicator trait has been implemented in several sheep industries. The research on which this development is based has been carried out on resource flocks with only limited information on how the same genotype performs under a wide range of conditions. Pollott and Greeff (2004a), using industry Merino data from Australia, have reported genetic correlations between FEC and sheep production traits to be zero. The only exceptions were fat depth (FAT), eye-muscle depth (EMD) which were moderately negatively correlated. Whilst investigating the genotype by environment interactions in this dataset Pollott and Greeff (2004b) described the way in which the heritability of FEC and production traits varied in a wide range of flock environments. This paper reports how the genetic correlations between FEC and production traits vary across a range of FEC environments.

Grazing sheep are invariably subjected to natural nematode parasitic challenge. Anthelmintic resistance is becoming widespread among parasites and alternative control measures are urgently needed. A potential alternative control method is breeding for improved resistance (Woolaston and Windon, 2001). The aim of this study is to investigate the genetic control of the component traits of parasite infection (worm length, worm burden and worm fecundity) and indicator traits of infection, and quantify genetic relationships between these traits. Indicator traits investigated in this study are fructosamine concentration, immunoglobulin A (IgA) activity, eosinophil counts and pepsinogen concentration. Fructosamine concentration reflects average glucose and protein concentrations and rates of protein turnover. IgA is a secreted antibody and is of key importance in gut infections. Eosinophils are a type of white blood cell associated with parasitic infection. Pepsinogen is a digestive enzyme precursor, which increases concentration in the plasma following the breakdown of intercellular junctions in the abomasum.

Selection objectives in sheep breeding are changing as the nature of the pressures upon the sheep industry change. Sheep breeders particularly need to address product quality traits, as these will determine consumer acceptance of lamb. Critical traits determining product quality are carcass composition and meat quality. New measurement technology, such as Computer Tomography (CT), offers the potential for more accurate measurement of carcass traits in the live animal and consequently improved genetic gains. On the other hand, meat quality traits pose particular problems for improvement, as measurement is generally restricted to the slaughtered animal. The present study was designed to investigate carcass composition (as measured by CT) and meat quality traits, determine the inheritance of these traits, relationships between them, and investigate the prediction of meat quality traits from CT measurements. At a later stage, these data will form the basis for QTL studies for carcass and meat quality traits.

Sire breed has been shown to have a major effect on growth rate, carcass characteristics and meat quality of lambs from hill sheep systems (Carson et al 2001). A research programme has been initiated in Northern Ireland to improve the genetic potential of the hill flock through crossbreeding, with the crossbred females being retained on the hill and used as replacement breeding females. However, as information is also required on the performance of the crossbred male lambs, the first objective of the current study is to assess the effect of crossbred lamb genotype on carcass characteristics. Lamb meat is high in fat and low in polyunsaturated fatty acids. Vegetable oil-based diets have been shown to influence the fatty acid composition of meat (Solomon et al, 1991). Therefore the second objective of the current study is to evaluate the effect of offering diets containing oilseed rape on lamb meat quality.