Feeding the dairy cow during the transition phase (dry to lactating) has been found to effect subsequent feed intake and milk yield (Moorby et al., 1996; Olsson et al., 1998). The aim of this study was to compare the effect of feeding a liquid feed during the prepartum period on; feed intake, milk yield, milk composition, live weight loss and blood metabolite levels.

Previous studies (e.g. Cia et al. 1998) have shown that modification of body composition of the prepubertal gilt has effects on responsiveness of gilts to exogenous gonadotrophin. Growing pigs are able to select a diet from different foods differing in protein:energy ratio (Dalby 1998); however there is little evidence of what effect the conflicting nutritional demands of growth and reproduction have on diet selection. The objectives of the experiment were to quantify the effects of choice feeding on responsiveness of gilts to exogenous gonadotrophin (Cia et al. 1998) and to investigate the effect of protein source on diet selection as Jones et al.(2000) have observed selection by breeding gilts against a high protein diet containing fishmeal.

The extent to which young sows, which still have a strong drive to continue maternal growth, partition nutrients from body reserves towards milk production, may be influenced by their genetic growth target. Modern genotype sows, with a high mature body protein mass, are thus particularly challenged. It has been suggested that to optimise their metabolic state for expressing lactational potential they will have to achieve a satisfactory proportion of their mature body protein mass before farrowing. This could be constrained by current feeding and breeding regimes. To test this hypothesis, gilts of genotypes differing in their body protein:lipid content were given the choice between a low and a high protein diet during rearing and pregnancy, and their intake, subsequent performance and metabolic state in lactation were measured.

The consumption and utilisation of feed during the growth period from 40-100 kg live weight, is a major determinant of efficient pig meat production. It has been previously observed that feed inputs to the sow at different phases of gestation, can profoundly influence the efficiency of lean tissue deposition in progeny through changes to foetal development (Dwyer et al 1994). The aim of the present study was to examine the effect of increased energy intake during a specific period of gestation (days 28-56), on progeny growth from weaning to slaughter.

Pre-weaning mortality is a major source of economic loss to the pig industry which despite improvements in husbandry and farrowing crate design remains about 10% of piglets borne alive. The causes of death are multi-factorial (Varley, 1995) but a large proportion may be due to low neonatal vigor. Commercial pig diets do not normally contain long chain n-3 fatty acids, a deficiency of which has been implicated in reduced visual and neural development in premature human babies and in experimental animals. The objectives of the present experiment were to quantify the causes of piglet mortality in sows of modern genotype and to determine the effects of salmon oil supplementation of the diet of the sow, providing long-chain n-3 fatty acids, on this mortality.

Post weaning performance is determined by weaning weight and week one growth rate (Miller, et al., 1999). Strategies which increase feed intake in the immediate post-weaning period would be expected to increase overall post-weaning performance through better week one growth rate. Top dressing normal pelleted feed following weaning with a palatable nutrient dense supplement should increase nutrient intake and hence week 1 growth rate. This strategy might be particularly beneficial for low weaning weight pigs. Inclusion of ingredients containing immunoglobulins (Ig) in immediate post-weaning diets have been shown to increase post weaning performance (Coffey and Cromwell, 1995). We hypothesise that the use of a palatable nutrient dense supplement containing bovine Igs will improve feed intake and growth rate post weaning. The aim of this experiment was to investigate this hypothesis using low weaning weight piglets.

Energy requirements for maintenance in pregnant sows increase when they are kept outdoors under temperate climates in comparison to indoors. However, there is little information on the energy requirements of breeding sows kept outdoors in tropical environments. Knowledge about the correct feeding management for pregnant sows kept outdoors will optimise the utilisation of feeding resources available in the tropics. The aim of this study was to evaluate the effect of energy level supply during pregnancy on backfat change and liveweight change of primiparous sows kept outdoors under tropical conditions.

Previous ADAS trials have shown the potential of Continental cross suckler dams to increase calf growth rates in a hill environment (Keatinge et al., 1994), and to improve carcass quality when the progeny are finished intensively (Chapple et al., 1995). The aim of this experiment was to compare the progeny of two Continental dam genotypes, using either Charolais or Aberdeen-Angus sires, when finished at 18 months of age.

In dairy cattle breeding programmes the knowledge of cow's lactation curve could be an effective tool to make selection decisions. In order to obtain an accurate shape of lactation curve a variety of mathematical models have been used in which parameters of production peak, inclining and declining phases of milk production over the course of lactation have been estimated by linear or non-linear techniques. The main purpose of this research was to compare four non-linear functions for the estimation of first lactation curve of Iranian Holstein dairy cows.

Veerkamp et al. (1998) make the case for including somatic cell count (SCC) in the index of total economic merit (ITEM, Veerkamp et al., 1995) used to rank dairy bulls and cows in the UK for breeding purposes. They go on to describe an empirical method to obtain a suitable economic value for SCC, reflecting the milk quality payment scheme. Since this work was carried out, the milk price has fallen while price penalties against SCC have risen. Bulk-tank SCC (BTSCC) has fallen in response. Some of this improvement may be due to culling cows with high cell counts. The objective of this work was therefore to establish an economic value for somatic cell counts which reflected the milk quality payment scheme and took into account culling strategy.

Longevity or lifespan has proved to be an important trait when it comes to profitability for the dairy farmer. Selecting for longer herdlife not only reduces the replacement rate and thereby the replacement cost, but also gives the opportunity to cull for low production (as opposed to health problems) and increases the milk yield through a higher proportion of mature cows in the herd. Predicted Transmitting Abilities (PTA's) for LS are calculated from a bivariate analysis including indirect information in the form of a phenotypic index of four linear type traits (fore udder attachment, foot angle, udder depth and teat length) closely related to longevity, and from direct lactation information, i.e. survival measured in number of lactations corrected for milk yield (Brotherstone et al., 1998). Genetic evaluations for LS were introduced in the United Kingdom (UK) in August 1998 (Mrode et al., 1999).

Getting reliable genetic parameter estimates for dry matter intake is difficult because recording it is expensive, hence it is tempting to combine data from research herds. However, there are large differences in feeding and management systems, which causes differences in means across herds. Furthermore, variances or heritabilities may differ and genetic correlations may be less than one between herds. This is one of the reasons why it is important to investigate effects of genotype by environment interaction (GxE). Another reason is that it is important to understand how high genetic merit cows perform in different feeding systems. The objective of this study was to estimate the effect of GxE for three feeding systems at two research herds belonging to ID-Lelystad (ID) and to SAC/University of Edinburgh (Langhill).

Differences in banding scales for milk quality penalties, as determined by bulk tank somatic cell count (SCC), prevent the use of a single economic value for SCC in an overall economic-genetic selection index (Veerkamp et al., 1998) such as, Profitable Lifetime Index or £PLI. But SCC could be used as a predictor of mastitis as genetic correlation estimates between mastitis and SCC are medium to high (review of Mrode and Swanson, 1996). This suggests that, although deriving a direct single economic value (EV) for SCC based on bulk tank SCC is difficult, a single financial value could still be assigned to SCC based on its relationship with mastitis. Here we use a genetic regression method to calculate the EV of SCC (EVSCC) as a predictor of mastitis. However, the dependency of regression coefficients on mastitis incidence (p) could make such EVSCC variable. The main objective of this study was to evaluate the impact of such relationship on EVSCC and genetic selection in dairy cattle using predicted transmitting abilities of SCC (PTASCC).

The transition period of the dairy cow is physiologically and nutritionally stressful as feed intake is reduced whilst nutrient demand for the support of foetal growth and initiation of milk synthesis are increased. Also during this period the diet of dairy cows changes from being predominantly forage, often of mediocre quality, to a diet often containing high levels of concentrate and high quality forage or mixture of forages. In the recent past nutritional management of the dairy cows during the transition period has centred on protein nutrition. While some studies have shown responses to milk yield or composition from protein nutrition in late gestation, many have shown no response. The objective of the present study was to examine the effects of level of concentrate in late gestation on subsequent reproductive performance. The effects of treatment on animal performance have been presented by Keady et al. (1999).

The live weight range 20-40 kg is a critical phase for lean growth optimisation. One of the constraints on efficient pig growth is floor space allocation which is often seen as a compromise between maximum performance and economic return / unit of floor space. It is documented that a reduction of floor space, usually by removing or increasing the number of pigs in the pen, decreases both pig growth and feed intake (Kornegay et al 1984). Interpretation of these experiments is difficult, as the modification of other pen resources such as feeding space are not adjusted for. It is therefore hypothesised that by reducing floor space provision whilst at the same time increasing feeding opportunity will optimise pig performance. The objective of this experiment was to test this hypothesis.

The effects of cannulation have not been widely studied in pigs. It is possible that digestive processes may be affected due to alterations in the gut micro-ecosystem and anaerobic conditions at the cannulation site. In studies where cannulated animals are used for digestibility measurements over the total tract as well as at the terminal ileum, it is important to determine if the process of cannulation can affect the results. The objective of this study was to evaluate the effect of cannulation on digestion in the pig by determining total tract digestibility of components from diets containing different raw materials (A-E) using both intact pigs and pigs fitted with simple T-pieces at the terminal ileum.

The assessment of the potential usefulness of enzymes as animal feed additives or treatments requires an understanding not only of the effect an enzyme has on its target substrate but also on the digestibility of that substrate. In vivo digestibility studies are expensive, time consuming and often involve invasive procedures that necessitate premature slaughtering of experimental animals. Preliminary laboratory screening methods can be used to indicate potential beneficial treatments prior to undertaking animal trials. The objective of this study was to assess the effect of protease pre-treatment of four differently processed soyabean meals on the digestibility of protein using an in vitro digestibility of nitrogen (Boisen and Fernandez 1997) technique as a screening method. The assumption implicit in this objective was that, if protease pre-treatment did not improve in vitro digestibility, it was unlikely to improve in vivo digestibility.

Swine production is gradually being practised in Nigeria in an integrated manner where farmers apart from keeping pigs also grow root and legume crops on the farms. One of such major crops often grown is cassava. The roots have been shown to be of tremendous value as an energy source in swine feeding (Iyayi and Tewe, 1994). The leaves which are often discarded on the farm after harvest can be processed and used as protein supplement for rearing pigs because of its high protein content (19.67-39.90%, Allen, 1984). The objective of this study was to use wilted cassava leaves as supplement to basal diets for weaner pigs and estimate the overall performance, serum metabolites and nutrient digestibility of animals on such diets.

Creep feeding enhances weaning weight (King et al., 1998) and may also enhance early post-weaning growth rate, both of which are positively correlated to subsequent performance (Miller et al., 1999). When preweaning feeds are offered, current practice in the UK is to feed either dry feed from day 14 to weaning or acidified milk replacer from days 3 to 18. Intakes of dry feed pre-weaning are generally low whereas liquid feeds are consumed more readily. Our objectives were 1) to offer creep feed as a gruel to test whether this would enhance intake of creep and provide an alternative to milk replacer, and 2) to provide all three forms of supplementary feeding together to determine whether this further increased performance. Piglets receiving no supplementary pre-weaning feed were the negative control.

Porcine plasma is known to improve immediate post-weaning performance but this is often only evident in the first week to ten days after weaning (Toplis and Miller, 1999). Few if any studies have investigated whether there are any long term effects over the entire growth period. It has previously been shown that piglets in poor health situations (Coffey and Cromwell, 1995) demonstrate markedly greater responses to porcine plasma. The objective of this study was to determine whether porcine plasma produced long-term benefits and whether this was modulated by health challenge during the weaning period.