Rape-seed production increased over the last years for industrial purposes such as production of diester. Small plants were set up both for oil extraction from the seed and oil processing. The oil is extracted by pressure so that the ether extract content of rape-seed meal is quite high at about 8%.

The study was designed to compare the effects of different incorporation rates of rape-seed meal in a fattening diet on food intakes and digestibility of the diet.

A total of eight bulls of the Belgian Blue breed-dual purpose type-were used in two 4x4 latin squares design. They were kept in metabolism stalls. There were 4 differents diets (table 1). The control diet was made of sugar-beet pulp, cereals, middlings, soja-bean meal, linseed meal, molasses and mineral mixture. In the three other diets, one third, two thirds and three thirds of the amount of protein from soja-bean meal and linseed meal were substituted by protein from the rape-seed meal. When offered to the bulls, the concentrate was mixed in a mixer trailler with straw at a rate of 90% concentrate and 10% straw. Food intakes were close to ad libitum by daily adjustments. Each period of the latin square lasted for six weeks on the end of which apparent digestibility was measured by total collection of the feces

Calf rearing systems vary greatly in the quantity of milk substitute fed and in the age of the calf at weaning (Webster, 1986). Husbandry conditions can affect disease incidence and welfare of young, bucket-fed calves and Andrews (1979) has suggested a relationship between age at weaning and disease incidence. This experiment was designed to investigate the effects of level of milk substitute powder fed and the age at weaning on the immune responses of bucket-reared calves compared with naturally suckled calves.

Two groups of 20 calves were kept at the Veterinary Field Station, University of Liverpool. All calves received pooled mixed-source colostrum at birth and were then randomly allocated to one of five treatment groups. After colostrum, bucket-reared calves were introduced to milk substitute (Volac Easi-Mix) which was reconstituted at 125g ADM per litre of water and fed twice daily. Calves were housed in individual pens arranged in four blocks with wood shavings as bedding. Suckled calves remained with their dams and were housed in the rear of the same building. These calves had access to a calf creep area. All calves were introduced to Keystart Quicklettes (BOCM Silcock) at 7 days of age and fed ad libitum. Small quantities of water and silage were also provided from 7 days of age. Table 1 lists the treatment groups, level of milk substitute received (g ADM/day), age of the calf at weaning and at inoculation with antigen (KLH), and also the age of the calf when the skin sensitivity response was measured.

Ad libitum feeding of lactating sows might ease the feeding management of group and individually housed sows. In this study a commercial feeding regime was compared with diet fed ad libitum to sows crated during the farrowing and lactating period. It was part of a larger project examining alternative farrowing systems.

In separate experiments, two feeding regimes were compared. The experimental building contained 5 farrowing crates. The first 10 sows were fed at commercial levels (2.2 kg/day before farrowing & 5.7 kg/day for litter size n=10, ± 0.4 kg per piglet). This was split between meals at 0700 and 1530 daily, fed via a trough at the front of the crate. For the following 30 sows the five farrowing crates were modified by the addition of an ad libitum hopper to the front of the farrowing crate. All animals received an identical lactating diet (DE=13.2MJ/kg, CP=17.9%) throughout the study. Sows entered the farrowing accommodation at day 110±4 of gestation. They remained crated throughout the experiment until weaning at 24±4 days post-partum. Measurements of sow entry and weaning weights were taken, together with records of sow feed intake and individual piglet weights at birth and weaning.

Dietary supplementation with folic acid has been shown to improve reproductive performance in sows (Lindemann 1993). However most studies have been for one cycle only and few have examined the effect of supplementation over several parities.

One hundred and thirty four crossbred sows ranging in parity from 2 to 4 were selected at farrowing and randomly allocated to two dietary treatments of low and high supplemental folic acid (0 and 10 g per tonne, Roche Products Ltd.). Treatments were applied for the following three lactations and post weaning periods, two full pregnancies and to day 30 of the pregnancy following the third lactation. The diet fed contained barley, wheat, soyabean meal and meat and bone meal with nutrient levels of 14.0 MJ DE/kg and 1.02% lysine. Sows were individually penned throughout with restricted feeding in pregnancy (2.2 kg/day increasing to 2.5 kg/day in the final month), and ad libitum in lactation (approx 5.0 kg/day) and post weaning (approx 3.4 kg/day). Blood samples for determination of plasma and red cell folate were taken from 14 sows per treatment on days 4, 50 and 110 of one cycle. These were determined by a microbiological assay (modification of methods of Scott et al 1974 and Wilson and Home 1982).

Grass silage provides an alternative feed for extensively kept sows, but previous experiments have indicated very variable intake and utilisation, dependant on silage quality. ‘Maxgrass’ silage additive (BP Nutrition) is a blend of compounds including ammonium hexamethanoate, ammonium hexapropanoate and octanoic acid. It is designed to modify fermentation, so that the resulting silage retains a higher proportion of water soluble carbohydrates. This should improve the nutritive value for pigs.

The experiment comprised two parts: an intake/growth study and a separate digestibility study. The same two experimental silages, either treated with Maxgrass or an untreated control, were offered to groups of pregnant sows in a randomised block experimental design in each experiment. Second cut, mainly perennial ryegrass herbage was cut by mower conditioner and direct ensiled. Alternate loads were left untreated or treated with Maxgrass at a mean rate of 6.04 litres/tonne.

Modern sows have been selected for increased mature body size and prolifacy while measured milk yields greatly exceed previously published levels. Optimum lysine to energy ratio in the lactation diet of such sows is likely to be influenced by lactation feed intake, lactation length as well as by body fatness at parturition. In a situation where high lactation feed intakes were achieved in a short lactation by high producing sows, a diet close to current commercial recommendations was compared to one with a lower lysine to energy ratio.

The study was conducted in a large commercial herd with Large White (LW) x Landrace (LR) first cross sows which had been mated to either LR or LW boars. Two lactation diets were formulated, one being close to current recommendations for modern, high producing lactating sows (Diet A) while the other had a 19 percent lower ratio of lysine to digestible energy (Diet B). The diets were based mainly on cereals (barley and wheat), both extracted and full-fat rape seed meal, soya bean meal and biscuit meal. The calculated nutrient content of the diets is presented in Table 1. A total of 85 sows were involved in the study and sows allocated to the two diets were balanced for parity and farrowing date. Feed allowances were increased gradually from a low level at day 1 after parturition which made it possible for sows to achieve an intake of 12 kg daily at Day 14 after parturition provided that a sow had previously consumed all food offered. Feeding management was good, with water being added to provide wet feed. Average temperature at sow level was 23.2°C (overall range 19 to 27°C).

Litter size and milk yield have been significantly increased in modern genotypes and gilts are now lactating at a stage when they still have the potential for substantial maternal lean tissue growth. Voluntary intakes are seldom adequate to meet the nutrient requirements for lactation, and catabolism of body tissue occurs. It is possible that higher ratios of ideal protein to energy are desirable in the first lactation to balance the energy contributed by fat catabolism. This possibility was tested in a controlled experiment.

The study was conducted in a large commercial herd with Large White (LW) and Landrace (LR) first cross sows which had been mated to LW, LR, LW x LR and Duroc boars. Three lactation diets were formulated, one being close to current recommendations for modern, high producing sows (Diet A) while diets B and C had, respectively a 9 and 33 percent higher ratio of lysine to digestible energy. The diets were based mainly on cereals (barley and wheat), both extracted and full-fat rape seed meal, soya bean meal and biscuit meal. The calculated nutrient content of the diets is presented in Table 1.

Previous experiments indicated that several fibrous raw materials in dry sow diets failed to prevent excessive nutrient intake. Only a diet high in unmolassed sugar-beet pulp (SBP) limited voluntary intake to acceptable levels. SBP consists of mainly soluble fibre. It is known that some types of fibre can affect blood metabolites and hormone profiles, which might affect intake regulation. The effects on blood metabolites and insulin of a diet containing soluble or insoluble fibre were compared to a diet containing readily available carbohydrates.

Experiments have demonstrated that inclusion of unmolassed sugar beet pulp (SBP) in diets for pigs gives rise to a major restriction in voluntary food intake in comparison with other high fibre materials (Brouns et al, 1991; Gill et al, 1992). The mechanisms for this are still not fully understood but appear to be related to the nature of the non-starch polysaccharides. SBP has a relatively high pectin content, so this experiment was designed to investigate whether another similar pectin containing material, citrus pulp (CIT), has similar intake regulating properties and whether these could be modified by treatment with a pectinase enzyme.

The design was a split plot experiment with two dietary treatments. Each diet was manufactured, with and without enzyme, giving the following treatments: (1) Citrus pulp diet - no enzyme [CIT-]; 2) Citrus pulp diet - with enzyme [CIT + ]; 3) Sugarbeet pulp diet - no enzyme [SBP-]; 4) Sugarbeet pulp diet - with enzyme [SBP + ]. The experimental treatments were applied in a crossover design with 8 pigs receiving each diet both with and without enzyme.

For over 50 years extrusion has been used as a method for processing human food. However during the last 10-15 years significant advances have been made in the development and application of extrusion technology, particularly in the pet and fish food industries. Extrusion may become economically advantageous and thus an strategy to be considered by feed manufacturers which applies to several farm livestock (Partridge and Gill, 1993). Cereals and oilseeds extruded mixtures based diets for young pigs fall into this category even though currently they are not commonly used by swine producers.

The objective of this experiment was to evaluate the effects on the performance and apparent faecal digestibility of weaned piglets of a diet with or without inclusion of an extruded mixture of 2 cereals (maize and wheat) and full-fat soyabeans.

Soya proteins can provoke an immune response and cause diarrhoea in pigs weaned at 3 weeks of age. An enzymatically treated soya protein isolate (NURISH protein) did not have these effects in isolator reared experimental pigs (Miller et al 1992). A blind trial on 4 commercial farms was set up to evaluate NURISH as an alternative to conventional protein sources.

On each farm 120 pigs (in 2 or 3 replicates) were fed either a typical commercial weaner diet containing cereals, fishmeal, milk proteins and full fat soya (the control) or a test diet matched for protein (22% CP), lysine (1.6%) and energy (DE 15.1 MJ/kg) with NURISH as the main protein source. Prophylactic antibiotics were not used.

Starter diets of low acid binding capacity (ABC) are sometimes recommended to ensure an acidic environment in the stomach of newly weaned pigs. A low stomach pH aids protein digestion and provides a barrier against the passage of bacteria into the small intestine. A diet of low ABC can be formulated through careful selection of ingredients (Jasaitis et al., 1987). The present study was undertaken to measure the ABC of feed ingredients commonly used in pig starter feeds and to determine if diet ABC can be predicted from the ABC of the ingredients.

Previous studies have examined the effect of the degree of saturation (as measured by th3 ratio of unsaturated to saturated fatty acids, U/S) and free fatty acid (FFA) content on the digestible energy (DE) value of fats fed to growing/ finishing pigs. However, there have been no detailed studies with the immediate post-weaning pig, which was the objective of the current programme.

Two fats of differing degrees of saturation (U/S) and their respective acid oils of high free fatty acid (FFA) content were obtained for evaluation. Fats were Soyabean Oil (SO), Soyabean Acid Oil (SAO), Tallow (T) and Tallow Acid Oil (TAO).

The dietary phosphorus requirement of young pigs is not well established. Values of a net requirement estimated by the ARC (1981) extend from 2.7 g/day for 5kg pigs to 4.6 g/day for 25kg pigs but current literature suggests that the actual requirement may be lower than this. Although maximum bone mineralization is not necessary for optimum growth, later bone development should not be impaired by a deficiency of phosphorus.

Use of phytase in piglet diets has resulted in increased rate and efficiency of gain (Beers and Jongbloed,1992) and increased metatarsal phosphorus (Young et al, 1993). The enzyme hydrolyzes phytate, releasing phosphorus into the gut, and could thus be used in place of expensive inorganic phosphates. Quantification of phytase/phosphorus substitution is as yet undetermined. Therefore this experiment was conducted to look at the phosphorus requirement for growth and bone development and to assess the effect of phytase on dietary phosphorus requirement.

There is evidence to suggest that individual pigs can differentiate and choose successfully between diets on the basis of their nutrient composition and change the proportion of the diet consumed to meet their changing nutritional requirements. Choice feeding may therefore provide an effective means of meeting the differing nutritional requirements of individual animals within a group and offers considerable productivity, dietary, managemental, welfare and environmental advantages. The present trial was therefore developed to establish the ability of young piglets to select their diet in the 5-week period following weaning and to examine the potential of choice feeding as a method of feeding piglets under commercial conditions.

Milk based diets remain one of the most successful means of introducing early-weaned piglets to solid food. However, the increased costs of dried milk by-products has stimulated the trend towards later weaning and the use of cheaper diets based on vegetable proteins. Such diets are often associated with digestive disturbance and reduced performance which necessitate the use of anti-microbial growth promoters.

In this study, we examined the scope for using the choice-feeding system to enhance the health and performance of early weaned piglets fed low-cost diets by offering them free-access to feed ingredients which may be selected when there is a need to correct digestive disturbance.

Weaning is a considerable challenge to the young piglet and represents the beginning of a critical period in its life. It is also the period which has a significant effect upon both short- and long-term growth and development. Rapid early growth results in higher and more efficient growth in the subsequent growing and finishing periods. Indeed, it is a common commercial experience that the ability to produce quality lean carcases from fast-growing modern genotypes is enhanced by rapid post-weaning growth. The objective of the current trial was to measure the performance and growth potential of modern pig genotypes in the 5-week post-weaning period, when offered non-limiting diets under commercial conditions.

Inadequate feeding space allowance could limit the performance of the early-weaned pig. No information is available on the amount of space required as group size increases; this is now more typical for some of the novel welfare systems. It has been suggested that the early-weaned pigs tend to feed together for an initial period. Indications exist that, if inadequate feeding space is provided post-weaning, a proportion of piglets may suffer.

The objective of the experiment was to investigate the effect of restricting access to feed on the performance of the early-weaned pig housed in large groups in a novel sloping bed weaner pen.

It is well recognised that the current move towards group housing for sows can put the welfare of individuals at risk if the method of feeding is inadequate. In a study of the levels of competition at feeding, Stewart et al (1993) showed that specialised fibrous diets could, successfully, be fed ad libitum to group housed gilts. It was, however, suggested that longer term effects on welfare and longevity should be investigated. This paper describes the growth characteristics and social rank variation of young sows over the first two parities on three feeding systems.

The activation of the hypothalamic-pituitary-adrenal axis is one of the best studied stress-related responses. In particular, the involvement of endogenous opioid peptides in response to pltysiological and pharmacological stimuli has been the subject of extensive study both in man and other animals (Nakao, 1979, Petraglia, 1985, Engler, 1988). However, in animal models of repeated stress, the acute response to a stressor often habituates when the stressor is presented repeatedly (Ottenweller, 1991). Hypoglycaemia is a stress which can be easily and repeatedly applied to experimental animals. The present study was performed to determine whether insulin-induced hypogrycaemia enhances the release of β-endorphin in pigs, and whether this response is maintained over repeated treatments on consecutive days.