Farmers are receiving a price incentive to produce more milk during the summer months. Bovine somatotropin (BST) could be used as a means of increasing milk yield from late winter/spring calving cows during the summer months. However, most of the research work with BST has been with housed cattle on winter feeding systems. The objective of this experiment was to evaluate the use of BST with grazing cattle supplemented with silage as a buffer feed.

Thirty-six January to March calving multiparous Friesian dairy cows were allocated to 4 treatments: CG - Control/Grazing, TG - Treated/Grazing, CB - Control/Buffer fed, TB - Treated/Buffer fed. The treated cattle were given 640 mg of recombinantly derived bovine somatotropin (Somidobove Elanco Products Limited) in a sustained release formulation at 28 day intervals. The treatment period at grass lasted for 8 weeks from 18 August 1988. The cattle were then housed for a further 8 weeks in 2 groups of sixteen cows (with one block of cows omitted from the experiment).

The accurate prediction of the replacement rate of forages by concentrate supplements together with digestive changes induced is essential for the prediction of responses in milk components to changes in feed input. Generalised hypothesis suggest that one feed substitutes for another in proportion to the amounts voluntarily consumed when given alone (Blaxter, 1980) but this is not always the case (Thomas, et al 1981). Little information is available on the metabolic constraints on intake or the effect of supplements on digestive factors that may be limiting intake. The present experiments were designed to study digestive factors that may be limiting the intake of different grass silages in cows given different levels of supplements.

Two formic acid (3 1/tonne) treated silages were prepared from perennial ryegrass harvested in the first week of June (early cut, EC) and at the end of June (late cut, LC). Four diets consisting of the two silages each supplemented with 3 kg (EC3; LC3) or 9 kg (EC9; LC9) dry matter of a dairy concentrate were offered to four lactating Friesian cows in a four by four Latin Square arrangement. The cows were fitted with a large (10cm u.d.) rumen cannula with a simple cannula in the proximal duodenum. The concentrates, which included (kg/tonne) 370 barley, 183 wheat, 139 wheat middlings and 139 maize gluten feed were given in two equal portions/d with silage available ad libitum.

Supplementary feeding of grazing dairy cows is often uneconomic, and whilst supplementation with silage (buffer feeding) can be worthwhile, this often leads to a depletion of winter forage stores. In this study, a mixture of brewers grains and treated straw was used as a supplement. Offered as a 1:1 mixture in the dry matter (DM), it is a purchased substitute for grass silage, having a similar cost, and similar metabolisable energy (ME) and crude protein (CP) contents. The high seasonality adjustments to milk price in mid-late season make supplementation potentially worthwhile.

Experiments were carried out from April to September in 1988 and 1989, which had moderate and very low rainfall respectively. Each year 20 British Friesian cows which calved December to March (1988 experiment) and February-April (1989) were allocated at random to either treatment B or C. In B, the cows were offered a 1:1 mixture (DM basis) of brewers grains and NaOH treated chopped barley straw for 60 minutes after morning milking. In C, the cows received no supplement. Both groups were fed 1.0 kg/day of concentrates in the milking parlour. Due to the severe drought in 1989, concentrate feeding was increased to 5.0 kg/day for all cows during the last 4 weeks of the experiment. Also, urea-treated whole crop wheat was fed at a level of 2.5 kg DM/day during the last 7 days.

Food accounts for 80-90% of the variable costs in dairying in the UK. In contrast to genetic improvement programmes in most other species, no account has been taken of food intake or gross efficiency In dairy breeding programmes, In the UK or elsewhere. This Is largely due to the expense and impracticality of recording food Intake in conventional dairy bull progeny testing schemes, Involving thousands of cows In many different herds. However, several studies show positive correlated responses in efficiency, following selection on milk or milk solids yield (Gibson, 1986; Korver, 1988; Persaud, Simm, Parkinson and Hill, 1990).

Recently nucleus breeding programmes based on sib testing and the use of multiple ovulation and embryo transfer (MOET) have been proposed as an alternative to national progeny testing schemes for dairy cattle Improvement (Nicholas and Smith, 1983).

One of the first problems which often faces experts from developed countries called upon to advise on aspects of animal production in developing countries is that he/she has no experience of the production systems encountered. The systems as well as products and resources are generally different. In Table 1 an attempt has been made to describe some categories of farming systems, their animal product listed in some order of priority of product and of the resources available for the animals.

Experience over three decades of international projects aimed at assisting developing countries has shown that direct transfer of technology from developed countries has widely failed in the sector of Animal Production as in many other sectors. At best this transfer of technology has led to systems requiring high levels of imports in capital, feeds, genetically high producing animals and equipment, which require external technical assistance. These imported inputs which are usually highly subsidized have to a certain extent sometimes allowed a substantial improvement in output levels (eg. in poultry production). In some cases self-sufficiency has been attained, but never self-reliance. This has maintained or increased the dependency of developing countries. Therefore there is a need to base projects on a technology which is more appropriate and may be acceptable and profitable to the beneficiaries.

This paper is about training young people to serve in agriculture and related industries (including food storage, preparation and distribution) in developing countries. Two types of training are considered: that needed by graduates who are citizens of the European Community (EC) to fit them to work in tropical countries and that needed by students coming from developing countries (predominantly, but not exclusively, tropical or sub-tropical) to take postgraduate courses in the UK.

It is assumed that postgraduate students coming from overseas will return home at the end of their training and will contribute to the improvement of agricultural production in their own country. However, it has to be admitted that this assumption is not always well founded. Some candidates regard escaping from their own harsh environment as a primary objective when seeking funds for overseas study. On completion of his course the student may seek to stay in the UK or to find work in another developed country, though immigration rules and the conditions attached to most studentships are designed to prevent this happening.

The pig industry in the UK now faces considerable public disquiet over the types of environments in which modern pigs are kept and the husbandry procedures they are subjected to. In response to this industry and Government have encouraged scientific research into pig welfare to obtain information by which to objectively assess well-being. The aim of this visit was to review current advances in the study of stress, a concept that has long been central to welfare research. A broad range of techniques for measuring stress are reviewed with special reference to the information they yield on the mechanisms and functions of stereotypic behaviour in sows. There is increasing reliance on the experimental analysis of behaviour and on methodologies that allow simultaneous recording of behavioural, physiological and neurological events. There is also greater attention on the adaptation of physiological systems to chronic stress. Recently it has been demonstrated that whilst close confinement of sows does not result in chronically elevated levels of Cortisol or heart rate, it does result in an increased sensitivity of these systems.

Ad libitum feeding provides the opportunity for animal scientists to explore the genetic and environmental factors which determine voluntary feed intake, a greater knowledge of which could help increase potential appetite thereby raising the level at which the latter may limit productivity. A Braude Travel Scholarship was used to finance a visit to a number of research establishments based in the Netherlands, Denmark and France to observe the extent to which diet and related factors are examined through experimentation, the results of which may contribute to our understanding of the mechanisms of feed intake control. Major differences in the production systems encountered in these countries when compared with the UK include the greater emphasis given to current environmental issues, expression of dietary energy as NE, production of castrated males, heavier slaughter weights and associated export demands. Such factors substantially influence the direction taken by nutrition research programmes. Although the primary purpose of the study tour was the appraisal of dietary factors in relation to food consumption, such effects could not be considered in isolation from associated genetic, physiological and environmental aspects, hence their inclusion in this report.

There has been an increasing interest in recent years in the feeding of high fibre diets to pigs, and especially to pregnant sows, with both economic and welfare advantages. The potential use of these diets will depend upon the extent to which the fibrous materials are fermented and the subsequent capacity of the products of fermentation, that is VFAs, to meet the energy needs of the animal. One ingredient that has considerable potential as a feed ingredient for sows is sugar beet pulp, and the present experiments were designed to study the extent to which diets containing varying proportions of plain sugar beet pulp influenced nutrient partition and the efficiency of nutrient utilisation in pregnant sows.

Many by-products available for feeding to pigs are high in fibre. The effects of such materials on feed in-take and killing-out percentage make them poorly suited for feeding to growing pigs, except at very low inclusion levels. These considerations are not limiting in the breeding sow, and the potential for utilising bulky by-products is consequently much greater. There may also be advantages for animal welfare and simplicity of management if diets containing such products can be fed ad libitum in loose housing systems.

This experiment was carried out to measure the effects of inclusion of very high levels of fibrous by-products in the diet of sows during late pregnancy on subsequent performance of the sow and litter.

Consumers are becoming increasingly aware of the importance of the dietary composition of the food they eat, and are demanding that it is labelled effectively. This demand has major implications for the meat industry because meat is a highly variable product and can be processed in many ways. One area currently under review is the methodology used to determine the water added to pig meat during processing (based on the fat-free nitrogen (FFN) content of fresh meat).

A rising plane of nutrition prior to mating increases ovulation rate in pigs (Anderson and Melampy, 1972), but this potential for increased Utter size is negated by the subsequent detrimental effect of high plane feeding on embryo survival. The mechanism underlying this effect may involve an increased rate of steroid clearance from the liver in animals on a high plane of nutrition (Symonds and Prime, 1989). The resultant lower circulating steroid levels would be expected to elevate pituitary gonadotrophin levels and consequently increase ovulation rate. However, after mating, such low steroid (particularly progesterone) concentrations may compromise embryo survival.

A further factor which may affect the ability of a gilt to carry a large number of fetuses to term is the spacing of fetuses within the uterus. Dzuik (1985) proposed that a uniform distribution of fetuses would optimise litter size, fetal growth and survival.

The docile temperament of the Chinese Meishan makes it promising as a nurse sow to which ill nourished pigs due to be weaned from their own dam around 3 weeks of age can be fostered for a further period of milk feeding. An alternative strategy to cater for such problem 3 week old pigs is to wean and attempt to rear them under very favourable conditions, including the provision of a highly digestible diet containing a high proportion of dried milk products. Such diets are now very expensive.

Cashmere goats exhibit seasonal cycles in hair growth and moulting which are an evolutionary response to seasonal changes in temperature. The winter coat of the cashmere goat consists of two types of fibre, a coarse outer coat of guard hair produced by the primary hair follicles and a dense Insulating undercoat of cashmere (<19 microns diameter) produced by the smaller and more numerous secondary follicles. In the Spring, under the influence of Increasing daylength, both guard hairs and cashmere are shed from the follicles and a sparse coat of guard hair remains.

The efficiency of harvesting fibre from cashmere goats is limited by the season of the moult, the long duration of the moulting period and by the variability between individual animals in the timing of the moult. Lynch & Russel (1989) reported that an earlier rise in plasma prolactin was associated with an advance In the onset of the spring moult in the cashmere goat.

Practically, the effect of selection for growth and efficiency on breeding performance has been largely ignored in the past, despite changes in the age and weight of animals at puberty. It has been demonstrated that it is beneficial to delay service in gilts, both to improve their condition and allow them to complete more oestrous cycles prior to service. It seems likely that performance of boars might also be enhanced if they were worked later.

This analysis was designed to examine the relationship between age and reproductive performance in the boar, with a view to developing guidelines for young boar management.

Circumstantial evidence exists that supplementing short daylengths in cattle increases productivity by reducing activity rates (Phillips and Schofield, 1989), and stress (Leining et al, 1980). However, little is known about the preferred daylength or light intensity for cattle. Before the latter can be determined the ability of cattle to distinguish intensity differences must be determined. Two experiments are reported here: the first describes the ability of cattle to distinguish light intensity differences and the second describes their preference for supplementary light and the effect that it has on their behaviour.

Prediction of voluntary food intake is Important in the formulation of rations for dairy cows. There are a number of prediction models which perform relatively well for diets based on dry forages but not for silage based diets (Neal, Thomas and Cobby, 1984). Prediction of intake of silage based diets is particularly important in the UK where 0.85 of the conserved forage fed to dairy cows is silage. A large and increasing proportion of herds are fed silage ad-libitum and concentrates at a flat rate. This study was an attempt to produce better prediction models for voluntary intake of silage by dairy cows under this feeding regime.

There is increasing interest in the addition of dry feed materials to grass at ensiling, primarily as a means of reducing effluent production, although other benefits claimed include improvements in silage fermentation and animal performance.

A large number of studies have demonstrated lower effluent outputs and improvements in silage fermentation due to the inclusion of materials such as cereals and sugar beet pulp, although experiments examining the effects on animal performance are limited.

Recently, Jones and Jones (1988) observed higher liveweight gains from beef steers fed silage produced by ensiling grass with molassed beet feed compared to animals fed the same quantity of beet feed mixed with silage produced from untreated grass at the point of feeding. The major objectives of the present study were to evaluate the possible use of sugar beet pulp as an absorbent material in silage making and to examine the effects of its inclusion with grass at ensiling on animal performance.

A number of workers have demonstrated the ability of high rates of methonoic add applied to grass at ensiling to restrict subsequent fermentation and preserve the grass sugars (Carplntero et al, 1979; Henderson et al, 1989). Other recorded effects have included an increased proportion of protein nitrogen (N) in the silage total N (Carplntero et al, 1979) and increased dry matter (DM) intake of silage by cattle and sheep (Henderson et al, 1989). There appears to be less information on the effect of high levels of methanolc acid on digestion and nitrogen utilisation of silage and in particular when applied in a mixture with other carboxylic adds.

A first cut perennial ryegrass based herbage was cut between 18 and 21 May 1988. The herbage was wilted for a maximum of 6h and was ensiled in bunker silos (capacity 50t DM) having been treated with either no additive or 5.95 1 t-1 of a mixture of aliphatic carboxylic acids. The mixture produced by BP Chemicals Ltd contained (gkg-1) 870 methanolc acid (85%), 100 propanoic add and 30 octanoic acid. Digestibility, energy value and utilisation of silage N was examined in mature wether sheep.