In the pig industry the mortality of piglets both during the birth process and in the subsequent 3 to 5 weeks is unacceptably high. This review attempts to summarize the major causes of these losses and to suggest means whereby such losses may be minimized in the commercial situation. Stillbirth rate is discussed in relation to various management regimes and it is concluded that anoxia (the primary cause of intra-partum piglet deaths) may be minimized by the provision of careful assistance during the birth process. Pre-weaning mortality is presented as a complex interaction of factors predominant amongst which are overlying by the sow, chilling, starvation and infection. Each of these areas is discussed in detail and recommendations are made to reduce their negative influence on the survival rate of piglets. Finally, the rōle of piglet activity level/vigour is considered in relation to pre-weaning survival rate. Various factors are discussed in relation to piglet vigour and it is concluded that the two major contributors to low activity level/vigour are intra-partum hypoxia and the endocrine status of the sow and piglet at birth. To reduce hypoxia, careful intervention is again suggested. The rôle of endocrine status is yet to be fully established but promising results are presented on the use of oestradiol treatment of piglets at birth to raise activity level and reduce pre-weaning mortality rate.

The production of food through fish-farming or aquaculture has become an area of increasing interest in the developing world, as the potential of unused water resources is realised and the spread of appropriate techniques for suitable fish species is encouraged. From a production through aquaculture of 6 million tonnes or approximately 10% of current captive fisheries in 1976 (Pillay 1976), estimates of as high as 4O% by the year 2000 have been given (Bardach, Rhyther and McLarney, 1972), a great part of which will be from developing countries. Where resources are limited, techniques Of aquaculture which are integrated with conventional agricultural or industrial activities by using their wastes, or which provide useful by-products, are especially to be encouraged.

The slaughter of animals for human consumption leads to the production of a large quantity of materials which with further processing can be converted into a form suitable for use in animal feedingstuffs. Currently, much of this material goes to waste because of the fragmentation of the abattoir industry into many small units (1700). This means that it is often uneconomic to transport by-products to central points for further processing. However, more stringent control of effluents from abattoirs and the need for high capital investment to bring units up to newly imposed standards means that slaughterings will be concentrated into fewer and larger units (250) (Gerrard and Mallion, 1977), so making the collection and further processing of waste more attractive from both the economic and environmental standpoint. Within the UK, some 13 to 13.5 million cattle units are slaughtered per year (Table 1). (1 cattle unit = 1 beast or 2 pigs, or 3 calves, or 5 lambs).

Whilst the quantity and nature of the forage available to grazing ruminants is known to vary quite dramatically throughout the growing season, there are still surprisingly few data on the energy and protein value of such materials and, consequently, supplementation of such diets to maintain high levels of animal performance remains empirical.

The recent development of portable equipment for the continuous intraruminal infusion of digesta markers (Corbett, Furnival, Inskip, Perez and Pickering, 1976; Evans, Hayes and Beever, 1981) and the automatic collection of duodenal digesta from T-piece cannulated cattle (Evans, Skelton and Beever, 1981) have, however, provided reliable means by which the flow of nutrients to the small intestine can be measured in grazing sheep (Corbett, Furnival, Inskip and Pickering, 1982) and cattle (Ulyatt, Beever, Thomson, Evans and Haines, 1980). The work reported in this paper is a continuation of the study commenced by Ulyatt et al. (1980), with the objective of this experiment being to examine the digestion of pure swards of perennial ryegrass and of white clover throughout the season when offered at two allowances to young growing cattle.

A rapid growth in per capita consumption of livestock products is occurring in developing countries (Delgado et al., 1999; FOASTAT 1983-2002). In the last two decades and until 2020, the increase in the consumption of meat and milk has been estimated to be much higher in developing countries compared to developed countries (Delgado et al. 1999). This increase in consumption and demand is fuelling an increase in production.

Only as recently as 1992 was the digestible crude protein approach to the calculation of protein requirements for ruminants abandoned in favour of a scheme in which metabolizable protein (MP) became the nutritional currency (Agricultural and Food Research Council, 1992). Application of this scheme requires reliable methods to characterize foods in a number of ways and whilst there are deficiencies in current methodology for this purpose there is now a sufficient body of information available to sustain use of the scheme. Evaluation of the MP approach shows it to be a considerable advancement on what went before but still with some inadequacies. More attention needs to be given to the impact of food constituents on digestive processes within the rumen. Tests of the relationship between predicted MP supply and dairy cow performance show that rules are needed to predict partition of available MP between alternative routes of use. With such rules it will become more likely that a useful response prediction system can be developed. Ideas are put forward as to how some progress might be made to develop frameworks which will bring together ideas about responses to protein and energy yielding nutrients. Clarification of partition rules will be important in promoting improved feeding strategies for cows of different genetic index for milk production. However, it is felt that, given adequate partition rules, the MP approach applies equally to high genetic index and low index cows as regards calculation of requirements. A concern is expressed, however, that the current UK research environment may not be conducive to the open sharing of information which will be important to make rapid progress towards the development of nutrient response frameworks. A technology transfer system is needed which will enable advances in knowledge to be organized for translation into practice.

Pell and Schofield (1993) described a gas production technique where cumulative pressure is related to gas production and hence organic matter (OM) fermentation. This technique has been used to describe rates of carbohydrate degradation for use in the Cornell net carbohydrate and protein system (CNCPS, Barry et al., 1994). Increasingly the CNCPS model is being utilized in the United Kingdom (UK) to ration dairy cows and, as a result, a UK foodstuff database has been developed containing the chemical description of the protein and carbohydrate pools. It was necessary to establish whether the gas production technique could be reproduced in a UK laboratory in order to provide rates of fermentation of the carbohydrate pools. Gas production techniques commonly used in the UK do not allow the vessel gas pressure to accumulate so a comparison of methodology was required.

Diets and habitats that allow animals to select among alternatives enable individuals to better meet needs for nutrients and to better cope with toxins. All plants contain toxins, and the amount of toxin an animal can ingest depends on the kinds and amounts of nutrients and toxins in the forages on offer. Nutrients and toxins both cause animals to satiate, and excesses of nutrients, nutrient imbalances, and toxins all limit food intake. Thus, individuals can better meet their needs for nutrients and regulate their intake of toxins when offered a variety of foods that differ in nutrients and toxins than when constrained to a single food, even if the food is “nutritionally balanced.” Food intake and preference also depend on differences in how individual animals are built morphologically and how they function physiologically, and marked variation is common even among closely related animals in needs for nutrients and abilities to cope with toxins. Transient food aversions compound the inefficiency of single–food diets – whether in confinement, on pastures, or on rangelands – by depressing intake among individual animals, even if they are suited “on average” to that nutrient or toxin profile. Thus, feeding and grazing practices that allow producers to capitalize on the individuality of animals are likely to improve performance of the herd by enabling the uniqueness of individuals to become manifest. Finally, past experiences play a crucial role in an animal's propensity to learn to eat different foods. When herbivores are allowed to eat only the most preferred plants, they are not likely to learn to mix foods high in nutrients with foods that contain toxins. Conversely, herbivores encouraged to eat all plants in an area are more likely to learn to eat mixes of plants that mitigate toxicity. Experienced animals that have learned to eat a variety of foods that differ in nutrients and toxins do so even when nutritious alternatives are available, whereas naive animals familiar only with the nutritious alternatives eat only that subset of familiar foods. Different systems of management alter how animals forage. Continuous grazing at low stock densities encourages selectivity and reduces diet and habitat breadth, whereas short-duration grazing at high stock densities increases diet and habitat breadth. Thus, what was traditionally considered proper grazing management – rotational grazing at low stock densities – may have trained generations of livestock to “eat the best and leave the rest” thus inadvertently accelerating a decline in biodiversity and an increase in the abundance of less desirable plant species.

Past improvement programmes in pigs have concentrated on lean growth, and have relied on direct comparisons of contemporaries in a common environment. The new mixed model technology now allows comparisons across environments and generations, and, by utilizing all possible genetic relationships, more accurate prediction of genetic merit for traits of low heritability. In addition, breeding programme design will benefit from more precise estimation of genetic parameters. Principal benefits of the new technology are greater flexibility of structure of breeding programmes, and faster improvement of litter size. The consequence will be larger populations under selection with lower costs per unit of genetic improvement. For national improvement schemes using a high proportion of AI matings, central testing stations could become unnecessary. Main research priorities are the optimum family structure to balance selection and inbreeding, more efficient computing strategies for large numbers of traits, and the incorporation of single genes into predictions of merit. The new technology will be important for the exploitation of biological advances in manipulation of both reproduction and the genome.

In relation to desirable future developments in the provision of suitable climatic conditions and accommodation for the pig, consideration has been given to the established physiological and behavioural requirements and the extent to which current systems fail to cater for these needs. Suggestions are made for improving the provisions for pigs at various stages of the production process including breeding, pregnancy, parturition and early lactation, weaning and in the growing-finishing period. In formulating future perspectives for accommodating pigs at all stages of the production process, an attempt has been made to maintain an appropriate balance between the objectives of catering more effectively for the requirements of the pig, acceptability from the welfare aspect of both pigs and stockmen, ease of management and cost-effectiveness.

Dietary manipulation of milk fat content and/or fatty acid composition is becoming a feasible, and for certain niche–markets, attractive means of boosting the nutritive value and acceptability of milk and its secondary products. However it is not yet possible to indicate equivalent ways of manipulating milk protein content and/or composition. This paper will consider current knowledge on milk protein biosynthesis and the opportunities for nutritional manipulation. Recent infusion studies which have linked changes in mammary amino acid metabolism with changes in milk protein content will be examined in an attempt to elucidate key features of the metabolic regulation of the dairy cow which need to be addressed if the British consumer is to have the choice of higher protein (possibly designer protein) milk products. This review will (in part) utilise data from a joint project at the Rowett Institute and Reading University funded by a consortium comprising government (MAFF, BBSRC and SOAEFD) and agribusiness (MDC, Purina Mills and Hendrix).

Smith (1976) points out that “the developing world is littered with schemes aimed at improving animal production that… have been only partially successful or… positively harmful, resulting in disruption of traditional ways of life and… destruction of the environment by overgrazing”.

Computers appropriate for small-to-medium sized businesses (such as large farms, agri-businesses, and management and production consultants) can be broadly classified into three groups: pocket sized programmable calculators (£50-£500); micro-computers (£500-£5000); mini-computers (£5000-£50000). There are also the main-frame computers which take up considerably more resources of both money and space. Main-frame computers are likely to be restricted for use in specialist functions such as the handling of very large programs, complex statistical packages and so on.

Of these, the simplest type to operate allows specific programs to be written onto magnetic cards which are fed in as required. Such programs may calculate: nutrient requirements for given levels of production; nutritional quality of a combination of ingredients in a farm mix; average herd performances to date; a register of input and output for the unit; and the like. The capacity of these machines is limited, both as to the extent and complexity of the calculations allowed and to the volume of data which can be stored and executed. The alphabetic printing and layout capability is rather poor and the user must be familiar with the input format and with the configuration for the output.

The birth weight of the piglet has an important influence on many aspects of later performance. There are, for example, relations between birth weight and growth rate as well as between birth weight and litter traits at farrowing (Rydhmer, Eliasson, Stern, Andersson and Einarsson, 1989). In a shorter perspective, birth weight affects piglet survival during the first weeks of life.

High Utter size (number born) is a common breeding goal. Piglet weight is related to the number of piglets in the Utter. Piglet weight is also related to survival; thus mortality increases with litter size.

The aim of this work was to study variation in piglet weight, some factors that may influence piglet weight and relations between litter size, piglet weight and piglet survival.

Individual piglet weights were registered in 747 litters from an experimental farm. Of the 8134 piglets born, 2326 were Swedish Yorkshire, 239 Swedish Landrace, and the rest were crosses between these two breeds. One-third of the piglets were born in gilt litters. The piglets were creep fed from the 2nd week and weaned at 6 weeks of age. They were individually weighed at birth and at 3, 6 and 9 weeks of age. Birth weight in this report refers to the weight of all piglets born, including those stillborn.

Most of the by-products from fish go into the production of fish meal and fish oil, the latter going directly to the human food chain, and therefore do not really come under the heading of industrial by-products and waste per se. Broadly speaking, fish meal made from fish offal is a by-product which otherwise would have been wasted. This paper discusses the quantities involved and the nutritional properties offish meal, and in addition, the contribution to fish meal and fish oil made from species which are not suitable for human consumption (e.g. sandeels) or where the quantities caught exceed the demand for human consumption (e.g. sprats).

Any method of utilizing fish by-products for animal feeding should minimize chemical changes in the product to avoid reduction in the nutrients which are present at the time of catching. In some respects chemical changes in fish by-products are brought about in a similar way to those in grass, cut for preservation. The fish material has a high water content, around 75%, and from the time of catching is subject to chemical changes by enzymes in the fish and also by bacterial action. Fish, however, differs from grass in that it contains oil and virtually no carbohydrates. The demersal, or lean fish, for example, cod, haddock, plaice, saithe, etc., contain high levels of oil in the liver which are removed for separate processing, but little in the flesh and in the offal produced. The ‘industrial’ fish caught are mainly pelagic species with high levels of oil in the flesh.

There is increasing demand to obtain fast and accurate dynamic nutritional information from forages. Near-infrared reflectance spectroscopy (NIRS) offers the possibility for obtaining such information for a range of nutritional constituents of foods. Herrero et al. (1996 and 1997) calibrated in vitro gas production measurements of a single grass species by NIRS. There would be greater practical benefit if the gas production predictions could be obtained using calibrations derived from a wide range of plant species, since a single equation could be used for all forages. The objective of this study was to investigate if in vitro gas production measurements of a broad based sample population could be calibrated by NIRS.

Intestinal digestibility of food protein is one of the important factors of most protein evaluation systems. Therefore it was determined in the experiments with duodenal infusions of foods (Hvelplund, 1985) or using mobile bags (Sauer et al., 1983; Hvelplund, 1985; de Boer et al., 1987; Antoniewicz et al., 1992). To avoid the use of cannulated animals, in vitro enzymatic methods have been developed (Antoniewicz et al., 1992). Incubation of food with pepsin and pancreatin correlates with the digestibility of food protein (Akeson and Stahmann, 1964) and is suitable (r = 0·95 to 0·99) to determine protein digestibility in pig foods (Babinszky et al., 1990). The aim of the study was to develop the best conditions of pepsin-pancreatin digestion and to evaluate the predictive ability of the method to determine protein disappearance measured using mobile bag technique.