Piglets are usually supplied with solid food - creep food - at a time when most are still obtaining adequate nutrition from milk. Getting piglets started on solid food may help their growth performance both before and after weaning. As young piglets are highly exploratory animals (A'Ness et al., 1997) and food restriction increases the tendency of older pigs to express foraging behaviour (Lawrence et al., 1988), the objective of this experiment was to examine the relative importance of exploratory behaviour and hunger on initiation of creep feeding by piglets.

Eight litters of Large White x Landrace piglets were used in this study. Each piglet was ear tagged and weighed within 24h of birth. When a litter was 16 days old (d16), each piglet was weighed and 8 piglets were taken in pairs, between nursings, to one of two experimental pens for 30 mins familiarization and filming, twice each.

Social facilitation occurs when one animal increases performance of a behaviour due to the presence of another animal engaged in that same behaviour. Gonyou et al. (1992) reported that pigs in adjoining pens ate simultaneously more often if the feeders were adjacent to the common wall. Feeders which allow pigs to see pigs in the adjacent pen increase feed consumption in short trials (Hutson, 1995). Although these studies reported some form of social facilitation, the studies were either too short to detect an improvement in productivity, or none resulted. The objectives of this study were to determine if social facilitation of eating between pens of pigs can best be achieved by allowing visual contact through the wall or the feeder, and if feed consumption can be increased over an extended period of time.

Sow welfare legislation has meant that many dry sows are now housed in large dynamic groups. The large group sizes involved in these systems and the constant turnover of sows does not allow stable relationships to be formed and so leads to agonistic behaviour (Moore, Gonyou and Ghent, 1993). The aim of this study was to determine if pre-mixing weaned sows in small groups for five weeks prior to introduction into the large group would reduce the overall level of agonistic behaviour.

Sixteen groups of four newly weaned and unfamiliar sows were allocated at one week intervals to one of the following treatments. Treatment 1 (T1) involved introducing sows into small static groups of four for a period of 5 weeks prior to introducing them into a large dynamic group. Treatment 2 (T2) involved introducing sows directly into a separate large dynamic group.

The mixing of unfamiliar sows usually results in fighting which can have adverse consequences for both welfare and production. It has been suggested that aggression may be moderated by both the presence of a boar and by allowing sows access to feeding stalls (Arey and Edwards, 1998). The objective of this experiment was to investigate these effects on the behaviour of newly weaned sows mixed into two loose-housing systems.

In the first system (dynamic), 24 Large White x Landrace mixed parity sows were introduced 4 days post weaning to a dynamic group of 22 sows and 2 boars with a replacement rate of 2 sows per week. Observations were carried out on the 2 newly introduced sows each week. The straw-bedded pen provided 4.5 m2 space per animal. The sows were floor fed 3 kg/sow at 08.00 each day.

The farrowing crate was designed to make sow management easier, allow higher stocking densities and reduce piglet mortality. Recently, concerns about sow welfare within farrowing crates have lead to a reappraisal of open farrowing systems. However, more freedom of movement for the sow places greater influence on the quality of maternal care, if piglet welfare is to be safeguarded. The aims of this study were to compare the behaviour of gilts housed in different farrowing systems and to determine any differences in behaviour, that may affect piglet survival.

After service, 38 LW x Landrace gilts (PIC, Abingdon, UK) were formed into groups of 3-5 and were assigned to either farrowing crates or a communal farrowing system. Each crate room housed six conventional crates with sow feeders, nipple drinkers and forward piglet creeps. Each pen room contained five individual strawed pens (2.7m x 1.9m) with a rectangular piglet creep at the rear, sloping walls along both sides and piglet and sow drinkers.

There are commercial benefits in being able to predict the time of ovulation, post weaning in the sow. These include the use of a single insemination, with associated decreased AI and labour costs, and increased litter sizes resulting from the correct timing of insemination (Waberski et al., 1994). To predict the time of ovulation in the sow, a variety of potentially influential factors have to be considered. Predictability may be increased by timed administration of gonadotrophin, which has been shown to reduce the variance in the weaning to oestrus interval in multiparous sows (Lancaster et al., 1985). This experiment was designed to determine the major factors influencing the weaning to ovulation interval and to examine the effects of exogenous gonadotrophin on the length and variation of this interval.

The occurrence of ovulation in the sow after parturition is usually inhibited for the duration of suckling. A system of management in which lactating sows are mated and conceive, therefore routinely commencing a successful pregnancy concurrent with lactation, would obviate the need for early weaning of piglets and promote adoption of economic systems incorporating more extensive lactation housing. Previous studies have shown that first parity sows rarely show ovulation during lactation when group-housed in multisuckling systems with multiparous sows, and suggested that reduced food intake through social competition and/or higher suckling intensity were responsible for this (Hulten, 1997). The object of this experiment was to investigate, in a more controlled way, the factors contributing to this parity effect by removing the possibility of social interactions between primiparous and multiparous sows, and investigating possible dietary influences within parity.

The transfer of passive immunity from sow to piglet is important for neonatal disease resistance. Piglet immune status will be influenced by the Ig concentration in colostrum, the amount of colostrum ingested and the duration of absorption of intact macromolecules across the gut. Despite the importance of the maternal contribution to this process, there has been no published information on the level and variability of colostral Ig concentration in modern sow geno types. A study was therefore designed to remedy this lack of knowledge.

Colostrum samples were taken at farrowing, prior to suckling by the first piglet, from 63 Landrace x Large White sows (Pig Improvement Company Ltd) on a large commercial unit in Scotland. During pregnancy, sows were housed in stalls and fed a standard commercial dry sow diet. At 2-3 weeks prior to expected parturition, they were vaccinated against E.coli, A.pleuropneumoniae and Clostridium.

An adequate intake of colostrum by the newborn piglet allows the piglet to acquire passive immunity and develop active immunity. Many studies have looked at the uptake of IgG by piglets in artificial situations rather than by natural suckling. Therefore we investigated the uptake of IgG by piglets whilst suckling naturally and estimated the time of gut closure.

A total of 8 multiparous sows (Newsham - Large White x Landrace) were induced to farrow on day 114 of gestation. Colostrum/milk was sampled, using oxytocin where necessary, at 0, 4, 8, 12, 16, 20, 24h and 2, 5 and 7 days after farrowing. Female piglets (average 3 per litter) were fitted with umbilical catheters to allow blood sampling at 0, 4, 8, 12, 16, 20, 24 and 48h; samples were taken at 5 and 7 days of age by venepuncture.

It has been suggested that the anterior glands may be larger, produce more milk or provide a more comfortable position for piglets (Donald, 1937; Gill and Thomson, 1956) while others have suggested that there is no difference in milk yield among teats (Hartman et al., 1962; Pond et al., 1962). The real advantage of the anterior mammary glands of sows for the suckling pig remains unclear. We have demonstrated that substantial mammary growth occurs during lactation in the sows (Kim et al., 1999). This study was designed to relate teat preference and piglet growth with gland size and composition. Our hypothesis is that there are differences between anterior and posterior glands in size and composition and that these differences may be related to piglet growth during lactation.

While it is accepted that environmental enrichment can improve the welfare of growing pigs by reducing harmful social behaviour (Beattie et al., 1995), the influence of environmental enrichment on physiological and pathological parameters remains unclear. The objective of this study was to monitor selected physiological and pathological parameters of pigs reared in barren and enriched environments.

In a randomised block design, three-hundred and twenty Large White x Landrace pigs were allocated to one of two environmental treatments from birth to slaughter. Five blocks were used, each containing eight groups of eight pigs. In each block, four groups were reared in barren environments which had slatted floors and recommended space allowances. The remaining four groups were reared in enriched environments which had three times the recommended space allowance, solid floors partially bedded with peat and pigs had access to straw from a rack. Both environmental treatments were located in separate buildings.

Environmental enrichment using substrates changes the behaviour of pigs by increasing the time spent exploring the environment and reducing the amount of penmate-directed behaviour (Beattie et al., 1995). The objective of the present study was to assess whether performance and meat quality are also affected by environmental enrichment.

In a randomised block design, three-hundred and twenty Large White x Landrace pigs were allocated to one of two environmental treatments from birth to slaughter. Five blocks were used, each containing eight groups of eight pigs. In each block, four groups were reared in barren environments which had slatted floors and recommended space allowances.

The calpain enzyme system plays an important role in the proteolytic events leading to the conversion of muscle to meat in livestock species. Evidence in beef has shown that the levels of calpastatin, the inhibitory component of the system, measured 24 h after slaughter can be used to predict the degree of tenderisation achieved at the end of the normal conditioning period (Koohmaraie et al., 1995). In pigs there is now evidence that calpastatin levels measured within the first hour of slaughter correlate with tenderness measured after conditioning (Sensky et al., 1998). In this study we report differences in the calpain system in pigs supplied by four different commercial production units who supplied pigs with predominantly tough (A and B below) or tender meat (C and D below) in a previous study (Sensky et al., 1998).

The calpain enzyme system plays an important role in the proteolytic events leading to the conversion of muscle to meat in livestock species. Increasing evidence suggests that calpastatin, the inhibitory component of the system, correlates negatively with tenderness in beef and pigs (Koohmaraie et al., 1995; Sensky et al., 1998). In this study, the immunoreactivity of calpastatin in three pig breeds with different meat quality traits have been measured.

Thirty-six female pigs, comprising equal numbers of Duroc (D), Large White (LW) and Duroc x Large White (50:50 DxLW) breeds were reared under identical conditions at a commercial pig unit and slaughtered at a commercial slaughterhouse on the same day by electrical stunning and severance of the carotid arteries. Carcass weight, backfat thickness, pH45 and pHu were all monitored.

The importance of considering public opinion in technology development and use is widely recognised. Several studies have assessed public opinion on modern biotechnologies used in animal production systems (Eurobarometer, 1997), but few have focused on specific technologies. The aim of this study was to evaluate attitudes to two defined technologies, bovine somatotrophin (BST) and automated milking systems (AMS), as part of a wider study of the role of ethical analysis in technology assessment. The preliminary results described below highlight only certain aspects of a much more comprehensive survey.

Postal surveys of consumers and farmers were conducted in the Spring/Summer of 1998. The farmers’ population sample (n=1,000) was randomly selected from the National Farmers Union Dairy Farmers database. The selection, based on an nth term sample, was stratified for geographical region only.

A key factor affecting economic efficiency and animal welfare on dairy farms is the performance of the employed stockperson in undertaking daily routine tasks. Little is known if the views of the stockperson as to which routine tasks are enjoyed and likely to be performed well, and which tasks are not enjoyed and likely to be performed less well. Stockpersons are a potential source of ideas for innovation and their views should be considered along with those of other in setting priorities for future research into milk production. The study reported here was undertaken to test the hypothesis that the routine tasks which were considered to be important were also those which were enjoyed. The study also sought to determine the priorities of stockpersons for innovations in milk production.

Most functions used to describe the lactation curve of dairy animals are empirical in approach and result in parameters with little or no biological meaning. A new model for describing lactation based on the biology of the pregnant and lactating animal is proposed and compared to several empirical models (Wood, 1967; Grossman and Koops, 1988; Morant and Gnanasakthy, 1989).

Lactation is thought of as the balance between an increase in secretory cell numbers (NSCP) and their later decline (NSCD). The difference between them is the number of active secretory cells, each of which secretes milk at a particular rate (S kg/cell/day). Thus daily milk yield (MY) = (NSCP – NSCD) x S.

The response in milk energy output to increasing metabolisable energy intake (MEI) is curvilinear and obeys the law of diminishing returns (Blaxter, 1966). This curvilinearity can be explained by the increased partitioning of MEI to body tissue as intake increases. Rationing dairy cows for cost-effective milk production requires prediction of the extent and nature of this partitioning phenomenon. However, the current rationing system in the U.K., the ME system, does not address this issue. The objective of this study was to examine two of the possible animal factors which might influence the partitioning of increments of MEI given above requirements i.e. days in milk (DIM) and physiological state (number of mammary glands milked) of the animal.

It is common practice to rear dairy heifers to calve at 24 months of age and expect first lactation milk yields of up to 10,000 litres. This requires growth rates of at least 0.7kg/d during rearing. Research has indicated that high growth rates in the prepubertal period can have a deleterious effect on mammogenisis (Capuco et al 1995), and a significant reduction in potential milk production (Sejrsen et al 1996) due to impaired mammary development. However, not all studies have found such effects (Sejrsen et al 1996). As a consequence, strategies of rearing are being studied to identify the optimum pattern of growth around puberty to achieve high milk yields. Skeletal measurements have also been demonstrated to be related to first lactation yields (Hoffman 1996). This study investigated the consequences of differing growth rates between 100 and 300kg liveweight on the size and relative dimensions of Holstein heifers.

The economic pressures on the dairy industry may force more farmers to consider reducing the amount of concentrates fed to cows in order to keep costs down. We have been testing whether the long-term performance of daughters of sires progeny tested in high concentrate systems maintain their advantage over cows of average genetic merit when managed in a lower input feeding system. This paper extends the scope of our initial report (Chalmers et al., 1997) and includes data on reproductive performance.

Data were from Holstein-Friesian cows managed at the Langhill Dairy Cattle Research Centre. Sires of the Selection (S) line are among the highest available in the UK for predicted transmitting abilities of weight of fat plus protein (PTA F+P). Sires of Control (C) line cows are about UK average for PTA F+P.