In view of the forthcoming UK ban on stall and tether housing for sows, the long-term consequences of housing pregnant pigs in alternative systems were assessed. The objective of the study was to examine the effects of two indoor group-housing systems on measures of the welfare of pregnant pigs, and to compare pigs housed in these systems with pigs housed in stalls. The study followed 63 female pigs from early life until their fourth pregnancy. A longitudinal experimental design was used to obtain information on how the pigs responded to their initial introduction to the three housing systems (during the first pregnancy), and how they adjusted to the systems over time (in the fourth pregnancy).

The forthcoming UK ban on stall and tether housing for sows will result in an increase in the use of group housing for these animals. In group housing systems, certain individuals may be particularly aggressive or bullied by others, and this may result in injury or socially induced stress. To attempt to overcome these problems we need to know the answers to questions such as whether removal of a particularly aggressive animal from a group will result in a general decrease in aggression, or whether it will simply result in other animals becoming more aggressive. Answers to these sorts of question require a fundamental understanding of pig social behaviour and individual characteristics. For example, is aggressivness a stable individual characteristic across time and situation? This research addressed these issues by examining the cross-time consistency of individual aggressiveness and social status in groups of pigs.

The Matebele goat is indigenous to the Gwanda-Thuli area of Matebeleland. It is relatively large in size compared to most goats of the tropics, males being around 65 cm at the withers and weighing more than 35 kg, and is similar to many of the goat breeds found in southern Africa.

Goats are usually kept by poor small-holder farmers and are frequently found in regions with few resources where other livestock have difficulties in surviving. Goats are important to the subsistence and economic development of peasant farmers because goats are cheaper to procure than cattle and provide a constant supply of essential food (both meat and milk) and cash income throughout the year. However, goats have a low priority in most households and little attention is given to their husbandry and welfare. This hampers attempts to improve the productivity of the goats. The results reported here demonstrate the effects of multiple births in Matebele goats upon the overall productivity of the animals.

Cows in low body condition exhibit a prolonged postpartum anoestrous period and a delayed return to normal follicular function (Prado et al 1990). Previous studies have shown that the effects of body condition on gonadotrophin profiles are inconsistent (Wright et al 1990; Rhind et al 1992) indicating that the effects of body condition on ovarian function cannot be explained by changes in gonadotrophin profiles alone. Since nutritional state influences growth hormone profiles which in turn can affect ovarian function (Gong et al 1991), it was postulated that the effects of body condition on the duration of postpartum anoestrus could be mediated through changes in profiles of this hormone.

The aim of the present study was to determine the effect of growth hormone on ovarian follicle development and associated gonadotrophin profiles in post-partum beef cows.

One of the major factors affecting the efficiency and profitability of sheep production is the number of lambs reared per ewe. In 1991 lambs reared per ewe accounted for 14% of the difference in gross margin per hectare between top third and average lowland spring lambing flocks (MLC, 1992). The hypothesis was developed that in managing the prolific ewe three possible management systems could be employed; frequent lambing (FL), early annual lambing (EAL), or late annual lambing (LAL). The choice of these lambing systems was based on minimising the problems of the prolific ewe. Of these systems FL (lambing on an eight month cycle), provided the best opportuity for achieving high numbers of lambs sold per ewe.

Artificial Insemination can be used in conjunction with controlled breeding to provide the following advantages. It can overcome the need for a 1 : 10 ram to ewe ratio, within a controlled breeding programme A.I. can be used to identify genetically superior sires, high merit rams may then be made more freely available to farmers so achieving higher rates of genetic improvement. As techniques within the U.K. have improved artificial insemination has now gained greater acceptance within the sheep industry. The objectives of this study were to examine the conception rates and litter sizes to first service, comparing natural and artificial insemination on a commercial farm.

Ovulation rate in the ewe is positively related to body condition score (Gunn, Doney and Smith, 1979). For optimum performance it has been recommended that ewes should be in body condition score 3.5 at mating (MLC. 1981). However excessive fatness (body condition score 3.5 and above) has been associated with a reduction in lambing performance as a consequence of increased embryo mortality (Rhind, Gunn, Doney and Leslie. 1984).

Previous studies at the Scottish Agricultural College-Aberdeen (King and Mitchell. 1990) have demonstrated superior reproductive performance for twenty month old female breeding sheep (gimmers) which have bred successfully as ewe lambs. The objective of the present study was to investigate the combined effect of body condition and breeding history (bred or unbred at eight months of age) on fecundity.

Normal reproductive function in female animals can be drastically impaired by a variety of stressful stimuli. For example, undernutrition and hypoglycaemia in sheep have been shown to suppress pulsatile LH secretion and to reduce the number of ewes showing pre-ovulatory LH peaks (Crump and Rodway 1986, Clarke et al. 1990). Similar stresses are also known to cause release of the opioid peptide β-endorphin into the circulation. Opioids are well-known to have a central inhibitory effect on LH release, although whether the elevated plasma concentrations of these peptides have any effect on LH secretion is unclear. The present study investigated the affect of insulin-induced hypoglycaemia on plasma concentrations of β-endorphin and LH.

The widespread availability of large amounts of cereal straw has led to a growing interest in its use in ruminant livestock although it has a low content of essential nutrients, especially nitrogen. Treatment and/or supplementation of nitrogen, energy and minerals are necessary for optimal utilization of straw.

The aim of the experiment was to investigate the effect of different sources of nitrogen supplements offered with straw-based diets on the milk yield and milk constituents of dairy cattle and digestibility of diets.

A polymer of acrylic acid has been used continuously on a number of dairy farms throughout the UK for the past five years. The polymer is fed as a gel and absorbs 100 times its own weight of water. Commercial farmers report that the polymer allows them to reduce concentrate allowances whilst maintaining milk yields. The results of an experiment with grazing cows in late lactation were reported to this meeting in 1988. It was found that the polymer did not affect milk yield but caused a significant increase in the rate at which cows laid down body reserves.

There is a lack of experimental evidence to support the commercial findings for cows in early lactation and little information on the mode of action. The main experiment reported here was conducted to investigate the effects of feeding a polymer gel to dairy cows in early lactation and in vitro studies were performed to investigate the mode of action.

In previous research grazing dairy cows showed no response to whole-crop barley silage (WCB) cut at different stages of growth, but the crop yield and quality, and DM losses were optimised at 350 to 450 g DM/Kg (early to hard dough) (Hargreaves and Leaver, 1992). However tha effect of herbage availability on the response to WCB supplementation is not known, therefore the objective of this study was to examine this effect during mid to late summer.

Winter barley (var. Puffin) was harvested on 16th July at 380 g DM/Kg (soft dough) and a yield of 14 t DM/ha. The chopped material was stored in a bunker silo.

The recommended post grazing stubble height for dairy cows in a rotational grazing system in spring is 8 to 10 cm. However, this height leads to much stem elongation and reduction in sward quality in mid and late season. Consequently, pastures require topping in June/July to maintain grass quality and reduce sward deterioration, particularly in rejected areas around dung pats. O'Riordan (1989) suggested that a leader/follower rotational grazing system with ewes following dairy cows could improve pasture utilisation and eliminate the need for topping. This was confirmed by Swift et al. (1991) who also demonstrated that grazing at one ewe with twin lambs per cow improved the utilisation of grass and allowed for acceptable ewe and lamb performance without apparently decreasing cow grazing days or milk output.

The objective of this work was to examine the effects of leader/follower rotational grazing with dairy cows and lambed ewes on grass tillering in a cool, wet western environment.

The aims of the experiment were to determine the intake, digestibility and particle passage kinetics of urea treated (40 g urea / Kg DM) whole crop wheat (UW), grass silage (GS) and a 0.5:0.5 UW : GS mixture (UG) on a DM basis.

The chemical composition of GS and UW were respectively, TDM (gTDM/Kg) 227, 648; NDF (g/Kg DM) 528,426; ADF (g/Kg DM) 346, 285; Ash (g/Kg DM) 74, 62; Starch (g/Kg DM) 3, 236; Nitrogen (g/Kg DM) 24.2, 30.2; Ammonia N (g/Kg TN) 91, 382; pH 3.9, 8.5; NCD (g/Kg DM) 681, 642 respectively.The UG was mixed daily, in an attempt to reduce selection of individual components by the animals.

The experimental design was based on two 3 x 3 latin squares with three animals per square and three periods of three weeks duration. Six Holstein Friesian x Brown Swiss pregnant heifers (mean liveweight 400 Kg) were used to assess (during the last 7 days of each period) the voluntary intake, digestibility and particle passage kinetics of the three forages.

Clements, Huckle and Wilkins (1991) reported that milk yield did not differ significantly between cows grazing grass-clover swards with compressed sward heights maintained at either 4.5 or 6 cm in early season. However, cows grazing the shorter sward produced milk with a lower protein concentration. The feeding of 4 kg concentrates/day resulted in an increase in milk yield at both sward heights but there was no effect on milk constituent concentrations. The present experiment was designed to investigate the effect of a wider range of sward heights and their interaction with concentrate supplementation.

Forty eight, multiparous, Holstein Friesian cows with a mean calving date of 21 March were continuously stocked on mixed grass-clover swards. The cows were blocked by calving date, parity and milk yield and randomly allocated to one of six treatments, 0 (U) or 4 kg concentrate supplementation (S) with swards maintained at 4, 6 or 8 cm compressed sward height. Sward heights were maintained by adjusting the grazed area. The swards were permanent pastures which had received no fertilizer nitrogen.

Cereal straw is the most abundant of crop residues and is an important feed resource especially in tropical countries. The limitations to its use arise from its high cellulose and lignin and low nitrogen content. The objectives of this research were to investigate the use of urea for the treatment of wheat straw and incorporation of the forage into dairy cow diets.

In Experiment 1, 8 lactating Holstein Friesian cows were used in two 4 x 4 Latin Squares with three week periods. The treatments were; A - red clover silage (CS) ad libitum. B - 5kg DM/day CS + urea treated straw (TST) ad libitum. C - as for B but using untreated straw (UST), D - as for C but the straw was wetted at feeding to produce the same DM as TST (WST 600 g DM/kg). TST was treated with 5% urea (DM basis) and stored for 4-13 weeks. All cows were fed 6.4 kg DM/day of molassed sugarbeet pulp (MSBP) and o.6 kg DM/day of cottonseed meal (CSM).

In Experiment 2, 10 Holstein Friesian cows were used in an incomplete Latin Square design of four 3 week periods. The treatments were; E - CS, F - 25% UST + 75% CS, G - 50% UST + 50% CS, H - 25% TST + 75% CS, I - 50% TST + 50% CS. All forages were offered ad libitum, arid in F to I pairs of forages were mixed. The urea was applied to TST at a rate of 7.5% (DM basis). The concentrate was 4.7 kg DM/day of MSBP and 2.3 kg DM/day of soya meal.

Existing techniques for estimating the weight of udder tissue in live farm animals are based on water displacement (Linzell, 1966) or gross external dimensions (Davis et al,1983). With goats, Linzell (1966) obtained a coefficient of variation (proportion) of 0.02 for a rather laborious casting technique and 0.11 for a water displacement technique. The water displacement technique is difficult to apply with dairy cows owing to the greater size and less accessible position of their udders. The lack of reliable estimates of udder weight limits our ability to assess the efficiency of synthetic tissue. The latter is an important measurement both experimentally and, potentially, inbreeding programmes. The present work investigated the possible use of quick-setting polyurethane foam to prepare udder casts from which udder weight could be estimated. The polyurethane foam used in this study was completely hardened within 30 seconds providing a rapid and easy technique.

There is a clear need to improve financial returns from hill sheep to help maintain rural populations in hill/upland areas while at the same time reducing the reliance of hill sheep farmers on social/production type subsidies. Particular problems with hill sheep are their small carcass size and poor conformation, which result in reduced values for both draft ewes and wether lambs. These poor carcass attributes are also passed down to the lowland producer through the production of poor conformation halfbred ewes out of hill ewes. With the increasing pressures being placed on the lowland sector to improve carcass quality, many producers are beginning to look at the possibility of breeding their own replacement top-cross ewes. Any widespread adaption of this practice will further undermine the profitability of sheep production in the hill and upland sectors.

SAC Edinburgh has a long established breed improvement programme to increase the lean growth rate of Suffolk sheep. Studies commenced in 1989 to evaluate the extra genetic gain which could be achieved through the application of multiple ovulation-embryo transfer (MOET). Theoretical studies show that rates of genetic progress in sheep could be increased by 100% through use of MOET to increase selection intensity amongst females and reduce female generation intervals (Smith, 1986). However, to achieve these levels of improvement requires good embryo transfer rates (10 progeny per donor) at 6 to 8 months of age. Smith (1986) identified that current transfer rates fell well short of these required by his calculations. Given that minimally invasive techniques for the recovery and transfer of embryos by laparoscopy are available (McKelvey, Robinson and Aitken, 1985a), the main impediment to achievement of the embryo transfer rates required is the low and variable superovulatory response in donor ewes. Previous studies investigating superovulatory drugs to increase the ovulation rate of donor ewes in MOET programmes identified Ovagen (Immuno-Chemical Products), as the most potent product (Dingwall, Fernie, FitzSimons and McKelvey, 1991). This trial reports the use of Ovagen in a large scale MOET programme applied to Suffolk ewes.

The common point at which lambs are compared is an important aspect of selection programmes for lamb carcase composition. Terminal sire flocks in the Meat and Livestock Commission's (MLC) Sheepbreeder scheme have an estimated breeding value for lean meat production calculated on their lambs at a fixed age, 20 or 21 weeks depending on the breed. However, lambs sold for slaughter from commercial flocks are killed at a commercially acceptable fat cover. In addition, many of the estimates of genetic parameters used to estimate breeding values for carcase characteristics have been calculated at a fixed weight. Little information is available on the relationship between genetic parameters calculated at these three endpoints or the effect of selecting lambs at one endpoint in breeding programmes and using a second endpoint for the slaughter generation. These issues are investigated in this paper.

The reproductive performance of ewes is an important contributor to flock profitability in many different situations. Although the heritability of reproductive traits is low there is often enough phenotypic variance to make a consideration of selection a possibility for improvement in litter size. Genetic trends in selection experiments have traditionally been monitored using a control flock which should be kept as an unseletced group. The recent availability of user friedly BLUP programs have added an extra method for estimating genetic trends. This paper reports the use of BLUP to estimate the genetic trends in a sheep population selected for litter size.