The objectives of this experiment were to investigate the effect of adding a multi-enzyme product to a diet based on wheat, barley and soybean meal on faecal nutrient digestibility and nitrogen retention in early-weaned piglets.

A total of 36 pigs, weaned between 21 and 25 days of age, were assigned on weight and litter origin basis to two dietary treatments and placed in flat-deck pens of 6 pigs each. The design of the pens allowed total collection of urine and faeces separately.

Rising living standards and an increasing awareness of the health risks of a diet high in saturated fats have led to strong consumer discrimination against animal fats. Additionally the surplusses of animal products in Europe suggest that more attention should be paid to the inputs in animal production, rather than solely increasing output. Improving the efficiency of lean meat production is therefore an important consideration in all meat animal systems. In 1976 Fowler, Bichard and Pease proposed the ‘biological indices’ lean growth rate and lean food conversion as selection criteria in pigs. These traits may be estimated as the product of growth rate (GR) or food conversion efficiency (FCE), and in vivo estimates of killing out and carcass lean proportions. However, in cattle and sheep the relatively low coefficient of variation of estimated killing out and of lean proportions, means that the biological indices are frequently dominated by GR and FCE. In such cases there may be little difference in response from selection solely on GR and FCE (Simm, 1983). The objective of the present study was to derive economic selection indices for terminal sire beef breeds, which might give appropriate economic weighting to the components of efficient lean meat production.

One of the major limitations in nutritional studies of lactation in dairy cows is the unknown contribution of body tissues to the energy status of the animal. Both fat and protein are thought to be mobilised in early lactation (Bauman and Elliot, 1983) when nutrient intake is insufficient to meet the demands for energy and amino acids. The present experiment investigates the effects of diet on changes in weights of chemically determined fat and crude protein (CP) in the carcass and non-carcass fractions over the first 29 weeks of lactation.

Body composition was measured by serial slaughter of autumn-calving dairy cows offered grass silage (206 g CP and 18.56 MJ GE per kg DM) ad libitum and 3(L), 6(M) or 9(H) kg DM/day of concentrate (206 g CP/kg DM)(Sutton, Aston, Beever and Fisher, 1992). Cows with post-calving live weights between 500 and 700 kg and previous lactation yields between 5000 and 7000 litres were used, and were blocked for parity and expected calving date before allocation across treatments and slaughter times. Six cows were slaughtered at 2 to 4 days post partum (week 0), and two from each treatment (one 2nd, and one 3rd or 4th parity) at 2, 5, 8, 11,14,19, 24 or 29 weeks post partum. After slaughter the right half carcass and all other non-carcass components were frozen and minced before chemical analysis for fat, CP, ash and water. All weights were adjusted by covariance for live weight post partum and parity. Energy content was calculated assuming values of 39.19 and 23.23 MJ/kg for fat and CP respectively.

There is increasing concern within all sectors of the UK pig industry with meat quality and particularly the eating quality of pork. Against this background, a collaborative study involving 6 organisations was carried out to investigate the relative influences of a number of production factors on the eating quality of fresh pigmeat. The results relating to two of these factors, namely feeding regime and sex of pig, are reported here.

The effect of routine induction of parturition on some reproductive and productive parameters during a year-long trial in 50 California doe rabbits allocated in two groups of 25 animals (treated and control), was studied. Intramuscular injections of 50 ug of the synthetic analogue of prostaglandin F2ct (Etiproston), were given at 10.00 h on day 29 of pregnancy. Control animals were untreated. When compared with the controls, treated does showed a significant reduction in the individual weight of pups at birth (49·7 (s.e. 0·41) and 52·2 (s.e. 0·53) g), number born dead per litter (0·42 (s.e. 0·11) and 0·81 (s.e. 0·16)), and parturition interval (42·9 (s.e. 1·5) and 53·5 (s.e. 1·7) days), and an increase in both sexual receptivity on days 6 to 9 post partum (70·4% and 43·0%), and in the conception rate to remating on days 6 to 7 post partum (82·2% and 66·6%), respectively. Litter size at birth, overall conception rate, mortality from birth to weaning, litter weight at 21 days, litter size at weaning, milk production, and mortality of does were not affected by the prostaglandin treatment.

Ensiled ear maize was compared with rolled barley as the cereal in a finishing diet for cattle weighing about 400 kg. The diets resulted in similar gains of about 1·2 kg/day.

Mating and the resultant conception is a critical event in the operation of a pig production unit. The boar's presence is known to influence the reproductive performance of the female pig in several ways, such as the onset of puberty, the weaning-to-conception interval, behavioural oestrus, conception and the number of piglets born in the subsequent litter. To optimise the productive benefits from this interactive process and for ease of husbandry there are several key requirements.

The boar must be housed to maintain his health, welfare and reproductive ability, the newly weaned sow must be aware of the boar's presence and an area must be provided where mating can be successfully executed. Additionally, there are second-order objectives of considerable importance: the easy and clean provision of feed and water, a minimal effort muck removal system, pens which provide easy access for stock and pigmen whilst allowing easy stock transfers. The multiplicity of objectives must be integrated and satisfied in a successful design.

Aitrenogest (17 α -allyl-17-hydroxyestra-4,9,11-trien-3-one; Regumate Porcine; Hoechst Animal Health) is a synthetic progestagen which has been used to control and synchronise the ovarian cycle particularly in cyclic gilts. However progestagens have also been used in various species to induce and synchronise the first ovulation post partum. The present study was undertaken to determine the effect of altrenogest treatment on the reproductive performance of primiparous sows.

When a highly digestible food is progressively diluted with one of greater ‘bulk’ the prevailing view is that the rate of food intake will initially increase at such a rate such that DE intake remains constant and, that beyond a critical point, intake of food and DE will fall as the dilution proceeds further. The critical point has been assumed to reflect the capacity of the pig for ‘bulk’. Current models which attempt to predict the voluntary food intake (VFI) of pigs use either food dry matter (DM) as a measure of bulk (eg Whittemore, 1983) or the undigested organic matter (eg Roan, 1991), or ignore the problem (ARC, 1981). It has long been known however, that such views are likely to be inadequate across the complete range of foods (eg the significant reduction in VFI of pigs on foods based on sugar beet pulp, compared to that on other more undigestible materials).

The experiment described here was designed (i) to try to identify the property of ‘bulky’ foods which might be responsible for limiting their VFI and (ii) to see the extent to which the capacity for a ‘bulky’ food might be modified by prior experience.

Two randomised block experiments, involving 64 British Friesian and Friesian cross steers, have been carried out to compare extracted soyabean, extracted sunflower and fish meals as protein supplements for yearling cattle offered grass silage ad libitum. Two formic acid-treated, precision chopped silages, each made from the primary growth and first regrowth of a perennial ryegrass sward, were used. The control concentrate consisted of (g/kg) 925 barley, 50 molasses, 25 minerals and vitamins. The three high protein concentrates were similar to the control but with 0.30, 0.54 and 0.20 of the barley replaced by soyabean, sunflower and fish meals respectively. The mean chemical compositions of the silages and concentrates used in the two experiments are given in Table 1. All animals received 1.3 kg concentrates per head daily. They were initially 11 months old and 334 kg live weight. The treatments were imposed for 126 days.

In order to understand the complex changes associated with lactation in the dairy cow it is necessary to assess the contribution of the non-carcass components. It has been shown with sheep (Cowan, Robinson, Greenhalgh and McHattie, 1979) that a number of tissues may be mobilised during lactation with a redistribution of tissues particularly towards the gut and udder, and that diet may have a significant effect. Butler-Hogg, Wood and Bines (1985), using Friesian dairy cows showed changes in the weights of guts, internal fat depots (omental, mesenteric and perinephric) and liver with stage of lactation although the number of stages examined was somewhat limited. The present experiment investigates changes in non-carcass component weights at 9 points over the first 29 weeks of lactation and with 3 levels of concentrate supplementation.

Angora and Cashmere goats produce two distinctive major fibres. The hair coat of the Angora goat consists essentially of a single fleece of Mohair grown by secondary hair follicles with a limited production of guard hair from primary follicles. The average fibre diameter ranges from 22 to 45 urn. In contrast, the Cashmere bearing goat has a double coat comprising coarse guard hair produced by primary follicles with the fine cashmere underhair (preferably 19 μm diameter or less) produced by secondary hair follicles. In the Angora goat, the fibres grow essentially continuously while in cashmere, hair follicle activity is determined largely by seasonal changes in photoperiod. The objective of this study was to investigate the effects of prolactin and melatonin, hormones implicated in the photoperiodic response, on the pattern of growth of secondary hair follicles isolated and maintained in vitro.

The majority of early lambing flocks in the UK consist of crossbred ewes which do not normally cycle at a time consistent with an early January lambing. Oestrus stimulation is therefore necessary and is generally achieved by the use of progesterone-impregnated sponges and Pregnant Mares Serum Gonadotrophin (PMSG). Alternative techniques to sponges and PMSG to induce oestrus may become increasingly important in the future if restrictions are placed on the use of synthetic hormones. The present study aimed to

• a) Investigate alternative ways of advancing the breeding season naturally using vasectomised males and ovariectomised, oestrus-induced females. (Teasing).

• b) Assess whether treatment of ‘teased’ ewes with melatonin would enhance any effect of teasers.

Freedom of movement and freedom to express normal behaviour are fundamental principles underlying most welfare guidelines (e.g. Brambell, 1965). The restrictive nature of the farrowing crate and its potential to limit the repertoire of species specific behaviours may influence the welfare of the sow (Higginson, 1985). The objective of this study was to examine sow behaviour in different farrowing systems and specifically to investigate the behavioural component of improved winter production results in a less restrictive farrowing pen system (Rudd et al., Paper 18, 1993 BSAP Winter Meeting).

Three farrowing systems in neighbouring rooms were compared. Two systems allowed the sows to move freely, i) five strawed pens (2.5m x 1.5m) with farrowing rail (Pen), and ii) five crates modified to allow the sows to walk through (Free Crate). Sows had access via a passageway to a transponder-controlled feeder and a North facing (shaded) outside area with two water drinkers. Piglets were contained in their home Pen or Free Crate area by a small barrier (30cm high).

In recent years the quantity of grass silage as big bales has increased substantially, both in the UK and elsewhere. Eyers (1989) reported that about 16% of the grass silage dry matter (DM) conserved in England and Wales was in the form of big bales.

Whilst there is now considerable information on the composition, nutritive value and laboratory procedures for predicting the digestibility and energy value of clamp silage, there are few comparable data for big bale silages. The objectives of the present work were to examine the composition, digestibility and energy value of a population of big bale silages and to compare relationships between laboratory measurements and digestibility in vivo with those derived earlier for clamp silages (Givens et al., 1989).

• 1. There are many ultrasonic machines using a range of techniques varying in sophistication to measure fat and muscle depths for predicting carcass composition. An evaluation of four techniques was conducted by the Meat and Livestock Commission (MLC) to enable potential users to select the most appropriate technique based on accuracy, practicality and cost.

• 2. A total of 150 commercial sheep comprising approximately equal numbers of castrates and ewes were evaluated in five batches of about equal size in lairage at one of two abattoirs. Live weight was recorded together with fat and muscle measurements from the Aloka, Dynamic Imaging, Dumatic and Velocity of Sound (VOS) ultrasonic techniques.

• 3. The Aloka is a B-Mode real-time medical scanner which is currently used on cattle in Australia. The Dynamic Imaging is also a B-Mode real-time medical scanner which is currently used in MLC's Sheepbreeder Service.

Genes from the Chinese Meishan pig have the potential to enhance reproductive performance of European pigs (Bidanel, 1989; Haley and Lee, 1990). In order to allow prediction of the impact of Meishan genes In a range of alternative improvement programmes all traits of economic importance must be evaluated and genetic crossbreeding effects estimated. This paper reports the results of a crossbreeding study of meat and carcass quality traits recorded at the last rib position.

Animals were purebred Meishan (MS) and Large White (LW) pigs, and reciprocal F1 crosses: Meishan ♂ x Large White ♀ (MS x LW) and Large White ♂ x Meishan ♀ (LW x MS). The animals were born In first and second parity litters at the Institute of Animal Physiology and Genetics Research, Edinburgh and performance tested at the University of Newcastle upon Tyne. The trial was performed in two replicates of equal size, each corresponding to a single parity, with a total of 273 animals. In both replicates, females and entire males of all four genotypes were tested (approximately equal numbers of each genotype and sex). Animals were housed indoors in like sex and genotype groups of six (three pairs of full sibs). Tests started at pen mean of approximately 35 kg of weight and ended at pen mean of approximately 70 kg. Animals were fed ad libitum on a commercial ration (195 g/kg crude protein, 13.2 MJ digestible energy/kg).

Recent trials with cows fed grass silage have shown significant increases in intake and in yields of milk and milk solids when the crude protein (CP) concentration in a supplementary concentrate was raised. Giving additional CP in the concentrate was a more effective strategy for improving yields of milk and milk protein than giving extra energy (Aston et al 1992). The objective of this trial was to examine the influence of changes to the amount and pattern of distribution of CP supplied in a fixed concentrate ration given with grass silage ad libitum.

Fifty-five Holstein-Friesian cows in their second and subsequent lactations were given a standard diet for two weeks from calving and then were used in a continuous feeding trial from weeks 4 to 21. The cows received 5 kg of fresh concentrate daily containing 156 (LP), 245 (MP) or 338 (HP) g CP per kg dry matter (DM), MP comprised equal amounts of LP and HP. Concentrate carbohydrate sources were cereals and digestible fibre and CP was increased by a mixture of 3:1 soya:fish meals. Grass silage contained 253 g toluene DM/kg, 162 g CP/kg DM, D value in vivo 0.723, pH 3.7, fermentation acids 135 g/kg DM of which 0.85 was lactic acid and NH3-N 91 g/kg total N.

The aim of this study was to examine if enzyme supplementation could improve the performance of early weaned piglets by increasing nutrient digestibility of diets in which energy content was reduced by replacing wheat with barley or sugar beet pulp.

The following diets were supplemented with (+) and without (-) stabilised multi-enzyme premixes (E1, E2 and E3 respectively): diet W containing 706g/kg wheat and formulated to supply 14 MJ DE/kg, diets B and SBP in which DE was reduced to 13.25 MJ/kg by completely replacing wheat with barley or 185g/kg sugar beet pulp respectively. All diets were formulated to provide 150g/kg of apparent ileally digestible ideal protein, giving a crude protein concentration of about 217g/kg. Soya bean (200g/kg) and fish meal (75g/kg) were added at equal levels to all diets. Main enzyme activities in E1 were xylanase (T . longibrachiatum), amylase (B. subtilis) and pectinase (A. niger), in E2 beta-glucanase (T. longibrachiatum), xylanase (T. longibrachiatum) and amylase (B.subtilis) and in E3 beta-glucanase (T. longibrachiatum), amylase (B. subtilis) and pectinase (A. niger). The feeds were pelleted (3mm).

The use of biological feed additives in animal production systems is becoming widespread, largely in response to consumer pressure and legislation concerning the use of antibiotics and hormone implants. Howewver, published data on their efficacy are limited. Yea-sacc,a high strength yeast culture, is one such product. A yeast-culture is a dry product composed of yeast and the media on which it was grown, dried in such a manner as to preserve the fermenting capacity of the yeast. The yeast used in Yea-sacc is a selected strain of Saccharomyces cerevisiae, and the yeast culture is produced using a high density fermentation technique. A trial was conducted to examine the effect of including Yea-sacc in the diet, on the performance of early-weaned calves.