Previous research in our laboratory has shown that lactating rats given low protein diets will readily mobilise approximately 20% of body protein to sustain lactational performance. However in such females lactational performance falls markedly around day 6 of lactation and remains at this low level for the remainder of lactation. The objective of this study was therefore to investigate whether this decline in lactational performance coincided with the exhaustion of labile protein reserves, and secondly whether such protein depleted females could reestablish effective lactation in mid lactation when given an increased supply of dietary protein.

Sixty six multiparous Sprague-Dawley rats were mated individually with a proven male breeder, mating being confirmed through the presence of vaginal plugs, then transferred to solid bottomed plastic cages for the remainder of the experiment.

Performance recording is generally necessary for the efficient management of dairy herds. There is a variety of recording systems currently available but interpretation of the results is hampered by an imprecise knowldege of attainable levels of performance and the magnitude of the shortfall that warrants interference. Mean values and standard deviations were calculated to provide standards for the assessment of other herds. Data were obtained for 6636 cows calving in one season in 50 herds (herd size ± s.d., 132.7 ± 44.5). Target values were considered to be the 75th percentile and interference levels the 25th percentile (Table 1).

Lameness in dairy cattle is a major cause of suffering and financial loss with an estimated cost to the dairy sector of £44 million in 1989 (Booth 1989). Surveys have shown that the most common forms of lameness in the dairy cow originate from lesions of the hoof. A variety of predisposing factors including stage of lactation, time of year, housing and nutritional management, and age of the cow and its genetics have been implicated. Although it is evident that solear haemorrhages which are often observed after calving generally precede the appearance of lesions which cause lameness, (Greenough & Vermunt 1991) there is still relatively little known of the patho-physiological factors which underly hoof lesion development. Greenough & Vermunt examined the feet of heifers in a herd with severe lameness problems and noted considerable solear haemorrhage up to four months before first calving. They associated this with mixing the heifers with dry cows as soon as they were diagnosed pregnant. However similar lesions have been seen in heifers in other problem herds where no such mixing took place (Bazeley & Pinsent 1984, Bradley, Shannon & Neilsen 1989). There is little knowledge of the development of hoof lesions in herds with little or no lameness, although this vital background information is essential to understanding the aetiology of these lesions and the development of lameness.

The recent introduction of penalties and premiums for bulk tank somatic cell counts (BTSCC) following the EC Directive of 5th August 1985 (no L 226/13) and subsequent EC Regulation of the 5th February 1990 (no COM(89)667) has reinforced the need for a greater awareness of the factors involved in herds with high BTSCC figures and their rapid identification. In the past a number of surveys have been conducted examining the major causes of mastitis in a cross section of the national herd (Wilson & Richards 1980) and these have demonstrated the importance of subclinical mastitis and in particular the so-called ‘cow-side organisms’, however more recently the impact of acute environmental mastitis has been of greater concern (Wilesmith Francis & Wilson 1986). Thus a reappraisal of priorities has become necessary, not least because these E C Regulations allow the sale of unpasteurised milk and milk products.

In a recent study of the efficacy of two methods of oestrous synchronisation in dairy heifers, progesterone profiles and ultrasound results showed that late embryonic/early foetal loss had a small but nevertheless important effect upon pregnancy rates (Logue & others 1991). Since some preliminary results were available which showed that the use of a 3 mg norgestomet ear implant alone, rather than in combination with a 3 mg norgestomet and 5 mg oestradiol valerate injection (Crestar Intervet UK Ltd), enhanced pregnancy rates in beef heifers (Favero & others 1989) and the technique was being used in Embryo transfer (ET) recipients (Broadbent pers com) it was felt that a further investigation of the technique was merited.

Somatic cell count of milk is a well established test of monitoring udder subclinical mastitis in dairy cattle. Its diurnal variation has been known for decades, (SMITH and SHULTZE 1967). However the association of somatic cell count to time of sampling has been poorly investigated (AOKI et al 1990), and little emphasis has been given to the representativity of samples for a period of 24h. By concentrating on the study of differences between morning and evening milkings throughout lactation, the objective of the current study was to stress the need for a standard representative sampling time, to avoid possible bias in the interpretation of somatic cell count data, whether for research purposes or routine health surveys.

In a recent study carried out over three years, on a commercial Cheshire dairy herd, 86% of animals were found to be lame at some time. This level of disease is considerably higher than has been reported, (Rowlands, Russell and Williams, 1983; Dohoo, Martin, Meek and Sandals, 1983) and may have important economic implications.

Lameness has been associated with reduced 305 day yields (Rowlands and Lucey, 1986), lower than average lifetime yield (Cobo Abreu, Martin, Wiiloughby and Stone, 1979), lower yields in early lactation (Enevoldson and Grohn, 1991), and a reduction in percentage milk protein (Bigras-Poulin, Meek and Martin, 1990).

Lactation records of Jersey cattle on Jersey Island are recorded within National Milk Records of England and Wales (NMR). Since it is a closed breed population, it is not possible to amalgamate these data with Jerseys recorded in the United Kingdom (UK). Presently genetic evaluations of Jersey Island bulls are carried out using heifer records with a modification of the model used in the UK to account for the smaller herd sizes. Cows are not evaluated.

The objective of this study was to analyse Jersey Island data in order to estimate genetic parameters and establish genetic trends after evaluating all bulls and cows using an Individual Animal Model (LAM).

In any genetic evaluation procedure connectedness among animals in different management groups (herds) is important in order to account for genetic differences among management groups. Kennedy and Trus (1991) mentioned that under an animal model (IAM), connections occur through the relationship matrix (A). They showed that connectedness can be measured in terms of the proportionate contribution of genes from one herd to the other. This is achieved by computing X1ZTQ, where X and Z are matrices that assign records to herds and animals respectively, Q a matrix that assigns ancestors of animals with records to a single genetic group and T is a lower triangular matrix derived from A, such that A = TDT1 , with D a diagonal matrix. In practice the calculation of T may not be feasible with large number of animals because of memory requirements.

Dairy Farmers receive information from the whole range of the sector relating to the dairying industry, whether they actively seek information or not. The survey carried out attempted to identify British farmers’ perception of the information sources of greatest value to them. This survey was limited to a sample of dairy farmers in England and Wales.

A postal survey was conducted with questionnaires being sent to 306 dairy farmers selected from the Public Register of the Milk Marketing Board of England and Wales. The sample size was 1.0% of registered dairy farmers from each of the eleven MMB regions. The questionnaire was in six parts. The first contained three questions on the farm itself (i.e. the MMB region, breed of cow, herd size). The remaining parts concerned five categories of potential information sources. These were: (1) hard copy (i.e. printed) publications from official or semi-official bodies, firms which provided agrochemicals, feedstuffs, machinery etc and their sales agencies, and the farming press; (2) broadcasting services on the radio and TV; (3) databases services from database producers or viewdata/teletext; (4) individual contacts which were precoded as MAFF/ADAS advisers, the MMB/Genus consultants, private consultants, other farmers, agrochemicals/fertilsers suppliers, feedstuffs suppliers, pharmaceutical suppliers, machinery suppliers and veterinary surgeons; and (5) other institutions which identified such remaining sources as educational institutes, research institutes, information centres, public libraries, and farming organisations.

Information on the conformation of Ayrshire cattle has been collected by the Ayrshire Cattle Society (ACS) since 1985. Seventeen traits are recorded on a scale of 1 to 9 where 1 and 9 represent the biological extremes of the population. Approximately 2000 records are collected annually and analysed by the Milk Marketing Board using Best Linear Unbiased Prediction to provide sire evaluations on Ayrshire bulls, fitting a sire model. In the past there have been insufficient records to produce reasonable estimates of heritabilities for the traits and those from the Holstein/Friesian population have been used. The purpose of this study was to produce heritability estimates for each trait for use in future analyses.

Selection for lean tissue growth rate in modern genotypes and the continued trend in favour of leaving boars entire may have significantly increased the ideal protein requirements of finishing pigs above the value of 8.6 g/MJ DE recommended by ARC (1981). The aim of this study was to measure differences in performance and carcass quality of genetically improved boars and gilts in response to increases in ideal protein content of the diet.

On some commercially available single space feeders there is a range of settings to dispense feed at various rates into the trough. The amount of feed which is dispensed into the trough each time a pig operates die mechanism will have an effect on how hard a pig has to work to satisfy its appetite. The feeder setting may also have effects on competition between pigs. In addition, high settings may result in excess feed deposited in the trough, a potential source of feed spillage.

General recommendations are made (e.g. Gomes, 1977; Dzuik, 1970) that, in order to achieve maximum conception rate and litter size, sows should be mated or inseminated 9 to 15 hours prior to ovulation and that this coincides with an interval of 30 to 36 hours after the start of standing oestrus (SO). This assumes that sows will be in standing oestrus for around 48 hours. Surprisingly little data is available on the length of SO In modern sows on current production systems. Accordingly length of SO was determined in a large commercial herd weaning at around 3 weeks of age.

A team of observers determined the start, completion and duration of SO in 101 multi parity sows. The sows were tested for SO daily from weaning at 8 hourly intervals (00.00, 08.00 and 16.00 hr) until the end of SO by taking sows individually from their small post-weaning groups to an oestrus checking area. Boars were penned around this area and SO was checked using the back pressure test.

Glucosinolate levels are thought to be the major factor limiting the use of rapeseed meals in pig diets. The greatest differences In glucoslnolate content between samples of rapeseed appear to be attributable to variety and site of cultivation. A growing pig feeding trial was set up to Investigate varietal and site differences in the nutritive value of different rapeseed meals.

Rapeseed of the double low varieties Tapidor, Cobra, Libravo and Ariana were obtained from each of two sites (High Mowthorpe EHF, North Yorkshire and Bridgets EHF, Hampshire) where agronomic practices at both sites were very similar. These materials were solvent extracted to yield eight rapeseed meals of commercial type.

Principal among a number of antinutritive factors which have historically limited the use of rapeseed meal in pig diets are a group of compounds known as glucosinolates. These sulphur containing compounds may be goitrogenic and/or heptatoxic and additionally produce volatile and pungent hydrolysis products resulting in reduced palatability of diets. Newlyweaned pigs between 6 and 20kg do not in general perform well when fed diets containing appreciable amounts of rapeseed meal nor when fed diets with glucosinolate levels higher than 10 μmol/g diet. This is probably due to the sensitivity of young piglets to unpleasant tastes and to antinutritional components of feedstuffs. A study was designed to determine the response of newly weaned pigs to levels of dietary glucosinolate lower than 10 μmol/g resulting from a relatively low inclusion rate of rapeseed meal in the diet.

The presence of tannins, sinapins, saponins and glucosinolates in rapeseed meal are known to have antinutritional effects. They may also act as anticonsumptional factors by rendering the meal bitter-tasting and pungent. The principal cause of low palatability of rapeseed meal diets has generally been considered to be the glucosinolates. A feeding trial with growing pigs provided the opportunity to look at the consumption time of diets containing meal from different varieties of double low rapeseed as an Indication of relative palatability. The time taken to eat one kilogram of food was adopted as a simple measure of palatability based on the assumption that if a diet was unpalatable it would be eaten more slowly than one which was relatively more palatable.

It is common practice for feed barley to be purchased on sample specific weight. It can be argued that this historic measurement may give a misleading indication of its energy and feeding value. If this were to be true, then 6-row barleys which have a number of agronomic advantages, including high yields, could be discriminated against when compared to the more common 2-row barleys. Manitou is such a 6-row barley, which has out-yielded the best performing 2-row varieties by 6% in England (NIAB Recommended List 1991), and by 28% in Scotland (Scotland Agricultural Colleges Recommended List 1991). Trials were undertaken to compare Manitou and Marinka (2-row barley) at similar thousand grain weights (TGW), but different specific weights (sp.wt), with growing and finishing pigs.

A number of recent experiments have indicated that growing pigs, given the choice between diets of differing protein content, have the ability to select a daily nutrient intake appropriate to their requirements. This experiment was designed to investigate this ability in pigs which are extremely different in their genetic potential for protein deposition rate. European pigs have undergone intensive selection for a high protein deposition rate, whereas the Meishan breed from China is still relatively unimproved and capable of only a low rate of protein deposition.

Increasing public concern has developed, in recent years, over the welfare of animals in agriculture. One aspect of this is the impact of the barren environments typical of commercial pig production systems, with bare concrete walls and floors, simple rectilinear layout and no objects to manipulate other than troughs and water nipples. The sensory impoverishment inherent in this severely limits the range of experience and behaviours open to pigs and may prevent the display of certain basic ‘behavioural needs’. Possible consequences include boredom, frustration, stress and diversion of energy to destructive activities like aggression.