Oilseed rape meal is high in protein and available in the UK relatively cheaply. Toxic constituents limit its inclusion in feeds for pigs and poultry but this is not a problem with ruminant animals where microbial action in the rumen removes them. However, the bitter taste of rape meal has been thought to reduce its palatability for ruminant animals (Stedman and Hill, 1987) and it is recommended that its inclusion in compound feeds for cows should not exceed about 150kg/tonne; masking agents are incorporated to reduce this limitation.

The question to be addressed can be summarized as “can higher rates of inclusion of rape meal in dairy compound feeds be concealed by more mask?”. Twelve dry cows in late pregnancy were offered feeds with various levels of rape meal in combination with several levels of mask and rate of consumption was monitored.

Ardacin is an antibacterial glycopeptide with ruminal activity. The objective of this study was to measure its effects on food intake and growth rate of growing and finishing steers. Two experiments were carried out simultaneously using the same foods and the same ardacin supplementation levels. In experiment 1, 72 growing steers (8 months old and 240 kg initial weight) in four treatment groups were individually offered a basal diet of grass silage ad libitum. In experiment 2, 44 finishing steers (19 months old and 463 kg initial weight), also in four treatment groups were individually offered a basal diet of grass silage ad libitum plus 3 kg (5 kg for the final 28 days) concentrates per head daily. The four treatments were 0, 50, 125 and 210 mg ardacin per head daily incorporated into 1 kg ground barley. This was offered in addition to the basal diet. The duration of the experimental period was 154 days after which 48 of the growing steers were put to pasture for a 196-day grazing season. The finishing steers were slaughtered following a withdrawal period of 7 days. Mean daily silage dry-matter intakes, and mean daily total metabolizable energy intakes for the treatments as listed above were 4·91, 5·15, 5·10 and 5·03 (s.e. 0·083) kg and 63, 66, 65 and 65 (s.e. 0·7) MJ (experiment 1), and 5·63, 5·62, 5·51 and 5·54 (s.e. 0·059) kg and 108, 108, 107 and 107 (s.e. 0·4) MJ (experiment 2), respectively. In the same order, mean daily live-weight gains during the treatment period were 612, 758, 784 and 798 (s.e. 25·2) g (experiment 1) and 911, 942, 851 and 860 (s.e. 40·0) g (experiment 2). In the growing steers proportionately 0·64 of the weight response to ardacin was retained to the end of the following grazing season. It is concluded that ardacin supplementation increased live-weight gain and improved the efficiency of conversion of food to live weight in growing steers but had no significant effect on finishing steers in this study.

Premature loss of wool from fleece casting prior to shearing is a problem in some sheep genotypes, in particular in the North Country Cheviot. The reasons for this ocurrence are not fully understood, but it is believed that it is due to a complex of factors including heredity, nutritional and managerial (stress) practices, the wool growth cycle, and physiological parameters such as pregnancy. Prolonged stress is reported to be particularly important in the case of wool slip in ewes which are housed and shorn (Morgan et al, 1986).

The present study aimed to investigate the incidence of visible fleece casting in the North Country Cheviot (NCC), Scotch Halfbred (HB) (Border Leicester x NCC), and Border Leicester (BL), which has no history of premature wool loss. The study was implemented on 8 commercial farms in Scotland, and links between key productive parameters and wool loss were studied, and an attempt to identify fleece types most liable to cast was also made.

By fitting a range of numerical values to a model, genetic responses from performance testing male pigs (boars) were examined in a population in which pig farms either conduct their own tests or send boars to a central station for testing. Where selection intensities are the same for station and farm tests the former almost always has an advantage over the latter. Factors which lead to this advantage are genetic differences between farms, genetic sampling within farms and limitations on the accuracy of performance measurement in farm tests. In a large station test response in a trait of 50% heritability is expected to be 15% greater than in tests comprising boars from 10 effective parents on farms whose average genotype contributes 5% of the total genetic variation and whose environmental variation is 25% greater than in the station. In populations with limited station testing space available, farm tests should be able to compensate for their lower efficiency by increasing selection intensities.

Bovine placental lactogen (bPL) is structurally related to prolactin (PRL) and growth hormone (GH). In synergism with steroid and thyroid hormones, bPL is crucial in stimulating the development of the mammary gland, mammary cell differentiation and function. To further explore whether bPL gene is associated with milk production traits, we herein analyzed single-nucleotide polymorphisms (SNPs) within eight regions of bPL gene, which are potentially associated with five milk production traits on 1028 Chinese Holstein cows. Among these, two SNPs, NT7409(T–C) and Nt11246(G–A), were identified. The former is within exon 2; it induces an alteration of amino acid from Val to Ala. The later is within exon 4. It is a synonymous mutation. We found that there were significant associations between NT7409(T–C) and milk and protein yield. Cows of the AA genotype yielded less milk (P = 0.001) and less protein (P = 0.003) than those of genotypes AB and BB. However, on the NT11246(G–A) locus, no significant association was observed in the five milk production traits studied. In addition, bPL has been localized near markers RM185 and CC549051 with a distance of 23.2 cR on BTA 23. It is at the same position as the region including quantitative trait loci (QTLs) affecting milk and protein yields by previous linkage analysis. In summary, our findings demonstrated that the SNP within exon 2 of bPL (NT7409(T–C)) is associated with two milk production traits, and this provided further evidence that bPL could be a major gene-controlling milk production trait in Holstein dairy cattle.

Experiments were conducted to observe the taste responses of male and female calves to various levels of sodium salts, chloride solutions, and trace minerals. Animals were penned individually and given a completely pelleted ration ad libitum. Trace mineralized salt was freely available.

Using water as a basis for determination, a non-discrimination zone was established. This zone represented an intake ranging from 63 to 37%. Preference threshold was set at 80% of intake, while the rejection threshold was set at 20% of intake. Responses were determined by expressing the intake of the test solution as a percentage of the total intake during the test period. Responses at a given chemical concentration were measured during two 8-hr periods.

Taste response observations were made on the following: 0·02, 0·08, 0·32 or 1·25% sodium chloride (NaCl), sodium sulphate (Na2SO4), sodium bicarbonate (NaHCO3), sodium carbonate, monobasic sodium phosphate (NaH2PO4), dibasic sodium phosphate (Na2HPO4), ammonium chloride, potassium chloride, calcium chloride, magnesium chloride, and manganese chloride. In addition, observations were made when 0·02, 0·08, 0·32 or 1·25% NaHCO3, Na2SO4, or Na2HPO4 were offered in opposition to equal concentrations of NaCl. The responses to 5, 10, 20, 40 and 60 p.p.m. concentrations of cupric chloride, zinc chloride, molybdenum trioxide and cobaltous chloride were observed also.

Least squares analyses were undertaken on 1519 gestation lengths of cows mated to Beef Shorthorn, Hereford, Charolais, German Simmental or British Friesian bulls. Gestation length was influenced largely by breed of sireand byindividual sires within breeds. Approximately 100 calvings are required to give a mean value with a standard error of 0·50 day. Heritability of gestation length was estimated to be 0·24±0·05. It is recommended that Artificial Insemination organizations survey and publish the mean gestation lengths of their bulls and that dairy farmers modify, where necessary, pre-partum feeding in the light of this information.

The influence of the physical structure level in the diet on animal performance was investigated in 52 Belgian Blue doublemuscled bulls starting from a live weight of 348 kg until slaughter at about 645 kg. Four diets with different concentrate/maize silage ratios were offered ad libitum. The structural value (SV), developed in Belgium as a measure of physical structure in the diet for dairy cows, amounted to respectively 0.63 (HSV; high SV), 0.54 (MSV; moderate SV), 0.43 (LSV; low SV) and 0.34 (VLSV; very low SV) per kg dry matter.

Growth rate, food intake and food conversion were all linearly affected by the decreasing SV of the diet. Among carcass parameters only the SEUROP conformation score showed a significant effect of the SV, with the MSV group having the highest score and VLSV the lowest. No important influence of the SV on the histological damage of the ruminal papillae or on the foot lesions was found.

Based on the lower growth rate and food intake of the LSV group versus the HSV group, a SV of the diet between 0.54 and 0.43 is considered as an absolute minimum for Belgian Blue double-muscled bulls.

The generally accepted view is that, in sheep and cattle, plane of nutrition (as indicated by growth rate) can influence body composition; the higher the rate of gain the greater the fatness at a particular live or carcass weight. However, exceptions to this view can be found which demonstrate that the effective protein: energy ratio of the diet can exert a considerable influence on the composition of live weight gain. Unfortunately most studies which have considered the effects of growth rate on composition (either directly or as a consequence of some treatment which resulted in different growth rates) have described their animals in terms of chemically determined protein, fat, ash and water. To assess the potential economic impact of different growth rates on body composition and the distribution of fat throughout the body requires dissection data, describing the animal in terms of lean, bone and individual fat depots. In this experiment the dissected composition of 44 Hampshire Down x Mule ewe lambs was determined in animals which had followed planned growth paths involving periods of high (H) and low (L) growth.

Calf rearing systems vary greatly in the quantity of milk substitute fed and in the age of the calf at weaning (Webster, 1986). Husbandry conditions can affect disease incidence and welfare of young, bucket-fed calves and Andrews (1979) has suggested a relationship between age at weaning and disease incidence. This experiment was designed to investigate the effects of level of milk substitute powder fed and the age at weaning on the immune responses of bucket-reared calves compared with naturally suckled calves.

Two groups of 20 calves were kept at the Veterinary Field Station, University of Liverpool. All calves received pooled mixed-source colostrum at birth and were then randomly allocated to one of five treatment groups. After colostrum, bucket-reared calves were introduced to milk substitute (Volac Easi-Mix) which was reconstituted at 125g ADM per litre of water and fed twice daily. Calves were housed in individual pens arranged in four blocks with wood shavings as bedding. Suckled calves remained with their dams and were housed in the rear of the same building. These calves had access to a calf creep area. All calves were introduced to Keystart Quicklettes (BOCM Silcock) at 7 days of age and fed ad libitum. Small quantities of water and silage were also provided from 7 days of age. Table 1 lists the treatment groups, level of milk substitute received (g ADM/day), age of the calf at weaning and at inoculation with antigen (KLH), and also the age of the calf when the skin sensitivity response was measured.

Perry (1964) has shown that piglets failed to absorb homologous Brucella abortus antibodies, whereas they absorbed homologous Salmonella pullorum antibodies much more readily. When S. pullorum antibody was used, piglets showed marked differences in their efficiency of absorption. These differences existed whether the antibodies were administered in serum or in colostrum (Perry and Watson, 1967a, b). Moreover, they could not be entirely accounted for by variation in concentration of antibody in the dose, age at dosage, genetical effects or maternal effects (Perry and Watson, 1967a).

In animal housing ammonia is an aerial pollutant resulting from the microbial conversion of nitrogenous materials excreted in faeces and urine. Ammonia is an irritant to cells lining the respiratory tract and an increased incidence of pneumonia in pigs and humans and atrophic rhinitis in pigs have been correlated with elevated ammonia levels. In a survey of 12 farms and 49 pig buildings concentration of ammonia was identified specifically as a causative agent in the aetiology of atrophic rhinitis (Robertson, Wilson and Smith 1990). Furthermore, high levels of ammonia can delay the onset of puberty in gilts perhaps as a result of the masking of boar odour (Malayer, Brandt, Green, Kelly, Sutton and Diekman 1988).

Regulations have been introduced (Control of Substances Hazardous to Health (COSHH)) limiting the exposure of humans to atmospheric ammonia to a mean level of 25 ppm over an 8h work shift and 35 ppm for 10 minute exposure. As part of a study on the effectiveness of a feed additive formulated to control atmospheric ammonia, levels of ammonia in pig housing were monitored.

Growing pigs spend considerable time orally manipulating their environment, which can include their pen-mates. In certain situations this leads to problems such as tail-biting. It is unclear if this active behaviour represents foraging or exploratory motivation, a problem exacerbated by the possibility that both share certain behavioural elements. The aim of this experiment was to distinguish appetitive foraging (extrinsic exploration) from intrinsic exploration by manipulating both feeding motivation and the content of the external environment. The objective was to discover which behavioural elements are common to either behavioural category. This would allow hypotheses to be proposed concerning the causation of oral-manipulation of the environment and inappropriate stimuli such as pen-mates, and furthermore to control for the effects of intrinsic exploration in continuing experiments concerning foraging behaviour.

Over recent years, the system of grazing management most commonly adopted by dairy producers has tended to oscillate between various forms of strip-grazing, on the one hand, and set-stocking, on the other. While arguments in favour of strip-grazing mainly revolve around the ease of grassland management, many of those for set-stocking are essentially behavioural -greater space for the cattle and, hence, less competition, aggression, and spoiling of localised areas of pasture. A current development in the southern hemisphere, ‘fast-rotation’ grazing, attempts to combine the merits of both systems. In this, the herd is given a fresh area each day, but a much larger one than in strip grazing, resulting in less close grazing and (given the same overall land allocation) a much quicker rotation over the total grassland.

This project, part of a larger one evaluating other aspects of the system, was designed to determine the effects a fast-rotation system, versus strip-grazing, on grazing, competition and aggression, and on the incidence and distribution of other basic activities.

Estimates of genetic parameters were obtained for weight, hip height, heart girth and shoulder to pin length measurements on Thai swamp buffalo, recorded at birth and weaning. Direct heritability estimates were 0·26 for weights at both ages and were low for skeletal measurements, ranging from 0·11 to 0·19. Low values could, in part at least, be caused by inaccuracies in recording. All traits were subject to maternal effects, permanent environmental maternal effects on traits recorded at weaning explaining proportionately up to 0·14 of the total variation. Estimates of genetic (direct and maternal) and permanent environmental correlations between traits recorded at the same time were high throughout, ranging from 0·83 to 0·97 for additive genetic effects and being close to unity otherwise. Except for heart girth measured at weaning, there appeared to be comparatively little genetic association between traits recorded at different times, direct additive correlation estimates ranging from 0·18 to 0·55 in contrast to estimates of 0·38 to 0·65 for correlations with heart girth at weaning.

A further experiment in a series of trials to look at the effects of treating straws on their feed values, and the responses to different supplements was carried out in the winter of 1982-83. The treatments were:-

1. 1) Untreated barley straw (DBS) plus 1.5 kg rolled barley/urea per day

2. 2) Ammonia treated barley straw (TBS) alone

3. 3) Ammonia treated wheat straw (TWS) alone

4. 4) Ammonia treated wheat straw (TWS) plus 0.5 kg rolled barley

5. 5) Ammonia treated wheat straw (TWS) plus 0.5 kg soya bean meal

6. 6) Ammonia treated wheat straw (TWS) plus 0.25 kg rolled barley and 0.25 kg fishmeal

There were 7 Hereford x Friesian cows per treatment, all mature animals (third calvers or more) calved in May, bulled with a Charolais bull in July and calves weaned off and cows yarded in November 1982. The trial ran for 145 days from 25 November 1982 to 19 April I983 covering about months 4 to 8 of pregnancy. They were group fed.

For the past 20 years specialised sire and dam lines have generally exploited existing breed differences, and there has been little within-breed selection for litter size. However, some lines may now be approaching optimum fatness. At the same time, more accurate methods are evolving for estimating genetic merit for litter size. This study therefore re-examines the benefits of selection for litter size in specialised dam lines.

A compound feed that is designed to be given in equal amounts with cereals for milk production would contain about 30% crude protein, and if rapeseed meal were the major high protein supplement to be used along with cereal, about 60% would need to be included. No observations have been reported in which this high proportion of rapeseed meal has been used and the experiment described was planned to provide this information, using low glucosinolate rapeseed meal. The control diet contained soyabean meal in place of rapeseed meal, and a third compound was used containing sunflower meal seed as the major protein supplement.

Thirty-nine Friesian cattle were used in a randomised block design: the three treatments, compounds containing low glucosinolate rapeseed meal, sunflower seed meal and soyabean meal, were applied for 16 weeks. There were 21 cows and 18 heifers, the mean days in milk at the start of the experiment was 62 days and the mean yield over the previous two weeks was 26.9 kg.

The main objective of this study was to develop a dynamic energy balance model for dairy goats to describe and quantify energy partitioning between energy used for work (milk) and that lost to the environment. Increasing worldwide concerns regarding livestock contribution to global warming underscore the importance of improving energy efficiency utilization in dairy goats by reducing energy losses in feces, urine and methane (CH4). A dynamic model of CH4 emissions from experimental energy balance data in goats is proposed and parameterized (n = 48 individual animal observations). The model includes DM intake, NDF and lipid content of the diet as explanatory variables for CH4 emissions. An additional data set (n = 122 individual animals) from eight energy balance experiments was used to evaluate the model. The model adequately (root MS prediction error, RMSPE) represented energy in milk (E-milk; RMSPE = 5.6%), heat production (HP; RMSPE = 4.3%) and CH4 emissions (E-CH4; RMSPE = 11.9%). Residual analysis indicated that most of the prediction errors were due to unexplained variations with small mean and slope bias. Some mean bias was detected for HP (1.12%) and E-CH4 (1.27%) but was around zero for E-milk (0.14%). The slope bias was zero for HP (0.01%) and close to zero for E-milk (0.10%) and E-CH4 (0.22%). Random bias was >98% for E-CH4, HP and E-milk, indicating non-systematic errors and that mechanisms in the model are properly represented. As predicted energy increased, the model tended to underpredict E-CH4 and E-milk. The model is a first step toward a mechanistic description of nutrient use by goats and is useful as a research tool for investigating energy partitioning during lactation. The model described in this study could be used as a tool for making enteric CH4 emission inventories for goats.

In ruminants, daily urinary excretion of purine derivatives (PD) reflects the absorption of microbial purines and can be used as an index of microbial protein supply (Chen, Ørskov and Hovell, 1991). The application could be extended to farm conditions if measurements based on spot urine samples or plasma could serve as an alternative index. The objective of this study was to examine whether PD concentrations in spot urine or plasma samples vary diurnally during a given feeding regime and if they reflect differences in daily PD excretion induced by varying feed intake.