The main purpose of this study was to find several early factors affecting stayability in rabbit females. To reach this goal, 203 females were used from their first artificial insemination to their sixth parturition. Throughout that period, 48 traits were recorded, considered to be performance, metabolic and immunological indicators. These traits were initially recorded in females’ first reproductive cycle. Later, removed females due to death or culling and those that were non-removed were identified. A first analysis was used to explore whether it was possible to classify females between those reaching and those not reaching up to the mean lifespan of a rabbit female (the fifth reproductive) cycle using information from the first reproductive cycle. The analysis results showed that 97% of the non-removed females were classified correctly, whereas only 60% of the removed females were classified as animals to be removed. The reason for this difference lies in the model’s characteristics, which was designed using early traits and was able to classify only the cases in which females would be removed due to performance, metabolic or immunologic imbalances in their early lives. Our results suggest that the model defines the necessary conditions, but not the sufficient ones, for females to remain alive in the herd. The aim of a second analysis was to find out the main early differences between the non-removed and removed females. The live weights records taken in the first cycle indicated that the females removed in their first cycle were lighter, while those removed in their second cycle were heavier with longer stayability (−203 and +202 g on average, respectively; P < 0.05). Non-removed females showed higher glucose and lower beta-hydroxybutyrate concentrations in the first cycle than the removed females (+4.8 and −10.7%, respectively; P < 0.05). The average lymphocytes B counts in the first cycle were 22.7% higher in the non-removed females group (P < 0.05). The females removed in the first reproductive cycle presented a higher granulocytes/lymphocytes ratio in this cycle than those that at least reached the second cycle (4.81 v. 1.66; P < 0.001). Consequently, non-removed females at sixth parturition offered adequate body development and energy levels, less immunological stress and a more mature immune function in the first reproductive cycle. The females that deviated from this pattern were at higher risk of being removed from the herd.

One hundred and sixty Friesian heifers were allocated to two groups 8 or 9 weeks before artificial insemination and group-fed to gain live weight at 0·8 or 0·3 kg/day. Half the heifers of each group were moved to the other group 2 weeks before first insemination. All heifers received two intramuscular injections of prostaglandin (cloprostenol) 11 days apart, followed by inseminations at 72 and 96 h after the second injection.

The feeding regimes applied did not significantly affect the fertility of groups of heifers as measured by pregnancy rates to fixed-time or all inseminations. There were significant differences between pregnant and nonpregnant heifers within groups where changes in feeding levels were imposed (P<0·1 to P<0·01). Heifers whose growth rate was most severely checked, or whose body condition deteriorated relative to others in the group, were less fertile. For heifers changed from the low to the high plane of nutrition, those experiencing the greater increase in growth rate and body condition were more fertile than others.

No relationship was found between live-weight change, plasma glucose concentrations and fertility. In a second trial 158 Friesian heifers received two injections of cloprostenol 11 days apart, followed by inseminations at 72 and 96 h after the second injection. After the fixed-time inseminations the heifers were divided into two groups and were group-fed to gain live weight at 0·8 and 04 kg per head per day. Although the mean live-weight gain of the high group was significantly higher than that of the lower group (P<0·001), the overall pregnancy rates were not significantly different.

Fertility of rams was studied following their exposure to heat for 1 or 3 days in a hot room. Eight to 16 days later exposed rams showed significantly lower fertility as judged by lambing rate of ewes compared with unheated control rams. From 25 to 36 days after exposure treated rams were not significantly less fertile than controls. There were no significant differences in fertility between rams exposed 1 day or 3 days to heat.

This experiment evaluated different strategies for allocating first-cut grass silages to dry dairy cows that had low body-condition score (BCS) at drying off. A total of 48 moderately yielding Holstein-Friesian cows were used, receiving one of three dietary treatments in the dry period and a single lactation diet based on a flat-rate of concentrates and grass silage ad libitum. Throughout the dry period, one group received a low-digestibility silage (harvested 15 June 1998; LL; metabolisable energy (ME) = 10.3 MJ/kg dry matter (DM)) and a second group received a high-digestibility silage (harvested 9 May 1998, HH; ME = 11.7 MJ/kg DM). A third strategy (LH) offered the low-digestibility silage in the early dry period and the high-digestibility silage in the final 3 weeks before calving. The silages had very different crude protein concentrations (144 and 201 g/kg DM) and intakes were widely divergent (10.1 v. 13.5 kg DM/day) across the dry period. No concentrates were fed during the dry period. Silage quality had a very large effect on liveweight change, with treatment means of 0.32 and 1.75 kg/day for LL and HH, respectively. BCS changes followed a similar pattern, though no cows became over-conditioned and blood metabolites were within normal ranges. Increased silage digestibility in the late dry period led to a substantial increase in milk fat concentration and a smaller increase in milk protein concentration, the latter confined to the first full week of lactation. Depression of milk fat appears related to low blood glucose when dry cows in low body condition are fed at a low level. The LH strategy avoided the tendency for lower milk yields and fat concentration that resulted from feeding the low-digestibility silage until calving. This strategy also avoided the higher calf weights that resulted from feeding the high-digestibility silage in the early dry period.

1. Three ultrasonic machines (Sonatest TE/6, Scanoprobe 731 and Scanogram 721) and the ruler probe were compared as techniques for estimating carcass introscope and caliper measurements of P2 backfat thickness on each of 96 pigs. The effect of operator experience was examined with the Sonatest and Scanoprobe machines. Scanogram measurements of P2 backfat and eye-muscle area were evaluated using two methods of restraint (crate and nose rope).

2. The Sonatest was judged to be more precise (increased R2) than the Scanoprobe in predicting P2 backfat depth. Operator experience improved Scanoprobe precision but had little effect with the Sonatest. Ruler probe R2 was intermediate between the Sonatest and Scanoprobe.

3. The Scanogram was the most precise live P2 backfat measurement technique. R2 was not affected by method of pig restraint.

1. Four treatments were employed in the rearing of colostrum-deprived piglets from birth to 14 days of age. The performance of the artificially reared piglets was compared with that of conventionally raised sow-suckled piglets.

2. Statistically significant differences in growth rate were found in favour of piglets receiving 22% cows' milk solids from birth when compared with the sow-suckled group and the other artificial treatments.

3. Small non-significant differences in feed conversion efficiency were found between the artificial treatments with one exception. Pigs receiving 22% cows' milk solids from birth possessed superior conversion figures when compared with pigs receiving 6% cows' milk solids after birth.

4. Each of the artificial treatments led to fewer deaths than the sow-suckled group.

5. Pigs on the artificial treatments did not undergo such rapid changes of serum protein profile as did the sow-suckled piglets. Serum protein values for the pigs on the artificial treatments rose from approximately 33% of the levels in the sow-suckled group at two days of age to approximately 60% at 14 days of age.

Microarray technology is a powerful tool for animal functional genomics studies, with applications spanning from gene identification and mapping, to function and control of gene expression. Microarray assays, however, are complex and costly, and hence generally performed with relatively small number of animals. Nevertheless, they generate data sets of unprecedented complexity and dimensionality. Therefore, such trials require careful planning and experimental design, in addition to tailored statistical and computational tools for their appropriate data mining. In this review, we discuss experimental design and data analysis strategies, which incorporate prior genomic and biological knowledge, such as genotypes and gene function and pathway membership. We focus the discussion on the design of genetical genomics studies, and on significance testing for detection of differential expression. It is shown that the use of prior biological information can improve the efficiency of microarray experiments.

Previously, sugar beet feed (SBF) was thought to be of limited value for feeding to growing pigs due to its high fibre content. Maximum inclusion rates recommended were 5 and 10 per cent for pigs from 20 to 45 and 45 to 90 kg live weight respectively (MAFF, 1986). However, the fibre is highly digestible and more recently Longland et al (1988) showed that replacement of cereals with SBF may be possible up to levels of 15 and 30 per cent for pigs of 20 and 75 kg live weight respectively. It was also shown that the performance of older pigs fed SBF was enhanced if SBF was introduced into their diets at an early stage. The work was undertaken on individually housed pigs over a wide range of inclusion rates. The experiment reported here investigated the effect of providing SBF to group-housed pigs from 15 to 35 kg live weight and its effect on subsequent performance during the finishing stage. A further objective was to determine the optimum inclusion rate of SBF when fed to finishing pigs.

The effects of recombinantly derived growth hormone (GH), oestradiol-17β plus trenbolone acetate, clofibrate, melatonin and fasting on basal plasma triglycerides (TG) and TG entry rate were determined in wether lambs given lucerene/barley pellets ad libitum. Clofibrate was administered at 2 × 0·5 g capsules orally, GH (0·25 mg/kg live weight) was injected subcutaneously daily whilst oestradiol-17β, oestradiol-17β plus trenbolone acetate and melatonin were slow release implants (either 4 or 4·8 mg, 4 nig and 20 nig and 18 mg respectively) placed subcutaneously in the ear. Both fasting and oestradiol treatments raised basal TG levels without influencing TG entry rates, defined as the maximum rate of change of plasma TG 3 to 6h following a dose of Triton WR1339 of at least 0·2 g/kg live weight. Entry rates were similar to those previously reported for goats but were higher than those reported for sheep. Triton WR1339 used to determine entry rates was found to reduce food intake at all levels in some sheep despite reports to the contrary. Among the various treatments, only oestradiol-17β and trenbolone acetate influenced body composition as determined by chemical analysis of minced carcasses, resulting in an increased gain of carcass protein and decreased gain of carcass fat. Clofibrate, melatonin and Triton, if allowance is made for Triton-induced loss in food intake, had no clear effects on body fatness. Overall the effects of hormones on plasma TG appeared to be small and it seems improbable that plasma TG are involved in effects of hormones on fatness.

In experiments involving measurements on beef carcasses, the animals can be slaughtered at a given degree of fatness, at a prescribed live weight or at a prescribed age. The ultimate choice depends upon the purpose of the experiment but where comparisons are being made between different breeds receiving the same diet it is usual to slaughter animals at the same degree of fatness. This subjective assessment of the time at which the animals are to be slaughtered results in widely different slaughter weights and ages. In order to aid the interpretation of results, Pomeroy (1965) suggested that animals should be killed at at least three different live weights so that an estimate of the rate of change of various parameters can be derived.

1. Four fitter-mates from 20 litters on each of 3 farms were divided equally and distributed at random between two treatment groups. Each piglet was injected intramuscularly with 2 c.c. of an iron preparation between 1 and 2 days of age. The control group received an iron-dextran complex which provided 150 mg. of iron per piglet and a second group received an irondextrin complex which provided 200 mg. of iron per piglet.

2. The body weight and the level of haemoglobin in the blood of each piglet were measured at 1, 8, 15, 22, and 56 days of age and the incidence and cause of disease and mortality were recorded.

3. The level of haemoglobin in the blood of both groups was comparable throughout the experiment.

4. At the 22nd and 56th day, the group receiving 200 mg. of iron was approximately 6% heavier than the group receiving 150 mg. of iron. These differences were highly significant at the 0·1% level.

5. From each of 3 additional litters, 3 piglets received no supplementary iron while 5 piglets received 200 mg. of iron provided by the iron-dextrin complex. The three whole litters were slaughtered on days 3, 8, and 22 respectively. The mean level of iron per 100 g. of liver and spleen within the untreated group on the above occasions was 5·8, 5·8, and 3·7 mg. respectively, compared with 72·9, 55·1, and 17·6 mg. respectively within the treated piglets. The differences were highly significant at 0·1 % level.

Mastitis is a major disease affecting the herds of dairy farmers worldwide. One of the indicators directly related to the widespread infection of this disease in herds is the bulk tank somatic cell count (BTSCC). Recent studies have shown that one of the risk factors associated with mastitis is the human factor. Therefore, understanding the influence of humans is essential to control and prevent the disease. The main goal of this study was to determine whether the motivations and barriers perceived by farmers could explain the variation in the BTSCC. This study was conducted at 75 dairy farms in southern Brazil. In the interviews with farmers, a survey based on Likert scale items was used to collect data. Structural equation models were used to explain the subjectivity in the ratio of observed variables and latent variables elucidating the possible causal relationships between the variables. The model indicated that some of the variation in the BTSCC can be explained by the farmer’s behavior, which is elucidated by his/her motivations and barriers. The correlations between motivations and the BTSCC and between barriers and the BTSCC were positive. These findings suggest that variations in the BTSCC can be explained by the motivations and barriers perceived by farmers and that the Fogg Behavior Model used in this study can be used to explain how human behaviors influence mastitis control. This study also indicates that consulting companies focused on improving milk quality should pay attention to the human factor to reduce these barriers.

Although numerous studies on the early weaning system of calf rearing have given information concerning the composition of milk substitutes and concentrate rations which may be used, and the subsequent growth rates which may be expected, few have given information concerning either the relative effects on subsequent growth rate of initial weight, weaning weight, concentrate and hay intakes, or the relationships which exist among these factors themselves.

Animal feed manufacturing involves the use of a variety of raw materials to produce complete diets. These diets are defined according to nutritional and technological specifications to meet the requirements of several animal species. Some raw materials, for example certain legume seeds, can satisfy these specifications only after some form of processing.

When comparing progeny-testing schemes with individual performance selection, one should use equivalent selection intensities and population structures in the two systems. Adapting formulae from open-nucleus theory, the relative efficiency of progeny testing has been tested for a range of heritabilities, fertility levels, upward gene-transfer rates, mating ratios and numbers of sires selected. In sheep and beef cattle breeding, the heritability of the trait under consideration has usually to be very low to make progeny testing worth-while. High fertility increases genetic gains but does not change the relative efficiency of progeny testing. Opening the nucleus to females from the base increases genetic gains and reduces relative efficiency of progeny testing, both effects being of small magnitude. For fixed mating ratios, only a small fraction of females should be in the nucleus, but for fixed sire numbers approximately one-third of the population should be mated to proven sires. In these analyses, variances were adjusted for the effects of repeated selection and for the effects due to mixing groups with different means. This adjustment did reduce absolute genetic gains, but did not change conclusions on progeny testing efficiency and optimum design.

Two experiments were made to determine the effects on digestion characteristics and live-weight (LW) gain of cattle consuming bermudagrass of supplementing with ground maize, soya-bean meal or a maizegluten— blood meal mix alone or maize plus the protein supplements. Experiment 1 was a Latin-square design with 14-day periods using six beef cows fitted with rumen and duodenal cannulas (490 kg). Cows were given bermudagrass hay at 12·7 g/kg LW alone (control, C) or with 2·4 g/kg LW of ground maize (M), 0·98 g/kg LW of soya-bean meal (S), 0·53 g/kg LW of maize-gluten plus 0·17 g/kg (dry matter basis) of blood meal (GB), M plus S (M + S) or M plus GB (M + GB). Nitrogen (N) intake was 106, 123, 143, 148, 166 and 166 g/day; total N at the duodenum was 101, 124, 117, 126, 140 and 161 (s.e. 5·91) g/day; and post-ruminal N disappearance was 61, 77, 72, 84, 87 and 110 (s.e. 5·6) g/day for C, M, S, GB, M + S and M + GB, respectively. In experiment 2, 96 crossbred beef heifers (203 kg LW) implanted with 200 mg testosterone and 20 mg oestradiol benzoate were allotted to 12 groups by LW (two groups per treatment). Heifers grazed bermudagrass paddocks for 84 days in two 42-day periods and supplement treatments were those in experiment 1. A period × treatment interaction in LW gain was noted (P < 0·05). LW gain was 0·78, 0·81, 0·79, 0·76, 0·70 and 0·95 kg in period 1 and 0·46, 0·51, 0·56, 0·53, 0·64 and 0·61 kg in period 2 for C, M, S, GB, M + S and M + GB, respectively (s.e. 0·049). In conclusion, duodenal flow and post-ruminal disappearance of N were similar for the protein sources when offered singularly, but when given with maize values were greater for the mix of protein meals high in ruminal undegradable protein as compared with soya-bean meal. LW gain by heifer calves grazing bermudagrass was increased only by supplementation with ground maize plus the protein meal mix of low ruminal degradability.

Development of new systems of lamb finishing for the late winter/spring market involving an extended housed store period on a predominantly straw diet are constrained by unacceptable reduction in muscle mass arising from inadequate protein supply during dietary adaptation from grass to straw. Problems with subsequent finishing on forage brassicas fedin situ arise from carcass contamination due to soiled wool of crossbred lambs which grow long fleeces over the extended store I finishing period. In order to study the effect of fish-meal supplementation on dietary change over from grass to straw 116 Mule wether lambs were allocated to four treatments, three of which received a supplement of 100 glday fish meal for 28 days from housing and introduction of a diet of straw ad libitum and 225 glday grain distillers' dark grains, the fourth group received no fish meal and was unshorn (No F/US). Shearing treatments of shorn (F/S), unshorn (F/US) and crutched (F/C) were applied to fish-meal supplemented group's. After 112 days, the housed lambs were grazed outside on swedes (Brassica napus) and effects of treatments on performance and bacterial contamination of carcasses (shearing treatments only) were studied. Fish-meal supplementation significantly reduced weight loss on dietary change by 2·2 kg after 45 days (P< 0·001). Of fishmeal supplemented lambs 83% eventually ‘finished’ (defined as Meat and Livestock Commission fat class 3LI3H) v. 34% of unsupplemented lambs. Shearing or crutching had little effect on store or finishing performance indicating adequate fleece regrowth for insulation purposes after turn-out. Shorn and crutched lambs had lower levels of bacterial carcass contamination with reductions of 0·06, 0·42 and 0·40 in counts for colony forming units per cm2, coliforms and Escherichia coli on leg sites (P < 0·05). Economic evaluation indicated financial advantage from fish-meal supplementation with an increase in margin over food costs of €3·50 as a result of heavier carcass weight and a reduced need for remedial concentrate feeding in the store period.

The effect of exercise (walking 10.6 km/day and climbing 480 m/day) on intake of barley straw and body weight changes in 12 pregnant lactating suckler cows was investigated. Three groups of four cows received ad libitum barley straw and 4 kg per cow per day of different supplements. Neither exercise nor supplement had a significant effect on straw intake. Cows gained weight when not exercised, but lost weight during the exercise period. The experiment confirms previous findings that animals performing moderate work and given poor quality roughage, in the short term cannot increase daily intake to meet energy requirements and that intake may decrease when animals work.

The level of glucosinolates in the seed of many double low varieties of rapeseed is still very close to 20 μM/g, which will be the limit for EEC subsidy from 1992. Besides the effects on the price, the high level of glucosinolates in rapeseed meal, and their possible products of decomposition, may limit their usefulness in feeding strategies and programmes for pigs.

The possibility that the agronomical conditions under which the rapeseed it grown and harvested may influence the glucosinolate content of the seed, and hence alter its nutritional value to pigs, was investigated in the present experiment. Substantial variation in glucosinolate levels between batches of seeds of the same variety has been found in different years, depending upon the site and conditions under which the crop is grown.