The work performance of two teams of four donkeys (heavy, 680 kg and light, 460 kg) and one pair of Jersey crossbred oxen (646 kg) was compared when they ploughed 4 hi day on four types of soil (clay, redsoil, sandy soil and sandy clay) using two types of plough, a conventional ox plough (40 kg) and a lighter prototype, the ‘Walco’ plough (32 kg) on an experimental farm. Work parameters were also measured with farmers’ cattle and donkey teams ploughing on f arms in Matobo and Nkayi districts. Working speed, power and effective field capacity (ETC) were higher for the ox-team (1·03 m/s, 920 W and 14·5 h/ha for the conventional plough and 0·99 m/s, 745 W and 13·9 h/hafor the Walco plough) and the heavier donkey team (0·87 m/s, 689 W and 14·2 h/hafor the conventional plough and 0·87 m/s, 787 W and 17·3 h/hafor the Walco plough) than for the lighter donkey team (0·59 m/s, 461 W and 22·1 h/hafor the conventional plough and 0·64 m/s, 445 W and 23·4 h/hafor the Walco plough). Expressed as a proportion of live weight or metabolic live weight there were no significant differences in draught forces exerted between teams but power output per unit live weight was greater in the ox-team than in the light donkey team but similar to that in the heavy donkey team. The Walco plough required a lower force (742 N) to operate than the conventional plough (816 N) but apart from this did not have any marked advantages over the conventional plough. On-farm, team sizes of donkeys varied from three to seven animals (team weight 340 kg to 1007 kg) and cattle team sizes from two to four animals (team weights 558 to 1709 kg). Regardless of team number, the heavier teams tended to out-perform the lighter teams (speed range 0·63 to 1·08 m/s, power 395 to 1136 W, EFC 9·1 to 25 h/ha)) with one exception, a well trained team of two oxen (team weight 879 kg, speed 1·02 m/s, power 775 W, EFC 9·1 h/ha). Donkeys tended to plough at a slower pace than oxen, with a lower power output, although when weight differences between teams were equalized (four heavy donkeys compared with two oxen), then there was little to chose between the species. Results suggested that teams of three or more donkeys can effectively be used for ploughing on the soils tested. The results highlighted the importance that team live weight and training/experience have in determining work performance.

Changes in ultrasound measures of muscle area (UtM) during lactation in different breeds and parities and with different feeding levels were examined. Random regressions were fitted to repeated measures of UtM in order to study changes in variance components of UtM during lactation. Correlations between measures taken in different stages of lactation and in different parities were also calculated. The shape of UtM curves during lactation appeared to be fairly consistent for all breeds and parities. The lowest point of all curves coincided with the expected nadir of body reserves during lactation. With lower-than-normal feeding level, the drop of UtM after calving was deeper and the overall level was lower. A major proportion of the variance in UtM was found to be determined by additive genetic variation. In all three breeds studied, repeatability and heritability estimates were high and fairly consistent during lactation and between parities. The very high genetic correlations between measures taken in different periods of lactation suggested that muscle growth and recovery are controlled by the same gene complex throughout lactation.

Our results suggest that UtM, if used jointly with other body measures such as body condition score, could be a useful indicator of tissue mobilization and deposition in the lactating cow, especially during the early stage of lactation.

1. An experiment was carried out with 24 individually fed castrated male, Large White pigs, to examine the effects upon growth and body composition of an anabolic steroid included in finishing diets of two protein levels.

2. There was a significant interaction between steroid and dietary protein level on the growth rate and food conversion efficiency. On the low protein diet growth rate and efficiency were improved by steroid treatment while with high protein intake the steroid significantly depressed growth. Analysis of the main effects showed no significant differences between steroid and protein means for food conversion efficiency and no significant difference between protein means for growth. There was a significant difference (P<0·05) for rate of growth in favour of the animals not receiving the steroid.

3. Steroid significantly improved the percentage of lean and the eye muscle area, but decreased the length of pigs. High protein feeding also improved the percentage of lean and the eye muscle area and also increased the length.

4. The results are discussed in relation to the use of steroids in other species, optimum time of application and the problem of ascertaining accurate physiological doses.

Countries, which import a significant amount of semen, embryos and animals, are faced with the problem of how properly to evaluate the animals in the national evaluation system when information on the foreign parents is generally missing. Additional problems arise when the foreign parents obtain an evaluation, usually on the basis of progeny, in the country of import with the result that there are two published evaluations for the animals in question. This paper presents a post-iterative method of incorporating foreign information into home country evaluations. The foreign information is initially converted to the same scale and base as in the home country using procedures recommended by the International Bull Evaluation Service. The method consists essentially of calculating a combined evaluation for animals with home and foreign information as a weighted average of yield deviations, parent averages and progeny contributions from the foreign and home countries. The combined evaluations are used to adjust the evaluations of progeny on the basis of formulae derived from the usual mixed model equations. The same principles were used to combine reliabilities from the respective home and foreign reliabilities. The results from the application of the method to the United Kingdom (UK) Holstein Friesian population are presented. There was re-ranking of both bulls and cows, especially foreign bulls with few UK daughters.

The feed value of whole crop maize silage (WCMS) depends on nutrient composition, ruminal degradability and whole tract digestibility. However, as the ruminal degradation rate is involved in physical regulation of feed intake, ruminal degradability of WCMS may also affect feed intake and milk production of dairy cows. Thus, the aim of this study was to examine relationships between nutrient composition, ruminal degradability, and whole tract digestibility of WCMS and feed intake and milk production of dairy cows. Nine varieties were tested in 3 consecutive years. Nutrient composition analyses included proximate analysis and determination of cell wall constituents. Whole tract digestibility was determined in vivo using wethers and ruminal degradability was examined in situ using four rumen-fistulated steers. Feed intake and milk production were measured using nine cows per variety. Cows were fed a ration consisting of 75.0% WCMS, 8.5% hay and 16.5% soya bean meal (dry matter basis) ad libitum. Variety did not influence nutrient composition, except for the concentration of ADF (ADFom), ADL and utilisable CP (uCP). In contrast, variety had a significant effect (P < 0.05) on ruminal degradability of NDF (aNDFom) and on whole tract digestibility of organic matter (OM) and non-fibre carbohydrates. Dry matter intake (DMI) of WCMS tended to be affected by variety (0.05<P < 0.10) whereas no effect on energy-corrected milk production (ECM) was observed. The year of harvest had an influence on net energy for lactation and uCP concentration, ruminal degradability and whole tract digestibility of nutrients, as well as on DMI and ECM of dairy cows. Whole tract aNDFom digestibility of WCMS was positively correlated with aNDFom concentration (R2 = 0.48) and whole tract OM digestibility (R2 = 0.58). Furthermore, ruminal OM degradability was positively correlated with DMI (R2 = 0.57) and ECM (R2 = 0.49) of dairy cows. The results indicate that ruminal degradability and whole tract digestibility have a greater impact on the feed value of WCMS than nutrient composition and should be focused on to optimise feed intake and milk production of dairy cows. Thus, maize breeders should include ruminal degradability and whole tract digestibility parameters in variety testing programs to increase the informative value of variety descriptions for farmers.

Boars have a decisive impact on the progress in pig production, however, there is no recent information about the optimal growth parameters during the rearing period for modern breed later used in artificial insemination (AI) stations. Therefore, the objective of the research was to conduct semen parameter and conception rate analyses on the basis of growth rate and meat content assessments made during the rearing of AI boars of different genotypes. The study was carried out between 2010 and 2014 and included 184 boars in five breed combinations: 46 Polish Large White, 50 Polish Landrace, 27 Pietrain, 36 Duroc×Pietrain and 25 Hampshire×Pietrain. Boars were qualified by daily gains and meat content assessment (between 170 and 210 days of life). A total number of 38 272 ejaculates were examined (semen volume (ml), spermatozoa concentration (×106 ml−1), total number of spermatozoa (×109) and number of insemination doses from one ejaculate (n)). The fertility was determined by the conception rate (%). Semen volume, spermatozoa concentration and conception rate (P<0.01), followed by the total number of spermatozoa and insemination doses (P<0.05) were characterized by the highest variability in relation to breed of boars. The effect of daily gains was reported for spermatozoa concentration, number of insemination doses, conception rate (all P<0.01) and total number of spermatozoa (P<0.05). The peak of growth for spermatozoa concentration, total number of spermatozoa, insemination doses and conception rate was achieved for 800 to 850 g gains. Meat content affected semen volume, number of insemination doses and conception rate (P<0.05). Rearing boars while maintaining daily gains at the 800 to 850 g level and 62.5% to 65% meat content helps AI stations to increase the efficiency and economic profitability, and the number of insemination doses to increase by up to 300 doses/boar within a year. The analyses of growth parameters may help increase the efficiency and economic viability of AI stations.

Fifty entire male pigs between 7 and 28 days and 50 entire male pigs between 28 and 56 days of age' were given basal diets containing peanut meal as the protein supplement. These diets contained 4·5 to 6·1 g threonine per kg and were supplemented with graded additions of synthetic L-threonine.

It was found that the amount of threonine required for maximum performance and nitrogen retention was 6·6 g/kg dry matter (DM) between 7 and 28 days of age and 5·4 g/kg DM between 28 and 56 days of age. These values were calculated to correspond to 0·43 and 0·36 g threonine per MJ digestible energy.

The concentration of threonine in the blood plasma did not give a clear indication of the threonine requirement of the pigs.

Eight diets based on barley and soya bean meal were formulated. Two basal diets, one of which included fish meal, were formulated to conform to the recommendations of the Agricultural Research Council (1981) for all amino acids except lysine. Four further diets were made by adding L-lysine to these diets, in two increments; the highest concentrations of lysine were also supplied in two further diets by the inclusion of a higher proportion of soya bean meal. Each diet was given ad libitum to 10 growing pigs, five castrated males and five females, which were housed and fed individually.

Measurements of performance were made over the weight range 22 to 55 kg. Carcasses were appraised after slaughter at a mean weight of 75 kg.

Addition of lysine, but not of soya bean meal, significantly increased daily food intake and carcass fatness. Daily growth and food conversion efficiency were not significantly affected. Because of the high food intake the daily lysine intakes on the basal diets greatly exceeded the suggested daily requirement and the results indicate that in such circumstances the response to the amino acid supplementation of an apparently inadequate protein may be negligible.

A simple model was derived relating the phenotypic effect (g) of a major gene to observed values of the population mean and variance for a trait, at specified values of the major gene frequency and at specified basal values of the population mean and variance (in the absence of the major gene). This model was applied to a total of 549 observed values of ovulation rate in ewes of the Cambridge breed at Bangor under a range of assumptions. The mean values of ovulation rate were 2·44 for 243 ewes of 1 year of age and 37·54 for 306 ewes of 2 and 3 years of age with a coefficient of variation for both age sets of 0·50.

The results indicate a minimum value for g, in this data set, of 1·07 for 1 year old and 1·72 for 2 and 3 year old ewes. The results are also consistent with a frequency value in the region of 0·3 to 0·4, with the absence of dominance and with a reasonable concordance with Hardy-Weinburg equilibrium. The results also indicate that the value of g varies according to the background phenotype since it is lower for younger as compared with older ewes.

Eight trials involving 522 fattening lambs were conducted to compare rations of shelled corn and either long or chopped alfalfa hay with complete pelleted rations containing various proportions of concentrate.

Feeding lambs on complete pelleted rations that contained 50–100% roughage resulted in increased feed consumption and significantly greater gains. However, efficiency of feed conversion was improved by pelleting in only one trial.

Feed consumption and rate of gain were not improved by pelleting ground ear corn. Conversely, lambs fed only pelleted alfalfa hay gained significantly faster than lambs fed only chopped hay.

Live-weight growth was studied for 64 female, 64 castrated male and 64 intact male indigenous Nigerian pigs at 16 ages from birth to 672 days. The weights obtained were fitted into four different growth functions to derive prediction equations for the models used. The quadratic (W = a + bt + ct2) and the Schmalhausen functions (W = at) described live-weight growth better than the simple linear function fW = a + bt). Estimating live-weight growth using Brody's function (Y = aebt) gave the least exact predictive ability. Linear growth in indigenous Nigerian pigs occurred between 112 and 336 days. Castrated male pigs exhibited higher live-weight growth rates than either the female or intact male pigs. Differences in the prediction of live weights using the four growth functions and the actual live weights are presented and discussed.

Ninety-six October calving, multiparous Friesian dairy cows were given from week 2 of lactation perennial ryegrass silage ad libitum, supplemented with one of four compound foods, offered at a flat rate of 3 kg/day. The compound foods differed in crude protein (CP) concentration (210 (LP) and 350 (HP) g/kg dry matter (DM)), achieved by including fish meal at 50 and 250 kg/t respectively; and in metabolizable energy (ME) concentration (12·8 (LE) and 14·0 (HE) M/kg DM), achieved by adding protected fat (approx. 100 kg/t). There were no significant interactions between supplement type in terms of animal performance. Over an average feeding period of 152 days, milk yields were significantly increased by 0·49 kg/day per 100 g supplementary CP (P < 0·01) and 0·50 kg/day per MJ of supplementary ME (P < 0·05).

Increasing the level of supplementary CP had no effect on milk composition but significantly increased yield of milk protein (67 g/day). An increase in supplementary ME significantly reduced protein concentration in the milk (1·1 gjkg) but had no effect on protein yield. Yield of milk fat was significantly increased (76 g/day). The additional energy also significantly improved cow fertility in terms of a reduced interval from calving to both first service and conception.

Genetic and phenotypic parameters were estimated for farmed red deer on eight farms distributed throughout the United Kingdom. Genetic parameters were estimated using restricted maximum likelihood (REML) analysis. Heritabilities for date of calving were low on seven of the eight farms (< 0–05), while repeatabilities were low to moderate (0·06 to 0·37). Heritabilities of all weights tended to be moderate to high on most farms (0·31 to 0·49; 0·22 to 0·89; 0·33 to 0·48; 0·37 to 0·45 and 0·37 to 0·90 for birth weight, weaning weight, mid-winter weight, turn-out weight and other weights respectively). The exception was farm 8 for which heritability estimates were very low (<0·08). This is attributed to inbreeding effects on this farm. Phenotypic and genetic correlations between post-weaning traits tended to be high, indicating selection at any stage of growth will be expected to lead to an increased growth at the other stages. Animals whose bloodlines originated in the forests of Eastern Europe (Yugoslavia, Hungary, Germany) were heavier at all stages indicating their usefulness as ‘terminal sire’ breeds. Hinds of mainland ‘European’ parentage also tended to calve earlier.

Feeding dried distillers grains with solubles (DDGS), a feed high in fat and protein, to lactating beef cows can alter milk production and composition, resulting in improved pre-weaning growth of progeny. This alteration in milk profile may consequently alter the growth and carcass composition of the offspring after weaning. Therefore, Angus×Simmental steers (n=48) whose dams were fed one of two diets supplemented with either DDGS or soybean meal (CON) from calving to mid-lactation were placed in a feedlot to determine the effects of maternal nutrition during lactation on progeny development and carcass composition. Cow–calf pairs were allotted to two treatments at birth based on cow and calf BW, breed and age. Maternal diets were isocaloric (3.97 MJ/kg NEg) and consisted of rye hay supplemented with DDGS at 1% of BW (19.4% CP; 8.76% fat) or rye hay and corn silage supplemented with CON (11.7% CP; 2.06% fat). After conclusion of the treatments at 129 days postpartum, cow–calf pairs were comingled and managed as one group until weaning at 219 days postpartum. Steers were then transitioned to a common diet composed of 60% DDGS, 34% corn silage and 6% vitamin/mineral supplement and were placed indoors in individual pens with slatted floors. An intravenous glucose tolerance test (IVGTT) was performed 134 days after feedlot entry on 16 steers (CON, n=7; DDGS, n=9) to determine the effect of maternal diet on glucose and insulin sensitivity. Steers were slaughtered at a target BW of 645 kg. Categorical and continuous data were analyzed using the GLIMMIX and MIXED procedures of SAS, respectively. Steers from DDGS dams tended to be heavier on day 85 of feedlot finishing (P=0.09) compared with steers from CON dams. However, there were no differences in final weight, average daily gain, dry matter intake or efficiency (gain:feed, P⩾0.18). Maternal treatments did not affect progeny days on feed (P=0.15), despite a mean difference of 9 days in favor of DDGS. Glucose and insulin concentrations and area under the curve of progeny as measured by IVGTT were not affected by maternal diet (P⩾0.16). Maternal DDGS supplementation decreased marbling score (P=0.04), but did not influence carcass grading percentage or any other carcass characteristic (P⩾0.17).

Ruminants generally succeed in selecting an appropriate diet relative to their nutrient requirements, and macronutrients such as energy and protein are considered as playing a primary role in their food preferences. Diet learning through post-ingestive consequences, evidenced by many studies that involved situations with simple discrimination tasks, may explain this ability to select a suitable diet. However, in more complex feeding environments where animals are faced with many plants varying both in their energy and protein contents, the extent to which such a mechanism operates is still uncertain. Our objective was to investigate a more complex feeding situation than previously tested and to determine whether lambs were able to associate three forages with both energy-based and protein-based post-ingestive consequences of various intensities. The doses of starch and casein used to elicit these post-ingestive consequences were chosen so that the apparent metabolisable energy and crude protein values of hays were within the range found in plants normally encountered under field conditions. We applied five treatments: EmPm, EhPm, EmPh, EhPh, where medium (m) or high (h) levels of nutrients (E = energy and P = protein) were associated with different hays, and E0N0 where no stimuli were associated. Each animal experienced only three treatments: E0N0–EmPm–EhPm or E0N0–EmPh–EhPh, each one being associated with one hay during conditioning, on the basis of one treatment per day over three consecutive days. Animals then had a choice between the hay associated with E0N0 and one of the two others, successively on the two following days. This procedure was repeated through five 1-week-long periods, and applied to two groups of lambs (n = 12) maintained at feeding levels sufficient for maintenance or for a 150 g/day growth rate. This experiment was complemented by a methodological trial that aimed to estimate the doses of starch and casein eliciting preferences and a post-trial that aimed to evaluate the effect of our treatments on sheep ruminal environment. The methodological trial showed that lambs perceived the stimuli and the doses, and the post-trial showed that treatments affected the ruminal environment. In the main experiment, the lambs preferred the rewarded hays but did not discriminate in their choices the variation of post-ingestive consequences due to energy and protein. This suggests that in situations closer to reality where animals experience many foods varying in nutrient contents, the learning process may be impaired. The lambs do not seem to have strictly relied on it for shaping their diet choices.

Boars from four pure breeds and three two-breed crosses were mated at two stations to sows from six two-breed crosses to produce three- and four-breed cross litters. Two types of three-breed crosses were produced either using purebred boars or by partial backcrossing using crossbred boars. From the 504 litters produced 965 male pigs were slaughtered at 90 kg live weight. The purebred boars produced litters which were 0·4 and 0·2 pigs larger and 0·14 and 1·14 kg heavier at birth and 21 days respectively than the crossbred boars. Differences between pigs sired by purebred and crossbred boars were negligible for growth rate and carcass quality. Little difference was also found between three- and four-breed cross pigs sired by crossbred boars (except for daily gain, P < 0·05). Breed of dam was a significant source of variation on all the traits except dressing-out percentage. Significant breed of sire effect was found on all the traits related to carcass quality but not on those related to growth. Breed of sire × breed of dam interaction was significant on backfat thickness, carcass lean yield percentage and average daily gain. The best crosses in carcass value were those of Duroc boars mated to Hampshire-Landrace and Landrace-Yorkshire sows, while those pigs with the fastest gain were from Landrace boars ×Duroc-Yorkshire sows and Duroc-Yorkshire boars × Large Black-Lacombe sows.

The objective of this experiment was to compare the effects of two concentrate feeding strategies offered with a grass silage and maize silage diet on the dry matter (DM) intake, milk production (MP) and estimated energy balance of autumn calved dairy cows. Over a 2-year period, 180 autumn calving Holstein Friesian cows were examined. Within year, cows were blocked into three MP sub-groups (n=9) (high (HMP), medium (MMP) and low (LMP)) based on the average MP data from weeks 3 and 4 of lactation. Within a block cows were randomly assigned to one of two treatments (n=54), flat rate (FR) concentrate feeding or feed to yield (FY) based on MP sub-group. Cows on the FR treatment were offered a fixed rate of concentrate (5.5 kg DM/cow per day) irrespective of MP sub-group. In the FY treatment HMP, MMP and LMP cows were allocated 7.3, 5.5 and 3.7 kg DM of concentrate, respectively. The mean concentrate offered to the FR and FY treatments was the same. On the FR treatment there was no significant difference in total dry matter intake (TDMI, 17.3 kg) between MP sub-groups. In the FY treatment, however, the TDMI of HMP-FY was 2.2 kg greater than MMP-FY, and 4.5 kg greater than LMP-FY (15.2 kg DM). The milk yield of LMP-FR was 3.5 kg less than the mean of the HMP-FR and MMP-FR treatments (24.5 kg). The milk yield of the HMP-FY treatment was 3.6 and 7.9 kg greater than the MMP-FY and LMP-FY treatments, respectively. The difference in MP between the HMP sub-groups was 2.6 kg, which translates to a response of 1.4 kg of milk per additional 1 kg of concentrate offered. There was no significant difference in MP between the two LMP sub-groups; however, MP increased 0.8 kg per additional 1 kg of concentrate offered between cows on the LMP-FR and LMP-FY treatments. The estimated energy balance was positive for cows on the LMP-FR treatment, but negative for cows on the other treatments. The experiment highlights the variation within a herd in MP response to concentrate, as cows with a lower MP potential are less responsive to additional energy input than cows with a greater MP potential. Cows with a greater MP capacity did not substitute additional concentrate for the basal forage, which indicates an additional demand for energy based on ability of individual cows to produce milk.

Forty-eight Suffolk × Clun lambs were used in an experiment to investigate the effects of two times of removal from the dam and two feeding frequencies upon milk intake over the first 4 days on an artificial rearing system.

Lambs removed at birth consumed significantly more milk replacer at feeding periods up to 32 hr after removal than lambs removed at 24 hr after birth. Removal at birth also significantly increased voluntary milk intake between feeding periods for up to 32 hr and from 64 to 80 hr after removal.

Feeding the lambs during a 16-hr period in a 4, 4, 8 hr sequence instead of 8, 8 hr intervals significantly improved milk intake at feeding periods.

From among a group of ewes in which oestrus had been induced following progesterone and PMS treatment and which had been mated in the spring, those lambing in early October were used for this experiment. They were divided into three treatment groups: (1) reared their lambs for 24 hr, (2) reared lambs for 16 days and (3) reared lambs for 75 days.

For the ewes rearing single lambs only in groups 1, 2 and 3, 100% (8 of 8), 93% (13 of 14) and 65% (11 of 17) respectively exhibited oestrus between lambing time in autumn and early winter (P<0·05). The average interval to post-partum oestrus was 29, 37, 50 days for group 1, 2 and 3 respectively. Group 3 exhibited first oestrus later than group 1 (P<0·01). These data show that lactation even during the peak of sexual activity has some suppressing effect on both the percentage of ewes showing oestrus and on delaying the onset of oestrus exhibition.

Recent legislation prohibiting the use of individual confinement systems for dry sows has led to the adoption of group housed systems which have perceived welfare advantages. The feeding system for dry sows and gilts is fundamental to welfare and production; problems such as abnormal behaviours, aggression and psychological stress, caused by poor nutrient distribution in group systems, must be addressed.

In this study the relative merits of three feeding systems for group housed gilts were investigated in relation to welfare and production.