During a survey of beef production in East Anglia carcasses of 163 Friesian, 87 Dairy Shorthorn and 45 Aberdeen-Angus × Friesian steers and 44 Aberdeen-Angus × Friesian heifers were measured and scored by visual assessment for fat development. They were also graded by the Ministry of Agriculture, Fisheries and Food.

Age data indicated that the Friesian steers were, on average, younger at slaughter than the other groups, but they were incomplete and comparison was based on carcasses of the same weight. The Dairy Shorthorn steers had higher mean values than Friesians in three of the carcass measurements taken. The Dairy Shorthorns had a higher average fatness score and a higher proportion of Grade A carcasses. Aberdeen-Angus × Friesian steers had lower mean values for measurements of the hind leg, higher fatness scores and a higher proportion of Grade A carcasses than either of the two pure breeds. Aberdeen-Angus × Friesian heifers had lower mean values for measurements of both fore and hind legs, higher fatness scores and a slightly higher proportion of Grade A carcasses than the steers.

The information gained by use of measurements and fatness scores explained, but did not materially add to, the assessment of the relative value of the groups of carcasses given by grade.

Smith (1986) identified the theoretical potential of multiple ovulation and embryo transfer (MOET) to increase the rate of genetic improvement within nucleus sheep breeding flocks by upto 100%. The likely genetic benefits of MOET arise from the potential to overcome limits to female reproduction thus allowing increased selection intensity and reduced generation intervals among females. The present study was conducted to evaluate the potential for MOET from 18 month-old maiden ewes (gimmers) in comparison with aged donor ewes.

In October 1991, a group of twenty 18-month old ewes and twenty aged ewes (3.5 year-old) were synchronised into oestrus using intravaginal pessaries containing 45 mg Cronolone (Chronogest, Intervet Laboratories Ltd.) inserted for 12 days. Superovulation was achieved using 20 i.u. of ovine follicle stimulating hormone (Ovagen, Immuno-Chemical Products N.Z. Ltd) given in eight equal doses at 12-hourly intervals starting 58 hours before progestagen pessary withdrawal.

Pure cultures of rumen microorganisms usually grow better when amino acids are present, particularly if the amino acids are present as peptides. However, it is less clear how important peptides, compared to free amino acids and ammonia, are to the mixed microbial population of the rumen. In vitro mixed cultures suggest that peptides permit more rapid microbial growth on soluble carbohydrates and greater amino acid incorporation than free amino acids (Wright, 1967; Argyle & Baldwin, 1989). However, amino acid N may have no beneficial effect if the energy source is more slowly degraded (Merry et al., 1990). The present experiment was undertaken to assess whether the response of rumen fermentation to additional nitrogen is different depending on whether the N is present as non-protein N, free amino acids, or peptides in sheep receiving a grass hay diet.

The feeding of molasses influences the rumen fermentation by changing the balance of microbes in the rumen and their metabolism. One of the consequences is a decrease in efficiency of utilisation of dietary protein when high molasses levels are fed. The dietary protein requirements of ruminants may therefore be higher for diets containing high molasses levels. A previous experiment with dairy cows has shown positive responses in feed intake and milk production to increases in both effective rumen degraded dietary protein (ERDP) and digestible undegraded protein (DUP) in diets containing 310 g/kg DM of molaferm 20 (a mixture of 800 g cane molasses with 200 g condensed molasses solubles per kg, supplied by United Molasses) (Yan and Roberts, 1993). The current experiment was undertaken to evaluate the effects of dietary ERDP and DUP levels on rumen fermentation, hay DM degradability and microbial growth in the rumen of wether sheep.

The effects of feeding supplements in relation to sward height in the autumn on the reproductive performance of ewes grazing predominantly perennial ryegrass swards were studied in four experiments with three genotypes. Treatments in which either no supplements were given or supplements were offered according to the height of the sward were compared when ewes were grazed on swards which were managed to decline in height from > 5 cm to 2·5 cm either before or after mating. At a sward height of < 3·5 cm, 400 g ground and pelleted barley was offered per head per day; at < 3·0 cm, 700 g was offered; and, at < 2·5 cm, hay was offered in addition to the barley. Responses to these treatments were compared with that of a treatment in which a sward was maintained at > 5 cm. Sward heights were controlled by varying stocking rate. In experiment 1, with 305 Scottish Blackface ewes, supplementation was not necessary until after the start of the mating period. In experiment 2, with 200 Brecknock Cheviot ewes, the supplementation protocol was examined on swards declining in height either before or after a synchronized mating. Experiment 3 repeated experiment 2 with 200 Beulah Speckled-face ewes and experiment 4 repeated only the pre-mating phase of experiment 3 with 195 Beulah Speckled-face ewes.

In experiment 1, ovulation, ova loss and potential lambing rates were determined from the number of corpora lutea and viable embryos at slaughter at 8 to 10 weeks after the start of mating in 103 ewes and lambing rate was determined from the number of lambs at lambing in the remaining 202 ewes. In experiments 2, 3 and 4, ovulation, ova loss and potential lambing rates were determined from the number of corpora lutea and viable embryos at slaughter at return to service or at 4 weeks after a synchronized first mating.

Grazing a sward declining in height below 3·5 cm in the pre-mating period significantly reduced ewe live weight, body condition and reproductive performance, particularly in the relatively prolific Beulah Speckled-face breed, compared with grazing a sward maintained at > 5 cm. Supplementation at the levels offered overcame some of the effects of the lower sward height treatment in the pre-mating period but did not compensate fully. Grazing a sward declining in height below 3·5 cm in the post-mating period, although reducing ewe live weight and body condition, had little effect on reproductive performance, compared with that achieved on a sward maintained above 4 cm. Supplementation at the levels offered at the lower sward height during the post-mating period produced no increase in overall reproductive performance and had a negative effect on some reproductive parameters.

Piglets are born with 8 very sharp ‘needle-teeth’ - 4 incisors and 4 canines. These pointed teeth grow outwards, two on either side in each jaw, leaving an open space in the front of the mouth. In intensively run units, the tips of these teeth are usually removed soon after birth, using a pair of side cutter pliers. This is said to reduce the severity of piglet face wounding, caused by natural competition for space at the udder and during play. Reducing injury by clipping teeth is also said to limit the sites of entry for micro-organisms. Blunt clippers and clipping teeth too close to the gum can shatter teeth, providing places of entry for microbes and leaving sharp edges which can lead to deep wounds in tongues and lips. The aim of this trial was to determine whether grinding teeth is a preferable alternative to clipping teeth

The paper reports an experiment conducted with 50 Scottish Blackface and 10 South Country Cheviot ewes all suckling twin lambs and grazing, from parturition for some 18 weeks, pasture previously shown to cause a molybdenum-sulphur induced copper deficiency. The objectives were to examine the efficacy of various means of prophylaxis and the susceptibility of the two genotypes to copper deficiency.

The treatment of ewes at parturition with copper, either as an injection of 90 mg copper as copper methionate or orally with cupric oxide needles (3·2 g copper), delayed the onset of signs of copper deficiency in their lambs but did not prevent completely the development of hypocupraemia or hypocuprosis.

The treatment of lambs with a single injection of 15 mg copper as copper calcium edetate at about 6 or 10 weeks of age was not effective in preventing the development of hypocupraemia. Four injections (1 × 5 mg and 3 × 15 mg) at approximately equal intervals maintained normocupraemic values in lambs, but the most effective treatment, as judged by plasma and liver copper concentrations and by live-weight gain, was the administration of cupric oxide needles (1.6 g copper) to lambs at about 6 weeks of age.

The between-genotype comparison indicated that the Cheviot ewes and their lambs were as severely affected by the induced copper deficiency as were the Blackfaces.

Multiple trait selection indexes in pig breeding programmes should take into account the population structure and time delay between parent selection and expressions of traits in all production levels next to the trait impacts on economic efficiency of production systems. Gene flow procedures could be used for the correct evaluation of maternal and direct traits of pig breeds involved in breeding or crossbreeding systems. Therefore, the aim of this study was to expand a previously developed bioeconomic model and computer program to calculate the marginal economic values by including a gene flow procedure to calculate the economic weights for maternal and direct traits in pig breeds. The new program was then applied to the three-way crossbreeding system of the Czech National Programme for Pig Breeding. Using this program, the marginal economic values of traits for dam breeds Czech Large White in the dam position and Czech Landrace in the sire position, and for the sire breed Pietrain were weighted by the number of discounted gene expressions of selected parents of each breed summarised within all links of the crossbreeding system during the 8-year investment period. Economic weights calculated in this way were compared with the approximate economic weights calculated previously without a gene flow procedure. Taking into account the time delay between parent selection and trait expression (using discounting with half-year discount rates of 2% or 5%) and including more than one generation of parent progeny had little impact on the relative economic importance of maternal and direct traits of breeds involved in the evaluated three-way crossbreeding system. These results indicated that this gene-flow method could be foregone when estimating the relative economic weights of traits in pig crossbreeding systems applying artificial insemination at all production levels.

The performance of pigs is affected by the rate of nutrient absorption in the gastrointestinal tract, which depends in turn strongly on the rate of stomach emptying. The 13C breath test provides a non-invasive diagnostic tool to measure gastric emptying patterns. Despite the wide acceptance of this method in human intervention studies, it has not found its way to the domain of animal sciences. In this study, we used the breath test to measure gastric emptying in young growing pigs using [1-13C] octanoic acid to trace digesta solids and [1-13C] glycine to study liquids. Pigs were fed a starch-rich diet, varying in starch source (isolated starch from barley, maize or high-amylose maize) or form (isolated barley starch, ground barley or extruded barley), after which 13CO2 enrichment was frequently measured during 11 h. Outliers in 13CO2 enrichment in the response curve of each pig were identified with a Cookʼs distance outlier test in combination with a leave-one-out analysis. Effects of experimental treatments on breath test parameters were tested using a GLM. In general, pigs were easy to train and the tailor-made mask allowed effortless sampling. Gastric emptying of all pigs followed a biphasic pattern, with a higher 13C recovery during the first peak. The first peak in gastric emptying of solids reached its maximum enrichment within 2 h after feeding in all cases. For digesta liquids, this peak was reached earlier for pigs fed ground barley (2.2 h after feeding), compared to pigs fed diets containing isolated starch (2.8 h after feeding). The second peak in gastric emptying of solids was reached later for pigs fed ground barley (5.9 h after feeding), compared with pigs fed extruded barley (4.5 h after feeding) and pigs fed diets containing isolated barley starch (4.8 h after feeding). In conclusion, the 13C breath test is a convenient, non-invasive tool to gain more insights into the gastric emptying pattern of pigs.

Data from 2032 Uruguayan Aberdeen Angus cows under extensive management and recording practices were analysed with Bayesian threshold-liability sire models, to assess genetic variability in calving success (CS), defined as a different binary trait for each of the second (CS2), third (CS3) and fourth (CS4) calving opportunities. Sire (herd) variances ranged from 0.08 to 0.11 (0.10 to 0.20) and heritability from 0.27 to 0.35, with large credibility intervals. Correlations between herd effects on CS at different calving opportunities were positive. Genetic correlation between CS2 and CS4 was positive (0.68), whereas those involving adjacent calving opportunities (CS2–CS3 and CS3–CS4) were negative, at −0.39 and −0.54, respectively. The residual correlation CS2–CS3 was negative (−0.32). The extent of uncertainty associated with the posterior estimates of the parameters was further evaluated through simulation, assuming different true values (−0.4, −0.2, +0.2 and +0.4) for the genetic correlations and changes in the degree of belief parameters of the inverse Wishart priors for the sire covariance matrix. Although inferences were not sharp enough, CS appears to be moderately heritable. The quality of data recording should be improved, in order to effect genetic improvement in female fertility.

The use of molecular genetic information in the evaluation of livestock has become more common. This study looks at the efficacy of using such information to improve the genetic evaluation of a rare breed of dual-purpose cattle. Data were available in the form of pedigree information on the Gloucester cattle breed in the United Kingdom and recorded milk and beef performance on a small number of animals. In addition, molecular genetic information in the form of multi-marker, multiple regression results converted to a 1 to 10 score (Igenity scores) and 123 single nucleotide polymorphism (SNP) genotypes for 199 non-recorded animals were available. Appropriate mixed-animal models were explored for the recorded traits and these were used to calculate estimated breeding values (EBV), and their accuracies, for 6527 animals in the breed’s pedigree file. Various ways to improve the accuracy of these EBV were explored. This involved using multivariate BLUP analyses, genomic estimated breeding values (GEBV) and combining Igenity scores with recorded traits in a series of bivariate genetic analyses. Using the milk recording traits as an example, the accuracy of a number of traits could be improved using multivariate analyses by up to 14%, depending on the combination of traits used. The level of increase in accuracy largely corresponded to the absolute difference between the genetic and residual correlations between two traits, but this was not always symmetrical. The use of GEBV did not increase the accuracy of milk trait EBV owing to the low proportion of variance explained by the 101 SNPs used. Using Igenity scores in bivariate analyses with the recorded data was more successful in increasing EBV accuracy. The largest increases were found in genotyped animals with no recorded performance (e.g. a 58% increase in fat weight in milk); however, the size of the increase depended on the level of the genetic correlation between the recorded trait and the Igenity score for that trait. Lower levels of improvements in accuracy were seen in animals that were recoded but not genotyped, and ancestors which were neither genotyped nor recorded. This study demonstrated that it was possible to improve the accuracy of EBV estimation by including Igenity score information in genetic analyses but it also concluded that increasing the level of performance recording in the breed would be beneficial.

Energy intake and nitrogen balance studies have been conducted on 12 lambs fed ad libitum on four all-concentrate diets of equal crude-protein content in an experiment of latin square design. Each diet contained one cereal, either barley or oats and one protein supplement, either white-fish meal or soya bean meal.

Protein supplements had no influence on energy intake, but intake was significantly higher when the lambs were given barley rather than oat diets.

There were highly significant differences in the degree of utilization of digested nitrogen between diets containing fish meal and soya bean meal, and between diets containing barley and oats.

The energy: nitrogen ratio of urine was inversely related to the proportion of urinary nitrogen present as urea and directly related to the degree of utilization of digested nitrogen.

In poultry and dairy cattle heterosis is occasionally found in crosses of different strains of the same breed (Hutt and Cole, 1952; Johansson, 1939; Nordskog and Ghostley, 1954). Limited data on the milk production of reciprocal crosses between Dutch and American strains of Friesian dairy cattle being available in Israel, an investigation was carried out to determine whether crossing these two strains resulted in a heterotic effect on milk production.

In 1945 the Milk Marketing Board (M.M.B.) of England and Wales undertook responsibility for the development of an A.I. service to cover large areas of the two countries.

By 1951, a total of 24 main Centres had been set up, housing some 600 dairy and beef bulls and supplying semen to 77 Sub-Centres. During the year ending 31st March, 1952, approximately 707,000 first inseminations were carried out, representing 25% of the available cattle population. Further progress continues to be made and it is estimated that this proportion will be raised to 30% for the corresponding year ending in 1953.

From the outset it has been agreed that the rate of cattle improvement through A.I. will be largely dependent upon the use made of the older progeny-recorded bulls available to the scheme. Here it should be noted that the M.M.B. took over responsibility for milk recording under ‘ National Milk Records ‘ in 1943. By adopting a system based upon lactation record cards, it was possible to establish in 1947 a central clearing house for milk records of animals registered with Breed Societies, viz. the Bureau of Records. One of the main services operated by the Bureau is that of progeny recording for sires and summaries of bulls fulfilling certain requirements are now published annually.

Grass silage provides an alternative feed for extensively kept sows, but previous experiments have indicated very variable intake and utilisation, dependant on silage quality. ‘Maxgrass’ silage additive (BP Nutrition) is a blend of compounds including ammonium hexamethanoate, ammonium hexapropanoate and octanoic acid. It is designed to modify fermentation, so that the resulting silage retains a higher proportion of water soluble carbohydrates. This should improve the nutritive value for pigs.

The experiment comprised two parts: an intake/growth study and a separate digestibility study. The same two experimental silages, either treated with Maxgrass or an untreated control, were offered to groups of pregnant sows in a randomised block experimental design in each experiment. Second cut, mainly perennial ryegrass herbage was cut by mower conditioner and direct ensiled. Alternate loads were left untreated or treated with Maxgrass at a mean rate of 6.04 litres/tonne.