Scrapie, a transmissible spongiform encephalopathy (TSE) or prion disease, is a fatal, neurodegenerative disease in sheep and goats. This disease has been known in Europe for more than 250 years. Susceptibility to scrapie is associated with polymorphisms in the sheep prion protein gene (PrP) gene. In sheep, polymorphism in the PrP gene has been identified at a number of codons, and polymorphisms at codons 136, 154 and 171 have reported linkage with susceptibility to scrapie. Polymorphisms at the PrP locus were studied in 413 animals representing three native sheep breeds (Imroz, Chios and Kıvırcık) in Turkey. Genomic DNA was obtained from blood, and genotypes were screened using PCR and direct DNA sequencing. We report 17 genotypes derived from seven different alleles. The most frequent genotype in the Kıvırcık sheep is ARQ/ARQ, whereas the ARR/ARQ genotype is predominant in the Chios and Imroz breeds. In general, the ARQ haplotype was the predominant haplotype. ARQ haplotype was also predominant in the Kıvırcık and Chios sheep breeds, whereas the Imroz sheep predominantly had the ARR haplotype. The susceptibility-associated VRQ haplotype was found in 2.38%, 0.35% and 0.81% of the Imroz, Kıvırcık and Chios sheep, respectively. Moreover, seven additional polymorphisms have been detected at codons G127S, G127V, H143R, G145S, Y172D, N174Y and Q189L. Among these polymorphisms, the N174Y allele is a novel polymorphism, and the G145S allele is a novel allele for a known polymorphic locus.

Many economic losses occur in the poultry industry due to leg fragility. Knowing the genomic regions that influence traits associated with the growth and composition of the leg’s bone can help to improve the selection process leading to increased leg resistance to fracture. The present study aimed to map quantitative trait loci (QTL) for mineral composition and morphometric traits of the tibia in 478 animals from an F2 broiler × layer cross. The measurement of weight, length and width of Tibia was carried out at 42 days of age. Ash, dry matter, levels of calcium (Ca), phosphorus (P), magnesium (Mg), Zinc (Zn) and Calcium:Phosphorus (Ca:P) ratio were also recorded. The population was genotyped for 128 microsatellite markers and one single nucleotide polymorphism, covering 2630 cM of the chicken genome. A likelihood ratio test was performed to find QTLs. Additive and dominance effects of the QTLs were included in the model. In the chromosomes 2 (GGA2), 6 (GGA6), 8 (GGA8), 24 (GGA24) and 26 (GGA26) some suggestive QTLs (P<0.00276) were mapped for tibia weight (GGA2 and GGA26), ash percentage (GGA2 and GGA6), dry matter percentage (GGA2), Ca (GGA8 and GGA24) and Ca:P ratio (GGA8), many of which are close to genes already identified as good candidates for those traits. The suggestive QTL on GGA2 has a pleiotropic effect on ash percentage, dry matter and bone weight, whereas in the GGA8 there seems to be two QTLs, one for Ca and another for Ca:P ratio. Thus, this study identified at least five genomic regions, in different chromosomes, that can be targeted for further research to identify potential mutations influencing the development and composition of leg bones in Gallus gallus.

Twelve male 8-month-old lambs were used in a 6-month feeding experiment to determine the effects of dietary Mo, Mo + S and Zn supplements on the body retention and tissue accumulation of dietary Cu, Zn and Fe. The lambs were divided into four groups of three lambs each and each group was fed ad libitum one of four diets. A control diet was based on palm kernel cake (PKC) and grass hay. Three additional diets were the control supplemented with either Mo or Mo + S or Zn. At 3 months of the experiment, feces and urine were collected and sampled for 6 days. At the end of the experiment (6 months), blood was sampled and then the sheep were slaughtered. The liver and kidney were removed and sampled for chemical analysis. In comparison with the control, each dietary supplement decreased (P < 0.05) the Cu concentration in the liver, but only the Mo + S supplement decreased it to a safe range of below 350 μg/g dry matter. This was accompanied by the body retention of dietary Cu of 24.6%, 6.7%, 2.5% and 6.5% for the control, Mo, Mo + S and Zn treatments, respectively. The blood plasma concentration of Cu was decreased (P < 0.05) by the Zn supplement, but was not affected by other supplements (P > 0.05). It was concluded that from the supplements tested, only Mo + S appeared to be effective in reducing the retention and liver accumulation of the dietary Cu to prevent chronic Cu toxicity in sheep fed PKC-based diets.

One of the main goals of selection schemes in beef cattle populations is to increase carcass weight at slaughter. Live weights at different growth stages are frequently used as selection criteria under the hypothesis that they usually have a high and positive genetic correlation with weight at slaughter. However, the presence of compensatory growth may bias the prediction ability of early weights for selection purposes. Recursive models may represent an interesting alternative for understanding the genetic and phenotypic relationship between weight traits during growth. For the purposes of this study, the analysis was performed for three different set of data from the Pirenaica beef cattle breed: weight at 120 days (W120) and at 210 days (W210); W120 and carcass weight at slaughter at 365 days (CW365); W210 and CW365. The number of records for each analysis was 8592, 4648 and 3234, respectively. A pedigree composed of 56323 individuals was also included. The statistical model comprised sex, year-season of birth, herd and slaughterhouse, plus a non-linear recursive dependency between traits. The dependency was modeled as a polynomial up to the 4th degree and models were compared using a Logarithm of Conditional Predictive Ordinates. The results of model comparison suggest that the best models were the 3rd degree polynomial for W120-W210 and W120-CW365 and the 2nd degree polynomial for W210-CW365. The posterior mean estimates for heritabilities ranged between 0.29 and 0.44 and the posterior mean estimates of the genetic correlations were null or very low, indicating that the relationship between traits is fully captured by the recursive dependency. The results imply that the predictive ability of the performance of future growth is low if it is only based on records of early weights. The usefulness of slaughterhouse records in beef cattle breeding evaluation is confirmed.

Marker-assisted gene pyramiding provides a promising way to develop new animal breeds or lines, in which genes responsible for certain favorable characters identified in different breeds or lines are incorporated. In consideration of features of animal populations, we proposed five schemes for pyramiding three genes, denoted Scheme A–E, and five schemes for pyramiding four genes, denoted Scheme F–J. These schemes are representative of the possible alternatives. We also provided an algorithm to compute the population sizes needed in each generation. We compared these schemes with respect to the total population size and the number of generations required under different situations. The results show that there is no scheme that is optimal in all cases. Among the schemes for pyramiding three genes from three lines (L1, L2 and L3), Scheme D (a three-way cross between the three lines are first performed, followed by a backcross to L1 and a subsequent intercross to obtain the desired genotype) has a significant advantage over the other schemes when the recombination rate between adjacent genes ranges from 0.1 to 0.4, while Scheme A (a two-way cross between L1 and L2 and a subsequent intercross are performed, followed by a cross with L3 and a subsequent intercross to obtain the desired genotype) is optimal when recombination rate is 0.5. Among schemes for pyramiding four genes from four lines (L1, L2, L3 and L4), Scheme I (seperately, a two-way cross between L1 and L2 (L3 and L4) followed by a backcross to L1 (L3) and a subsequent intercross are performed, then the offspring from the two sides are crossed and followed by a backcross to L1 and a subsequent intercross to obtain the desired genotype) is optimal when the recombination rate ranges from 0.1 to 0.4, while Scheme F (cross and subsequent intercross between the four lines are performed successively) is the optimal when the recombination rate is 0.5. We also disscuss how the animals’ reproductive capacity, the probabilities of obtaining the desired genotypes and genetic distance between adjacent genes would affect the design of an optimal scheme.

This article presents an uncertainty analysis of the productivity of cattle herds in traditional farming systems of West and Central African drylands. The study focused on productivity rates in animal numbers (RN) and meat weights (RW) estimated from a herd growth model, which were compared with FAOSTAT-based estimates. The uncertainty analysis contained the following two steps: uncertainty propagation and a global sensitivity analysis. The analysis was based on a state-of-the-art of the current knowledge and a set of available data on the herd performances. The calculations used Monte Carlo simulations to estimate the 95% confidence intervals (CI) of RN and RW and the standardized regression coefficients method to estimate the contribution of the input variables to the outputs variances. The mean rate RN was estimated to 0.127 animal/animal-year with a 95% CI of (0.091, 0.163) and the mean rate RW to 11.7 kg/animal-year with a 95% CI of (8.8, 14.7), corresponding to relative variation around the mean of about ±29% and ±25%, respectively. The input variables that contributed most to the variance of RN (almost 76% of the output variance) were the calving rate, the adult female mortality rate and the female proportion in the population (determined by the pattern of the male offtake in the herds). The input variables that contributed most to the variance of RW were the same as those for RN plus the adult live weights. The CI ranges that were estimated in this article indicate that productivity rates based on literature data or expert estimations of the herd performances should be considered with caution. Research efforts based on gold-standard herd monitoring protocols accounting for temporal and spatial variations should be undertaken in future to decrease the knowledge gaps on the input variables that contribute most to these ranges.

Nutritional alternatives to strengthen animal immunocompetence are critical for welfare and productivity in livestock systems, such as beef cattle operations. This experiment evaluated physiological and innate immunity effects of supplementing an immunomodulatory feed ingredient (Omnigen-AF; Phibro Animal Health, Teaneck, NJ, USA) to beef heifers administered bacterial lipopolysaccharide (LPS). In total, 8 non-pregnant, non-lactating nulliparous Angus×Hereford heifers (676±4 days of age) were ranked by BW (473±8 kg), and assigned to crossover design containing two periods of 34 days each. Heifers were housed in individual pens and had ad libitum access to meadow foxtail (Alopecurus pratensis L.) hay, water and a granulated commercial vitamin+mineral mix. Within each period, heifers received (as-fed basis) 227 g/day of dried distillers grains including (OMN) or not (CON) 56 g of Omnigen-AF for 34 days. On day 28 of each period (0800 h), heifers received an intravenous bolus dose (0.5 μg/kg of BW, diluted in 5 ml of 0.9% sterile saline) of bacterial LPS (Escherichia coli 0111:B4). Hay DM intake was recorded daily from day 0 to 34. Blood was collected at −1, 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 24, 48, 72, 96, 120 and 144 h relative to LPS administration. Heifer intravaginal temperature was recorded every 10 min from −0.5 to 10 h relative to LPS administration. No treatment effect was detected (P=0.35) for hay DM intake during the experiment. No treatment effects were detected (P⩾0.64) for intravaginal temperature and plasma concentrations of tumor necrosis-α, cortisol and haptoglobin, which increased (time effect, P<0.01) for OMN and CON heifers and peaked at 4.5, 2, 4 and 48 h, respectively, after LPS administration. No treatment effects were detected (P⩾0.35) for whole blood mRNA expression of chemokine ligand 5, tumor necrosis-α, cyclooxygenase 2 and interleukin 8, which also increased (time effect, P<0.01) for OMN and CON heifers and peaked at 0.5, 1.5, 2 and 2.5 h, respectively, after LPS administration. Whole blood mRNA expression of interleukin 8 receptor and L-selectin were also similar (P⩾0.61) between OMN and CON heifers, and decreased (time effect, P<0.01) for both treatments reaching nadir levels at 1 and 2.5 h, respectively, after LPS administration. Collectively, OMN supplementation did not modulate the physiological and innate immunity responses of beef heifers to bacterial LPS administration.

Genetic evaluation of Piétrain sires in Flanders occurs under standardized conditions, on test stations with fixed dam breeds, standardized diets and uniform management practices. As environmental conditions vary on commercial farms and differ from the test stations, this study aimed at understanding to what extent the sire, the dam breed and the interaction between both affects the translation of breeding values to practice. Dams of two commercial breeds were inseminated with semen from one of five different sires selected for contrasting breeding values (daily gain, feed conversion ratio and carcass quality). For each sire by dam breed combination, six pen replicates (with three gilts and three barrows per pen) were evaluated for growth performance from 9 weeks of age (20 kg) to slaughter (110 kg), and for carcass and meat quality. In our experimental setup, both sire and dam breed affected growth, carcass and meat quality traits. No significant sire×dam breed interactions on performance could be detected. Though a tendency for interaction on average daily feed intake between 20 and 110 kg (P=0.087), and on pork colour (lightness) (P=0.093) was present. In general, offspring of all tested sires behaved similarly in both dam breeds, indicating that estimated breeding values for Piétrain sires determined in one dam breed are representative in other dam breeds as well.

Mid-Pregnancy nutrition has been shown to have both positive and negative effects on lamb birth weight in primiparous Scottish Blackface ewes. The direction of the effect depends on the level of body condition at mating, being negative in ewes in high body condition (Russel, Foot, White and Davies, 1981). In the same study, it was argued that the effect in younger ewes could be due to their greater sensitivity to both under- and over-nutrition during the earlier to mid stages of their first pregnancy than is evident in older ewes. Russel et al. (1981) also suggested that the level of mid-pregnancy nutrition is likely to have effects on other aspects of production such as embryonic loss, foetal mortality and even ewe mortality.

Forty-eight Landrace × (Landrace × Large White) gilts were randomly allocated at 70 days of age to each of three rearing treatments: (1) fence-line contact with a mature boar, (2) olfactory/aural contact with a mature boar, (3) no boar contact. At 160 days of age, all gilts were relocated adjacent to a novel mature boar and exposed to full contact with a mature boar for 30 min each day. At the first, second and third oestrus, 16 gilts from each treatment group were mated twice and the reproductive tracts were examined at slaughter 21 days later, to determine ovulation rate and embryo survival. The rearing treatments had no significant effects on the attainment of puberty. Neither rearing treatment nor oestrus of mating had any significant effect on behaviour, sexual receptivity at first service, conception rate, ovulation rate, the number of embryos and embryo survival at 21 days of pregnancy.

Twenty-four Friesian steers, initially 5 months of age, were involved in a 2 × 2 factorial experiment which spanned grazing and silage feeding periods of 22 weeks' duration. In the first period, cattle were stocked at a uniformly high density, with half of the group being fed 1·25 kg/head per day of supplementary barley. In the second period, the cattle were subdivided into four groups and fed varying levels of barley with silage. Finally all the animals received 3·65 kg/head per day of barley. Replicates of the four treatments were slaughtered at random after 5 to 11 weeks on this treatment. Whilst supplementary cereal feeding significantly increased the live-weight gains of steers at grass by 11%, this live-weight advantage was offset by their slower gains in the final weeks before slaughter. Feeding cereals to grazing cattle had little effect on carcass composition or the proportions of carcass joints, but their beef was considered, by a tasting panel, to be more tender than the meat from the control steers.

Increasing the level of barley fed with silage only increased live-weight gains by 2%, and had little effect on carcass or meat quality.

1. Attributes desired in the gammons of bacon pigs are discussed, together with the methods whereby they are measured.

2. An experiment is described in which 16 judges made visual assessments of the qualities of the gammons of 10 carcasses of bacon weight from photographs, both of the fresh carcasses and of the cured bacon sides.

3. The judges did not show a high level of agreement in their rankings of the gammons. Although the overall rankings by the panel of the gammons on the fresh carcasses and on the bacon sides were similar, neither ranking was related to the composition or yield of the gammons.

4. The judges showed better agreement in their rankings of photographs of the cut surfaces of these 10 gammons and the cross-sections of the cooked gammons produced from them; in this case their preferences were related to the lean content of the gammons.

5. A second trial in which 25 judges scored 12 actual bacon sides for the quality of their gammons showed an even lower level of agreement between the judges' rankings, and again there was little agreement between the overall rankings of the panel and the results of dissections.

In mammals ‘maleness’, i.e. the presence of testes, is thought to be controlled by a single gene on the Y chromosome. Recently, a candidate gene termed the SRY (sex-determining region Y) gene has been located. If the SRY gene is the gene causing maleness then a transgenic male with the SRY gene on an autosome would produce a greater proportion of male offspring than a normal male. This would be advantageous in situations where male offspring are more valuable than females. Such transgenic males have a reduced probability of propagating their genotype and an effort has to be made to avoid their extinction. This is at the cost of genetic progress which must be made to enable the transgenics to remain competitive with normal males.

In a simulated beef cattle breeding scheme if half of the annual matings were made to transgenics then after 15 years of selection the transgenic males fell the equivalent of 2·6 years of selection behind males in a traditional herd. If all matings were made to transgenics they fell over 9 years behind. Selection for lean food conversion ratio was considered as an example. After 15 years of selection the gain in biological efficiency from more male offspring outweighed the loss from reduced genetic progress only when more than 0·5 of the bulls used in the breeding scheme were normal males. In practice, the difficulty of maintaining a small population of transgenic males along with other costs not included in the calculations suggest that breeding schemes in beef cattle with an SRY transgene would not be practicable without further technology.

Two experiments, involving 144 and 168 pigs weaned at 22 to 31 days, to investigate the response to inclusion of copper (CuSO4.5H2O), copper plus carbadox/sulphadimidine or copper plus avoparcin supplements in starter and grower diets were made. The carbadox and sulphadimidine levels were 50 and 100 mg/kg diet respectively in both diets. Avoparcin was included at 40 mg/kg in the starter diets and 20 mg/kg in the grower diets. In the first experiment the levels of copper were either 180 or 340 mg/kg in the starter diets and either 90 or 270 mg/kg in the grower diets. In the second experiment the levels were either 20 or 180 mg/kg in the starter diets and either 10 or 180 mg/kg in the grower diets.

In the starter period of the first experiment, supplementation with carbadox/sulphadimidine or avoparcin proportionately increased the rate of growth by 0·41 and 0·07 respectively in relation to supplementation with 340 mg copper per kg diet (P < 0·05). Neither supplement improved growth rate in the grower period. In the second experiment there were no significant differences in growth rate. However the rates of growth in both the starter and grower periods were higher in pigs receiving carbadox/sulphadimidine than in those receiving avoparcin, while these in turn grew slightly faster than those receiving copper only.

Taking into account the costs of the supplements the inclusion of the carbadox/sulphadimidine supplement produced an economic benefit compared with the other treatments.

Data were available from 11 474 gilts performance-tested on 137 farms. The data were analysed to provide pooled within-farm sire component estimates of h2 and genetic correlations.

Estimates of h2 of 0·43 ± 0·10, 0·44 + 0·09 and 0·49 ±009 were obtained for weight for age, C + K and shoulder fat depths respectively in 3583 gilts in 49 Large White herds. Comparable Landrace values derived from 2810 gilts in 43 herds were 0·44 + 0·11, 0·40 ±0·10 and 0·51 ±0·12 respectively. Estimates were consistent from herd to herd.

Estimates of h2 made on data from 5081 crossbred pigs, of mainly Large White and Landrace parentage, varied with herd from 0·10 to 0·40 for weight for age and from 0·08 to 0·96 for shoulder fat depth. Significant differences between breeds were found for the genetic correlations between weight for age and the fat depths, and between shoulder and mid-backfat depths. The variance was partitioned into various components. For index score, the within-herd variance averaged 73% of the total variance.

The mean daily water intakes of individually penned wether sheep were determined over consecutive 7-day periods. Increased intakes of dry matter and/or crude protein resulted in higher intakes of water. The drinking pattern throughout the day was directly related to the type of food offered and its distribution during the day.

Pre-weaning growth data from 3822 calves reared in 11 Victorian herds were analysed. The results suggested that the superiority of males (bulls) over castrated males (steers) in pre-weaning growth was due, at least partly, to the early castration of poorly growing male calves, i.e. to the effects of early selection. The extent of this selection bias was further examined using results from similar studies and from experiments in which bulls and steers were selected without bias. These studies strongly supported the view that the superiority of bulls over steers was primarily due to selection and not to sex effects. If sex did influence the bull-steer difference it was of no statistical or practical importance.

In the Victorian data, the ratio of bulls to steers was higher in subclasses in which average growth rates were higher. When selection effects are correlated in this way with other environmental effects such as age of dam effects further biases may arise in estimation of those effects and hence in individual or mass selection.

The results indicated, therefore, that unless bulls and steers are treated as one sex biases can arise in both individual selection and progeny selection.

1. Two trials were carried out to investigate the effects of high-copper supplementation of isonitrogenous diets containing either white-fish meal or soya bean meal as the sole protein supplement.

2. There was no difference in performance between the two diets when they were fed unsupplemented with copper in trial 1. The addition of 250 mg copper per kg diet significantly and similarly improved performance on both diets.

3. Liver-copper stores, but not kidney-copper stores, were significantly increased when the copper-supplemented diets were fed. The level of the liver-copper stores on the soya bean meal supplemented diet was, however, some 400g/kg less than that on the white-fish meal supplemented diet. The significance of this clearly established finding is discussed.

Fifty-four multiparous Yorkshire × Landrace sows were allocated equally to receive an intramuscular (i.m.) injection of 3 ing oestradiol-17β (E2) or no injection at 112 days of gestationto determine the effect of E2 on the timing and duration offarrowing. All sows received an injection (i.m.) of 10 mg prostaglandin F2x af 113 days of gestation. Of the soivs allocated to treatment, 21 oestrogen-treated and 19 control sows were assigned to be observed for the onset of parturition. A further six oestrogen-treated and eight control sows were included to increase the data base for litter production. The time of piglet delivery was monitored between 08·00 and 18·00 h on day 114 of gestation. Blood samples were obtained from each offour piglets from four E2-treated and five control litters. More E2-treated (8/21) than control sows (1/19) farrowed before 08.00 h of day 114 (P < 0·05) although, for those sows farrowing during the observation period, there was no effect on the time to onset or duration of parturition. Plasma oestradiol concentrations were higher (P < 0·06) in piglets delivered by E2-treated sows. However,this was not associated with any effect on piglet pre-weaning survival. It is concluded that exogenous oestradiol can influence the timing of onset offarrowing in some sows. Although further refinement in terms of timing of E2 injections is required, it seems likely that exogenous E2 may have a useful role to play in hastening the induction of parturition in sows.

An abrupt fall in live weight of grazing cattle occurs at the beginning of the growing season in the seasonally dry tropics. In an experiment with grazing crossbred bulls in central Tanzania designed to monitor changes in gut fill, 16 were slaughtered in the dry season and 14 in the early wet season. Bulls were measured and weighed before, and weighed after, a 20-h fast and then slaughtered. Gut fill was measured and empty body weight (EBW) calculated.

During fasting, the ratio gut fill/EBW fell from 0·291 to 0·217 in the dry season and from 0·207 to 0·119 in the wet season. Heart girth/EBW1/3 was 0·2577 and 0·2567 m/kg1/3 in the dry and wet seasons respectively.

It was concluded that live weight before or after fasting is seriously affected by season and can give biased predictions of EBW change. On the other hand, heart girth is little affected by season and can be used to monitor relative increases or decreases of EBW within animals.