bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Bayesian inference in the comparison of lactation curves of Merino ewes
Authors: Groenewald P. C. N. , Ferreira A. V. , van der Merwe H. J. , Slippers S. C. 
Published: September 2010

AbstractBayesian theory is applied to compare the characteristics of the estimated lactation curves of two groups of 5-year-old Merino ewes. The diets of the two groups were supplemented respectively by DL-methionine and maleyl-DLmethionine. The purpose is to illustrate the Bayesian approach when analysing for the effect of supplement on the lactation pattern of the sheep. Using Wood's model, the posterior distributions of the model parameters are determined for the two groups. This is achieved by assuming a hierarchical Bayes model and applying the Gibbs sampler, a sampling based computer intensive algorithm that is very efficient in obtaining marginal distributions of functions of parameters. The Gibbs sampler enables us to obtain marginal posterior distribution of characteristics of the lactation curve such as peak yield, time of peak yield, persistency and total milk yield. The results are notable differences in the marginal posterior distributions of mean peak milk yield and mean total yield. The posterior probability that the mean peak milk yield of the group supplemented by maleyl-DL-methionine is higher than that of the group with DL-methionine supplement is 0·98, while the same probability for mean total yield is 0·83.
A comparison of ovulation rate and late embryonic mortality in ewe lambs and ewes and the rôle of late embryo loss in ewe lamb subfertility
Authors: Beck N. F. G. , Davies M. C. G. , Davies B. 
Published: September 2010

AbstractAn investigation was conducted to compare late embryonic losses in ewe lambs and ewes and to determine the effect of inducing embryonic mortality on day 15 of pregnancy on reproductive function in ewe lambs. Ovulation rate and embryo survival were determined, at 15 and 30 days after mating, in a total of 83 ewe lambs and 67 ewes. Ovulation rate was lower, at spontaneous oestrus, in ewe lambs (1·07) than in ewes (1·25; P < 0·05). There was no difference in embryo survival at day 15, as 79% of ewe lambs and 80% of ewes contained expanded conceptuses. However, embryo survival was lower in ewe lambs (69%) than ewes (88%) at day 30 (P < 0·05). Embryonic mortality was induced in an additional 18 ewe lambs with an intrauterine injection of colchicine on day 15 post mating. Four of these animals had normal length oestrous cycles, six had inter-oestrus intervals ranging from 22 to 35 days and eight did not return to oestrus. Overall, the results of this study demonstrate that low ovulation rate and late embryonic losses make a significant contribution to subfertility in ewe lambs. Moreover, conceptus death is associated with luteal persistence, which may reduce reproductive performance by preventing remating.
Oestrus synchronization in ewes: the effect of combining a prostaglandin analogue with a GnRH agonist (buserelin)
Authors: Beck N. F. G. , Jones M. , Davies B. , Peters A. R. , Williams S. P. 
Published: September 2010

AbstractAn experiment was designed to determine whether an injection of 4 μg of the GnRH agonist buserelin (GnRH) followed, 5 days later, by an injection of 100 μg of prostaglandin F2α analogue (PGF), would give a level of oestrus synchronization and fertility comparable with a standard double dose PGF regime. A total of 200 Welsh Halfbred ewes were divided by live weight into two treatment groups using a system of random stratification during the 1994 breeding season. Ninety-one percent of the ewes treated with GnRH combined with PGF were mated by fertile rams within a 3-day period compared with 94% of ewes treated with two injections of PGF, 11-days apart. Returns to service for the two groups were 11·1% and 7·4%, respectively. There was no effect of treatment on lambing performance, as a similar percentage of ewes in the GnRH plus PGF group (88·8%) and the double dose PGF group (92·5%) lambed to synchronized oestrus. Gestation length, litter size and lamb birth weight were similar for both groups. These results demonstrate that GnRH combined with PGF will produce levels of oestrus synchronization and fertility comparable with a double dose PGF regime.
Effect of draught force and diet on dry-matter intake, milk production and live-weight change in non-pregnant and pregnant cows
Authors: Zerbini E. , Wold A. G. , Demissie D. 
Published: September 2010

AbstractEighteen F1 crossbred dairy cows (Friesian × Boran and Simmental × Boran) were allocated to one of three diet groups (H: natural pasture hay; H+3: natural pasture hay + 3 kg concentrate; and H+5: natural pasture hay + 5 kg concentrate) using a stratified random sampling procedure, with parity, milk production genotype, body weight and body condition score as blocking variables. Cows on each diet were then allocated to three draught forces (7, 11 and 15 kg draught force per 100 kg live weight) in a cross-over design to investigate relationships between work output, live-weight changes, dry-matter intake (DMI) and milk yield. Each cow worked for 36 days in early lactation (from calving to 90 days) and for a further 36 days in late lactation (from 250 to 340 days post partum). Work output was similar for cows on each of the three diets. Cows on the H diet consumed more hay than cows on H+3 and H−5 diets. Hay and total DMI, milk yield and milk fat were similar across draught forces and during working and resting days when the cows were not pregnant. Similar results were obtained when cows were from 82 to 172 days pregnant. Pregnancy did not affect the ability of cows to perform work at different intensities. During working days cows lost live weight both when pregnant and when non-pregnant. During rest days, non-pregnant cows on diets H, H+3 and H+5 compensated proportionately 0·12, 0·59 and 0·59, respectively, of the live weight lost during working days. Pregnant cows on diet H+3 and H+5 compensated proportionately 0·95 and 1·77 live weight, respectively. Lower total live-weight losses during the pregnant period could be attributed partly to relatively greater DMIs and lower milk production, but also to gestation. Prediction of live-weight change from total DMI above maintenance, milk yield and work output during periods of 6 working days was poor (R2 = 0·18). However, the same parameters explained adequately changes in live weight for supplemented and non-supplemented working cows (R2 = 0·38 and 0·79, respectively) during a period of 90 days.
Towards automatic interpretation of sheep ultrasound scans
Authors: Glasbey C. A. , Abdalla I. , Simm G. 
Published: September 2010

AbstractUltrasound imaging is widely used in animal breeding to provide in vivo estimates of the carcass composition of candidates for selection. Although the technique is less accurate than more recent medical imaging methods, such as X-ray computed tomography and magnetic resonance imaging, it is relatively cheap and mobile. Therefore large numbers of animals can be measured. Most current ultrasound scanners require some degree of manual interpretation of images, which is time consuming and liable to vary both between and within individuals. Hence, this study investigated the automatic interpretation of ultrasound scans from sheep. A computer algorithm is proposed for identifying tissue boundaries. Estimates of tissue depth are shown to be comparable with those obtained by manual interpretation, for images of 72 sheep scanned twice at the position of the 13th thoracic vertebra. The root-mean-square errors of subcutaneous fat depth and m. longissimus muscle depth ivere 0·7 mm and 1·7 mm, respectively.
Taql growth hormone gene polymorphism and milk production traits in Holstein-Friesian cattle
Authors: Falaki M. , Sneyers M. , Prandi A. , Massart S. , Corradini C. , Formigoni A. , Burny A. , Portetelle D. , Renaville R. 
Published: September 2010

AbstractThe positive effect of administration of growth hormone (GH) on milk production and its presence in selected dairy cattle lines of higher GH concentrations prompted an examination of the presence of restriction fragment length polymorphism (RFLP) in the growth hormone gene using the enzyme Taq/ and to investigate associations between this polymorphism and milk production traits. Blood was sampled from 251 Italian Holstein-Friesian cows. Three fragment bands, arbitrarily denoted A, B and E, of 6·2, 5·2 and 1·9 kilobase (kb), respectively, were observed. Their combinations exhibited six patterns, AA, AB, ABE, AE, BB and BE with frequencies of 64·5, 24·3, 2·4, 6·8, 1·4 and 0·4%, respectively. The statistical analysis was performed using linear mixed animal models. The results indicated an effect of the GHgene polymorphic Taq/restriction fragment on 305-day productions of milk, fat and protein; the low frequency pattern AE showed productions inferior to those for AA or AB patterns. Effect estimates of AA, AB and AE were, respectively, 200 (s.e. 215), 218 (s.e. 267) and -910 (s.e. 380) kg for milk production, 7·75 (s.e. 7·98), 16·10 (s.e. 9·79) and -22·14 (s.e. 14·42) kg for fat production, and 6·78 (s.e. 6·21), 8·57 (s.e. 7·58) and -20·74 (s.e. 11·14) kg for protein production. The average substitution effect estimates of E were -891 (s.e. 278), -26·56 (s.e. 10·16) and -24·50 (s.e. 9·43) kg for milk, fat and protein yields, respectively. In conclusion, these results suggest that the E fragment deserves further designed and specific study.
Milk acetone concentration as an indicator of hyperketonaemia in dairy cows: the critical value revised
Authors: Gustafsson A. H. , Emanuelson U. 
Published: September 2010

AbstractAcetone concentration in milk is correlated with subclinical and clinical ketosis and also with milk yield and reproductive efficiency. The purpose of this study was to assess a threshold of milk acetone at which cows tend to be adversely affected. The critical values were estimated on data from 11690 lactations where the change in daily milk yield from weeks 1 to 2 to weeks 5 to 6 of lactation was evaluated in relation to different milk acetone concentrations. Daily milk yield tended to be reduced in cows with acetone concentrations between 0·7 and 1·4 mmol/l, but responses were not entirely consistent. At concentrations >l·4 mmol/l, daily milk yield was clearly reduced. Long-term milk yield (day 0 to 100 and day 0 to 200) was about 190 kg of 40 g/kg fat-corrected milk (FCM) less in cows with acetone concentrations >l·4 vis-à-vis <0·7 mmol/l. Reproductive efficiency was also impaired in cows with acetone concentrations >l·4 mmol/l; 4·9 days longer interval from calving to first service (first parity and parity 2+ cows) and 5·7 times a greater risk of cystic ovaries (parity 1), compared with cows with milk acetone <0·7 mmol/l. However, no significant effects on long-term milk yield or on reproductive efficiency were found in cows with acetone concentrations 0·7 to 1·4 vis-à-vis <0·7 mmol/l. The results suggest that 1·4 mmol/l acetone in milk may be used as the most important critical value, as higher concentrations are detrimental to productivity. The interval 0·7 to 1·4 mmol acetone per I milk may be used as a warning class, since early lactation yield may be reduced.
Responses in gilt traits measured during performance test, at mating and at farrowing with selection for components of efficient lean growth rate
Authors: Kerr J. C. , Cameron N. D. 
Published: September 2010

AbstractThe responses in traits measured at the start of the mating period and at farrowing were examined after seven generations of divergent selection for daily food intake (DFI), lean food conversion (LFC), lean growth rate (LGA) on ad-\ibitum feeding and lean growth on scale feeding (LGS). Weight and backfat depth at mating were measured on 330 gilts and 74 boars, which were selected on the basis of performance test traits. Farrowing information was available on 259 gilts. At the start of the mating period, gilts selected for high DFI, LGA or LGS had similar live weights (135, 137 and 137 (s.e.d. 4·5) kg) but different backfat depths (20·3, 14·0 and 11·3 (s.e.d. 1·3) mm) while the corresponding low lines had different live weights (129, 117 and 124 kg), but similar backfat depths (17·5, 17·8 and 17·8 mm). Gilts selected for high LFC had lower mean live weight and backfat depth (114 kg and 10·7 mm) than gilts in the other selection lines. Conception rates of gilts selected for low DFI or high LGS were similar (0·62 and 0·64, s.e.d. 0·12) and lower than for the alternative selection strategies (0-78), but the low DFI gilts were significantly older at farrowing than gilts selected for high LGS (424 v. 408 (s.e.d. 5·5) days). Responses in live weight, backfat depth, age at mating and particular reproduction traits were selection strategy dependent, such that identification of relationships between growth and reproduction traits will require measurement of additional growth traits at an earlier age than in the current study
The effect of genotype and sex on the patterns of protein accretion in pigs
Authors: Thompson J. M. , Sun F. , Kuczek T. , Schinckel A. P. , Stewart T. S. 
Published: September 2010

AbstractProtein accretion curves were derived using food intake, growth and body composition data from a total of 320 pigs, which comprised castrated males and gilts from five genotypes. The 32 pigs from each genotype/sex subclass were offered ad libitum a series of isoenergetic diets (13·8 MJ metabolizable energy per kg) designed to provide a non-limiting intake of nutrients and to allow maximum protein deposition rates. Four pigs from each subclass weren slaughtered at each of the live weights (kg) 25, 44, 65, 85, 100, 115, 130 and 150. Daily food intake (dF/dt) was described as an increasing exponential function of age (t), live weight (W) as an increasing exponential function of cumulative food consumed (F), and protein weight (Pr) as an allometric function of live weight (W). The rate of protein accretion in the body of pigs [d(Pr)/dt] was calculated as d(Pr)/dt = (dF/dt).(dW/dF).(dPr)/dW). Bootstrap procedures were used to estimate standard errors for the food intake, growth and compositional parameters and to obtain the confidence bands for the dependent variables (dF/dt, W, Pr and d(Pt)/dt).Protein accretion rate as a function of live weight was curvilinear, increasing to a maximum, then decreasing with increasing live weight. There were significant differences between subclasses in the maximum rate of protein accretion, although there was no relationship between this rate and the live weight, stage of maturity, or age at which maximum protein accretion occurred. Describing protein accretion as a multiplicative function of food intake, food efficiency and the partitioning of nutrients in the body allowed changes in the magnitude and shape of the protein accretion curve to be ascribed to one, or a combination, of the above mechanisms.
Effect of energy intake on the performance of different types of pig from 45 to 100 kg body weight. 2. Tissue gain
Authors: Quiniou N. , Noblet J. , Dourmad J.-Y. 
Published: September 2010

AbstractThe effect of energy supply on physical composition of body weight gain between 45 and 100 kg was studied in Large White castrated males (cLW), crossbred Pietrain × Large White castrated males (cPPX) and boars (bPPX). The pigs were either given food ad libitum and kept in individual pens in experiment 1, or allocated to four energy levels (0·70, 0·80, 0·90, and 1·00 ad libitum) and kept in metabolism cages in experiment 2. Daily protein supplies were calculated to be the same at the four energy levels within each type of pig and non-limiting for growth. Five additional animals for each type of pig were slaughtered at 45 kg. Daily tissue gain was measured according to the comparative slaughter technique. The daily lean gain increased with metabolizable energy (ME) intake according to a linear-plateau relationship whereas the daily fat gain increased linearly. The type of pig significantly affected the slope of the relationship between lean gain and ME intake (from 15 to 22 g per extra MJ ME) but not the slope of the relationship between fat gain and ME intake (10 g per extra MJ ME on average). Increased energy intake was associated with increased fatness of body-weight gain, which was higher in cLW and cPP× than in bPP×.
The use of the excretion of nitrogen compounds as an indirect index of the adequacy of dietary protein in chickens
Authors: Fernández Fígares I. , Nieto R. , Aguilera J. F. , Prieto C. 
Published: September 2010

AbstractAn experiment was carried out to study the effect of changes in either the quality or the quantity of dietary protein intake on the excretion of nitrogen (N) compounds in the chicken. Thirty-two White Rock male broilers (1 day old) were raised in batteries and fed a commercial starter diet for 9 days. Then they were randomly divided into eight groups each of four birds, of similar body weight (mean live weight: 178 (s.e. 1·9) g), and individually housed in metabolism cages. Following a paired-feeding design based on metabolic body weight (kg M0·75), each group of birds was given, for an experimental period of20 days, each of four levels of protein (60, 120, 180 or 240 g/kg: 5 days each) in two groups of isoenergetic (14·5 kj metabolizable energy per g dry matter) and semisynthetic diets based on soya-bean meal, known to be first limiting in methionine, either unsupplemented (diets S) or supplemented with 2 g/kg DL-methionine (diets SM). Excreta were collected every 3 days for 48 h, frozen and stored at −20°C. The excreta samples were subjected to chemical analysis for uric acid by a rapid high-performance liquid chromatographic method, for urea and ammonia by a colorimetric method, and for total N by the Kjeldahl procedure. In general, the excretion of major N compounds was markedly affected by either the quality or the content of dietary protein. Overall, the excretion of total N, uric acid-N, ammonia-N and urea-N significantly (P < 0·05) decreased with improvement in dietary protein quality and significantly (P < 0·05) increased with increase in protein intake. Regression equations were obtained relating the excretion of uric acid, urea, ammonia and total N on protein supply. For the partition ofN compounds output, the ratios of uric acid-N and ammonia-N to total N significantly (P < 0·05) decreased on improving dietary protein quality and increased or remained unchanged, respectively, with the increase in dietary protein content. The use of the ratio of ammonia-N to total N is recommended as a rapid, easy and accurate indicator of dietary protein adequacy, as an alternative to measures based on total N balance, without the need for separation of urine and faeces.
Production, fertility and hatchability of ostrich (Struthio camelus) eggs on a farm in the United Kingdom
Authors: Deeming D. C. 
Published: September 2010

AbstractThe farming of ostriches is well established in South Africa and is gaining in popularity in agriculture around the world but few scientific data are available for rates of egg production and the factors affecting incubation and hatching. Production and hatchability of over 1200 ostrich eggs on a farm in the United Kingdom were recorded during the 1995 season. Females of breeding ages (no. = 43) were kept in 13 enclosures in sex ratios of 1: 1 or 1: 2 (M: F). Productivity of all ostriches over the laying season was 25·2% although when results from individual enclosures, and from individual birds, were examined higher rates of production were achieved although only one bird achieved her full laying potential. As group size increased productivity decreased. Overall fertility was 78·7% although fertility greater than 90% was achieved by females kept in pairs or trios. Larger group sizes had lower fertility. Mean weekly hatchability was only 24·1% with hatch of fertile eggs being 31·9%. Maximum hatchability of eggs produced from an individual female was 73% of fertile eggs. Microbial contamination of eggs was 32·6% and this was the biggest cause of failure to hatch, although rates of contamination varied between females. These results for productivity are similar to those published for ostriches in Israel and South Africa. Hatchability is lower, and microbial contamination is higher than published information although this is the most comprehensive study of ostrich production yet published. Future development of ostrich breeding programmes needs to concentrate on small breeding groups, preferably pairs, and on improvements in nest site hygiene and post-laying egg management.
Customized selection indices for dairy bulls in Australia
Authors: Bowman P. J. , Visscher P. M. , Goddard M. E. 
Published: September 2010

AbstractCustomized sire selection indices were developed for Australian dairy bulls in order to promote more objective use of estimated breeding values in commercial breeding programmes. It was assumed that the breeding goal for commercial dairy farmers is the profitability of a bull's progeny. Seven characteristics of the progeny were identified as having a major impact on profitability and were included in the breeding objective: milk, fat and protein yield, survival, body weight, milking speed and temperament. Traits in the selection indices used to predict profit were milk, fat and protein yield, survival, milking speed, temperament, size, overall type and fore teat placement. Size was included because of its correlation with body weight, and overall type and front teat placement because of their correlation with survival. To avoid double counting the benefits of milk production traits, temperament and milking speed, the survival trait in the objective was defined as survival independent of voluntary culling for these traits. Customization of the breeding objective was achieved by adjusting the economic weights for traits in the objective to take account of important characteristics of farmers' herds, the milk payment system under which they operate and make allowance for their own value judgements. An assessment of the impact of customization suggested that, even though there is a wide range in the economic weights that are applicable in different areas of Australia, there would be little loss of efficiency in using a single national index. However, customization is still believed to be desirable given that it is likely that a substantial proportion offarmers will be reluctant to use a national index, especially in those states which have quotas and focus on the liquid milk market. The algorithms described in the paper have been incorporated into a user-friendly microcomputer program called $electabull which is now commercially available to farmers.