Heritabilities and genetic correlations for live weight and fibre traits in New Zealand Cashmere goats

Data were obtained at Whatawhata on the growth of goats to the yearling stage and on their cashmere production as hoggets. There were 884 animals recorded from the 1985 to 1989 birth years, comprising the progeny of 60 sires. Records from kid shearings were also obtained in the last two years. Mixed-model restricted maximum likelihood (REML) models were fitted. Heritabilities from yearling fleece records were 0.42±0.13 for fleece weight, 0.57±0.15 for yield, 0.62±0.15 for down weight, 0.35±0.12 for guard hair weight, 0.99±0.19 for down fibre diameter and 0.57±0.15 for mean down length; corresponding values from kid fleeces (23 sires only) were smaller in most cases than from yearlings, being respectively 0.14±0.06, 0.19±0.07, 0.20±0.07, 0.04±0.04, 0.19±0.07 and 0.87±0.29. The phenotypic and genotypic correlations between down weight and fibre diameter in yearlings were 0.50±0.03 and 0.81±0.08 respectively, representing an unfavourable relationship when selecting for heavier but finer down. The genetic correlations of yearling weight with down weight and down fibre diameter were slightly negative (−0.34 and −0.25), but the estimates were non-significant.     

A review of genetic parameter estimates for wool, growth, meat and reproduction traits in sheep

Genetic parameters for a range of sheep production traits have been reviewed from estimates published over the last decade. Weighted means and standard errors of estimates of direct and maternal heritability, common environmental effects and the correlation between direct and maternal effects are presented for various growth, carcass and meat, wool, reproduction, disease resistance and feed intake traits. Weighted means and confidence intervals for the genetic and phenotypic correlations between these traits are also presented. A random effects model that incorporated between and within study variance components was used to obtain the weighted means and variances. The weighted mean heritability estimates for the major wool traits (clean fleece weight, fibre diameter and staple length) and all the growth traits were based on more than 20 independent estimates, with the other wool traits based on more than 10 independent estimates. The mean heritability estimates for the carcass and meat traits were based on very few estimates except for fat (27) and muscle depth (11) in live animals. There were more than 10 independent estimates of heritability for most reproduction traits and for worm resistance, but few estimates for other sheep disease traits or feed intake. The mean genetic and phenotypic correlations were based on considerably smaller numbers of independent estimates. There were a reasonable number of estimates of genetic correlations among most of the wool and growth traits, although there were few estimates for the wool quality traits and among the reproduction traits. Estimates of genetic correlations between the groups of different production traits were very sparse. The mean genetic correlations generally had wide confidence intervals reflecting the large variation between estimates and relatively small data sets (number of sires) used. More accurate estimates of genetic parameters and in particular correlations between economically important traits are required for accurate genetic evaluation and development of breeding objectives.     

人工草地绵羊放牧系统研究—产羔期试验

试验监测了在划区轮牧条件下的放牧系统中两种产盖期中的牧草生长速度、绵羊采食量以及绵羊生产性能等有关指标的动态变化，探讨了两种产羔期对放牧系统中草地和绵羊产生的影响。     

Genetic correlations among and between wool, growth and reproduction traits in Merino sheep

Summary Data from seven research resource flocks across Australia were combined to provide accurate estimates of genetic correlations among production traits in Merino sheep. The flocks represented contemporary Australian Merino fine, medium and broad wool strains over the past 30 years. Over 110 000 records were available for analysis for each of the major wool traits, and 50 000 records for reproduction and growth traits with over 2700 sires and 25 000 dams. Individual models developed from the single trait analyses were extended to the various combinations of two-trait models to obtain genetic correlations among six wool traits [clean fleece weight (CFW), greasy fleece weight, fibre diameter (FD), yield, coefficient of variation of fibre diameter and standard deviation of fibre diameter], four growth traits [birth weight, weaning weight, yearling weight (YWT), and hogget weight] and four reproduction traits [fertility, litter size, lambs born per ewe joined, lambs weaned per ewe joined (LW/EJ)]. This study has provided for the first time a comprehensive matrix of genetic correlations among these 14 wool, growth and reproduction traits. The large size of the data set has also provided estimates with very low standard errors. A moderate positive genetic correlation was observed between CFW and FD (0.29 ± 0.02). YWT was positively correlated with CFW (0.23 ± 0.04), FD (0.17 ± 0.04) and LWEJ (0.58 ± 0.06), while LW/EJ was negatively correlated with CFW (−0.26 ± 0.05) and positively correlated with FD (0.06 ± 0.04) and LS (0.68 ± 0.04). These genetic correlations, together with the estimates of heritability and other parameters provide the basis for more accurate prediction of outcomes in complex sheep-breeding programmes designed to improve several traits.     

运用贝叶斯方法估计中国美利奴羊(新疆型)毛用性状及繁殖性状的遗传参数

为了解中国美利奴羊（新疆型）近年来遗传结构的变化趋势以及探讨毛用性状与繁殖性状的遗传关系,需要进一步研究这些性状的遗传力以及它们之间的关系。本研究收集额敏县聚鑫细毛羊养殖专业合作社1985-2018年中国美利奴羊（新疆型）共计9 428只羊毛生产记录和1987-2018共计5 887只年繁殖记录,运用BLUPF90软件结合Gibbs抽样方法,利用单性状模型对中国美利奴（新疆型）毛用性状（细度支数、等级、总评分、毛长、污毛重和鉴定时体重）和繁殖性状（配种次数、妊娠天数、胎产羔数和总产羔数）进行方差组分和遗传力估计,利用双性状模型分析毛用性状与繁殖性状之间的遗传相关与表型相关。结果显示,中国美利奴羊（新疆型）毛用性状细度支数、等级、总评分、毛长、污毛重、鉴定时体重的遗传力估计值分别为0.471±0.020、0.088±0.030、0.114±0.018、0.426±0.025、0.328±0.041、0.317±0.046;繁殖性状配种次数、妊娠天数、胎产羔数及总产羔数的遗传力估计值分别为0.056±0.009、0.022±0.010、0.120±0.018、0.163±0.016;毛用性状与胎产羔数、总产羔数之间的遗传相关范围为-0.031~0.286,鉴定时体重与胎产羔数（0.286）、总产羔数（0.204）遗传相关最高,细度支数与胎产羔数（-0.143）、总产羔数（-0.048）呈负的遗传相关;毛用性状与胎产羔数、总产羔数之间的表型相关范围为-0.210~0.216,毛长与总产羔数（0.216）表型相关最高,细度支数与胎产羔数（-0.137）、总产羔数（-0.210）呈显著负表型相关。本研究结果发现,毛用性状与繁殖性状之间存在一定的关系,这一结果可为今后制定中国美利奴羊育种规划提供数据基础,为选育优质高产、繁殖性能好的细毛羊提供理论依据,从而进一步提高细毛羊产业经济效益。     

应用灰色关联度分析法评价放牧绵羊增重和羊毛生长的营养限制因素

本文应用灰色系统理论中的灰色关联度分析法,对影响放牧绵羊生产性能的主要营养限制因素进行了研究。关联度分析结果表明,饲粮粗蛋白质水平是影响绵羊体重变化的主要营养因素,饲粮代谢能的影响次之;影响育成母羊羊毛生长速度的主要营养因素是其干物质采食量;而成年母羊羊毛生长的营养限制因素是饲粮粗蛋白质水平。影响绵羊采食量的主要营养因素是饲粮代谢能浓度,其次是牧草质量。影响牧草消化率的主要营养因素是绵羊瘤胃发酵水平,其次是牧草中的木质素含量。     

微卫星座位与超细型细毛羊羊毛性状的关联性分析

本研究选取了绵羊基因组1号和3号染色体上的8个微卫星座位,对超细型细毛羊的232个个体的遗传多样性进行了检测。计算了各微卫星座位的等位基因频率（p）、杂合度（H）、多态信息含量（PIC）和有效等位基因数（N）。同时检测了研究样本的羊毛纤维直径（WFD）,毛纤维直径离散度（FD-D）,单纤维绝对强力（WAS）,单纤维相对强力（WRS）,强力离散（WSD）,单纤维自然长度（WNL）,单纤维伸直长度（WEL）和单纤维弯曲度（FW）等羊毛性状的8个表型数据。微卫星座位与羊毛性状表型数据的关联性分析结果表明,微卫星 BL-4和KRT2-13两个座位与WEL之间极显著相关（P<0.01）。微卫星Oarcp43座位与WSD之间、微卫星座位Bms1248与羊毛单纤维直径之间极显著相关（P<0.01）。座位Fcb5和OarDB6分别与FW和WAS表现出显著性关系（P<0.05）。     

Depression of productivity in sheep infected with Fasciola hepatica

The productivity of 24 Corriedale weaner wethers in eight groups of 3, artificially infected with a range of fluke burdens, was studied by measuring body weight change, midside patch wool growth, fleece weights and feed digestibility over a period of 24 weeks.Data from bodyweight and patch wool measurement and feed digestibility were analysed by regression procedures. All parasitised groups exhibited a reduction in growth rate, patch wool growth and fleece weight, when compared with the control groups. Reduction in feed conversion efficiency was detected in groups having mean burdens of 45, 67 and 117 flukes. Because groups with mean burdens of 230 or more flukes had reduced feed intake, and sheep in these groups died, the feed conversion information from these groups cannot be considered unequivocal.The group mean liveweight changes, patch wool growth and fleece weights were closely related to the mean number of flukes in the respective group. Prediction equations for wool growth rate and body weight gain in fluke infected sheep are presented.     

Genetic variation of plasma insulin-like growth factor-1 in young crossbred ewes and its relationship with their maintenance feed intake at maturity and production traits

The genetic variation of plasma IGF-I in crossbred ewe lambs postweaning was evaluated together with its potential use as a physiological marker for selection in meat sheep. Genetic variation for IGF-I was analyzed among 1,246 young crossbred ewes that were the progeny of 30 sires from various maternal breeds and Merino dams. The estimate of heritability of IGF-I was 0.28 +/- 0.10, with sire breed not being significant. Genetic correlations were estimated between IGF-I and performance traits of the ewes, including feed intake, growth, body composition, wool, and reproduction over 3 matings. Although the genetic correlations had high standard errors because of the limited size of the data set, the correlation between IGF-I and grazing feed intake of the mature ewes at maintenance was positive (0.32 +/- 0.31). The genetic correlations of IGF-I with other traits ranged from positive and low to moderate for growth (0.05 to 0.36), positive for ultrasound eye muscle depth (0.15), and negative for ultrasound fat depth (-0.12) in the mature ewes, and close to zero for the wool traits. The genetic correlation between IGF-I and the average number of lambs born per ewe mated was negative (-0.18), whereas that for the average number of lambs weaned per ewe mated was positive (0.10). The parameters indicated that genetic variation exists for IGF-I in sheep, and selection for low IGF-I in young ewes may result in some reduction in feed intake and improvement in maintenance efficiency of mature ewes under grazing, with little impact on other production traits. However, the genetic correlations had high standard errors, and more precise estimates of these parameters are required for genetic evaluation and to predict with confidence the outcome of breeding programs.     

Selection response to fleece weight,wool characteristics,and heritability estimates in yearling Romney sheep

The juvenile live weights, yearling fleece weight and wool characteristics of 2987 Romney progeny of 114 sires born over 9 breeding seasons in a fleece-weight-selected and a random control line were analysed. The high fleece weight-selected flock performance was higher (P < 0.001) for weaning weight and spring weight (6.9 and 8.4%), higher (P < 0.001) for greasy and clean fleece weight (23.8 and 24.3%), and also higher (P < 0.001) for FD by 1 μm, staple length by 6 mm, and wool yellowness by 0.3 unit than random control yearling sheep. Heritability estimates for weaning and spring live weight, greasy fleece weight, clean fleece weight, yield, fibre diameter, staple length, staple strength, loose wool bulk, brightness and yellowness were 0.15, 0.51, 0.35, 0.36, 0.40, 0.57, 0.41, 0.24, 0.46, 0.12 and 0.14 respectively. The heritability estimates are within the range of the long wool sheep breeds studied previously. The high selection differential achieved in the initial screening commercial flocks however facilitated to approach a selection response peak in a shorter selection duration and thus resulted in a non-significant genetic gain in greasy fleece weight when averaged over the 9 years of selection.     

Variance components due to direct genetic, maternal genetic and permanent environmental effect for growth and feed-efficiency traits in young male Japanese Black cattle

Variance components and genetic parameters were estimated using data recorded on 740 young male Japanese Black cattle during the period from 1971 to 2003. Traits studied were feed intake (FI), feed‐conversion ratio (FCR), residual feed intake (RFI), average daily gain (ADG), metabolic body weight (MWT) at the mid‐point of the test period and body weight (BWT) at the finish of the test (345 days). Data were analysed using three alternative animal models (direct, direct + maternal environmental, and direct + maternal genetic effects). Comparison of the log likelihood values has shown that the direct genetic effect was significant (p < 0.05) for all traits and that the maternal environmental effects were significant (p < 0.05) for MWT and BWT. The heritability estimates were 0.20 ± 0.12 for FI, 0.14 ± 0.10 for FCR, 0.33 ± 0.14 for RFI, 0.19 ± 0.12 for ADG, 0.30 ± 0.14 for MWT and 0.30 ± 0.13 for BWT. The maternal effects (maternal genetic and maternal environmental) were not important in feed‐efficiency traits. The genetic correlation between RFI and ADG was stronger than the corresponding correlation between FCR and ADG. These results provide evidence that RFI should be included for genetic improvement in feed efficiency in Japanese Black breeding programmes.     

不同营养水平对4～6月龄荷斯坦犊牛尿中嘌呤衍生物排出量的影响

本试验采用3头(120±5)日龄、体重为(72±2)kg的荷斯坦公犊牛,通过调整日粮营养水平来观察其尿中嘌呤衍生物(PD)的排出规律,比较其与成年反刍动物之间的差异,考察犊牛期能否用尿嘌呤衍生物法来估测瘤胃微生物蛋白。试验设计3种营养水平日粮,采用随机区组试验设计。结果发现,犊牛尿中嘌呤衍生物中尿酸大约为50%～75%,而在成年反刍动物尿酸不到15%。PD的排出量随可消化有机物(DOM)和可消化粗蛋白(DCP)进食量升高而上升,存在弱的相关性(R2=0.76,n=9)。其排出水平为0.12～0.24mmol/(BW0.75·d)。作为估测成年反刍动物微生物蛋白合成量的另一个指标[PD]×BW0.75/[C](其中[PD]为嘌呤衍生物浓度,[C]为尿中肌酐酸浓度,BW0.75为代谢体重,简称PDC),与DOM和DCP进食量存在负相关,这与成年反刍动物的研究结果是相反的。     

The effect of large doses of thiamine on the horse

Extract

In conjunction with a trial to determine the effect of nematode infestation upon the liveweight gain and wool production of young sheep (Brunsdon, unpublished), information was sought on the seasonal succession and availability on pasture of infective larvae of the principal trichostrongyle genera parasitic in sheep. Data were collected in the form of nematode populations found at postmortem examination of Romney lambs, previously maintained worm-free, which were exposed to risk of parasitism in the field. A series of these lambs ran with the flock in the above-mentioned trial and served as indicators of the abundance of infective larvae on the pasture.     

高山美利奴羊重要经济性状遗传参数估计

本研究旨在估计高山美利奴羊重要经济性状的遗传参数,为优化高山美利奴羊选育方案、建设品种完整结构、进行遗传评估及实施育种值选种提供理论技术支撑。采用甘肃省绵羊繁育技术推广站2003—2018年高山美利奴羊核心群数据资料,基于ASReml运用单性状个体动物模型和多性状个体动物模型估计高山美利奴羊体重、产羔数、产毛量、净毛量、净毛率、羊毛纤维直径、羊毛纤维直径变异系数、毛丛长度等重要经济性状的遗传参数。结果表明:高山美利奴羊产羔数为低等遗传力,其他所有性状均为中高等遗传力;大部分经济性状间呈正遗传相关,体重、产毛量、羊毛纤维直径与净毛率间呈负遗传相关,羊毛纤维直径变异系数与体重、产毛量、纤维直径呈负遗传相关。     

The combined effects of the provision of feed and healthcare on nutrient utilization and growth performance of sheep during the early or late dry season

An on-farm study was conducted to determine the combined effects of the provision of feed and healthcare on nutrient use and growth performance of sheep during the early or late dry season. A total of 36 smallholder sheep farmers with a flock size of ≤7 was randomly selected within each of the three administrative regions in Northern Ghana. The sheep grazed on a heterogeneous natural pasture and offered crop residues as basal diet (control) or were additionally provided with a concentrate feed plus orthodox healthcare to control diseases and pests (CH) in a completely randomized block design. The provision of orthodox healthcare included scheduled control of endo- and ecto-parasites and administration of broad-spectrum antibiotics. Data was analyzed for the fixed effects of CH, season, or CH × season using the mixed model procedure of Genstats^®. The CH regimen had no effect (P = 0.098) on intake of natural pasture but pasture intake increased (P = 0.012) during the late dry season. Sheep on the CH regime had higher DM (P = 0.026) and N (P = 0.068) digestibility and improved ADG (P = 0.001) and feed conversion efficiency (P = 0.020) than those on the control. We hypothesize that improvements in growth performance of sheep on the CH regimen could be related to availability of nutrients for growth that will otherwise have been used for repair of damaged tissues caused by gastrointestinal parasites and ticks. Sheep on the CH regimen also had a higher concentration of fecal N during the late dry season when CP concentration was relatively higher than that in the early dry season (63.2 vs 60.9 g/day DM) when CP concentration of pasture was lower.     

用食道瘘管测定放牧绵羊日采食牧草干物质量

采用食道瘘管技术与两级离体消化试验及外源指示剂Cr_2O_3测定日排粪量技术3结合的方法,在新疆南山夏秋两季牧场分别进行放牧中国美利奴细毛绵羊牧草干物质采食量的测定。测得夏牧场上18只放牧母羊采食牧草干物质量平均为96.02±7.408克/体重公斤~(0.75)和日排粪干物质量平均为38.72±4.20克/体重公斤~(0.75)。秋牧场上8只放牧母羊采食牧草干物质量平均为75.41±5.799克/体重公斤~(0.75)和日排粪干物质量为38.31±2.73克/体重公斤(0.75)。测得用3只食道瘘管羊采集夏秋牧场上牧草标样的干物质消化率分别为59.65±2.376％与49.02±5.538％,秋季采食牧草干物质量及消化率均显著大于秋季(p<0.001)。两季牧场的日排粪干物质量没有显著性差异(p>0.05)。     

陶赛特羊与青海半细毛羊杂交试验

试验在高寒牧区天然草地放牧条件下 ,测定陶×半细杂交一代羊出生到 4月龄和 6月龄的生长发育指标 ,结果表明 :在青海高原严酷的生态环境条件下 ,杂交一代羔羊生长发育快于青海半细毛羊 ,4月龄活重为 2 2 .73kg ,6月龄活重为 2 7.96kg ,分别比青海半细毛羔羊提高 3 .0 2kg、3 .64kg(P <0 .0 1)。体长、体高、胸围、胸宽、管围和尻宽显著高于青海半细毛羔羊 (P <0 .0 1)     

国毛毛丛直径形态特征的探讨

通过对毛丛直径形态的分析和研究来达到以下两个目的：一是了解羊毛在生长过程中毛丛中纤维细度的变化和原因，为羊毛生产者在育种和改进羊群管理方面提供一些科学试验依据；二是根据毛丛直径形态的特征，结合强力和断裂位置等原毛指标，来分析和判断在毛条加工过程中毛条的质量情况，如毛条中纤维的长度和长度分布等，来指导羊毛加工和生产。     

New infection with Corynebacterium pseudotuberculosis reduces wool production

SUMMARY The effect of natural Corynebacterium pseudotuberculosis infection on wool production and quality in sheep was examined in light of evidence that artificial C pseudotuberculosis infection causes wool production loss. A toxin ELISA was used to identify sheep that had been infected with C pseudo tuberculosis. Greasy and clean fleece weights and fibre diameter were compared in infected and uninfected sheep. C pseudotuberculosis infection caused a 3.8 to 4.8% decrease in greasy wool production and a 4.1 to 6.6% decrease in clean wool production. C pseudotuberculosis infection did not affect fibre diameter. The effects of caseous lymphadenitis (the disease caused by C pseudotuberculosis infection) cause an annual loss of about $17 million in wool production to the Australian wool industry.     

Digestible energy intake, dry matter digestibility and mineral status of grazing New Zealand Thoroughbred yearlings

AIM: To measure the nutritive value of pasture in terms of digestible energy intake (DEI) and dry matter (DM) digestibility, and to determine the effect of Ca, P, Cu, Zn, and Se supplementation on growth rate and degree of physeal swelling in Thoroughbred yearlings grazed on pasture. METHODS: Fourteen yearling horses were randomly allocated to 1 of 2 groups and rotationally grazed on a ryegrass/white clover pasture for 7 months. One group was supplemented daily with a mineral mix. Liveweight changes were recorded at fortnightly intervals and pasture mineral composition determined at monthly intervals. The DM intake (DMI) was determined from daily faecal DM outputs divided by the indigestible DM fraction (1 - digestible DM) determined from a digestibility study. The DEI was determined from the difference between the gross energy intake and the gross energy faecal output. The DM, gross energy content, crude protein (CP), soluble carbohydrate, acid detergent fibre (ADF), neutral detergent fibre (NDF), lipid and mineral composition of pasture offered and faeces were analysed and their digestibility or apparent absorption calculated. RESULTS: The DM digestibility of pasture averaged 0.64 while the daily DMI and DEI of a 350 kg yearling, gaining 0.6 kg liveweight/day, averaged 6.9 kg DM/day and 78 MJ DE/day, respectively. The mineral supplement had no significant effect on the growth of yearlings grazing pasture that had a mineral composition of (g/kg DM) Na 0.17, K 32.8, Ca 3.6, P 3.4, Mg 2.1, S 3.0, and (mg/kg DM) Cu 7.9, Fe 177, Mn 83, Zn 28 and Se 0.016. Plasma Se was elevated (e.g. 40-218 microg/l) by Se supplementation while Cu supplementation had no effect on plasma and liver Cu concentrations. Physeal swelling was observed in all horses, regardless of treatment. CONCLUSION: Good quality ryegrass/white clover pasture that had a DE content of 11.3 MJ/kg DM and adequate mineral composition (as observed in this study, with the possible exception of Se) will provide an adequate intake of nutrients to ensure good growth in yearling horses.