不同细度类型细羊毛纤维直径变异研究

共采集150个中国美利奴羊（新疆型）3个细度类型（18 μm以下、18～20 μm及20 μm以上）羊毛样本，分析了沿毛丛长度方向及毛丛内纤维间直径变异。结果表明，不同细度类型羊毛沿毛丛方向纤维直径有相似的变异规律且与饲草料资源的季节性变化吻合，但细度18 μm以下羊毛纤维直径变异最小（P<0.01）；相反地，毛丛内纤维间直径变异随羊毛细度的降低而增大（P<0.01）。     

环境因素对甘肃高山细毛羊羊毛生产和羊毛品质影响的研究

本试验通过对甘肃高山细毛羊穿上罩衣来控制环境因素.提高绵羊生产性能和羊毛品质,结果表明,控制环境因素后,羊毛净毛率提高30.57%,个体净毛量提高22.68%,毛丛污染深度降低71.83%,油汗长度提高47.06%,毛条制成率提高20.39%,同时提高了羊毛长度。因此,控制环境因素,对提高绵羊个体产毛量和羊毛品质是一项很有效的措施。     

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。     

低温高湿地区半细毛含脂率及羊毛品质月度动态变化研究

采集云南低温高湿地区昭通永善马楠种羊场２４只４８－５０＇ｓ半细毛羊一年生长期内各月的羊毛样品，分析羊毛的含脂率及羊毛品质指标的月度动态变化。结果得出，该地区原毛含脂率一个生长年度内在１１８９％～１４６０％范围内变动；原毛含脂率随羊毛的增长而增加，但月份间变化不显著；提示雨季雨水对羊毛冲刷的影响不显著。原毛含脂率变化对羊毛单纤维绝对强度、鳞片数和纤维直径影响不大；而随原毛含脂率月度的变化，羊毛洁白度、ｐＨ值、羊毛伸长度和含脂毛长相应变化。ｐＨ值和含脂毛长随原毛含脂率的增加而增加，羊毛洁白度随原毛含脂率的增加而下降，而羊毛伸长度的变化规律与原毛含脂率相反。羊毛纤维直径在一个生长年度内相对稳定，未出现随羊毛毛丛长度增长而增加的现象。原毛含脂率与这些指标的变化规律为育种中含脂量的选择提供了理论依据。     

新疆阿克苏地区羊驼毛品质分析

试验旨在研究阿克苏地区引进羊驼的毛绒品质现状。采用相关方法标准对新疆阿克苏地区塔格拉克牧场引进的158只羊驼进行平均纤维直径、毛丛自然长度、净毛率、单纤维强力、原毛油脂含量及卷曲指标的测定，统计分析性别、年龄、被毛颜色对测定指标的影响。结果表明，阿克苏地区引进羊驼毛平均纤维直径23.36 μm，毛丛自然长度106.14 mm，净毛率80.90%，断裂强力8.04 cN，断裂伸长百分比40.11%，原毛油脂含量2.08%，卷曲6.70个/2.5 cm。不同性别的羊驼毛丛自然长度、净毛率、原毛油脂含量差异显著（P<0.05）；不同年龄的羊驼纤维直径、毛丛自然长度、断裂强力及原毛油脂含量差异显著（P<0.05）；不同被毛颜色的羊驼毛丛自然长度、纤维直径、原毛油脂含量及卷曲差异显著（P<0.05）。综上可知，阿克苏地区引进的羊驼在纤维直径、毛丛自然长度方面较优良，且性别、年龄、被毛颜色对羊驼毛纤维遗传性状存在显著影响。     

波德代羊羊毛品质分析研究

通过对波德代羊毛纤维的自然毛丛长度、伸直长度、细度、强伸度的试验研究，表明：成年波德代羊毛自然毛丛长度公羊为17．08cm，母羊为14．79cm；羊毛细度公羊为31．9μm，母羊为28．37μm；羊毛强度公、母羊分别为35.13cN、33.73cN；伸度公、母羊分别为51．54％、51．91％；羊毛油脂率公、母羊分别为12．51％、11．03％；净毛率公、母羊分别为68.26％、65．71％。     

影响羊毛品质的因素及控制措施

文章从羊毛检测的参数出发,包括纤维细度与离散、毛丛长度、净毛率、强力、弹性、色度6个方面,分析了影响羊毛品质的因素,并提出了相应的控制措施。     

高山美利奴羊个体毛样采集与检测分析

本文主要对选拔优质高山美利奴羊进行毛样采集，从而开展羊毛毛丛自然长度、细度、净毛率等实验室检测。对选优羊只个体进行一一采集或者抽样采集的办法，掌握羊毛品质具体情况。毛样采集与检测是育种指标中重要组成部分，也是掌握羊毛品质关键所在。通过分析，选拔更优质细毛羊来育种与推广。     

中国美利奴羊超细型羊毛理化性能研究及灰评估

测定中国美利奴羊超细型羊毛理化性能,并与主要经济性状进行相关性分析,运用灰色理论评估不同品系羊毛品质。研究结果表明,超细型羊羊毛纤维直径极显著低于其它品系（P<0.01）;弯曲数显著提高（P<0.05）;纤维直径与其它各性状间均不相关（P>0.05）;毛丛长度增加,净毛量随之增加（P<0.05）;弯曲数增加,抗压缩弹性增强（P<0.01）;净毛光泽度、白度、黄度间呈显著正相关（P<0.05）。超细型羊毛综合品质优良,在本品种内品质较高。     

中国美利奴多胎肉用细毛羊羊毛品质分析

对正在培育的中国美利奴多胎肉用细毛羊的羊毛品质做了综合分析.在毛丛自然长度方面，断奶公羔为4.37cm，母羔为4.43cm，周岁公羊为12.60cm，周岁母羊为11.47cm；羊毛的伸直长度周岁公羊为15.01cm.周岁母羊为14.86cm；羊毛纤维直径周岁公羊为21.67μm.周岁母羊为20.36μm；羊毛密度周岁公羊为5212根/cm^2.周岁母羊为5430根/cm^2.比2002年中国美利奴羊周岁羊相比还有较大差距；羊毛净毛率周岁公羊为64.60％.周岁母羊为65.64％。由上可知.除羊毛密度外.中国美利奴多胎肉用细毛羊总体上符合品种培育的要求.在今后的选育中要注意羊毛密度的提高。     

基于广义回归神经网络的羊毛性状预测

凉山半细毛羊初生到断奶的5个生产性状（羔羊初生重、羔羊断奶重、初生-断奶日增重、断奶毛长度、断奶毛细度）预测成年羊毛（2．5年）的3个生产性状（成年剪毛量、成年毛长度、成年毛细度）,用Matlab6．5软件构建广义回归神经网络预测模型,并通过预测结果和实测结果的统计分析验证本研究所构建的广义回归神经网络预测模型的有效性。预测结果和实测结果的统计分析结果显示该预测模型具有较高的准确性,基于广义回归神经网络构建的预测模型在凉山半细毛羊成年羊毛3个性状上的预测被证明是有效的。     

广义回归神经网络在凉山半细毛羊成年性状早期预测中的应用研究

通过凉山半细毛羊初生到断奶的5个生产性状:羔羊初生重、羔羊断奶重、初生至断奶日增重、断奶毛长度、断奶毛细度,预测成年(2.5年)的2个生产性状:成年体重、成年剪毛量。用Matlab7.1软件建立广义回归神经网络,并通过预测结果和实测结果的统计分析验证了所构建的广义回归神经网络的有效性。结果显示,该预测模型具有较高的准确性,可以快速高效地预测羔羊成年后的体重和剪毛量,为羔羊的选育和养殖场经济的预算提供依据。     

BP神经网络在凉山半细毛羊成年生产性状早期预测中的应用研究

用matlab软件建立BP神经网络,通过凉山半细毛羊初生到断奶的5个生产性状(羔羊初生重、羔羊断奶重、初生至断奶日增重、断奶毛长度、断奶毛细度)预测成年(2.5年)的2个生产性状(成年体重、成年剪毛量),并通过预测结果和实测结果的统计分析验证了所构建的BP神经网络的有效性,预测结果和实测结果的回归分析相关系数(R)分别为0.74和0.711,为羔羊的选育和养殖场经济的预算提供依据。     

Responses to betaine and inorganic sulphur of sheep in growth performance and fibre growth

Sulphur‐containing amino acids (SAA) are essential and usually the first limiting amino acids for growth, milk and wool production. The keratin fibre that grows from epidermal tissue is rich in SAA. The rate of fibre growth and its S content are influenced by the availability of SAA. Betaine is a dietary source for a labile methyl group and actively participates in methionine metabolism by donating methyl groups for the remethylation of homocysteine to methionine. Ruminants are capable of synthesizing SAA from inorganic S sources, and most bacteria in the rumen can use inorganic S to meet their requirements for growth. The objective of this study was to examine whether betaine and an inorganic sulphur supplement could provide methyl groups and sulphur amino acids in a way that growth performance and wool production of ewes and lambs are improved. Treatments performed included betaine supplementation, sulphate supplementation and betaine plus sulphate supplementation with five replications for each treatment. The dry matter intake of the ewes was affected by betaine plus sulphate supplementation (p < 0.05). In the ewes, betaine plus sulphate supplementation increased (p < 0.05) the wool growth rate, wool yield, staple length and wool sulphur concentration, while decreasing wool wax and wool yellowness (p < 0.05). In the lambs, wool growth rate, wool yield, fibre diameter, staple length, staple strength, wool sulphur concentration, wool wax and fibre percentage did not differ (p > 0.05) between treatments. In the ewes, plasma methionine concentration increased (p < 0.05) with betaine plus sulphate treatment. No corresponding difference (p > 0.05) was observed in plasma methionine concentration in the lambs. It can be concluded that betaine plus sulphate supplementation has the potential to change wool characteristics in the ewes, while these compounds were without any effect on growth and wool production of the lambs. Combining the two supplements was advantageous.     

用MTDFREML估计中国美利奴羊(新疆型)产毛性状的遗传参数

利用新疆巩乃斯种羊场饲养的2001-2005年出生的5 425只中国美利奴羊(新疆型)周岁资料,采用动物模型多性状非求导约束最大似然法(MTDFREML),估计了中国美利奴羊(新疆型)在新疆自然条件下产毛性状的遗传参数.结果表明:毛长度、剪毛后体重、产毛量和纤维直径的遗传力估计值分别为0.13、0.29、0.22和0.36.     

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.     

OBSERVATIONS ON FIBRE DIAMETER VARIATION OF SHEEP IN RELATION TO FLEECE-ROT AND BODY STRIKE SUSCEPTIBILITY

SUMMARY: A comparative study of various fleece properties known to influence fleece-rot susceptibility was made in a merino flock consisting of sheep which were found to be either resistant or susceptible to fleece-rot and body strike following heavy rains. The fleece properties measured were fibre diameter, fibre diameter variation, wax content, suint content, wax to suint ratio, suint pH, insoluble nitrogen content, wool colour and wettability. Fibre diameter variation, due mainly to the presence of coarse, secondary fibres in the staple, was the only fleece property which differed significantly (p < 0.001) between resistant and susceptible animals. The coefficient of variation of fibre diameter was lowered from a mean value of 22.7 ± 0.3% in susceptible sheep to 20.0 ± 0.3% in resistant sheep. A causal relationship between high fibre diameter variation and fleece-rot susceptibility is suggested. Sheep with irregular fibre size may retain free moisture in the fleece for longer, and thereby become more susceptible to fleece-rot than sheep with uniform fibre diameter, other predisposing factors being equal.     

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.