若干因素对粗毛型长毛兔粗毛率的影响

季节对粗毛率和产毛量有影响，夏季的粗毛率最高，为２８．１３％，比春、秋、冬三季分别高１３．３４％（Ｐ＞０．０５）、５８．０３％（Ｐ＜０．０１）、８８．６７％（Ｐ＜０．０１）。产毛量以夏季最低，为１２５．６克，比春、秋、冬三季分别低５６．０５％（Ｐ＜０．０１）、５４．１４％（Ｐ＜０．０１）、６１．８６％（Ｐ＜０．０１）。３岁以内，随着年龄的增大，公、母兔粗毛纺均逐渐升高。繁殖仅对母兔的粗毛率有影响，     

皖Ⅲ系长毛兔主要性状遗传力的初步估测

利用父系半同胞组内相关估测法，对皖Ⅲ系长毛兔几个主要性状的数据进行了抽要估测，结果表明，其１１月龄粗毛率，产毛量和体重的遗传分别为０．２１２４，０．３２９６和０．４２９３，窝产仔数，泌乳力及断奶窝仔数的遗传力分别为０．１５６４，０．１３４３和０．１４４７。     

粗毛型长毛兔繁殖性能研究

粗毛型长毛兔公兔，在适温季节，精子密度达２亿／ｍｌ，有效精子数１－２亿／ｍｌ，精液品质显著高于德系兔与法系兔；高温应激后，虽然其生精机能受到影响，但与德系兔比较，则表现出明显的抗热性能，如精液品质下降慢，无精期短，平均不育时间（４４天）比德系兔（６１天）短１７天（Ｐ＜０．０５）。粗毛型母兔的繁殖性能显著高于德系母兔，除断乳成活率略高于德系兔外，其中产仔数、泌乳力、断乳窝重分别比德系兔高２６．８６％、２０．０４％、２１。７６％（Ｐ＜０．０１）；产活仔数、初生窝重各比德系兔高３３．３３％和１９．８５％（Ｐ＜０．０５）；表明了粗毛型长毛兔母兔的良好繁殖性能．     

粗毛型长毛兔选育研究

以杂交育种的方法，在德系长毛兔中导人粗毛率高的基因，经过三代以上的杂交，所获得杂种粗毛兔１２００只，平均粗毛率１４．０９％，年产毛量７４４克。从中途出粗毛率高、产毛量高的粗毛型兔２５０只进行横交固定，经过四个世代选育后已进入五世代，其生产性能如下：平均产活仔数７．２９±２．４８只，２１天泌乳力达２０８２±５８．５克，４２日龄断奶个体重达１０８０±１４５克，６月龄体重达３４０５±６５克，８月龄体重达４１４５±３４０克，１１月龄体重达４４００±３９２克，粗毛率达１５．５６％±４．９１％，产毛量达８８０±４０克，均达到和超过原定选育指标。粗毛型长毛兔经过八年的培育，其遗传性状已基本趋于稳定。运用半同胞组内内相关系数的方法测定：粗毛率的遗传力为０．１３４，产毛量的遗传力为０．２９５，与德系长毛兔产毛量遗传力０．３相近，初生个体重、２１天窝重、断奶个体重的遗传力分别为０．１１７、０．２３３、０．１６１，粗毛率与产毛量的遗传相关系数为０．１３１，表型相关系数为０．１４７，均呈正相关。     

粗毛长毛兔繁殖性能研究

粗毛型长毛兔公兔，在适温季节，精子密度达２亿／ｍｌ，有效精子数１－２亿／ｍｌ，精液品质显著高于德系兔与法系兔；高温应激后，虽然其生精机能受到影响，但与德系兔比较，则表现出明显的抗热性能，如精液品质下降慢，无精期短，平均不育时间（４４天）比德系兔（６１天）短１７在（Ｐ＜０．０５）。粗毛型母兔的繁殖性能显著高于德系母兔，除断乳成活率窝重于德系兔外，其中产仔数，泌乳力、断乳窝重分别比德系兔高２６．８６％     

结合研究进展大力推广粗毛型长毛兔

结合研究进展大力推广粗毛型长毛兔浙江省“粗毛型长毛兔新品系培育”课题组，浙江省农业科学院３１００２１赵力知（执笔）近几年来，国际市场对外观效果极佳的兔毛针织品看好，因而粗毛含量在１５％以上的兔毛比较畅销，价格也比一般兔毛高４０％左右。根据国内外兔毛市...     

中国粗毛型长毛兔新品系培育研究

中国粗毛型长毛兔新品系培育研究沈幼章张振华翟频（江苏省农业科学院畜牧兽医研究所，南京２１００１４）赵力知冯尚连陈立新（浙江省农业科学院畜牧兽医研究所，杭州３１００２１）朱秀柏赵辉玲李立冰张东红（安徽省农业科学院畜牧兽医研究所，合肥２３００３１）朱瑾...     

粗毛型长毛兔主要经济性状的遗传参数和选择指数研究

本文对粗毛型长毛兔横交五世代６月龄体重（Ｘ１）、６月龄剪毛量（ｘ２）及１１月龄粗毛率（ｘ３）三个主要经济性状进行了遗传分析。体重和剪毛量样本数２７９只，粗毛率样本数１５６只。结果表明，６月龄体重、６月龄剪毛量和１１月龄粗毛率的遗传力分别为０．３６０４，０．２６４８和０．１３１２；６月龄体重与６月龄剪毛量，６月龄体重与１１月龄粗毛率，６月龄剪毛量与１１月龄粗毛率等均呈正遗传相关，相关系数分别为０．６７４７，０．０８３７和０．６３７４。同时利用本次估计的参数制订综合选择指数，Ｉ＝０．０７０２ｘ１＋０．４０９５ｘ２＋０．２３９５ｘ３，并对其选择效果进行了估计。     

粗毛型长毛兔兔毛若干物理性状的分析测定

粗毛型长毛兔兔毛若干物理性状的分析测定浙江省新昌县长毛兔研究所３１２５１３徐海明，高柏绿浙江省农业科学院３１００２１陈立新，冯尚连，赵力知浙江培育的粗毛型长毛兔是由法系、德系双品系之间的杂交一代，经过五个世代横交选育而成的产毛量和粗毛率均较高、繁殖性...     

撒坝猪繁殖性状的表型和遗传参数分析

对 6个世代共 2 31头撒坝母猪的繁殖性能数据资料进行了分析。在建立混合线性模型的基础上 ,采用HARVEY程序估计了总产仔数、活产仔数、初生窝重、 2 0日龄窝重、 60日龄断奶仔数和断奶窝重等 6个繁殖性状的表型和遗传参数。结果表明 ,撒坝猪繁殖性能在选育过程中有一定程度的提高 ,但速度平缓 ;上述 6个性状的遗传力分别为 0 0 37,0 0 75,0 1 1 1 ,0 1 55 ,0 1 0 3和 0 31 0 ,多为低遗传力性状 ;各性状间的遗传相关介于 0 532～ 0 773之间 ,表型相关和环境相关分别在 0 30 3～ 0 946和 0 442～ 0 972之间     

粗毛型长毛兔新品系毛质分析研究

为了提高长毛兔兔毛纤维中的粗毛率和毛品质，在德系安哥拉兔群中导入了高粗毛率的基因，以新西兰兔、法系安哥拉兔、ＳＡＢ德系兔的血液参入。从８８年开始，经过三代杂交所产生的杂交粗毛型兔群中选出粗毛率高、产毛量高的兔进行横交，然后进行世代选育。目前已进入四世代。１１月龄的粗毛兔选育群，平均粗毛率达１５．５５％，少部分核心群兔粗毛率达２１．４５％，参加繁殖１－２胎的周岁成年母兔粗毛率平均达１７．７２％，年产毛量达８５０～８７０克（９－１１月龄的估测产量）。８月龄的平均体重达４０６５克，成年兔体重达４５０６克。８月龄的绒毛细度１２．８０微米，粗毛细度４０．４９微米，强力２．８１克，伸长率为５０．４１％，兔毛的吸湿率达１６．９６％。     

Estimation of genetic parameters and season effects for semen traits in three pig breeds of South China

The economic profitability of a boar station largely depends on semen quantity and quality traits. However, genetic analysis of semen traits has not yet been done in the boar population in China. In this study, we aimed to estimate genetic parameters for semen traits and the influence of seasons on these traits by using data of Duroc, Landrace and Yorkshire boars in South China. The following four semen traits were analysed: semen volume (ml; VOL), sperm concentration (10⁶/ml; DEN), sperm motility (MOT) and percentage of abnormal sperm (ABN). Genetic parameters and season effects were estimated simultaneously for each breed by using a multiple‐trait (4 × 4) repeatability animal model. The four traits had a moderate heritability with average estimates of 0.23, 0.28, 0.26 and 0.17 across the three breeds, respectively. The estimates of genetic correlations among four traits differed in the three breeds. In particular, in Yorkshire, the four traits were nearly genetically independent. The season of collecting semen had a significant impact on these four semen traits except ABN in Duroc (Bonferroni adjusted p < 0.05/6). The moderate heritabilities indicate the possibility of effective selection of boars for semen traits. Different genetic correlations for the three breeds suggest that the selection strategy for the four traits should be investigated separately for each breed. Some necessary actions should be taken to reduce the influence of seasons on semen traits.     

Estimation of genetic parameters for growth and feed utilization traits in Japanese Black cattle

Performance test results of 3250 sire candidates were used to estimate the genetic parameters of growth and feed utilization traits in Japanese Black cattle. Growth traits analyzed were six body measurements at the end of the performance test and daily gain (DG) during the test. Feed utilization traits were intakes and conversions of concentrate, roughage, digestible crude protein and total digestible nutrient (TDN). Genetic (co)variance components were estimated by the restricted maximum likelihood procedure using an expectation maximization algorithm under the two‐trait animal model. Heritabilities for growth traits ranged from 0.40 to 0.70 and for feed utilization traits from 0.21 to 0.74. Genetic correlations of DG were positive with feed intake (0.15–0.77) and negative with feed conversions (?0.63 to ?0.30). These relationships indicate that the selection based on DG improves feed efficiency but it simultaneously increases feed intake. Feed conversions showed genetic correlations ranging from ?0.09 to 0.03 with total available energy consumption, TDN intake. Thus the results suggested that feed conversions were not efficient selection criteria to decrease TDN intake and to improve comprehensive feed utilization ability.     

Estimation of genetic parameters for superovulatory response traits in Japanese Black cows

The aim of this study was to estimate genetic parameters for superovulatory response traits in order to explore the possibility of genetic improvement in Japanese Black cows. We analyzed 19 155 records of the total number of embryos and oocytes (TNE) and the number of good embryos (NGE) collected from 1532 donor cows between 2008 and 2018. A two-trait repeatability animal model analysis was performed for both. Because records of TNE and NGE did not follow a normal distribution, the records were analyzed following no, logarithmic, or Anscombe transformation. Without transformation, the heritability estimates were 0.26 for TNE and 0.17 for NGE. With logarithmic transformation, they were 0.22 for TNE and 0.18 for NGE. With Anscombe transformation, they were 0.26 for TNE and 0.18 for NGE. All analyses gave similar genetic correlations between TNE and NGE, ranging from 0.60 to 0.71. Spearman’s rank correlation coefficient between breeding values of cows with more than 10 records was ≥0.95 with both transformations. Thus, the genetic improvement of TNE and NGE of donor cows could be possible in Japanese Black cattle.     

Heritability and genetic correlation estimates for performance,meat quality and quantitative skeletal muscle fiber traits in broiler

Broiler feed efficiency and meat quality are the primary factors considered by the poultry industry. This study was conducted to estimate heritability and genetic correlation coefficients for skeletal muscle fiber number, area and diameter and performance and meat quality traits of Pectoralis major in a single male broiler line. (Co) variance components were estimated by restricted maximum likelihood method, using the software MTDFREML. The numerator relationship matrix was composed by 77,474 individuals. Heritability coefficient estimates ranged from moderate to high for juvenile BW, breast weight, ultrasound record of pectoral muscle, lightness and thawing meat loss. Genetic correlation estimates for performance and skeletal muscle fiber traits indicated that selection for higher breast weight and juvenile BW could reduce muscle fiber number and increase muscle fiber diameter and area, which could prejudice the meat quality of this line. Selection for muscle fiber number and against muscle fiber diameter and area might improve meat water retention ability and tenderness in this broiler line, and selection programs could consider those traits as selection criteria, although this may be costly. We recommend the evaluation of the indirect selection caused by the use of the performance traits as selection criteria especially for juvenile BW and breast weight. Direct, intense selection for both traits might be unfavorable for most of the meat quality traits analyzed, which could lead to losses to both the chicken meat processing industry and consumers.     

Divergent selection for fleece weight in French Angora rabbits: Non-genetic effects, genetic parameters and response to selection

In order to explore genetic variability of wool production and other quantitative traits, an 8-cohort divergent selection experiment for total fleece weight (TFW) was carried out in French Angora rabbits. Studies were made on the wool production of 669 female rabbits born between 1994 and 2001 and having produced wool from the third to 12th harvests. The aim of the selection experiment was to obtain two divergent lines (low and high) on total fleece weight. The studied traits included total fleece weight, weight of the two qualities of wool (WAJ1 and WAW1), homogeneity (HOM), live body weight at ages of 4 (LW4), 8 (LW8), 12 (LW12), 16 (LW16), and 20 (LW20) weeks and then 9 weeks before each harvest (9LW). A preliminary analysis of non-genetic factors was done with the GLM procedure. The genetic parameters and genetic trends were analysed using a BLUP animal model. Heritability estimates for TFW, WAJ1, WAW1, HOM, LW4, LW8, LW12, LW16, LW20 and 9LW were 0.38, 0.30, 0.10, 0.06, 0.30, 0.09, 0.14, 0.32, 0.39 and 0.45, respectively. Genetic and phenotypic correlations between TFW and WAJ1 were high (0.98 ± 0.01 and 0.89 ± 0.01, respectively). There was a low genetic correlation between TFW and 9LW (0.26 ± 0.12). After eight cohorts of selection, the divergence between the lines was approximately three genetic standard deviations. Selection for total fleece weight had a generally beneficial effect on fleece quality.     

Reduced-rank estimation of genetic parameters for egg production traits and cluster analyses with predicted breeding values

The aims of this study were to compare the suitability of the multi-trait (MUT) model to estimate genetic parameters with that of 13 reduced-rank principal component models (PC1 to PC13), and then to explore the additive genetic patterns of the breeding values obtained from these using clustering analyses of egg production traits. A total of 1,212 records were used to estimate genetic parameters using the MUT and PC models. The PC4 model was the best representation of the data since it had a lower AIC value and was more parsimonious than the MUT model. The estimated heritability of the age at the first egg (AFE) trait from this model was 0.28?±?0.06, and the estimated genetic correlation between AFE and total egg production (TP) was ?0.52?±?0.23. Potentially animals from cluster 2 are more likely to be in the selected group to help improve the egg production.     

Estimates of genetic parameters for chemical traits of meat quality in Japanese black cattle

Genetic parameters for 54 carcass and chemical traits, such as general composition (moisture, crude fat and crude protein), fatty acid composition and water‐soluble compounds (free amino acids, peptides, nucleotides and sugars) of 587 commercial Japanese Black cattle were assessed. Heritability estimates for carcass traits and general composition ranged between 0.19–0.28, whereas those for fatty acid composition ranged between 0.11–0.85. Most heritability estimates for water‐soluble compounds were lower than 0.30; these traits were affected by aging period. Moderate heritability was observed for glutamine, alanine, taurine, anserine, inosine 5′‐monophosphate (IMP), inosine and myo‐inositol. In particular, heritability estimates were the highest (0.66) for taurine. Traits with moderate heritability were unaffected by aging period, with the exception of IMP, which was affected by aging period but exhibited moderate heritability (0.47). Although phenotypic correlations of water‐soluble compounds with carcass weight (CW), beef marbling standard (BMS) and monounsaturated fatty acid were generally low, genetic correlations between these traits were low to high. At the genetic level, most of the water‐soluble compounds were positively correlated with monounsaturated fatty acid but negatively correlated with CW and BMS. Thus, our results indicate that genetic variance and correlations could exist and be captured for some of the water‐soluble compounds.     

肉兔微卫星标记与生产性能的相关性研究

本研究检测了13个卫星标记与兔生产性状(产仔数、初生窝重、21 d、28 d、90 d窝重)间的相关性,研究结果表明,13个微卫星标记中有5个标记与家兔生产性状相关。位点5L1E8及D7Utr5不同基因型除对初生重影响显著外(P>0.05),位点19L1G5除对产仔数影响不显著外(P>0.05),分别对其余四个性状的影响均达到显著水平(P<0.05);而位点D3Utr7对五个生产性状均达到显著影响(P<0.05)。其余8个位点对各性状影响均未达到显著水平(P>0.05)。