乌骨鸡新品系产蛋性能选育效果及相关分析

本文统计和分析了丝羽乌骨鸡新品系四个世代的产蛋性状,采用SAS系统中GLM模型进行冬世代间产蛋性能的多重比较,用Excel软件描绘了父母系各世代产蛋曲线,并在各开产性状间进行了相关分析。结果表明,各产蛋性状各世代间大部分差异显著;开产日龄与开产体重和开产蛋重呈极显著表型正相关(0.39565,0.19906),与300日龄产蛋量呈极显著负相关(-0.24193);开产体重与开产蛋重呈极显著正相关(0.28654),与300日龄产蛋量和300日龄蛋重呈极显著负相关(-0.64308,-0.28698);开产蛋重与300日龄产蛋量呈极显著负相关(-0.64308)。开产日龄是影响产蛋性能的一个重要因素。     

二郎山山地鸡一世代产蛋性能选育效果研究

通过比较二郎山山地鸡SD02和SD03品系一世代的产蛋性能,并进行产蛋性状间的相关分析,为二郎山山地鸡配套系的后续选育提供科学依据。结果表明,品系间大部分产蛋性状差异显著,SD03品系开产日龄早于SD02品系,开产体重、蛋重均极显著高于SD02品系(P0.01)。此外,鸡群300日龄时,SD03品系产蛋数、体重、蛋重均显著高于SD02品系(P0.05)。相关性分析结果显示,开产日龄与300日龄产蛋数呈极显著负相关(P0.01),与开产蛋重呈极显著正相关(P0.01);300日龄体重与300日龄蛋重呈极显著正相关(P0.01);300日龄产蛋数与300日龄体重、300日龄蛋重呈极显著负相关(P0.01),与开产第1、2、3、4、5月的产蛋数均呈极显著正相关(P0.01)。综上所述,SD03品系产蛋性能优于SD02品系,开产日龄是影响产蛋性能的一个重要因素。     

丝羽乌骨鸡新品系开产性能选育效果及相关分析

通过分析丝羽乌骨鸡白羽母系选育第六、七世代开产日龄、开产体重、开产蛋重,作开产日龄、开产体重、开产蛋重之间相关分析和两世代产蛋性能的均数差异显著性检验和相关分析。结果表明,两世代开产性能有极显著差异;开产体重与开产蛋重、开产蛋重与开产日龄、开产体重与开产日龄均呈显著正相关(相关系数分别为0.32246、0.32942、0.21078,P<0.01)。     

三个蛋鸭品种生产性能的观测与分析

本试验以金定鸭、褐色菜鸭和攸县麻鸭为素材,在相同的饲养管理和孵化条件下,对3个蛋鸭品种的产蛋性能、青壳率、受精率、受精蛋孵化率和不同阶段体重进行观测。结果表明:3个蛋鸭品种中攸县麻鸭300日龄产蛋量(144个)最高,见蛋日龄(96d)和开产日龄(123d)最早,因此3个蛋鸭品种中以攸县麻鸭产蛋性能最好;褐色菜鸭和攸县麻鸭公、母鸭30日龄体重、开产体重、300日龄蛋重差异均不显著(P0.05),由此可见,褐色菜鸭与攸县麻鸭属于同一类型蛋鸭品种。3个蛋鸭各品种的入孵蛋重与出壳重均呈极显著正相关(P0.01)。     

微卫星标记与丝羽乌骨鸡产蛋性能的关系研究

从鸡的遗传图谱中选择9个与产蛋性能相关的微卫星基因座,对在产蛋性能上有明显差异的丝羽乌骨鸡个体共170只进行标记基因型与产蛋性状的最小二乘分析,结果表明：有4个标记G31913、X82867、Z95315、G01672与丝羽乌骨鸡的4个月连产蛋量、开产蛋重及500日龄产蛋量间存在显著的关系。标记G31913中基因型AB所对应的开产体重最小二乘均值与其它基因型的对应值间的差异达显著或极显著,开产蛋重间无显著差异。标记Z95315的基因型CC所对应开产蛋重、开产体重最小二乘均值最高,并且均显著高于其余8种基因型所对应的开产蛋重、开产体重最小二乘均值。标记G01672基因型为EE、AE所对应开产蛋重最小二乘均值与基因型为CE、CC的对应值间差异显著;等位基因E与开产蛋重有显著正相关,等位基因C与开产蛋重有显著负相关。标记X82867基因型CD所对应500日龄产蛋量最小二乘均值显著低于AB型,4个月连产蛋量、300日龄产蛋量也低于基因型为AB个体。研究表明,标记G31913的基因型AB和标记Z95315的基因型CC有望作为开产蛋重、开产体重早期选择的辅助标记。     

"邵伯草鸡"母系(S2系)主要产蛋性状的遗传参数估测

估测了邵伯草鸡母系(S2系)的主要产蛋性状的遗传参数,结果表明开产日龄、开产体重、开产蛋重、43周蛋重、43周产蛋量和66周产蛋量的遗传力分别为0.5240(P＜0.01)、0.5631(P＜0.01)、0.2597(P＜0.05)、0.4759(P＜0.01)、0.2621(P＜0.05)、0.3081(P＜0.01).66周产蛋量与43周产蛋量呈强正遗传相关(0.5126,P＜0.01).43周产蛋量与开产日龄、开产体重、开产蛋重及43周龄蛋重的遗传相关分别为-0.4221、0.0873、-0.5714(P＜0.01)和-0.4311(P＜0.05).     

番鸭产蛋规律的研究

采用"泄殖腔外托蛋法"对番鸭产蛋规律跟踪测试,结果表明:①番鸭产蛋分为第一、二产蛋期,第一产蛋期持续22-25周,换羽期10-12周;换羽后进入第二产蛋期,经20-22周产蛋后即可淘汰。第一、二产蛋期平均产蛋频率分别为0.48和0.46,两者差异不显著(P>0.05),经测定番鸭(60周)平均产蛋量为156.57个,高产者达213个,少者仅73个。②番鸭冬季日产蛋高峰于凌晨4点,而夏季的高峰时间出现在凌晨5点,且夏季产蛋多、持续时间也较长。环境温度对番鸭产蛋性能有较大影响,冬、夏季平均产蛋率分别为27.48％和51.5％。③番鸭开产体重与开产日龄呈显著正相关,相关系数为0.198(P<0.05),但与第一产蛋期产蛋量呈弱负相关(r=-0.015);开产体重与第一产蛋期产蛋量呈极显著负相关(r=-0.272)(P<0.01)。     

如皋黄鸡产蛋性能与遗传参数分析

研究以如皋黄鸡第4世代的15个家系351只母鸡为实验素材,测定开产日龄、开产体重、开产蛋重和40周龄产蛋数,统计各周龄群体产蛋率,估算开产性状和40周龄产蛋数的遗传参数。结果表明:如皋黄鸡开产日龄为(153.9±13.13)d,开产体重为(1 366.5±135.51)g,开产蛋重为(32.8±3.17)g,40周龄产蛋数为(101.0±8.94)个;高峰产蛋率为82.1%,70%以上产蛋率维持16周;开产日龄、开产体重、开产蛋重和40周龄产蛋数均为中等遗传力0.177~0.320;开产日龄、开产体重和开产蛋重间两两呈遗传正相关0.736~0.971,40周龄产蛋数与开产日龄、开产体重、开产蛋重间均呈遗传负相关-0.832~-0.639;性状间的表型相关性质和遗传相关一致,且均达到极显著的程度。     

禽白血病对如皋草鸡产蛋性能的影响

试验旨在研究如皋草鸡禽白血病与产蛋性能(包括开产日龄、开产蛋重、开产体重、40周龄体重和280日龄产蛋数)的相关性,为鸡群净化做准备。选用562羽黑羽系(♂:♀=112:450)与765羽黄羽系(♂:♀=123:642)如皋草鸡,取泄殖腔棉拭子,用ELISAp27抗原试剂盒进行检测。结果表明:(1)在黄羽系母鸡中,P27抗原的测定值S/P与开产日龄没有显著相关性,但与开产蛋重显著负相关(P<0.05),与开产体重、40周龄体重、40周龄产蛋数极显著负相关(P<0.01)。(2)在黑羽系母鸡中,P27抗原的测定值S/P与开产蛋重、开产体重没有显著相关性,但与40周龄体重显著负相关(P<0.05),与40周龄产蛋数极显著负相关(P<0.01),与开产日龄极显著正相关(P<0.01)。     

峪口褐壳蛋鸡B系开产日龄对其体重、生产和蛋品性状的影响

为了探究峪口褐壳蛋鸡B系开产日龄与体重、生产和蛋品性状的关系,指导蛋鸡纯系选育,试验以峪口褐壳蛋鸡B系11世代第二批次1 502只母鸡为研究对象,记录蛋鸡的开产日龄,根据蛋鸡开产日龄划分为1,2,3,4,5,6,7,8组,测定各组蛋鸡开产体重和蛋重;28,36,56周龄体重和蛋重;38,56周龄产蛋数和39～56周龄产蛋数;36,56周龄蛋壳厚度和蛋壳强度,分析各组鸡开产日龄对开产体重、开产～56周龄体重、蛋重、产蛋数、蛋壳强度、蛋壳强度等指标的影响及相关关系研究。结果表明:不同开产日龄组别之间的开产体重存在极显著正相关(P0.05),随着开产日龄的增大,开产体重呈增加趋势;不同开产日龄组别之间的开产蛋重、28周龄至56周龄蛋重存在极显著正相关(P0.01),随着开产日龄的增大,蛋重呈增加趋势;不同开产日龄组别之间的38周龄和56周龄产蛋数存在极显著负相关(P0.01),随着开产日龄的增大,产蛋数呈降低趋势;不同开产日龄组别之间的56周龄蛋壳厚度存在显著正相关(P0.05),但相关系数小。说明峪口褐壳蛋鸡开产日龄在127～154日龄之间的鸡只其开产体重、生产和蛋品质等性状指标比较理想。     

Genetic parameters for egg production traits in purebred and hybrid chicken in a tropical environment

1. Genetic parameters were estimated for 5 economically important egg production traits using records collected over 9 years in chickens reared under tropical conditions in Thailand. The data were from two purebred lines and two hybrid lines of layer parent stocks.

2. The two purebred lines were Rhode Island Red (RIR) and White Plymouth Rock (WPR) and the hybrid lines were formed by crossing a commercial brown egg laying strain to Rhode Island Red (RC) and White Plymouth Rock (WC), respectively.

3. Five egg production traits were analysed, including age at first egg (AFE), body weight at first egg (BWT), egg weight at first egg (EWFE), number of eggs from the first 17 weeks of lay (EN) and average egg weight over the 17th week of lay (EW).

4. Fixed effects of year and hatch within year were significant for all 5 traits and were included in the model.

5. Maternal genetic and permanent environmental effects of the dam were not significant, except for EN and EW in RIR and BWT and EW in WPR.

6. Estimated heritability of AFE, BWT, EWFE, EN and EW were 0.45, 0.50, 0.29, 0.19 and 0.43 in RIR; 0.44, 0.38, 0.33, 0.20 and 0.38 in WPR; 0.37, 0.41, 0.38, 0.18 and 0.36 in RC; and 0.46, 0.53, 0.36, 0.38 and 0.45 in WC lines, respectively.

7. The EN was negatively correlated with other traits, except for BWT in RC and AFE and BWT in WC.

8. It was concluded that selection for increased EN will reduce other egg production traits in purebred and hybrid chicken and therefore EN needs to be combined with other egg production traits in a multi-trait selection index to improve all traits optimally according to a defined breeding objective.

     

Genetic evaluation of Ethiopian Boran cattle and their crosses with Holstein Friesian for growth performance in central Ethiopia

Breed additive and non-additive effects, and heritabilities of birth weight (BWT), weaning weight (WWT), 6 months weight (SMWT), yearling weight (YWT), eighteen months weight (EWT), 2 years weight (TWT) and average daily weight gain from birth to 6 months (ADG1) and from 6 months to 2 years (ADG2) were estimated in Ethiopian Boran (B) cattle and their crosses with Holstein Friesian (F) in central Ethiopia. The data analysed were spread over 15 years. Ethiopian Boran were consistently lighter (p < 0.01) than the B-F crosses at all ages. Ethiopian Boran also gained lower weight than all the crosses. At birth, 50% F crosses were significantly (p < 0.01) lighter than all the other crosses. However, the differences in SMWT, YWT, EWT, TWT, ADG1 and ADG2 were all non-significant among the crosses. The individual additive breed differences between B and F breeds were positive and significant (p < 0.01) for all traits. The individual heterosis effects were significant (p < 0.05) for all traits except WWT for which the effect was non-significant. The maternal heterosis effects were significant (p < 0.01) for BWT (2.5 kg) and WWT (-3.0 kg). The heritability estimates for all traits in B and crosses were generally moderate to high indicating that there is scope for genetic improvement through selection. Selection within B and crossbreeding should be the strategy to enhance the growth performance under such production systems.     

Estimation of genetic parameters for body weight and egg production traits in Mazandaran native chicken

Native chicken breeding station of Mazandaran was established in 1988 with two main objectives: genetic improvement through selection programs and dissemination of indigenous Mazandarani birds. (Co)variance components and genetic parameters for economically important traits were estimated using (bi) univariate animal models with ASREML procedure in Mazandarani native chicken. The data were from 18 generations of selection (1988?C2009). Heritability estimates for body weight at different ages [at hatch (bw1), 8 (bw8), 12 (bw12) weeks of ages and sex maturation (wsm)] ranged from 0.24?±?0.00 to 0.47?±?0.01. Heritability for reproductive traits including age at sex maturation (asm); egg number (en); weight of first egg (ew1); average egg weight at 28 (ew28), 30 (ew30), and 32 (ew32) weeks of age; their averages (av); average egg weight for the first 12?weeks of production (ew12); egg mass (em); and egg intensity (eint) varied from 0.16?±?0.01 to 0.43?±?0.01. Generally, the magnitudes of heritability for the investigated traits were moderate. However, egg production traits showed smaller heritability compared with growth traits. Genetic correlations among egg weight at different ages were mostly higher than 0.8. On the one hand, body weight at different ages showed positive and relatively moderate genetic correlations with egg weight traits (ew1, ew28, ew30, ew32, ew12, and av) and varied from 0.30?±?0.03 to 0.59?±?0.02. On the other hand, low negative genetic correlations were obtained between body weight traits (bw1, bw8, bw12, and wsm) and egg number (en). Also, there is low negative genetic correlation (?24?±?0.04 to ?29?±?0.05) between egg number and egg weight. Therefore, during simultaneous selection process for both growth and egg production traits, probable reduction in egg production due to low reduction in egg number may be compensated by increases in egg weight.     

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.     

促卵泡激素受体基因第2内含子多态性对如皋黄鸡繁殖性状的遗传效应分析

试验以260只如皋黄鸡为素材,采用飞行质谱技术对位于促卵泡素受体(follicle stimulate hormone receptor,FSHR)基因第2内含子的3个SNPs位点进行检测,并对其与繁殖性状的相关性进行了分析。结果表明,C+29329A突变对开产日龄、开产蛋重及40周龄蛋重有显著影响(P<0.05);而C+30582G只与40周龄总产蛋数呈显著相关(P<0.05);G+51411A则对开产日龄、开产体重及40周龄总产蛋数有显著影响(P<0.05)。研究结果显示,FSHR基因有望成为选育高产蛋鸡的分子标记,辅助选育、开发中国地方鸡品种资源。     

Genetic heterogeneity of variance in production traits of laying hens

Genetic parameters for mean and for environmental variation in egg weight, body weight, age at first egg, and egg production were estimated in eight layer lines. The data were recorded from years 1999-2007, with on average of 6500 birds per line. An iterative mean-variance REML method was applied with a sire-plus-dam model for mean, a sire model for variance, and a fixed effect of hatch within generation for both mean and variance. The estimated heritability of environmental variation averaged about 5% for body weight, 3% for egg weight, and 11% for age at first egg, but was inconsistent among the lines for egg production (0-15%). Correlations between means and variances were slightly positive for body weight, egg weight, and age at first egg; and strongly negative for egg production. Age at first egg had the highest heritability of environmental variation; and favourable correlations with egg production and with variation in other production traits indicate that reducing variation in this trait may have potential benefits for the breeding industry.     

Multivariate analysis of mixed inheritance model of performance traits in layers using Gibbs sampling

The Gibbs sampling under a multitrait animal model was applied to detect the single gene affecting chicken performance traits and their pleiotropic actions as well as to estimate the heritability and correlations for these traits. A total of 14 823 individuals of a Rhode Island Red line (RIR) and 18 653 individuals of a Rhode Island White line (RIW) from six generations under long-term selection were recorded. Five performance traits were studied: initial egg production (IEP; until 38th week), egg production (until 54th week), egg weight at 33rd week (EW), age at first egg (AFE), and body weight at 20th week (BW). An analysis was based on the estimated marginal densities of the following parameters: frequencies, additive and dominance effects and variances and covariances (for single gene) as well as additive genetic and residual variances and respective covariances (for polygenes). An inference concerning the mixed inheritance model is performed by visualising the marginal posterior densities of major gene variance separately for all traits. The pleiotropic effect of single locus is expressed as the single gene correlation coefficient. It shows contributions of single genes to BW (10 and 15% of total variance for A22 and K44, respectively) and EW of K44 (9% of total variance). Moreover, a small positive pleiotropic single locus effect in line K44 was also registered. The polygenic heritability estimates obtained were low, except for EW and BW of both lines. Generally, the correlation estimates were in agreement with results reported in literature.     

Sodium bentonite as a component in layer diets

1. Two hundred and forty Amber-link pullets were individually caged in a naturally-ventilated laying house and fed one of four isoenergetic, isonitrogenous diets containing 0, 20, 40 or 80 sodium bentonite/kg for 44 weeks. 2. No significant dietary effects were observed between treatments with regard to body weight at 20 or 64 weeks, age at first egg, egg weight, Haugh score or egg shell thickness. 3. Significant positive linear responses were observed with live weight at first egg (P less than 0.01), food consumed/hen d (P less than 0.05) and faecal moisture percentage (P less than 0.01). Significant negative linear (P less than 0.01) responses were observed with bacterial counts in the proximal and distal ends of the intestine. 4. A significant negative quadratic (P less than 0.05) response was noticed with egg production per hen. 5. A significant negative cubic (P less than 0.01) response was found with food conversion ratio (g food/g eggs).     

Effect of size and timing of photoperiod increase on age at first egg and subsequent performance of two breeds of laying hen

1. ISA Brown and Shaver 238 pullets were changed from 8 h to 8, 10, 13 or 16 h photoperiods at 42, 63, 84, 105, 126 or 142 d of age.

2. Age at first egg (AFE) was curvilinearly affected by the size and timing of the change in photoperiod. AFE was advanced most by a photoperiod change from 8 to 13 h made at 63 or 84 d. ISA birds were generally more responsive than Shaver to the photoperiod changes.

3. Longer photoperiods significandy increased survivors' egg production, but decreased liveability to 504 d, so that eggs per hen housed were unaffected. Retarding AFE by 10 d reduced survivors' egg numbers by 7.0, but increased mean egg weight by 1.26 g. Egg output by Shaver birds was unaffected by AFE, but that of ISA was curvilinearly affected, with an apogee at an AFE of 135 d. In both breeds, egg weight and egg output were greater following an early or late, rather than a mid‐term photostimulation.

4. Photoperiod significandy increased mean daily food intake during lay by 1.26 g/h. A 10 d retardation in AFE resulted in a reduction in food intake of 1 g/d. Efficiency of food conversion deteriorated according to the square of the photoperiod, and changed curvilinearly according to age at photostimulation. Food conversion efficiency improved by 0.05 g/g for each 10 d delay in AFE.

5. Shell quality was unaffected by AFE, but deteriorated with increasing photoperiod and was curvilinearly affected by age at photostimulation with the smallest shell weights associated with photostimulation at 63 d. The incidence of double‐yolked (DY) egg production increased with photoperiod and decreased with delayed photostimulation. There was an exponential regression of DY eggs on AFE.

6. Body weight at first egg increased by 75 g/d delay in AFE, but body weight at 504 d of age was unaffected by AFE, photoperiod or age at photostimulation. Body weight gain during lay increased by 15 g/h increase in photoperiod, decreased by 6 g per 10 d delay in photostimulation and by 40 g per 10 d delay in AFE. Fat content at 504 d increased by about 10 g/kg and by 23 g/bird for each 10 d delay in AFE.

7. Mortality in lay increased by 0.8%/h increase in photoperiod, but was unaffected by either age at photostimulation or AFE.     

Heritabilities and genetic correlations of laying performance in Muscovy ducks selected in Taiwan

1. Genetic parameters in the base population of a closed experimental strain of Muscovy ducks, selected for body weight at 10 weeks of age, were estimated from data in 8 successive generations, for the following traits: age at first egg (AGE1EGG), total number of eggs laid at 40 and 52 weeks of age (NEGG40 and NEGG52), number of eggs laid during 15 and 22 weeks in the first laying cycle (NEGG15W and NEGG22W), and their Box-Cox transformed data. 2. The method of multi-trait restricted maximum likelihood with an animal model was used to estimate genetic parameters. Only the results obtained with non-transformed data are shown. 3. Heritability estimates for laying performance showed moderate values, increasing little with age: 0.20+/-0.03 (AGE1EGG), 0.23+/-0.03 (NEGG40), 0.27+/-0.03 (NEGG52), 0.20+/-0.03 (NEGG15W), and 0.22+/-0.03 (NEGG22W). 4. Genetic correlations between laying traits were high. Genetic correlation between AGE1EGG and egg number was negative, it was positive between total numbers of eggs at 40 and 52 weeks and egg numbers in the first laying cycle. 5. Body weight at 10 weeks of age exhibited positive genetic correlations (0.46+/-0.06) with age at first egg and negative with egg production traits (-0.28+/-0.06 to -0.41+/-0.06). 6. The cumulated predicted genetic gains, after 7 generations of selection, expressed per genetic standard deviation unit (sigma(g)) were 0.06 sigma(g), 0.07 sigma(g), 0.17 sigma(g), 0.23 sigma(g), and 0.25 sigma(g) for AGE1EGG, NEGG40, NEGG52, NEGG15W, and NEGG22W, respectively. 7. Selecting Muscovy ducks to improve laying in Taiwanese climatic conditions would be possible using the number of eggs laid up to 52 weeks of age as the selection criterion. Because unintended selection effects for laying traits were present, the selection experiment for body weight at 10 weeks of age was not antagonistic with laying traits.