双肌臀大约克种猪的应激敏感基因净化研究

应用PCR RFLPs技术对双肌臀大约克 (Ⅰ系 )、普通大约克 (Ⅱ系 )和Ⅰ系与Ⅱ系系间繁殖后代 (Ⅲ系 ) 3个选育群体的全部种猪普检应激敏感基因 (RYR1基因 )。Ⅰ系和Ⅲ系全部为阴性纯合体 ,Ⅱ系检出阳性纯合体和杂合体分别为 1头和 1 5头 ,阳性率为 1 4 2 %。对Ⅱ系的阳性个体和相同数量的阴性个体进行复检 ,其检测结果复重率达 1 0 0 %。经过系统选育 ,培育成了无RYR1基因的双肌臀大约克种猪Ⅰ、Ⅱ和Ⅲ系 1 1 7、 97和 49头的育种核心群。     

引用双肌臀大约克种公猪对南昌白猪的改良效果初报

南昌白猪选育至第7-8世代时,于2000年引进加系双肌臀大约克公猪与南昌白猪杂交,以改善南昌白猪后躯的丰满度。南昌白猪导入双肌臀血缘后8世代母猪头胎产仔数9.18头,产活仔数8.30头,初生窝重9.6kg,20日龄窝重31.14kg,60日龄窝重115.15kg;后备母猪6月龄体重87.37kg,日增重633.27g,三点均膘2.23cm;肥育测定日增重606g,屠宰测定瘦肉率61.63％,肉质优良。通过导入双肌臀大约克种猪血后,在生长发育、胴体性状等重要经济性能上取得了比较理想的改良效果。     

二花脸猪和双肌臂大约克、新丹系长白猪的选育与杂交利用研究

二花脸、双肌臀大约克、新丹系长白纯种和长·二、大·二杂种经产母猪46、389、215、34、42窝的窝总产仔数分别是15.57、11.81、11.89、14.97、15.02头,窝产活仔数分别是14.80、11.45、11.66、14.44、14.60头;前三组纯种和大×二、长×二、大×长·二、长×大·二杂种共7组每组各20头育肥猪的全期日增重分别是480.3、829.8、806.3和741.4、720.4、781.5、770.3g,料重比分别是3.89、2.81、2.83和3.26、3.29、3.23、3.26,每组各屠宰6头的平均瘦肉率分别是43.65%、65.54%、65.81%和53.93%、54.02%、58.73%、59.46%,各组母猪平均每头年产瘦肉量分别是737.15、1283.38、1282.88和1236.48、1230.43、1298.65、1368.46kg。     

新美系大约克猪繁殖性能初报

武汉市金龙畜禽有限责任公司2004年3月一次性引进新美系大约克母猪180余头.经过初产和第二胎繁殖共300窝的统计分析,美系大约克具备较高的繁殖率和增长速度。现统计分析的主要目的为广大养殖客户引进品种、确定饲养标准提供可靠的饲养依据。     

二花脸猪和双肌臀大约克、新丹系长白猪的选育与杂交利用研究

二花脸、双肌臀大约克、新丹系长白纯种和长@二、大@二杂种经产母猪46、389、215、34、42窝的窝总产仔数分别是15.57、11.81、11.89、14.97、15.02头,窝产活仔数分别是14.80、11.45、11.66、14.44、14.60头;前三组纯种和大×二、长×二、大×长@二、长×大@二杂种共7组每组各20头育肥猪的全期日增重分别是480.3、829.8、806.3和741.4、720.4、781.5、770.3 g,料重比分别是3.89、2.81、2.83和3.26、3.29、3.23、3.26,每组各屠宰6头的平均瘦肉率分别是43.65%、65.54%、65.81%和53.93%、54.02%、58.73%、59.46%,各组母猪平均每头年产瘦肉量分别是737.15、1283.38、1282.88和1236.48、1230.43、1298.65、1368.46kg.     

热应激对种猪繁殖性能的影响

自然生态因素对公猪的生精配种、母猪发情周期的作用是不能低估的。本文着重讨论高温热应激对种猪繁殖性能的影响。一、高温热应激对受胎率的影响农谚称:“马驴惊蜇至白露,一年四季配猪牛。”猪全年均有发情周期循环,猪的繁殖效率的季节性变化由热应激或日照长短所致。热应激对繁殖作用程度,取决于动物的种类、品种、气温的变动和热应激的持续时间。猪在配种前处于热应激之下,会降低受     

双肌臀大约克夏、长白、杜洛克猪的生产性能

随着人民生活水平的提高 ,市场上不仅瘦肉猪需求量愈来愈大 ,而且还要求无有害物质的残留 ,这就要求产品必须符合市场的要求。因此 ,瘦肉品种猪首先引起了养猪者的高度重视 ,近几年来我国从国外引进了不少瘦肉型品种猪 ,其中双肌臀猪的引进就是为了满足市场的需求。双肌臀猪是在具备该品种基本特征的基础上 ,还具有明显的双肌臀特征 ,即脊背宽、体躯长、前躯宽深、后躯特别大圆 ,生长发育期体形呈现明显哑铃型。双肌臀猪具有生长发育快 ,饲料转化率高 ,胴体瘦肉率高的特点。烟台益生种畜禽有限公司分别于 2 0 0 0年 3月和 4月从加拿大和美国…     

长大二元杂种母猪泌乳性能的研究

从 5 6头长大二元杂种母猪群中选择系谱记录清楚 ,分娩时间相近 ,体型较好 ,体质健康 ,带仔数 9～ 1 1头的经产母猪 5头进行泌乳性能的观测研究 ,结果表明 ,二元杂种母猪在 35天的哺乳期内 ,日平均放乳次数 2 1 2 3次 ,日泌乳量 5 2 1kg ,全期泌乳总量 1 82 2 5kg。     

半胱胺对泌乳母猪生产性能影响的研究

此文研究泌乳母猪饲粮中添加半胱胺对其采食量及生产性能的影响。采用单因子试验设计,按照半胱胺添加水平设0mg/kg组(对照组)、125mg/kg组和150mg/kg组3个处理,选择胎次(3～5胎)和体重相近、距离预产期7d之内的经产大白母猪12头,随机分到3个处理中,每个处理4个重复,每个重复1头。试验期21d。结果显示,半胱胺能有效提高母猪泌乳期的总采食量,减少泌乳期体重损失,促进哺乳仔猪生长。此试验条件下,半胱胺最佳添加水平是125mg/kg,超过此剂量,半胱胺的效果反而随添加剂量增加呈降低趋势。     

Estimation of litter size variability phenotypes in Large White sows

The objective of this study was to obtain new phenotypes of phenotypic variability for the total number born (TNB) in pigs using the residual variance of TNB. The analysis was based on 246,799 Large White litter observations provided by Topigs Norsvin. Three animal models were used to obtain estimates of residual variance for TNB: the basic model (BM) containing fixed effects of farm–year and season and random effects of animal and permanent environmental sow, the basic model with an additional fixed effect of parity (BMP) and a random regression model (RRM). The within-individual variance of the residuals was calculated and log-transformed to obtain three new variability traits: LnVarBM, LnVarBMP and LnVarRRM. Then, (co)variance components, heritability, the genetic coefficient of variation at the standard deviation level (GCV_SDe) and genetic correlations between the three LnVar's and between the LnVar's and mean total number born (mTNB) were estimated with uni-, bi- and trivariate models. Results indicated that genetically LnVar's are the same trait and are positively correlated with the mTNB (~0.60). Thus, both traits should be included in breeding programmes to avoid an increase in TNB variability while selecting for increased TNB. Heritability of the LnVar's was estimated at 0.021. The GCV_SDe for LnVar's showed that a change of 8% in residual standard deviation of TNB could be obtained per generation. Those results indicate that phenotypic variability of litter size is under genetic control, thus it may be improved by selection.     

Analysis of longevity and exterior traits on Large White sows in Switzerland

Records of length of productive life, from first farrowing to culling, of 16,464 Large White purebred sows from SUISAG were studied using survival analysis. The major aims of the study were to model the risk of culling within parity and to assess the influence of exterior traits, such as the number of teats or feet and leg scores, on culling. Culling was concentrated at the first day after each farrowing or at the first day after weaning. Weaning itself was mostly between 21 and 49 d after farrowing, with an average weaning age of 35 d. Because of the definition of culling date used, there was practically no risk of culling from these periods. The culling rates at different periods suggested a modeling of the baseline hazard function within parity instead of over the entire productive life of the animals. A piecewise Weibull function and a simple graphical method to validate its adequacy were proposed for sow longevity analysis. The risk of culling increased with older parities (P < 0.001) and with decreasing litter size at weaning (P < 0.001). The exterior traits analyzed (number of teats, and feet and leg scores, on a scale from 1 to 7) had a moderate effect on the risk of culling compared with other factors but were still influential on survival, productive life expectancy, and annual replacement rate. Sows with less than 13 good teats had 1.35 times greater risk of being culled than sows with more good teats (P < 0.05). Sows with an X-O rear leg score of 2 had 1.4 times greater risk of being culled than sows with an intermediate score of 4 (P < 0.05). Sows at the optimum score of 4 for the size of inner claws of the rear leg had 0.83 times less risk of being culled (P < 0.01) than sows with scores of 2 and 3. Furthermore, when a phenotypic index for feet and legs was used to group these variables, the effect was highly significant (P < 0.001). Therefore, a means to improve longevity is through phenotypic selection of replacement gilts based on exterior traits: gilts with 13 or less good teats or with extreme feet and leg scores should be culled. From a genetic point of view, sows with the best value in the current index for exterior traits had a lower risk of culling (P < 0.01), and therefore, it is possible to obtain a response for sow longevity via indirect selection for exterior traits. From 1999 to 2003, the trend has been to eliminate extreme animals on exterior traits. This may partly explain the improvement of sow length of productive life longevity from 560 d in 2000 to nearly 710 d in 2003 observed in the data set.     

Influence of gestation energy level on the production of Large White x Landrace sows

Sixty-four Large White x Landrace primiparous sows were utilized to evaluate the influence of feeding 6 vs 9 Mcal ME/d during gestation on reproductive performance. The sows remained on their respective gestation diets for four parities if they successfully farrowed, rebred and conceived. Sows fed 9 Mcal ME/d gained more weight (P less than .05) through the gestation period during parities 1 and 2 and were heavier (P less than .01) on d 110 of gestation for combined parities. Lactation weight loss was greater (P less than .05) for the sows fed 9 Mcal ME/d, resulting in similar weights at weaning. Ultrasonic backfat measurements were greater (P less than .01) on d 110 of gestation for sows fed 9 Mcal ME/d during parity 1 and remained higher (P less than .01) through the fourth-parity gestation. Although sow weaning weights were similar, sows receiving 6 Mcal ME/d scanned less backfat thickness. Gestation treatment significantly affected consumption of a common lactation diet provided ad libitum. Sows fed 6 Mcal ME/d during gestation consumed an average of 22 kg more feed (P less than .01) during lactation than those sows receiving 9 Mcal ME/d. Litter performance as measured by number and weights of pigs born alive and weaned was not altered (P greater than .10) by gestation energy intake. Days to return to estrus and the number of sows remaining in the study for four parities were similar (P greater than .10) between the two treatment groups. The number of farrowings for the four parities totaled 164, with 83 and 81 farrowings for the sows fed 6 and 9 Mcal ME/d, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

大白猪繁殖性状的相关及通径分析

对大白母猪总产仔数,活产仔数,出生窝重,出生均重,断奶仔数,28日龄断奶均重,28日龄断奶窝重7个性状进行相关分析、偏相关分析和通径分析。结果表明各繁殖性状在表型值上都存在不同程度的相关。28日龄断奶仔数和28日龄断奶均重对28日龄断奶窝重影响最大,在此基础上建立估计28日龄断奶窝重的最优回归方程为:y^=-11.4892+2.4946X5+6.0171X6。     

长大、长本和内江母猪繁殖成绩调查分析

本研究调查了97头农民散养哺乳母猪（其中长大二杂母猪33头,长本二杂母猪33头,内江母猪31头）的繁殖成绩,结果表明,在窝产间隔、窝产仔数、产活仔数、断奶窝重上,长本二杂母猪、内江母猪表现正常,长大二杂母猪在断奶窝重上表现较好成绩,但其余3项指标差,存在着严重的繁殖障碍,问题在于圈舍规划不合理、营养水平不科学和饲养管理技术不成熟.     

Threshold-linear estimation of genetic parameters for farrowing mortality, litter size, and test performance of Large White sows

Up to 109,447 records of 49,656 Large White sows were used to evaluate the genetic relationship between number of pigs born dead (BD) and number born alive (BA) in first and later parities. Performance data (n = 30,832) for ultrasound backfat (BF) at the end of the test and days to reach 113.5 kg (AD) were used to estimate their relationships with BD and BA at first parity in a four-trait threshold-linear analysis (TL). Effects were year-farm, contemporary group (CG: farm-farrowing year-farrowing month) and animal additive genetic. At first parity, estimates of heritability were 0.09, 0.09, 0.37, and 0.31 for BA, BD, AD, and BF, respectively. The estimate of genetic correlation between BD and litter size was -0.04 (BD-BA). Corresponding values with test traits were both -0.14 (BD-AD, BD-BF). Estimates of genetic correlation between BA and performance traits were 0.08 (BA-AD) and 0.05 (BA-BF). The two test traits were moderately negatively correlated (-0.22). For later parities, a six-trait (BD, BA in three parities) TL model was implemented. The estimates of additive genetic variances and heritability increased with parity for BD and BA. Estimates of heritabilities were: 0.09, 0.10, and 0.11 for BD, and 0.09, 0.12, and 0.12 for BA in parities one to three, respectively. Estimates of genetic correlations between different parities were high (0.91 to 0.96) for BD, and slightly lower (0.74 to 0.95) for BA. Genetic correlations between BD and BA were low and positive (0.02 to 0.17) for BA in Parities 1 and 2, but negative (-0.04 to -0.10) for BA in Parity 3. Selection for increased litter size should have little effect on farrowing piglet mortality. Intense selection for faster growth and increased leanness should increase farrowing piglet mortality of first-parity sows. A repeatability model with a simple correction for the heterogeneity of variances over parities could be implemented to select against farrowing mortality. The genetic components of perinatal piglet mortality are independent of the ones for litter size in the first parity, and they show an undesirable, but not strong, genetic association in second parity.     

配种前补饲对绵羊繁殖性能的影响

选择健康、空怀、膘情中等以上的细毛母羊274只分为3组（试验Ⅰ组87只、试验Ⅱ组92只、对照组95只），比较孕前补饲对绵羊情期受胎率、总受胎率、产羔率等繁殖性状的影响。结果表明，试验组与对照组母羊的情期受胎率、双羔率差异显著（P〈0．05）。因此在配种前搞好放牧抓膘和补饲，是提高母羊繁殖性能的重要措施。     

A comparison of seasonal effects on fertility of Landrace and Large White sows in a subhumid tropical environment

Forty sows comprising equal numbers of Landrace (LR) and Large White (LW) breeds were studied for 20 months to determine the effects of dry and rainy seasons on their fertility traits in Nigeria. Ambient temperature (14.0-35.5 degrees C) was lowest at night and highest in the day and peaked during the dry season. A relative humidity range of 60-82% peaked during the late rainy season. LR produced 218 and 278 piglets from 23 and 28 litters, while LW produced 193 and 316 piglets from 20 and 30 litters during dry and rainy seasons respectively. Fertility traits did not differ significantly between the breeds due to season (P greater than 0.05). Mean post-weaning oestrus at 10.9 and 9.0 days and preweaning mortality rates of 14.2% and 16.9% during dry and rainy seasons for LR differed significantly (P less than 0.5) from those of LW which were 12.2 and 8.2 days and 14.5% and 18.9% respectively. The significance of seasonal effects on sow fertility and necessary management techniques are discussed.