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试验一：在山区牧场采用双盖苗处理８００只母羊，试验结果：小群中水剂双羔苗提高双羔率平均为３５．６５％（１８％－６０％）；油剂双羔苗平均为２２．４２％（１３．６％－３１．２５％）。大群中水剂和油剂双羔苗提高双羔率分别为３２．５％和２０．８％。结果表明，水剂苗明显比油剂苗要好（Ｐ＜０．０１）。试验二：采用双羔苗处理１８６５只母羊，分两种处理。结果表明，注射双羔苗后，激素处理并不影响双羔苗的作用。在大群 相似文献
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应用TIT双羔素不同注射次数对青海半细毛羊进行了免疫试验,共免疫健康母羊939只,试验结果表明,注射了3次TIT双羔素,青海半细毛羊双羔率为10．90％,与注射2次1Tr双羔素(双羔率为7．Ol％)差异显著(P＜O．05)。 相似文献
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多产疫苗对母羊产羔性能的影响及应用的研究 总被引：2，自引：1，他引：1
采用十一酸睾丸素制成多产疫苗主动免疫绵羊以获得母羊多产。 1999年的研究结果表明 ,对 1～ 4岁母羊免疫后 ,产双羔率分别达到 2 5 % ,4 0 % ,6 0 %和 6 5 % ;2 0 0 0年研究则进一步证实 ,主动免疫后 ,母羊的产双羔率可分别达到30 % ,5 0 % ,70 %和 70 % ,显著高于同类产品 (P <0 .0 1)。经过连续 2次免疫后 ,母羊的免疫记忆增强 ,产双羔性能持续表现 ,不同年龄的母羊分别达到 86 %～ 10 0 % (P <0 .0 1)。绵羊双羔技术的研究一直是国内外学者关注的热点 ,曾尝试过多种方法试图将母羊的双羔率提高到 30 %以上。随着工厂化高效养羊的兴起 ,人们对大幅度提高母系列率的要求不断高涨 ,如何顺应这一潮流和需求 ?在实施“规模化高效养羊综合配套技术研究”课题中 ,我们采用生殖免疫技术 ,研制了多胎疫苗 ,并在多个农场进行了实验。现将 1999～ 2 0 0 0年在新疆兵团工一师红旗农场的部分试验结果报告如下 相似文献
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应用具有特异免疫功能的双羔抗原,促使绵羊产双(多)胎是一项被广泛推广使用的先进技术。通过使用外源抗原,可以大大提高绵羊产双羔的比例,加快绵羊繁殖速度,提高畜牧业生产效益。凡是具有潜在怀双胎哺育双羔能力的母羊,均有免疫效果。我们对303只兴安细毛羊进行免疫处理,双羔率54.4％(自然双羔率10％左右),三羔率10.2％,四羔率0.3％。这项技术使用 相似文献
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用注射双羔素的方法研究提高巴什拜羊母羊产羔率。选择经产母羊50只为试验组,并以同一养殖小区内的未经处理的经产巴什拜母羊452只作为对照组,观察测定其产羔率和双羔率。结果2008年试验组50只,产羔61只,产羔率122%。其中产双羔的母羊11只,双羔率22%。对照组452只,产羔464只,产羔率102.66%。其中产双羔的母羊12只,双羔率2.66%。试验组产羔率比对照组提高了19.34%(P<0.01)。结果表明,双羔素可以提高巴什拜羊产双羔率。 相似文献
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这是一种高超的肉羊技术 ,即双胎免疫技术 ,也称双胎苗。它无需专业技术人员操作 ,不需用专门的仪器设备 ,不受场地空间的限制 ,饲养人员自行皮下免疫注射就能提高产羔率。对绵山羊提高产羔率的幅度因其品种和营养水平不同而异。饲养条件好 ,提高幅度大 ;本身产羔率高的品种提高得幅度亦高。对于单胎母羊 ,它能有控制地挖掘母羊自身怀双胎、产双羔及哺育双羔的潜力 ,提高母羊的双羔率 ,而不出现 3羔、4羔。免疫的效果是在羊群体本身自然产羔率的基础上提高双羔率2 0 %～ 5 0 %。饲养条件优越 ,效果越佳。以绵羊为例 ,配种时体重 40 kg以上的… 相似文献
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这是一种高超的肉羊技术 ,即双胎免疫技术 ,也称双胎苗。它无需专业技术人员操作 ,不需用专门的仪器设备 ,不受场地空间的限制 ,饲养人员自行皮下免疫注射就能提高产羔率。对绵山羊提高产羔率的幅度因其品种和营养水平不同而异。饲养条件好 ,提高幅度大 ;本身产羔率高的品种提高得幅度亦高。对于单胎母羊 ,它能有控制地挖掘母羊自身怀双胎、产双羔及哺育双羔的潜力 ,提高母羊的双羔率 ,而不出现 3羔、4羔。免疫的效果是在羊群体本身自然产羔率的基础上提高双羔率2 0 %～ 5 0 %。饲养条件优越 ,效果越佳。以绵羊为例 ,配种时体重 40 kg以上的… 相似文献
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Genetic selection for increased mean and reduced variance of twinning rate in Belclare ewes 
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下载免费PDF全文 D.J. Cottle A.R. Gilmour T. Pabiou P.R. Amer A.G. Fahey 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2016,133(2):126-137
It is sometimes possible to breed for more uniform individuals by selecting animals with a greater tendency to be less variable, that is, those with a smaller environmental variance. This approach has been applied to reproduction traits in various animal species. We have evaluated fecundity in the Irish Belclare sheep breed by analyses of flocks with differing average litter size (number of lambs per ewe per year, NLB) and have estimated the genetic variance in environmental variance of lambing traits using double hierarchical generalized linear models (DHGLM). The data set comprised of 9470 litter size records from 4407 ewes collected in 56 flocks. The percentage of pedigreed lambing ewes with singles, twins and triplets was 30, 54 and 14%, respectively, in 2013 and has been relatively constant for the last 15 years. The variance of NLB increases with the mean in this data; the correlation of mean and standard deviation across sires is 0.50. The breeding goal is to increase the mean NLB without unduly increasing the incidence of triplets and higher litter sizes. The heritability estimates for lambing traits were NLB, 0.09; triplet occurrence (TRI) 0.07; and twin occurrence (TWN), 0.02. The highest and lowest twinning flocks differed by 23% (75% versus 52%) in the proportion of ewes lambing twins. Fitting bivariate sire models to NLB and the residual from the NLB model using a double hierarchical generalized linear model (DHGLM) model found a strong genetic correlation (0.88 ± 0.07) between the sire effect for the magnitude of the residual (VE) and sire effects for NLB, confirming the general observation that increased average litter size is associated with increased variability in litter size. We propose a threshold model that may help breeders with low litter size increase the percentage of twin bearers without unduly increasing the percentage of ewes bearing triplets in Belclare sheep. 相似文献
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A performance data set from 376 Ripollesa purebred ewes of the experimental flock of the Universitat Autònoma of Barcelona was analyzed using a bivariate Bayesian threshold-linear model. The data set contained 1,598 litter size records and 1,699 days-to-lambing records. The model included the additive genetic effect of each animal and 3 nongenetic sources of variation: ewe age, year of lambing, and the permanent environmental effect characterized by the ewe. The flock was phenotypically selected for litter size since 1986, and replacement ewes and rams were selected from the progeny of the more prolific ewes, which had at least 3 deliveries recorded. The phenotypic trend for litter size was positive, whereas days to lambing followed an unclear pattern. Both traits had low heritabilities; 0.13 for litter size and 0.11 for days to lambing. Response to selection was evaluated through (a) the average breeding value of the ewe lambs chosen annually, and (b) the average breeding value of the overall flock. The first measurement suggested a positive trend for litter size, although it showed important oscillations. On the other hand, the average breeding value for the overall flock showed a stable positive tendency after yr 4 of selection, with estimates clearly different from zero after yr 11 of selection. A significant increase in the incidence of multiple births was observed, with a mode of approximately 10%. The correlated response in days to lambing did not show a significant trend. The effect of year of lambing also positively influenced both litter size and days to lambing, although important oscillations were observed between years. Results indicated that litter size in sheep can be effectively improved through phenotypic selection, even in small flocks; moreover, days to lambing could also be genetically improved, given the estimate obtained for its heritability. 相似文献
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Ewes from lines selected for high and low reproductive rate and a control line bred and selected randomly were endoscopically examined 3 to 5 d after breeding to determine ovulation rates in the fall of 1985, 1986 and 1987. Fertility (ewes lambing per ewe exposed), lambing rate (lambs born per ewe exposed) and litter size (lambs born per ewe lambing) were evaluated at lambing in the spring of each year. Embryonic survival was estimated as the number of lambs born per corpora lutea. Ovulation rates were 1.28, 1.73 and 1.46 for low, high and control lines, respectively. More (P less than .01) single ovulations occurred in low-line ewes than in the other two lines; high-line ewes had more (P less than .01) twin ovulations than did low- or control-line ewes. Fertility did not differ among lines. Selection line affected (P less than .01) lambing rate at first and all services. Control-line ewes had mean lambing rates at first and all services that were intermediate between those of the low and high lines, which were different from each other. Line x age of ewe interactions existed (P less than .01) for lambing rate at all services and litter size at first and all services. High-line ewes had lower lambing rates and litter sizes as 2-yr-olds than other lines, but their performance increased steadily to 6-yr-olds, whereas the low and control lines remained relatively constant. Embryo survival differed (P less than .10) between lines, being 74%, 63% and 67% for low, high and control lines, respectively.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Season of lambing and other environmental effects on ewe performance were analyzed for purebred Finnsheep (F), Rambouillet (R), Dorset (D), Targhee (T) and Suffolk (S) and the generations of crosses in development of two maternal composite lines (1/2F1/4R1/4D) and (1/2F1/4T1/4S) in accelerated (January, May and September) or annual April lambing. The data involved 10,959 ewe breeding season records for 4,219 ewes of 412 sire families over 4 yr. Various measures of ewe productivity and its components (fertility, litter size, neonatal and preweaning survival and weaning weight) were analyzed. Fertility was higher for annual April than for accelerated May or January lambing and was sharply lower for September lambing. Fertility of F and F-cross ewes was significantly higher for May and lower for January lambings relative to R and D ewes. Litter size also was higher in annual April (1.9) than in January (1.8) or May (1.7) and September (1.4). Neonatal and preweaning survival was higher in September when litter size was smaller. Mean weaning weights were depressed in the larger April and May litters. Thus, weight of lambs weaned/ewe exposed was higher for annual April than for May and January lambing and was very low for September lambing. Hormone treatment of ewes for September lambing increased fertility from 16 to 44% and litter size from 1.6 to 1.8. Short lambing interval (8 mo vs 12+ mo) reduced mean ewe fertility by five percentage points, and most for the January lambing of Finnsheep ewes. 相似文献
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The reproductive performance of 255 Rambouillet (R), Dorset (D), Finnsheep (F) and F1 ewes born in 1978-1979 (group I) and 1979-1980 (group II) and managed in a semiconfinement fall/winter lambing system was evaluated through 4 yr of age of all ewes and through 5 yr for a portion of group I ewes. Ewes were with rams from approximately May 1 to late September each year, with a 2-wk break late in July/early August. Traits considered were fertility (ewes lambed/ewes exposed), lambing date, litter size, lamb survivial and 70-d lamb weights. Breeds and crossbred groups differed significantly in lambing date, with DR crossbred ewes earliest and F ewes latest. Repeatabilities for groups I and II were .31 and .22, .24 and .24 and .11 and .07 for lambing date, fertility and litter size, respectively. There was no significant heterosis in lambing date, although DR ewes in both groups I and II were superior to (D + R)/2, by about 1 wk on average. There was significant positive heterosis for fertility and traits of which fertility is a component in FR ewes in group I, but none in group II. The FD ewes showed negative heterosis for litter size, -.23 (P less than .05) for group I and -.09 for group II. The results indicate: F and FD ewes are not well adapted to the Mediterranean climate where this experiment was conducted; there is little, if any, useful heterosis in crosses among these three breeds for lambing date or other reproduction traits and RD and R ewes are most suitable of the groups tested, while late onset of the breeding season limits the usefulness of even 50% Finnsheep ewes for an autumn lambing system in this environment. 相似文献
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Leontides L Fthenakis GC Amiridis GS Saratsis P 《Preventive veterinary medicine》2000,44(1-2):113-120
We defined retention of fetal membranes (RFM) in dairy ewes as failure to expel the placenta within 6h after lambing the last lamb and designed a matched case-control study to identify factors that affect the risk of retention. For each ewe with RFM, the next ewe in the flock that lambed and expelled the placenta in <6h after lambing the last lamb was selected as control. Data analyzed included 92 pairs of ewes from 25 flocks comprising a total of 7275 ewes (median flocksize 270 ewes). Factors investigated for associations with RFM were induction of lambing, obstetrical assistance because of dystocia, parity, the number of liveborn lambs, the occurrence of stillbirth(s), the mean weight of the litter on the third day post-lambing and the occurrence of neonatal death in the litter. Conditional logistic regression indicated (1) that the risk of RFM increased linearly with increasing number of liveborn lambs and (2) that the risk of retention was 4-fold higher in ewes that received assistance at lambing than those that lambed normally. 相似文献
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The effects of exogenous melatonin on reproductive performance of 737 Polypay and Polypay-cross ewes were evaluated during a late March and April breeding period. Different concentrations (2 or 10 mg) routes of administration (fed vs implanted) and durations of administration (20 or 40 d before breeding) were studied. Estrus was synchronized in all ewes using 60 mg medroxyprogesterone acetate (MAP) in a vaginal pessary. Number of mature ewes lambing/ewe present at lambing was increased (P less than .05) nearly 20% by implanting for 40 d with melatonin (75%) or by feeding either 2 (72%) or 10 mg (73%) melatonin for 40 d before spring breeding compared with untreated control ewes (54%) or ewes implanted for only 20 d before breeding (58%). Date of lambing, number of lambs born/ewes lambing and number of lambs born alive/ewe lambing were not altered significantly by treatments. Number of yearling ewes (n = 166 for ewes 1.5 yr old at lambing time) lambing/ewe present at lambing was lower (P less than .01; 26%) than that of mature ewes (n = 381, greater than or equal to 2.0 yr; 68%). We concluded that feeding 2 or 10 mg melatonin or implanting melatonin for 40 d enhanced reproductive performance and effectively overcame the restrictions of seasonality of breeding in mature ewes. In yearling ewes, 10 mg melatonin increased the number of ewes lambing. 相似文献
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The analysis focused on model fitting of 2 ewe reproductive traits, litter size, and days to lambing (interval between the introduction of the ram into the flock and the subsequent parturition of the ewes). The experimental data set of the Universitat Autònoma of Barcelona flock was used, including 1,598 records of litter size and 1,699 records of days to lambing from 376 Ripollesa ewes between 1986 and 2005. Univariate and bivariate models were considered as beginning points with linear or threshold approximation for litter size. Model fitting was evaluated in terms of goodness-of-fit and predictive ability, using the mean square error and the correlation between phenotypic and predicted records (rho(y,?)) as reference parameters. The bivariate model was preferable for both variables, minimizing mean square error and maximizing rho(y,?). A threshold approximation for litter size was preferable over a linear approximation. Models were also compared with a simulation study, comparing the correlation coefficient between simulated and predicted breeding values (rho(a,a)). The bivariate threshold model was favored, with a rho(y,?) of 0.677 and 0.834 for litter size and days to lambing, respectively. Correlation coefficients between simulated and predicted breeding values in the bivariate linear model were reduced slightly to 0.651 and 0.831, respectively, and they were lowest with linear univariate models (0.642 and 0.802). Although the bivariate models for ewe litter size and days to lambing were more accurate than the univariate models, the threshold approaches showed a greater advantage under the bivariate model. For the purpose of genetic evaluation of litter size in sheep, use of the threshold-linear model seems justified. In the Ripollesa breed, the evaluation of litter size can benefit from recording birth weight. 相似文献
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By C. Hagger 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2000,117(1):57-64
Fixed effects of age at first litter and of season of lambing as well as variance components for additive genetic, flock × year and sire of litter effects on size of first litter were estimated for an animal model by a derivative-free REML procedure. Data of the four Swiss sheep breeds White Alpine (WAS), Brown-headed Meat (BFS), Black-Brown Mountain (SBS) and Valais Black Nose (SN) were available. Number of first litters used were 21 384, 21 607, 15 013, 12 394 and 18 110 the WAS (two data sets, WAS1, WAS2), BFS, SBS and SN, respectively. Litter size of ewes lambing the first time at 2 years of age was 0.27, 0.31, 0.41, 0.46 and 0.26 lambs larger than of ewes lambing the first time at 1 year of age. The largest increase occurred for the two breeds (BFS, SBS) with the lowest average age at first litter. The largest difference between any two lambing seasons within breed were 0.16, 0.16, 0.29, 0.22 and 0.07 lambs. Estimates of additive genetic variance of size of first litter were between 0.0269 (SN) and 0.0765 (SBS). Heritability estimates for this trait were 0.171, 0.156, 0.114, 0.225 and 0.122 for WAS1, WAS2, BFS, SBS and SN, respectively. A large flock × year component (relative to phenotypic variance) of 0.148 was found for SN, compared with estimates between 0.042 and 0.067 for the other breeds. A sire of litter component (relative to phenotypic variance) of 0.066 was found for SN, compared with estimates between 0.016 and 0.039 for the other breeds. It can be concluded that all nongenetic effects investigated should be taken into account for the estimation of additive genetic variance and breeding values for size of first litter, and that considerable variation in size of genetic and nongenetic effects exists in the sheep breeds under consideration. 相似文献
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黄淮山羊微卫星多态性及其与产羔数相关性的研究 总被引：6，自引：0，他引：6
以绵羊FecB、GDF9和BMP15为候选基因,同时选择绵羊6号染色体与FecB基因紧密连锁的6个微卫星标记,分析其在黄淮山羊中的多态性及其与产羔数的关系。结果表明:在黄淮山羊中均未发现FecB、GDF9基因和BMP15基因突变。微卫星Lscv043、BMS2508、300U、GC101均为多态位点;而GC101与产羔数具有较强的相关性,在GC1013种基因型中200bp/238bp基因型群体对应的第1胎产羔数和第2胎产羔数均显著高于其他2种基因型群体的对应产羔数(P<0.05);但是各基因型群体之间第3胎产羔数差异不明显;同样基因型200bp/238bp对应群体的平均产羔数极显著高于其他2种基因型群体的平均产羔数(P<0.01)。其他位点的不同基因型群体之间产羔数差异均不明显。这些结果表明,FecB基因所在区域位点对山羊产羔数亦具有一定影响,可以作为山羊早期选育的理论依据。 相似文献