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《Animal : an international journal of animal bioscience》2015,9(2):208-217
Market failures are the main cause of poor acknowledgement of the true impact of functional sheep traits on the management and economic performance of farms, which results in their omission from the breeding goal or the estimation of non-representative economic weights in the breeding goal. Consequently, stated-preference non-market valuation techniques, which recently emerged to mitigate these problems, are necessary to estimate economic weights for functional traits. The purpose of this paper is to present an example of the use of a choice experiment (CE) in the estimation of economic weights for sheep traits for the design of breeding goals. Through a questionnaire survey the preferences of sheep farmers are recorded and their marginal willingness to pay (MWTP) for 10 production and functional traits is estimated. Data are analysed using random parameter logit models. The results reveal unobserved preference heterogeneity for fertility, adaptability to grazing and resistance to disease, thus highlighting that these traits are appreciated differently by farmers, because their needs are diverse. Positive MWTP is found for Greek breeds, high milk production and lambs with low fat deposition, for which there is high demand in Greek markets. On the other hand, MWTP for the cheese-making ability of milk is negative, stemming from the fact that sheep milk prices in Greece are not formulated according to milk composition. In addition, farmers seem to understand differences between udder shapes and attribute different values to various types. This application of the CE method indicates that communication channels among farmers and breeders should be established in order to enhance market performance and to provide orientation to the design of breeding programmes. Non-market valuation can be used complementarily to market valuation techniques, in order to provide accurate estimates for production and functional traits. 相似文献
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Genetic parameters were estimated for birth-, 42-day, and 100-day (weaning) weight in the Dorper flock of the Glen Agricultural Institute in South Africa. Direct heritability estimates of 0.11, 0.28 and 0.20 and maternal heritability estimates of 0.10, 0.10 and 0.10 were obtained for body weights at birth, 42 and 100 days, respectively. The corresponding genetic correlation estimates between direct and maternal effects were 0.35, −0.63 and −0.58, respectively. Both direct and maternal genetic correlation estimates among the traits were of moderate to high magnitude and positive. It is concluded that the traits can be improved by selection with no serious antagonisms among traits studied. 相似文献
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Krupová Z Wolfová M Krupa E Oravcová M Daňo J Huba J Polák P 《Animal : an international journal of animal bioscience》2012,6(3):440-448
The objective of this study was to carry out a sensitivity analysis on the impact of various production strategies and performance levels on the relative economic values (REVs) of traits in dairy sheep. A bio-economic model implemented in the program package ECOWEIGHT was used to simulate the profit function for a semi-extensive production system with the Slovak multi-purpose breed Improved Valachian and to calculate the REV of 14 production and functional traits. The following production strategies were analysed: differing proportions of milk processed to cheese, customary weaning and early weaning of lambs with immediate sale or sale after artificial rearing, seasonal lambing in winter and aseasonal lambing in autumn. Results of the sensitivity analysis are presented in detail for the four economically most important traits: 150 days milk yield, conception rate of ewes, litter size and ewe productive lifetime. Impacts of the differences in the mean value of each of these four traits on REVs of all other traits were also examined. Simulated changes in the production circumstances had a higher impact on the REV for milk yield than on REVs of the other traits investigated. The proportion of milk processed to cheese, weaning management strategy for lambs and level of milk yield were the main factors influencing the REV of milk yield. The REVs for conception rate of ewes were highly sensitive to the current mean level of the trait. The REV of ewe productive lifetime was most sensitive to variation in ewe conception rate, and the REV of litter size was most affected by weaning strategy for lambs. On the basis of the results of sensitivity analyses, it is recommended that economic values of traits for the overall breeding objective for dairy sheep be calculated as the weighted average of the economic values obtained for the most common production strategies of Slovak dairy sheep farms and that economic values be adjusted after substantial changes in performance levels of the traits. 相似文献
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目的 羊毛是高档纺织原料,羊毛的物理性质直接关系到羊毛品质。本研究旨在挖掘影响羊毛性状的基因,探索影响羊毛性状的复杂分子机制。方法 本研究选取萨福克羊和小尾寒羊各3只作为试验样本,取背部皮肤组织,采用转录组学（RNA-seq）和蛋白质组学测序分析造成羊毛性状差异的基因、蛋白质及相关信号通路。结果 转录组测序表明：测序完成后,共得到230 406 674个原始数据和222 049 370个干净数据,其中Q20碱基百分比为99.9%以上,Q30碱基百分比为98%以上。以差异倍数FC≥1.4或FC≤0.714且P<0.05作为标准,由此筛选出1 213个差异表达基因（DEGs）,其中萨福克羊与小尾寒羊相比,上调基因有644个,下调基因有569个。GO富集发现中间丝、钙离子结合、角蛋白丝显著富集,表明其可能与羊毛性状相关。KEGG富集发现,影响羊毛性状的信号通路可能是ECM-受体相互作用。蛋白质组测序表明：以差异倍数FC≥1.4或FC≤0.714且P<0.05作为标准,由此筛选出99个差异表达蛋白（DEPs）,其中萨福克羊与小尾寒羊相比,上调蛋白有47个,下调蛋白有52个。GO富集... 相似文献
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Francis Barillet Rachel Rupp Sandrine Mignon-Grasteau Jean-Michel Astruc Michèle Jacquin 《遗传、选种与进化》2001,33(4):397-415
Genetic analysis for mastitis resistance was studied from two data sets. Firstly, risk factors for different mastitis traits, i.e. culling due to clinical or chronic mastitis and subclinical mastitis predicted from somatic cell count (SCC), were explored using data from 957 first lactation Lacaune ewes of an experimental INRA flock composed of two divergent lines for milk yield. Secondly, genetic parameters for SCC were estimated from 5 272 first lactation Lacaune ewes recorded among 38 flocks, using an animal model. In the experimental flock, the frequency of culling due to clinical mastitis (5%) was lower than that of subclinical mastitis (10%) predicted from SCC. Predicted subclinical mastitis was unfavourably associated with the milk yield level. Such an antagonism was not detected for clinical mastitis, which could result, to some extent, from its low frequency or from the limited amount of data. In practice, however, selection for mastitis resistance could be limited in a first approach to selection against subclinical mastitis using SCC. The heritability estimate of SCC was 0.15 for the lactation mean trait and varied from 0.04 to 0.12 from the first to the fifth test-day. The genetic correlation between lactation SCC and milk yield was slightly positive (0.15) but showed a strong evolution during lactation, i.e. from favourable (-0.48) to antagonistic (0.27). On a lactation basis, our results suggest that selection for mastitis resistance based on SCC is feasible. Patterns for genetic parameters within first lactation, however, require further confirmation and investigation. 相似文献
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Association of the heart fatty acid-binding protein (FABP3) gene with milk traits in Manchega breed sheep 总被引：5，自引：0，他引：5
The ovine fatty acid-binding protein type 3 gene has been chosen as a functional candidate gene for milk traits. Two different single nucleotide polymorphisms (SNPs) of ovine FABP3 gene have been tested in a daughter design comprising 13 families. No association was found between estimated breeding values for milk yield, protein and fat contents (FC) and genotypes across families using anova and transmission disequilibrium test (TDT). In within-family analysis, one family showed a significant effect for FC. These results could indicate linkage disequilibrium between the FABP3 gene and a quantitative trait loci (QTL) for FC, with the heterozygous genotype associated with a positive effect in this trait. 相似文献
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阿黑皮素原(Pro-opiomelanocortin, POMC)在动物采食和能量平衡调控中发挥重要作用, 文章对绵羊POMC基因外显子3进行扩增和测序, 筛选多态性位点, 并分析多态位点与湖羊和东弗里生×湖羊杂种羊生长性状的相关性。测序后发现湖羊POMC基因外显子3有2个单碱基突变(g.273 T/C和g.456 G/A), 根据273位点处发生的T/C突变, 建立PCR-RFLP分析方法, 并对162只湖羊和130只东湖杂种羊进行检测分析。结果发现, 在湖羊群体中检测到TT(0.469)、TC(0.438)和CC(0.093)3种基因型, 而在东湖杂种羊群体中仅检测到TT(0.754)和TC(0.246)两种基因型。POMC基因外显子3的273位点多态性与生长性状的相关性研究结果显示：湖羊群体中CC基因型个体的2月龄断奶重、4月龄尻高及TC基因型个体4月龄体长和管围均显著高于TT型个体(P<0.05); CC基因型个体的4月龄重、6月龄重极显著高于TT和TC基因型个体(P<0.01); CC基因型个体的4月龄体高和体长极显著高于TT型个体(P<0.01), 且显著高于TC基因型个体(P<0.05)。此外, CC型个体的管围极显著高于TT基因型个体(P<0.01)。东湖杂种羊群体中TC基因型个体的2月龄断奶重、4月龄重及4月龄体高、体长、胸深和管围都显著高于TT型个体(P<0.05), TC型个体的6月龄重极显著高于TT型个体(P<0.01)。研究结果表明, POMC基因外显子3与绵羊生长性状相关, C等位基因对体重及体尺性状的增加更有利。该结果为进一步探讨POMC基因作为绵羊生长性状的辅助选育标记奠定了基础。 相似文献
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母体遗传效应对青海细毛羊生产性能遗传参数估计的影响 总被引：3，自引：0，他引：3
为了研究母体遗传效应对青海细毛羊生长性状、产毛性状的影响,文章采用平均信息最大约束似然法应用不同混合动物模型估计青海细毛羊生产性状的遗传参数,并采用似然比检验对不同模型进行比较分析。各模型中均包括固定效应、个体直接加性遗传效应、残差效应;随机效应为:个体永久环境效应、母体遗传效应、母体永久环境效应。不同模型对随机效应作了不同考虑:模型1不考虑个体永久环境效应、母体遗传效应、母体永久环境效应;模型2考虑母体永久环境效应;模型3考虑母体遗传效应;模型4考虑母体遗传效应和母体永久环境效应;模型5考虑个体永久环境效应和母体遗传效应;模型6考虑个体永久环境效应、母体遗传效应、母体永久环境效应。各模型估计的初生重遗传力为:0.1896~0.3781;断奶重遗传力为:0.2537~0.2890;周岁重遗传力范围:0.2244~0.3225;成年羊体重遗传力范围:0.2205~0.3983;产毛量遗传力为:0.1218~0.1490;羊毛细度遗传力为:0.0983~0.4802;羊毛长度遗传力为:0.1170~0.1311。与模型1相比,模型3对于初生重、断奶重差异显著(P<0.01),对于周岁重、成年羊体重各模型与模型1的似然比检验差异不显著(P>0.05);与模型6相比,模型4、5对于羊毛细度差异显著(P<0.01),模型4对羊毛长度差异显著(P<0.05),对于产毛量各模型与模型6似然比检验差异不显著(P>0.05)。生长性状中初生重、断奶重受母体遗传效应影响显著,周岁重、成年羊体重受母体遗传效应影响不显著;产毛性状中羊毛细度、长度受母体遗传效应影响显著,产毛量受母体遗传效应影响较弱。 相似文献
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Pritchard TC Cahalan CM Ap Dewi I 《Animal : an international journal of animal bioscience》2008,2(10):1421-1426
The UK national scrapie plan (NSP) for sheep is based on selection for the resistant ARR/ARR genotype and elimination of susceptible types of the ovine prion protein (PrP) gene. The aim of this study was to estimate the possible association of the PrP genotype and performance traits by using data from the CAMDA Welsh Mountain flock. Four alleles (ARH, ARQ, ARR and VRQ) and 10 genotypes covering all five NSP risk groups were present in the CAMDA flock. Overall, the most common allele was ARR (35.2%), and VRQ was the least common (5.4%). The commonest genotypes were ARR/ARQ (23.7%) and ARR/AHQ (23.1%). The most resistant genotype, ARR/ARR, and the most susceptible genotype, VRQ/VRQ, were found in 10.2% and 0.3%, respectively, of the population tested. The associations of PrP genotypes with weight and ultrasonically scanned traits were investigated in three analyses, the first using genotypes, the second using risk categories and the third using number of alleles. These associations were evaluated by univariate analysis of each trait using an animal model with maternal effects where appropriate, and PrP was included as a fixed effect. Selection for scrapie resistance will not adversely affect progress in the traits considered and is consistent with improvements in muscle depth. 相似文献
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为了研究母体遗传效应对青海细毛羊生长性状、产毛性状的影响, 文章采用平均信息最大约束似然法应用不同混合动物模型估计青海细毛羊生产性状的遗传参数, 并采用似然比检验对不同模型进行比较分析。各模型中均包括固定效应、个体直接加性遗传效应、残差效应; 随机效应为：个体永久环境效应、母体遗传效应、母体永久环境效应。不同模型对随机效应作了不同考虑：模型1不考虑个体永久环境效应、母体遗传效应、母体永久环境效应; 模型2考虑母体永久环境效应; 模型3考虑母体遗传效应; 模型4考虑母体遗传效应和母体永久环境效应; 模型5考虑个体永久环境效应和母体遗传效应; 模型6考虑个体永久环境效应、母体遗传效应、母体永久环境效应。各模型估计的初生重遗传力为：0.1896~0.3781; 断奶重遗传力为：0.2537~0.2890; 周岁重遗传力范围：0.2244~0.3225; 成年羊体重遗传力范围：0.2205~0.3983; 产毛量遗传力为：0.1218~0.1490; 羊毛细度遗传力为：0.0983~0.4802; 羊毛长度遗传力为：0.1170~0.1311。与模型1相比, 模型3对于初生重、断奶重差异显著(P<0.01), 对于周岁重、成年羊体重各模型与模型1的似然比检验差异不显著(P>0.05); 与模型6相比, 模型4、5对于羊毛细度差异显著(P<0.01), 模型4对羊毛长度差异显著(P<0.05), 对于产毛量各模型与模型6似然比检验差异不显著(P>0.05)。生长性状中初生重、断奶重受母体遗传效应影响显著, 周岁重、成年羊体重受母体遗传效应影响不显著; 产毛性状中羊毛细度、长度受母体遗传效应影响显著, 产毛量受母体遗传效应影响较弱。 相似文献
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Abstract. In order to develop and evaluate control strategies for blowfly strike, a greater understanding of the epidemiology is essential. A postal survey of sheep farmers yielded information about ten farm and management factors and their relationship to blowfly strike prevalence. The risk of a farm reporting at least one case of blowfly strike increased as flock size and stocking density increased (adjusted odds ratio of 1.13 for an increase in flock size of 100 sheep and 1.38 for an increase in stocking density of ten sheep per hectare). As farm altitude increased, the risk of blowfly strike decreased (adjusted odds ratio 0.67 for an increase in farm altitude of 100 m). The risk of high strike prevalence (more than 2% of sheep struck) decreased as both farm altitude and flock size increased. High strike prevalence was also associated with on-farm sheep carcase disposal (odds ratio 1.35). Farmers in the south-west of England were more likely to report at least one case of blowfly strike and high strike prevalence compared to all other regions. 相似文献
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Fatty acid-free bovine serum albumin (BSA(FAF)) can be added to supplement medium used in the culture of sheep embryos. BSA(FAF) was able to support blastocyst and subsequent embryo development at rates equivalent to that of fetal calf serum (FCS)-supplemented medium when fresh embryos were transferred. Furthermore, culture with BSA(FAF) significantly increased development of vitrified blastocysts transferred into synchronized sheep. The addition of the glycosaminoglycan, hyaluronan (HA) to the culture medium in the third and fifth day also increased cryo-tolerance of blastocysts and in turn lambing rate was improved. 相似文献
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Gbangboche AB Glele-Kakai R Salifou S Albuquerque LG Leroy PL 《Animal : an international journal of animal bioscience》2008,2(7):1003-1012
The objectives of this study were to compare the goodness of fit of four non-linear growth models, i.e. Brody, Gompertz, Logistic and Von Bertalanffy, in West African Dwarf (WAD) sheep. A total of 5274 monthly weight records from birth up to 180 days of age from 889 lambs, collected during 2001 to 2004 in Betecoucou breeding farm in Benin were used. In the preliminary analysis, the General Linear Model Procedure of the Statistical Analysis Systems Institute was applied to the dataset to identify the significant effects of the sex of lamb (male and female), type of birth (single and twin), season of birth (rainy season and dry season), parity of dam (1, 2 and 3) and year of birth (2001, 2002, 2003 and 2004) on the observed birth weight and monthly weight up to 6 months of age. The models parameters (A, B and k), coefficient of determination (R2), mean square error (MSE) were calculated using language of technical computing package Matlab®, 2006. The mean values of A, B and k were substituted into each model to calculate the corresponding Akaike’s Information Criterion (AIC). Among the four growth functions, the Brody model has been selected for its accuracy of fit according to the higher R2, lower MSE and AIC. Finally, the parameters A, B and k were adjusted in Matlab®, 2006 for the sex of lamb, year of birth, season of birth, birth type and the parity of ewe, providing a specific slope of the Brody growth curve. The results of this study suggest that Brody model can be useful for WAD sheep breeding in Betecoucou farm conditions through growth monitoring. 相似文献
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B. Moioli M. C. Scatà G. De Matteis G. Annicchiarico G. Catillo F. Napolitano 《Animal genetics》2013,44(5):601-603
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凉山半细毛羊微卫星标记与羊毛性状的相关分析 总被引：19，自引：3，他引：19
利用微卫星技术对凉山半细毛羊核心育种群206个个体第1、2、3、9号染色体上的18个微卫星位点进行研究, 检测其基因型, 利用SAS 程序下的GLM对18个微卫星位点与羊毛性状的关系进行方差分析和多重比较, 结果发现7个微卫星位点对部分羊毛性状存在显著或极显著影响, 同时, 在这些位点上找到对羊毛性状有利的基因型。 相似文献
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J. M. Milner† S. D. Albon A. W. Illius‡ J. M. Pemberton‡ T. H. Clutton-Brock§ 《The Journal of animal ecology》1999,68(3):472-488
1. Long-term studies allow the outcomes of repeated selection events to be monitored. Here, we investigate phenotypic selection in successive winter mortality events in the Soay sheep of St Kilda, Scotland, between 1985 and 1996. Selection of three quantitative morphometric traits, body weight, hindleg length and incisor arcade breadth, was investigated in different sectors of the population.
2. Evidence from fitness differentials of positive directional selection for large size was repeatedly found in lambs and adult females. Selection in the opposing direction was only found in one year in lambs.
3. Selection gradients showed that in most years when significant selection occurred, body weight was the focus of direct selection, whereas selection of hindleg length and incisor breadth was indirect, arising from their correlation with body weight.
4. Selection was strongest in years of low over-winter survival and almost absent in years when survival was high. Intensity of selection was greatest in lambs, emphasizing the differences in selection pressure experienced by different sectors of the population, in addition to the temporal variation in selection pressure due to population density and environmental conditions.
5. Despite repeated positive selection of body weight, no evidence of a change in the population mean was found over the course of the study. 相似文献
2. Evidence from fitness differentials of positive directional selection for large size was repeatedly found in lambs and adult females. Selection in the opposing direction was only found in one year in lambs.
3. Selection gradients showed that in most years when significant selection occurred, body weight was the focus of direct selection, whereas selection of hindleg length and incisor breadth was indirect, arising from their correlation with body weight.
4. Selection was strongest in years of low over-winter survival and almost absent in years when survival was high. Intensity of selection was greatest in lambs, emphasizing the differences in selection pressure experienced by different sectors of the population, in addition to the temporal variation in selection pressure due to population density and environmental conditions.
5. Despite repeated positive selection of body weight, no evidence of a change in the population mean was found over the course of the study. 相似文献