Genomewide association for a dominant pigmentation gene in sheep

Most published genomewide association studies (GWAS) in sheep have investigated recessively inherited monogenic traits. The objective here was to assess the feasibility of performing GWAS for a dominant trait for which the genetic basis was already known. A total of 42 Manchega and Rasa Aragonesa sheep that segregate solid black or white coat pigmentation were genotyped using the SNP50 BeadChip. Previous analysis in Manchegas demonstrated a complete association between the pigmentation trait and alleles of the MC1R gene, setting an a priori expectation for GWAS. Multiple methods were used to identify and quantify the strength of population substructure between black and white animals, before allelic association testing was performed for 49 034 SNPs. Following correction for substructure, GWAS identified the most strongly associated SNP (s26449) was also the closest to the MC1R gene. The finding was strongly supported by the permutation tree‐based random forest (RF) analysis. Importantly, GWAS identified unlinked SNP with only slightly lower p‐values than for s26449. Random forest analysis indicated these were false positives, suggesting interpretation based on both approaches was beneficial. The results indicate that a combined analytical approach can be successful in studies where a modest number of animals are available and substantial population stratification exists.     

长途运输和体外保存对美利奴肉羊胚胎移植效果的影响

为研究远距离运输及鲜胚体外保存时间超过5h对胚胎移植效果的影响,将超数排卵供体羊与同期发情的受体羊两地饲养,并将取自供体羊的新鲜胚胎于体温下经直线距离超过300km的长途运输后,移植到受体羊体内。结果发现,供、受体羊经同期发情处理后,其发情率分别为100%和97.9%,供体羊输卵管冲胚获得胚胎数平均为13.5枚/只;受体羊产羔率为79.2%,略高于鲜胚直接移植的产羔率。由此可知,只要受体羊的营养状态良好、后期管理得当、胚胎体外保存方法适当,长途运输及体外保存时间超过5h对胚胎移植的效果无明显影响。     

新吉细毛羊5个生殖激素受体基因多态性分析

本研究旨在检测新吉细毛羊促性腺激素释放激素(GnRHR)、促黄体素(LHR)、促卵泡素(FSHR)、催乳素受体(PRLR)、雌激素(ESR)5个生殖激素受体基因多态性,为绵羊繁殖力的标记辅助选择和育种提供理论依据。以119只新吉细毛羊个体为研究对象,利用ABI测序仪检测基因多态性;用DNASTAR软件与I-TASSER软件预测蛋白质三级结构;用Excel计算基因型频率;用GraphPad prism 6软件进行新吉细毛羊群体5个生殖激素受体基因多态性与产羔数的相关性分析。经测序分析发现,FSHR基因不存在突变位点,其余4个基因存在13个突变位点。GnRHR基因存在A505G、G720C突变,LHR基因存在T1262G、A1991G、C2012T、A2032T、T2041A的突变,PRLR基因存在A1263G、C1544G突变,ESR基因存在A106T、C181T、G612A、C735T突变。在新吉细毛羊群体4个基因多态性与产羔数相关性分析结果中,只有ESR基因A106T突变对新吉细毛羊产羔数影响显著。其中AA、AT、TT 3种基因型个体的平均产羔数分别为1.391、1.101、1.417。AA基因型、TT基因型平均产羔数比AT基因型分别多0.290、0.316个(P<0.05)。AA基因型、TT基因型平均产羔数之间差异不显著(P>0.05)。     

Prevention of blowfly strike on coarse and fine woolled sheep with the insect growth regulator dicyclanil

OBJECTIVE: To assess a ready-to-use formulation of dicyclanil to prevent blowfly strike on coarse and fine woolled sheep under New Zealand conditions. DESIGN: Randomized clinical field trials. PROCEDURE: In a first field trial, coarse wooled sheep treated with a ready-to-use, 5% dicyclanil formulation were compared with untreated control sheep for up to 21 weeks. In a second field trial, fine woolled sheep, treated with the same dicyclanil formulation, were compared with untreated sheep for up to 19 weeks. Efficacy was assessed by calculating the aggregated cumulative strike rate. RESULTS: For trial 1 (coarse woolled sheep) the aggregated cumulative strike rate at the end of the trial at week 21 after treatment reached 3.9% and 19.1% for treated and untreated sheep, respectively. For the treated animals the aggregated cumulative strike rate reached the 1% and 2% benchmarks between weeks 11 and 12. For trial 2 (fine woolled sheep) the aggregated cumulative strike rate at the end of the trial at week 19 reached 0.6% and 7.5% for treated and untreated sheep, respectively. Wool length at the time of application did not substantially influence the efficacy of dicyclanil. CONCLUSION: Under New Zealand field conditions, a ready-to-use 5% spray-on formulation of dicyclanil protected coarse woolled sheep for at least 12 weeks and fine woolled sheep for at least 19 weeks.     

冷季放牧补饲对甘肃高山细毛后备母羊瘤胃代谢参数及瘤胃微生物数量的影响

旨在筛选出甘肃高山细毛羊后备母羊科学合理的补饲料,改变牧区由于营养供给不足导致甘肃高山细毛羊2.5岁才能配种的饲养方式。试验选择甘肃高山细毛羊(12月龄)48只,随机分为试验a(1号料)、b(2号料)、c(3号料)组和对照组(不补饲),进行90 d放牧补饲试验。结果表明,1)瘤胃pH试验a组和b组差异极显著(P<0.01)、c组显著(P<0.05)低于对照组,瘤胃氨态氮、蛋白氮、总氮浓度试验组均极显著高于对照组(P<0.01),总挥发性脂肪酸(VFA)试验a组和b组均极显著高于对照组(P<0.01),b组显著高于c组(P<0.05);乙酸和丙酸摩尔比a组极显著高于对照组(P<0.01),b和c组显著高于对照组(P<0.05);丁酸摩尔比a组极显著高于c组(P<0.01);乙/丙b组显著低于对照组(P<0.05)。2)瘤胃纤维降解菌和原虫数目试验组均极显著(P<0.01)或显著(P<0.05)高于对照组。综上所述,补饲均能正向影响甘肃高山细毛羊后备母羊瘤胃代谢参数及瘤胃微生物数量,以1号料补饲效果最优,2号料也能起到理想效果。     

Prevalence of gastrointestinal helminths,lungworms and liver fluke in sheep and goats in Norway

The present study describes the occurrence of various gastrointestinal helminths, lungworms and liver flukes in Norwegian sheep and goats as assessed from faecal samples and post mortem examinations performed between 2007 and 2010. Faecal samples for gastrointestinal nematode egg counts were collected from 77 sheep flocks and 30 dairy goat flocks from three geographical regions in Norway. Additionally, thirty-two lambs and 16 adult goats were euthanized for necropsy examination and for identification of adult gastrointestinal nematodes and tapeworms, lungworms and liver flukes. The survey showed that there was a higher mean excretion of trichostrongyle eggs in sheep than in goats at the individual level (392 EPG vs. 154 EPG, p < 0.001). For both host species, the mean prevalence and intensity of excreted trichostrongyle eggs were significantly higher in the southern coastal region compared with the inland and northern regions (p < 0.001). Third stage larvae of Trichostrongylus/Teladorsagia, Haemonchus and Nematodirus type were the most prevalent ones in the coprocultures from sheep, whereas larvae of Trichostrongylus/Teladorsagia and Nematodirus type dominated in goats. The most prevalent gastrointestinal nematode species found at necropsy was Teladorsagia circumcincta (75.0 and 81.2% respectively in sheep and goats), while the largest mean worm burdens were recorded for Haemonchus contortus in sheep (724 ± 623) and T. circumcincta in goats (377 ± 529). Other gastrointestinal nematode species were present at low prevalence or in low numbers.     

A mail survey of factors affecting performance in 627 selected sheep flocks in south-eastern Norway

Abstract

Factors influencing rate of barren ewes, number of lambs born per pregnant ewe, and autumn live weight of the lambs were studied in 627 Norwegian sheep flocks based on herd level data from the Norwegian Sheep Recording System and a mailed questionnaire to the sheep farmers. The following factors were significantly associated (P<0.05) with rate of barren ewes: breed, herd average lambing date, type of production/age of farmer, routines for treatments for parasites, and housing type. Number of lambs born per pregnant ewe was significantly associated with rate of barren ewes, herd average lambing date, breed, percentage grass silage of total roughage, and no separation of gimmers during the housing period. Corrected autumn live weight of the lambs was significantly associated with breed, flock size, lambs born per pregnant ewe, no separation of gimmers during the housing period, and type of summer pasture.     

Seroprevalences for ovine enzootic abortion in Switzerland

Our aim was to assess the seroprevalence of Chlamydophila (Cd) abortus (Chlamydia psittaci serotype 1), denoted ovine enzootic abortion (OEA), in the Swiss sheep population. A competitive enzyme-linked immunosorbent assay (cELISA) was adapted for the investigation of pooled serum samples (pool approach) and receiver-operator characteristic (ROC) analysis was applied to define the cut-off of the pool approach. At a cut-off value of 30% inhibition, the flock-level pooled sensitivity and specificity were 92.9% and 97.6% when compared to classifying the flock based on individual-animal samples.

Subsequently, sera from 775 randomly selected flocks out of 11 cantons of Switzerland were investigated using the pool approach. The cantons included in the study represented 72% of the Swiss sheep flocks and 76% of Swiss sheep population. Antibodies against Cd. abortus were found in almost 19% (144) of the 775 examined sheep flocks. Test prevalences were adjusted for the imperfect test characteristics using the Rogan–Gladen estimator and Bayesian inference. Seroprevalence was highest (43%) in the canton Graubünden. In the remaining 10 cantons the seroprevalence ranged from 2 to 29%. The cELISA in combination with testing pooled sera and statistical methods for true prevalence estimation provided a good survey tool at lower costs and time when compared to other approaches.     

人胰岛素原基因转染绵羊成纤维细胞及细胞株的建立

从动物耳皮肤组织采样 ,采用将组织块剪碎后直接贴附于培养瓶底部的方法进行原代培养 ,该方法使原代细胞出现率及可传代率均达到 10 0 %。根据上皮样细胞和成纤维样细胞贴壁紧实程度的不同 ,用 0 .0 5 %的胰蛋白酶-EDTA对其进行消化 ,可将两种不同类型的细胞进行分离和纯化。通过脂质体介导 ,以BLG -hINS(含乳球蛋白调控基因的人胰岛素原基因 )基因作为目的基因、GFP(绿色荧光蛋白 )基因作为标记基因共转染绵羊成纤维细胞 ,经G - 4 18筛选后 ,得到转染细胞。对转染的细胞分别用单细胞显微操作法和有限稀释法进行细胞克隆 ,两种方法均可得到克隆细胞。选形态正常、生长均匀的 5个细胞克隆进行PCR检测 ,结果 5个克隆均转有GFP基因 ,其中两个转有BLG -hINS基因。高代培养细胞、转染细胞和克隆细胞经核型分析后 ,染色体数目均为 2 7对 ,表明绵羊耳的成纤维细胞建立细胞株后 ,可以作为外源基因转染的有效供体细胞。