Exogenous eFSH, follicle coasting, and hCG as a novel superovulation regimen in mares

The objective of this study was to evaluate various equine follicle-stimulating hormone (eFSH) treatment protocols and the effect of “follicle coasting” on ovulation and embryo recovery rates in mares. Cycling mares (n = 40) were randomly assigned to one of four groups 7 days after ovulation: (1) 12.5 mg eFSH twice daily until follicles were 35 mm or larger; (2) 12.5 mg eFSH twice daily until follicles were 32 mm or larger; (3) 12.5 mg eFSH twice daily for 3.5 days followed by 12.5 mg eFSH enriched with luteinizing hormone (LH) twice daily until follicles were 35 mm or larger; and (4) 25 mg eFSH once daily until follicles were 32 mm or larger. Mares in groups 1 and 3 were injected with human chorionic gonadotropin (hCG) (2500 IU intravenously) at the end of eFSH treatment, whereas mares in groups 2 and 4 were given hCG approximately 42 and 54 hours, respectively, after the last eFSH treatment (“follicle coasting”). Nonsurgical embryo collection was performed 6.5 to 7.5 days after ovulation. Each mare experienced a nontreated estrous cycle before being reassigned to a second treatment. Ovulation rates for mares in treatment groups 1 to 4 were 3.3 ± 0.4, 4.1 ± 0.4, 3.5 ± 0.4, and 2.8 ± 0.4 (mean ± SEM; P < .05), respectively. One or more embryos were recovered from more than 80% of mares in each treatment group, and embryo recovery rate per flush was similar among treatment groups (1.9 ± 0.3, 2.6 ± 0.3, 1.9 ± 0.3 and 1.9 ± 0.3, respectively; P > .05). The overall embryo recovery rate was 2.1 ± 1.5 embryos per flush. In summary, ovulation rate was higher for mares treated with eFSH (3.4 ± 0.4) compared with non-treated controls (1.1 ± 0.2). Ovulation rate in mares in which hCG was delayed (follicle coasting) was higher (P < .05) when treatments were given twice per day versus once per day. Administration of equine luteinizing hormone (eLH) in conjunction with eFSH did not have an advantage over mares treated only with eFSH.     

应用鸭胚组织培养液酶活性进行蛋鸭早期选种的研究

根据亲代产蛋性能,将10个家系320个13日龄的鸭胚分成Ⅰ和Ⅱ两组,进行活组织培养,测定培养液中的碱性磷酸酶(AKP)和谷草转氨酶(GOT)的活性。结果:AKP活性与其亲代产蛋指数、半同胞姐妹鸭的开产日龄和500日龄产蛋数有密切相关,其相关系数分别为0.8736、-0.6616和0.7954;GOT活性与上述性能的相关系数分别为-0.7737、0.4331和-0.9024。AKP活性高、GOT活性低的Ⅰ组比AKP活性低、GOT活性高的Ⅱ组,其半同胞姐妹鸭开产日龄提早18.8天(P<0.01);500日龄产蛋数多21.8个(P<0.05)。AKP和GOT活性的遗传力分别为0.7993和0.3410,它们间的关系为负相关,相关系数为-0.8641。根据鸭胚组织培养液中的AKP和GOT的活性,对蛋鸭进行早期选种,比常规选种法可提早半年。     

天祝抓喜秀龙草原区旅游发展现状与制约因素调查

结合天祝抓喜秀龙地区草原旅游资源特点,对当地草原旅游发展状况进行分析,探寻制约其发展的主要因素,提出扩大宣传、加强管理、合理配置资源等解决对策。     

胚胎冻融技术及其在我国肉羊产业中的应用

胚胎冻融技术可使胚胎移植不受时间、地点的限制,从而达到提高胚胎移植效率的目的,研究和优化胚胎冻融技术对胚胎移植工程的发展具有重要的意义。主要对胚胎冻融技术的原理、特点及其在肉羊产业中的应用情况进行了综述,旨在阐明胚胎冻融技术对我国肉羊产业发展的重要作用。     

猪繁殖与呼吸综合征疫苗的研究进展

猪繁殖与呼吸综合征(PRRS)是由猪繁殖与呼吸综合征病毒(PRRSV)引起的严重危害世界养猪业的一种传染病,该病可造成猪的繁殖障碍、呼吸系统病症与生长受阻。本文着眼于PRRSV疫苗的免疫原性、保护效力和安全性,涉及市场上现有的商品化疫苗与已报道的处于试验阶段的相关疫苗研究成果,以期为PRRSV的防控与疫苗研发提供有益的参考。     

塞北兔生长发育及生长曲线的拟合

采用Logistic非线性动物生长模型拟合塞北兔初生到6月龄的平均体重,进行生长曲线分析．结果表明：①根据Logistic生长曲线方程原理,确定了塞北兔生长曲线方程参数a=24．2593,b=0．9297,并对方程进行了拟合,建立了塞北兔生长曲线方程y^^=6596．5589／（1＋24．259 3e^-0.9297x）（P〈0．05）;②Logistic方程能很好的拟合塞北兔的生长过程,拟合度均在0．95以上,生长的拐点时间为3．43月龄,拐点体重为3298．28g,极限体重参数6596．5589g。     

细胞因子对绵羊体外受精胚胎发育的影响

绵羊卵巢采自乌鲁木齐市屠宰场，卵母细胞体外成熟24－25h后，由体外获能的附睾精子授精，50h后，将卵裂至2－8细胞的绵羊胚胎移入添加了不同浓度细胞因子的培养液中继续培养，结果表明，加入5、10、15μg/ml胰岛素（Insulin)分别得到17.46%、23.81%、22.95%的囊胚率，与对照组9.52%相比差异显著（P＜0.05)。高浓度（500μg/ml)的粒细胞巨噬细胞集落刺激因子（Granulocyte-macrophage colony stimulating factor,GM-CSF)可获得21.82%的囊胚率，与对照组7.27%相比差异显著（P＜0.05)。胚胎培养液中分别加入10、100、500ng/ml的白细胞介素－3（Interleukin-3,IL-3)、白细胞介素－8（IL－8）和神经生长因子（Nuclear growth factor,NGF)与对照组相比，囊胚率差异不显著。本研究表明，胰岛素、GM－CSF对绵羊体外受精胚胎早期发育有促进作用，IL－3、IL－8、NGF对绵羊胚胎的早期发育无明显作用。     

人胚胎角膜的肾上腺素能神经纤维分布及其特点

用乙醛酸诱发灾光技术研究了14－30周胎儿眼结膜的肾上腺素能神经纤维的分布。发现角膜巩缘的肾上腺素能神经纤维主要与角巩膜的血管伴行，纤维数量随胎龄增加而增加，角膜基质层于16周以后有少量纤维，角膜内皮层和上皮层未发现神经纤维。     

优质乳是奶业发展的方向

发展方向决定兴衰存亡。我国奶业经历了30年的快速发展,取得了巨大成就,但是也正在面临发展新方向的抉择。这个新方向就是发展优质乳,需要明确提出"一杯优质牛奶振兴一个民族"的理念。我国有关奶业科研团队,经过近20年的艰苦探索和协同创新,已经形成了适合国情的"优质乳生产的奶牛营养调控与规范化饲养技术"成果并示范应用,示范结果表明,在奶牛生产中使蛋白质饲料利用效率提高8%~15%,乳脂率和乳蛋白率分别达到3.5%和3.1%,牛奶体细胞数低于40万个,细菌总数低于10万CFU/mL,完全达到国际上优质乳的营养品质和卫生安全水平。如何从国家政策的战略设计上进一步明确优质乳的发展方向,积极组织推广优质乳科技成果,大力发展和弘扬优质、健康、向上的奶业文化,应该引起重视。     

獭兔毛密度变化及毛囊分化研究

为了了解獭兔在不同月龄毛囊和毛密度的变化,选择1～7月龄的獭兔为研究对象,通过活体取样,Sacpic法染色,对不同阶段切片进行观察统计,结果表明:毛密度在1～3月龄处于平台期,无显著变化(P0.05);4～7月龄毛密度处于一个波形变动期,其中通过切片观察5～7月龄为全休止期;4～6月龄为换毛期。本研究摸清了毛密度的变化趋势、变化阶段、各阶段毛囊群特点,为獭兔取皮时间的确定及提高毛密度的研究提供理论支撑。