不同生产期对澳美型鄂尔多斯细毛羊羔羊初生重的影响

为了探讨不同生产期对澳美后代(即用澳美公羊授精鄂尔多斯细毛羊母羊所产羔羊)初生重的影响,该试验选取400只基础母羊,随机分为4组(全部试验羊的日粮水平及饲养管理条件均相同),分别在不同月份授精,待妊娠母羊产羔后,记录其初生重。结果发现,2009年1、2、3、4月妊娠母羊所产单羔的平均初生重依次为(4.81±0.51)、(4.30±0.68)、(3.95±0.70)、(3.98±0.47)kg,双羔的平均初生重依次为(4.03±0.85)、(3.08±0.24)、(3.08±0.53)、(2.87±0.40)kg;2010年1、2、3、4月妊娠母羊所产的羔羊单羔平均初生重分别为(5.43±0.63)、(4.63±0.55)、(4.60±0.73)、(4.54±0.63)kg,双羔的平均初生重分别为(4.10±0.48)、(3.30±0.94)、(3.28±0.68)、(3.10±0.18)kg。由此可见,澳美后代羔羊的初生重与生产期有密切关系,1—4月出生的澳美后代羔羊的初生重呈下降趋势,其中,1月出生的羔羊其初生重均高于2、3、4月出生的羔羊,且每年1月与4月出生羔羊的初生重差异均显著(P<0.05)。     

Relationships among steroid hormone levels in newborn piglets,birth weight,placental weight,vitality of offspring and litter size

Blood estrone sulfate (E₁S), estrone (E₁), estradiol (E₂) and progesterone (P₄) in newborn piglets were measured to clarify the relationships among birth and placental weight, vitality of offspring and litter size. First, the association between vital status (normal, weak and stillborn) from 165 newborn piglets of 18 litters and steroid concentrations; second, steroid concentrations from 152 newborn normal piglets and litter size; and third, steroid content in fetal placenta from 50 newborn normal piglets of six litters and litter size, were investigated. In the normal group, the birth and placental weight were significantly higher than those in the other groups. Blood E₁S levels in the stillborn group were significantly lower, whereas E₁, E₂ and P₄ were significantly higher compared to the normal group. Blood and placental E₁S levels in the small litter group were significantly higher than those in the other groups. However, there was no significant difference among the three litter size groups in the levels of steroid hormones in maternal blood. These results indicate that vitality of newborn piglets is related to E₁S concentration of neonate, to birth weight and placental weight. However, steroid hormone concentrations of newborn piglets were greatly affected by the number of littermates.     

母羔自身因素与其超排卵母细胞数量的相关性分析

为讨论羔羊自身因素与其超排后卵母细胞数量的关系,选取6～8周龄的健康杜晋绵羊（杜泊羊（o）×晋中绵羊♀）母羔31只,进行超数排卵,手术法收集卵母细胞,统计其卵母细胞数量,分析其与全同胞羔羊数、初生重、超排时体重的相关性.结果表明：全同胞羔羊数与卵母细胞数量呈极显著负相关（P＜0.01）,初生重与卵母细胞数量呈极显著正相关（P＜0.01）;超排时体重与卵母细胞数量相关不显著（P＞0.05）.全同胞羔羊数和初生重是羔羊超排卵母细胞数量的影响因素,但仍需进一步增加羔羊数量来验证.     

半胱胺对大鼠出生重及血浆生长激素,生长抑素含量的影响

选用１２只Ｗｉｓｔａｒ受孕大鼠进行配对实验，从确定受孕开始，实验母鼠每周了半胱胺（ＣＳ）１次，剂量为８０ｍｇ．ｋｇ＾－１ＢＷ，直至分娩，分娩后立即称仔鼠出生重有房，肝，肺，肾湿重，并用ＲＩＡ法测定血浆血浆生长抑素（ＳＳ）和生长激素（ＧＨ）含量，结果ＣＳ能明显提高仔鼠出生重，降低仔鼠血浆ＳＳ含量；并使母鼠血浆ＳＳ含量明显下降，ＧＨ水平显著提高，结果提示，ＣＳ能促进胎儿的宫内发育，而这种作用与ＣＳ耗竭     

Genetic analysis of twinning rate and milk yield using a threshold‐linear model in Japanese Holsteins

The objective of this study was to estimate genetic parameters and breeding values for the twinning rate of the first three parities (T1, T2 and T3) and 305‐day milk yield in first lactation (MY), using a four‐trait threshold‐linear animal model in Japanese Holsteins. Data contained 1 323 946 cows calving between 1990 and 2007. Twinning was treated as a binary character: ‘single’ or ‘twin or more’. Reported T1, T2 and T3 were 0.70%, 2.87%, and 3.73%, respectively. Individual 305‐day milk yield was computed using a multiple trait prediction for cows with at least eight test‐day records. (Co)variance components were estimated via Gibbs sampling for randomly sampled subsets. Posterior means of heritabilities for T1, T2 and T3 were 0.11, 0.16 and 0.14, respectively. Genetic correlations between parities were 0.92 or greater. Genetic correlations of MY with twinning rate were not ‘significant’ (i.e. their 95% highest probability density intervals contained zeros). Multiple births at different parities were considered as the same genetic trait. The average evaluations of T1 (T2) for sires born before 1991 was 0.48% (2.25%) compared with a mean of 0.76% (3.37%) for sires born after 1992. A recent increase in the reported twinning rate reflects the positive genetic trend for sires in Japanese Holsteins.     

安徽现代生育文化建设思路研究

与生育政策和行政干预相比，现代生育文化对生育行为的影响更具根本性。加强对传统生育文化的改造，推进现代生育文化建设，是新时期人口计生工作的重要任务。本文基于生育文化的发展规律和我省的实际情况，提出了我省应从加强舆论宣传着手，重点加强对流动人口、学生群体和地方党政干部的宣传教育来推进现代生育文化建设，并对这种舆论宣传所依存的硬环境和软环境作了阐述。     

RYRl基因对母猪繁殖性能的影响

用 PCR- RFL P法检测 2 2 5头大约克母猪的 RYR1(ryanodine receptor,RYR1)基因 ,它具有 NN、Nn和 nn3种基因型 ,其频率分别为 0 .76、0 .14和 0 .10 ;等位基因 N和 n的基因频率分别为 0 .83和 0 .17。该基因处于遗传不平衡状态 (P<0 .0 1)。具有 NN、Nn和 nn基因型母猪第 1胎产仔数分别为 10 .2 1、9.6 2和 8.2 2头 ;断奶仔猪数分别为9.2 1、8.13和 7.11头。等位基因 n使仔猪断奶应激效应具上升趋势 ,对增重有不利影响 ;降低母猪的产仔数和仔猪成活率 ,对繁殖性能有不良的遗传效应 ,有必要从母猪群中清除该等位基因。     

湖羊初生重性状影响因素分析及遗传力估计

【目的】研究旨在分析场、出生季节、出生月份、出生类型和性别对湖羊初生重性状的影响,并估计该性状的遗传力。【方法】运用SAS 9.2软件对2021年新疆地区3个规模化湖羊养殖企业共计4 570只母羊所产的8 352只羔羊初生重作非遗传因素分析,使用DMU软件对湖羊初生重性状进行方差组分估计,并使用两种单性状动物模型估计该性状的遗传力,根据赤池信息准则(Akaike’s information criterion,AIC)确定最佳固定效应组合和动物模型。【结果】场、出生季节、出生月份、出生类型和性别对湖羊的初生重均有极显著影响(P＜0.01)。场1和场2羔羊初生重无显著差异(P＞0.05),且均极显著大于场3羔羊的初生重(P＜0.01);冬季出生的羔羊的初生重整体较大,其中以1月出生的羔羊初生重最大;出生类型越丰富,其羔羊初生重越小,各出生类型间羔羊初生重均呈现出极显著差异(P＜0.01);根据单性状动物模型(考虑母体效应)的计算得出,湖羊初生重性状的直接、母体、总体遗传力分别为0.251、0.668、0.211,属于中等遗传力。【结论】在对羊场首年的生产数据分析时,选用出生月份作为时令因素相比出生季节更为合适,不仅可以剖析各月份养殖单位湖羊的生产情况以做出相应的繁殖计划调整,而且选用月份固效组可增加性状遗传参数估计值的准确性;对于湖羊初生重性状在不考虑母体效应的情况下,会导致该性状的遗传力估计值偏大,故在受母体效应影响较大的早期阶段理应优先考虑母体效应。     

《马贩子的女儿》赏析

《马贩子的女儿》是劳伦斯的一部有着明显写实框架和坚实生活内容的小说。作者用寥寥数笔道出了一家三兄弟和一个妹妹在马贩子父亲死后家道中衰,树倒猢狲散之前各自的心态,勾勒出了三个兄弟冷漠丑陋的小市民嘴脸,以及对那个孤立无援的小妹妹的同情。该小说取胜的主要原因是他在叙事中使用了两个重要的原型:北欧神话之命运三女神;《圣经》故事中夏娃的诞生与堕落。