荷斯坦奶牛冷配情况下的情期受胎率

新疆呼图壁种牛场牧一场1955年建立,舍饲荷斯坦奶牛已有五十多年的历史,1979年开始使用冷冻精液人工授精繁殖技术。1980年新疆呼图壁种牛场培育的中国荷斯坦奶牛新疆品系获“国家科技进步三等奖”。几十年来该场一直走自繁自育的发展道路,目前全群饲养规模900余头,成母牛近500头。现对该场多年来奶牛情期受胎率的统计分析如下,仅供业内人士参考借鉴。     

中国荷斯坦奶牛空怀期对受胎率影响的探讨

对南通市某奶牛场746头次中国荷斯坦奶牛从2011年12月到2012年4月的繁殖受胎情况进行了统计分析,结果表明：产后60d内不适宜配种;产后60～180d内的牛与产后180～210d的牛配种差异极显著（P〈0．01）。     

新疆地区荷斯坦奶牛冷配情况下的情期受胎率

新疆呼图壁种牛场牧一场1955年建立,舍饲荷斯坦奶牛已有五十多年的历史,1979年开始使用冷冻精液人工授精繁殖技术．1980年新疆呼图壁种牛场培育的中国荷斯坦奶牛新疆品系获“国家科技进步三等奖”。几十年来该场一直走自繁自育的发展道路,目前全群饲养规模900余头,成母牛近500头。通过对该场多年来奶牛情期受胎率的统计分析,仅供业内人士参考借鉴。     

胎次和配种月份对荷斯坦奶牛受胎率影响的研究

受胎率是衡量奶牛繁殖性能的重要指标 ,也是影响奶牛业经济效益的直接因素。为了解在我省高原气候条件和自然状态下 ,胎次和配种月份对荷斯坦奶牛受胎率的影响规律 ,笔者根据西宁某奶牛场多年的生产记录作了此项研究 ,以便为生产单位合理组织生产提供理论依据。1　材料与方法1.1　材料西宁某奶牛场 1993年至 2 0 0 0年奶牛的配种、产犊记录。1.2　方法根据配种、产犊记录 ,首先按胎次统计出参配牛头数、情期数、妊娠头数 ,计算出牛群的第一情期受胎率和平均受胎率 ;再按配种月份统计出参配牛头数、妊娠头数、情期数 ,计算出牛群的平均受胎率…     

南北舍温度差对荷斯坦奶牛受胎率的影响

在兵团农八师大量引进荷斯坦奶牛之后,由于受本地地理环境、人为环境、自然环境等因素的影响,使其在繁殖性能方面受到了不同程度的影响,造成了荷斯坦奶牛受胎率的下降,本试验是在其它试验条件基本一致的前提下就南北舍由于地理方位差异造成的光照温度差对荷斯坦奶牛受胎率是否有影响以及影响是否显著进行了研究。试验牛共计190头,牛舍分为1、2、3号舍,每个舍分为南、北两面。结果表明:由于南北舍的温度差造成了荷斯坦奶牛受胎率的不同,并且是南面牛舍荷斯坦奶牛的受胎率要高于北面牛舍荷斯坦奶牛的受胎率。南面牛舍试验牛在产后70d内配上的百分比要显著高于北面。     

影响荷斯坦奶牛受胎率的气候因子的分析

通过对广州市1982到1991年荷斯坦成年母牛6897头和青年母牛1508头的月均情期受胎率与同期的主要气候因子进行分析发现,温度是影响成年母牛受胎率的第一位因子,其直接作用大于间接作用。日照时数是仅次于温度和营养条件的第3位因子。相对湿度和风速直接作用较小。笔者提出的几个估计妊娠率的回归方程,可为牛奶生产者参考。     

不同因素对情期受胎率影响初探

不同因素对情期受胎率影响初探宋宝芹陈有家（黑龙江省８５４农场畜牧技术中心１５８４０３）李娟（黑龙江省畜牧兽医学校）影响奶牛情期受胎率的因素很多，我们结合实际，对现有牛群进行调查和统计分析。对其中几个主要因素进行了初步探讨。１母牛胎次对情期受胎率的影响...     

腧穴生物电技术可提高奶牛情期受胎率

本试验以经络学为理论基础,并根据经穴具有相对低电阻特征,其低电阻变化与内在脏腑机能状态密切相关为依据,针对发情奶牛在其卵泡发育及其在发育过程中对生殖激素的要求,在相对腧穴低阻敏感点的雁旁、卵巢和肾旁穴进行无针电脉冲刺激,分析引起相应腧穴阻抗失衡。其与直肠检查结果吻合率为７８％以上;同时后可使奶牛机体分别释放出１７β－雌二醇和孕酮,经过３～５ｇ后激素释放达峰值;经过相关腧穴雁旁、卵巢和肾旁的无针电脉     

应用小剂量黄体酮提高奶牛情期受胎率

为了寻求提高奶牛受胎率的新途径，我们于１９９７年３月至１９９８年１０月对４６头母牛进行应用小剂量黄体酮提高奶牛受胎率的试验，取得满意效果。１试验材料１．１药物：国营天津和平制药厂生产的黄体酮，规格１mL×２０mg×１支。１．２试验牛：庆丰２０队户养奶牛４６头，发情较明显，生殖道无炎症，卵巢机能正常，饲养管理基本相同，胎次为２～７胎。１．３冻精：购自黑龙江省家畜繁育指导站０．２５mL细管冻精，公牛号为９０１３６。２方法与步骤２．１于１９９７年３月１日至１９９８年１０月３１日每月随机选择相同头数和胎次的…     

注射国产LRH-A对产后母牛卵巢活动、发情和受胎的作用

<正> 引言 促性腺激素释放激素(GnRH)是下丘脑神经内分泌细胞分泌的一种释放激素。由于本身结构和功能上的特点,自七十年代初人工合成后,GnRH及其类似物被广泛用于牛繁殖的研究和生产中。国外有报道认为GnRH有促进产后母牛发情周期恢复,缩短产后空怀天数等作用。国内用LRH-A提早牦牛产后发情和受胎收到良好效果。     

促排卵3号在荷斯坦供体母牛超排中的应用效果

采用CIDR＋FSH＋PG法对114头进口新西兰荷斯坦供体母牛进行超排。其中LRH—A3处理60头，共回收卵651枚，回收率95．0％（651／685），可用胚362枚，头均6．0枚，可用率56．0％；对照组54头未用LRH—A3处理，共回收卵526枚，回收率93．8％（526／561），可用胚总数250枚，头均4．6枚，可用率47．6％。结果表明，LRH—A3对荷斯坦母牛超数排卵有显著影响。     

不同季节不同生产因素对荷斯坦奶牛性控冻精人工输精受胎率的影响

为研究不同季节、不同胎次、不同发情方式及不同泌乳天数等因素对奶牛单个情期受胎率的影响,选取2169头奶牛进行统计分析。结果显示,奶牛秋冬季配种受胎率较春夏季高,冬季情期受胎率显著高于春、夏两季（P＜0.05）,初产奶牛情期受胎率高于经产奶牛（P＜0.01）,自然发情情期受胎率极显著高于同期发情药物处理奶牛（P＜0.01）,不同泌乳阶段对受胎率影响不大（P＞0.05）。     

The economic value of days open in Holstein cows in Japan based on simulated changes in conception rate

Increasing herd‐life length and culling parity with increasing conception rate (CR) is necessary to increase lifetime profit from dairy cow production. Economic values of days open (DO) were determined by calculating changes in fertility traits, herd‐life length, and milk yield when the simulated CR were changed in increments of 1% from ?5% to 5% from the basal levels, which were obtained for Hokkaido and regions other than Hokkaido separately. When CR increased, number of artificial inseminations, DO, and milking length decreased. Furthermore, culling parity, and annual milk yield increased. Herd‐life length increased in Hokkaido and decreased in the other regions. The economic values of CR were 1,623.8 to 946.8 yen and of DO were 857.4 to 399.0 yen. Relative economic values of milk yield to days open per genetic standard deviation were higher in the other regions than in Hokkaido where the economic effect of selection for DO was expected to be equal to selection for 305‐day milk yield and herd life. If the survival rate of multipara cows in the other regions increases, then the economic value of DO would similarly increase in Hokkaido.     

同窝公母比例不等对留种母猪受胎率的影响研究

按同窝中公猪所占百分经不同，利用计算机分区统计了31682头留种母猪的受胎率。结果表明，同窝公母比例对母猪受胎率的影响效果明显（P＜0．05）。因此同窝中公猪所占比例高于60％时，该窝母猪不宜作种用。     

The effect of nutrition on conception rate in beef cows at cumberland house, Saskatchewan

The conception rate of cows in the Cumberland House area of Saskatchewan fed native forage grown in the area was observed to be unacceptably low. Supplementation with 12g of calcium and of phosphorus daily, and provision of cereal silage seemingly improved conception rates. It would appear that phosphorus may have been the first limiting nutrient and that a portion of the improved pregnancy rate was due to phosphorus supplementation. The low energy content of the forage, especially in years when it was badly weathered, was also judged to be a factor in conception rate in the subsequent year. It was also noted that there is a potential widespread phosphorus problem for beef cattle in Saskatchewan based on Feed Testing Service analyses of feeds.     

Effect of time of progesterone supplementation on serum progesterone and the conception rate of cooled Holstein heifers during the summer

To investigate the effects of progesterone supplementation at two different times on serum progesterone (P₄) concentration, conception rate and resynchronization of cooled Holstein heifers in summer, 90 heifers were randomly assigned to two groups: (i) heifers subjected to TAI (timed artificial insemination) and progesterone supplementation from days 4 to 14 after TAI (S_1; n = 45); and (ii) heifers under the same TAI protocol as S₁ and progesterone supplementation from days 17 to 22 after TAI (S₂; n = 45). The groups S₁ and S₂ were cooled 10 days before and 21 days after TAI. Respiratory rate, body surface temperature, vaginal temperature and rectal temperature recorded during the experiment were not different (P > 0.05) between S₁ and S₂ groups. Progesterone concentration was not different (P > 0.05) in S₁ compared to S₂. The conception rates on days 30 and 55 were similar between groups (P > 0.05). Progesterone supplementation did not increase either conception rate or concentrations of P₄ in heifers during the summer. Heifers not pregnant to first service in the group S₂ were resynchronized (77.7%) for a second breeding.     

LRH-A3 and HCG increase pregnancy rate during timed artificial insemination in dairy cows

The objective of this study was to use luteinizing hormone-releasing hormone A3 (LRH-A3) and human chorionic gonadotrophin (HCG) to improve pregnancy rate of dairy cows during timed artificial insemination (TAI). In experiment 1, the TAI process (0 d, GnRH, 100 μg; 7 d, PGF2α, 0.4 mg; 56 hr, GnRH, 100 μg; 16 hr, AI) was applied to 160 dairy cows on 50th and 60th days after parturition respectively. In experiment 2, 320 postpartum dairy cows were treated with TAI (Group A), TAI + 25 μg LRH-A3 (Group B), TAI + 1,500 IU HCG 5 days after AI (Group C), and TAI + 25 μg LRH-A3 + 1,500 IU HCG 5 days after AI (Group D). In experiment 3, endometrial cells were treated with HCG. The results showed that TAI did not affect the pregnancy rate, while LRH-A3 and HCG increased the pregnancy rate of the cow. HCG of 5 IU/ml and 10 IU/ml increased the expressions of leukemia inhibitory factor but decreased those of interleukin-6, epidermal growth factor and vascular endothelial growth factor in endometrial cells. This study provided a plan for the use of LRH-A3 and HCG to increase pregnancy rate during TAI in dairy cows.     

LRH-A3对母猪繁殖性能的作用及效果观察

为了观察促排卵素3号（LRH-A3）对母猪繁殖性能的作用和效果，发情母猪配种前4—6h，用LRH-A3进行处理，并与不使用激素的发情母猪进行比较。结果地方品种母猪的受胎率、平均产仔数、仔猪成活率分别为93．3％、14．6头和89．5％。与对照组相比，母猪受胎率无显著差异（P〉0．05），平均产仔数显著高于对照组（P〈0．01），仔猪成活率比对照组低4．6％，差异显著（P〈0．01）。经产瘦肉型母猪的配种受胎率、平均产仔数、仔猪成活率分别为86．7％，12．3头和93．8％，与对照组相比，配种受胎率、仔猪成活率无显著性差异（P〉0．05），母猪平均产仔数显著高于对照组（P〈0．01）。青年瘦肉型母猪的配种受胎率、平均产仔数、仔猪成活率分别为83．3％、10．6头和94．5％，与对照组相比，母猪的配种受胎率、平均产仔数均显著高于对照组（P〈0．01），仔猪成活率与对照组无显著差异（P〉0．05）。试验结果表明，发情母猪配种前肌注LRH-A3后，青年瘦肉型母猪繁殖效果最理想，经产瘦肉型母猪次之，地方品种母猪不理想。     

用LRH-A3治疗屡配不孕母猪的效果观察

用LRH-A3治疗连续配种2、3、4个情期屡配不孕母猪40头,经配种输精受胎32头,受胎率为80%,窝平均产仔10.34头.试验组受胎率和产仔数比对照组分别提高57.78个百分点和1.84,差异极显著(P＜0.01).LRH-A3对连续配种输精2个情期不孕母猪治疗效果最好,3个情期不孕次之,4个情期不孕效果最差.LRH-A3可极显著提高屡配不孕母猪受胎率和产仔数,但对患生殖道炎症和生殖机能衰退引起的不孕无效.