【作者】 刘强；

【导师】 杨利国；

【作者基本信息】 华中农业大学 ， 特种经济动物饲养， 2011， 硕士

【摘要】 我国奶水牛业有巨大的发展潜力,农业部也明确提出在奶业生产能力薄弱的南方地区大力发展奶水牛产业带。然而,目前存在水牛产奶量和繁殖力“双低”的问题严重制约了奶水牛产业的发展。其中,繁殖性能直接关系着水牛生产和养殖效益,也是生产可持续发展的重要条件之一。水牛产后生殖机能恢复情况直接反映繁殖性能的优劣,产后子宫复旧和卵巢功能恢复对确保产后水牛再次受孕及缩短产犊间隔非常重要。从国外引进奶水牛杂交改良本地水牛,是提高产奶量的重要举措。然而,由于引进的水牛为河流型,染色体核型为2n=50,而本地水牛为沼泽型,染色体核型为2n=48,导致其杂交后代染色体具多态性(2n=50,2n=49和2n=48),产生非整倍性,繁殖性能更低。因此,阐明杂交水牛繁殖机能,最大限度挖掘杂交水牛繁殖潜能、开发繁殖新技术对成功建立奶水牛产业带具有重要的意义。目前,国外对河流型水牛产后生殖机能恢复的研究比较多,国内对沼泽型水牛也做了一些相关研究,但对杂交后代的研究资料则很少。本研究通过应用B-超诊断技术分析杂交奶水牛产后生殖机能恢复的规律,旨在为人工调控产后杂交母水牛的发情周期,促进卵泡发育与成熟排卵和提高杂交奶水牛繁殖效率以及养殖经济效益提供理论依据。主要内容如下：1、杂交奶水牛产后子宫复旧及其影响因素的研究(1)杂交母水牛产后子宫颈、孕角、空角的复旧时间分别为33.5±4.1 d(n=31)、34.4±6.1 d(n=31)和31.5±5.3d(n=31),空角复旧速度最快,子宫颈次之,孕角复旧所需时间最长。(2)分析影响产后子宫复旧的因素,发现产后患胎衣不下、子宫炎症等产科疾病的母水牛子宫复旧时间(45.0±7.3 d,n=5)显著长于正常产犊母水牛(32.8±3.2d,n=26)(P<0.05)；夏季产犊母水牛子宫复旧时间(38.4±4.0d,n=5)明显长于其他三季产犊的母水牛；高产奶量组(34.9±3.2 d,n=12)与低产奶量组(32.8±4.5d,n=19)产后子宫复旧的时间差异并不显著(P>0.05)；尼杂、摩杂和三元杂交水牛产后子宫复旧的时间分别是34.0±4.7 d(n=21)、32.7±3.0 d(n=7)和333±2.5 d(n=3)(P>0.05)；体况评分为2.5、3.0、3.5、4.0分的母水牛产后子宫复旧的时间分别是33.0±2.0 d(n=3)、34.5±5.1 d(n=12)、33.2±3.8 d(n=14)、32.5±2.1 d(n=2)(P>0.05)；体重在500kg以下、500-700kg、700kg以上的母水牛子宫复旧时间分别为34.8±5.9 d(n=6)、33.1±3.5 d(n=17)、34.0±4.1 d(n=8)(P>0.05)。这些结果表明,子宫内膜炎、胎衣不下等产科疾病和分娩季节显著影响杂交奶水牛产后子宫复旧速度(P<0.05),而产奶量、杂交品种、分娩时膘情及体重对产后子宫复旧没有显著影响(P>0.05)。2、杂交奶水牛产后卵巢机能恢复及排卵规律的研究(1)杂交奶水牛产后空角一侧卵巢机能恢复明显比孕角一侧卵巢快,77.3%(17/22)的母水牛产后第一次排卵发生在空角一侧卵巢。(2)杂交奶水牛产后首次排卵的平均时间为产后40.6±11.0 d(n=22),产后第二次排卵的平均时间为57.3±10.0 d(n=22),产后第一次和第二次排卵的平均间隔时间(发情周期)为16.6±4.5 d。大部分水牛首次排卵前没有发情表现(81.8%,18/22),第二次排卵前优势卵泡的最大平均直径18.3±2.6 mm(n=22),比第一次排卵前优势卵泡的最大平均直径16.7±2.4 mm(n=22)大。由此可见,产后卵巢活动恢复时间晚及安静发情比例高是水牛产犊间隔时间长的原因之一(3)大多数杂交母水牛产后第一个排卵周期由2个(54.5%,12/22)或3个(22.7%,5/22)卵泡发生波组成,主要为2个。2波杂交母水牛第1波、第2波分别出现在发情周期第1.7±0.6d(n=12)和第10.3±1.9 d(n=12),3波母水牛第1波、第2波、第3波分别出现在发情周期第1.6±0.6 d(n=5)、第9.6±1.1 d(n=5)、第16.2±1.3 d(n=5)。(4)第一次排卵后,56%(9/16)的产后杂交母水牛形成的黄体发育异常,其中,有36.6%(6/16)的母水牛发生持久黄体,有18.8%(3/16)的母水牛黄体持续时间较短。第一次排卵后形成非正常黄体的比例高是造成水牛比荷斯坦牛繁殖力低、发情配种效果不佳的主要原因之一更多还原

【Abstract】 There is great potential of long-term development for the buffalo industry in China, especially in southern where milk production capacity is very poor. Furthermore, milk yield and fertility of buffaloes are so low that seriously restrict the development of buffalo industry. Reproductive performance of buffalo has effects on its milk production and breeding efficiency, which is one of the important conditions for produce sustainable development. Recovery of reproductive function directly affects the reproductive performance in postpartum buffalo. Postpartum uterine involution and ovarian function recovery are very important to ensure the buffalo pregnant again and shorten the calving interval. Introduction of excellent buffalo varieties from overseas to crossbreeding local buffaloes is a very useful way to improve buffalo milk yield. In order to successfully establish buffalo industry, we must clarify and improve the reproduction function of hybird buffalo, and develop new reproductive technologies. Moreover, because of the difference of the chromosome number between the abroad-introduced river buffaloes (2n=50) and the local swamp buffaloes (2n=48), the Chromosome number (2n) of the offsprings varies among 48,49 and 50, which leads to an even lower fertility due to the aneuploidy of chromosome. Currently, many abroad studies focused on recovery of reproductive function in river buffalo, and domestic researches were interested in swamp buffalo. However, research in the hybrid buffalo is very few. Attempt to provide a theoretical basis for improve fertility and economic benefits of dairy buffaloes, this study is investigating the law of uterine involution and ovarian function resumption of hybrid buffaloes by B-mode ultrasound during postpartum. The results are as follows:1. Study of uterine involution and factors influencing in postpartum hybrid dairy buffaloes.(1) The involution interval of postpartum female buffalo’s uterine cervix, pregnant horn, un-pregnant horn are 33.5±4.1 days (n=31),34.4±6.1 days (n=31),31.5±5.3 days (n=31). respectively. Involution speed of un-pregnant horn is fastest, and uterine cervix is second, involution interval of pregnant horn is longest.(2) Compared to the uterine involution interval (32.8±3.2 days, n=26) of normal female buffalo, the uterine involution intervalof female buffalo with placenta retention and endometritis (45.0±7.3 days，n=5) is significantly delayed (P< 0.05).The uterine involution interval (38.4±4.0 days,n=5) of female buffalo which calving in the summer is significantly longer than other seasons. There was no significant difference of the uterine involution interval between high-(34.9±3.2 days, n=12) and low-(32.8±4.5 days, n=19) milk production group (P>0.05).The uterine involution interval of Nili-Ravi×Jianghan Buffalo, Murrah×Jianghan Buffalo and triple cross Buffalo are 34.0±4.7 days (n=21), 32.7±3.0 days (n=7) and 33.3±2.5 days (n=3) respectively, there’s no significant difference (P> 0.05). The uterine involution interval of body condition score (2.5,3.0,3.5 and 4.0) in postpartum female Buffaloes is 33.0±2.0 days (n=3),34.5±45.1 days (n=12), 33.2±3.8 days (n=14),32.5±2.1 days (n=2) respectively, there’s no significant difference (P>0.05). The uterine involution interval of body weight less than 500 kg,500-700 kg, more than 700 kg in female Buffaloes is 34.8±5.9 days (n=6),33.1±3.5 days (n=17), 34.0±4.1 days (n=8) respectively, there’s no significant difference (P> 0.05).These results indicate that obstetric diseases, such as endometritis, placenta retention and others, and calving saeson significantly affect the rate of uterine involution in postpartum dairy Buffaloes (P< 0.05). Howerever, milk yield, hybrid varieties, BCS and body weight have no significant effect on postpartum uterine involution of dairy Buffaloes (P> 0.05).2. Study of resumption of ovarian activities and ovulation in postpartum hybrid dairy buffaloes.(1) Follicular activity started earlier in the ovaries contralateral to the gravid horn compared to the ipsilateral ovaries and most of ovulation in the same ovaries during the first 25 postpartum days. And the fisrt time ovulation after calving occurs in the ipsilateral ovaries accounted for 77.3%(17/22).(2) The average interval of the fisrt ovulation time after calving is 40.6±11.0 days (n=22), and the second ovulation time is Day 57.3±10.0 (n=22). The average interval of estrus cycle is 16.6±4.5 days. The fisrt ovulation time of the most water buffaloes (81.8%, 18/22) without show estrus. The maximum average diameter of the dominant follicle before the second ovulation time (18.3±2.6 mm) is larger compared wtih the first ovulation time (16.7±2.4 mm). These results indicate that postpartum delayed resumption of ovarian activity and the high proportion of silent estrus is the main reason of buffalo calving interval for a long time. (3) 2 (54.5%,12/22) or 3 (22.7%,5/22) follicular waves were discovered in one estrous cycle in the most hybrid female buffaloes and the former was dominant. Follicular wave 1 and 2 emerged on day 1.7±0.6,10.3±1.9 in hybrid female buffaloes for 2 follicular wave model. Follicular wave 1,2 and 3 emerged on day 1.6±0.6,9.6±1.1 and 16.2±1.3 for 3 follicular wave model, respectively.(4) After the first ovulation time of postpartum female buffaloes, the formation ol" persistent corpus luteum accounted for 36.6%(6/16), while 18.8%(3/16) corpus luteum of female buffaloes were maintain a very short time. In other words,56%(9/16) corpus luteum of female buffaloes development abnormally which are produced after the first ovulation time. These results suggest that the high proportion of the abnormal corpus luteum which is produced after the first time ovulation in buffaloes, is one of the reasons caused Buffalo’s fertility lower and estrus and breeding less effective than Holstein.更多还原