Animal Production Research Institute, Agricultural Research Center, 4 Nadi El-Said, 12311 Dokki, Giza, Egypt.
Animal Production Department, Faculty of Agriculture (El-Shatby), Alexandria University, Alexandria 22545, Egypt.
J Dairy Sci. 2017 Jun;100(6):5028-5039. doi: 10.3168/jds.2016-12240. Epub 2017 Apr 5.
The objective of this study was to compare the efficiency of hormonal treatments on ovarian activity and reproductive performance in anestrous Anglo-Nubian does during the nonbreeding season (February to May). A total of 48 multiparous does were divided into 2 groups (24 lactating does and 24 dry does). In each group, animals were allocated randomly into 2 equal subgroups (12 does each). In the first subgroup, does received a single 18-mg melatonin implant for 42 d followed by a controlled internal drug release (CIDR) device for 19 d in conjunction with 500 IU of equine chorionic gonadotropin (eCG) i.m. on the day of CIDR device removal. The second subgroup received CIDR combined with eCG in parallel with the first subgroup. Melatonin implantation induced a luteotrophic effect, expressed as an increasing number of corpora lutea, increased serum progesterone concentration, and reduced estradiol concentration. Regardless of treatment, dry does showed greater value of progesterone concentration. With the advancement of day of treatment, number of total follicles, small follicles, and medium follicles tended to increase to the greatest values at the day of CIDR device insertion. Furthermore, at day of mating, the numbers of large follicles reached the greatest value, which was associated with the lowest value of the number of corpora lutea. At day of mating, serum progesterone concentration achieved the lowest value, which increased until d 56 of pregnancy. The estradiol:progesterone ratio showed the opposite trend. The detrimental effect of reproductive seasonality, expressed as cessation of estrus behavior and fertile mating during the nonbreeding season, was successfully alleviated by the CIDR-eCG protocol. Furthermore, melatonin implantation in conjunction with the CIDR-eCG protocol enhanced conception rate and fecundity at d 28 of pregnancy and prolificacy at d 56 of pregnancy compared with does that were not implanted. Interestingly, does that failed to conceive did not come to heat again. In conclusion, the beneficial effect of melatonin implantation in conjunction with the CIDR-eCG protocol on the luteotrophic effect was reflected in the increasing number of corpora lutea, increasing progesterone concentration, and decreasing estradiol concentration. Furthermore, conception rate, prolificacy, and fecundity were improved compared with does that were not implanted during the nonbreeding season.
本研究旨在比较激素处理对非繁殖季节（二月至五月）乏情安格斯努比亚母羊卵巢活动和繁殖性能的影响。共有 48 头经产母羊分为两组（24 头哺乳期母羊和 24 头干乳期母羊）。每组动物随机分为 2 个相等的亚组（每组 12 只）。在第一亚组中，母羊接受了一次 18mg 褪黑素植入物，持续 42 天，然后与 CIDR 装置一起使用 500IU 马绒毛膜促性腺激素（eCG）肌肉注射，CIDR 装置去除当天。第二亚组与第一亚组同时接受 CIDR 和 eCG。褪黑素植入物诱导了黄体营养作用，表现为黄体数量增加、血清孕激素浓度增加和雌二醇浓度降低。无论治疗如何，干乳期母羊的孕激素浓度都较高。随着治疗天数的增加，总卵泡、小卵泡和中卵泡的数量趋于增加，在 CIDR 装置插入当天达到最大值。此外，在交配当天，大卵泡数量达到最大值，与黄体数量的最低值相对应。在交配当天，血清孕激素浓度达到最低值，直到妊娠第 56 天才增加。雌二醇：孕酮比值呈现相反的趋势。CIDR-eCG 方案成功缓解了生殖季节性的不利影响，表现为非繁殖季节停止发情行为和可繁殖交配。此外，褪黑素植入物联合 CIDR-eCG 方案可提高妊娠第 28 天的受孕率和产仔数，以及妊娠第 56 天的繁殖力，与未植入的母羊相比。有趣的是，未受孕的母羊不再发情。总之，褪黑素植入物联合 CIDR-eCG 方案对黄体营养作用的有益影响体现在黄体数量增加、孕激素浓度增加和雌二醇浓度降低上。此外，与非繁殖季节未植入的母羊相比，受孕率、繁殖力和产仔数得到了提高。
