Ronquillo Julio César Camacho, Martínez Arturo Pró, Pérez Carlos Miguel Becerril, Sandoval Benjamín Figueroa, Martin Graeme B, Valencia Javier, Gallegos Sánchez Jaime
Benemérita Universidad Autónoma de Puebla, 4 sur 104, C.P. 72000 Puebla, Mexico.
Anim Reprod Sci. 2008 Aug;107(1-2):85-93. doi: 10.1016/j.anireprosci.2007.06.021. Epub 2007 Jun 23.
To determine the effects of suckling on postpartum (pp) reproductive efficiency in Pelibuey ewes, two experiments were performed. In Experiment 1, 112 ewes were randomly assigned to one of two groups at parturition: Without restriction of suckling (WRS) 24 h day(-1) for 60 days (n=56), and Weaned Ewes (WE), weaned at 40 days pp (n=56). On Day 30 pp, all ewes were given Prostaglandin (PGF2alpha) and one of four treatments (n=14): T1, intravaginal progestagen (FGA; 40 mg) for 12 days from day 30 pp+equine chorionic gonadotropin (eCG; 300 UI) until 2 days before removing FGA; T2, FGA was applied for 12 days; T3, a second application of PGF2alpha was given on day 40 pp+eCG on the same day; T4, a second injection of PGF2alpha was applied on day 40 pp only. In all the analyzed characteristics, the best results were obtained in WE. Within the WE group, the best treatment (P<0.05) was T1 with 85.7% of the ewes in oestrus, 71.4% pregnant and a prolificacy of 1.9. Within the WRS group the best results were observed in T1. In both groups, the lowest results (P<0.05) were obtained in T4. In Experiment 2, 75 ewes were randomly assigned to one of three groups (n=25) immediately after parturition: Group 1, Without restriction of suckling (WRS, as in Experiment 1); Group 2, with restriction of suckling (RS; suckling for 30 min day(-1)); Group 3, Early Weaning (EW: at 7 days pp). All ewes were given PGF2alpha at 30 days pp and the same hormonal treatment, FGA for 12 days+PGF2alpha and eCG 2 days before removing FGA. No differences were observed (P>0.05) between RS and EW for the presentation of oestrus (96% vs. 92%), pregnancy (72% vs. 76%) or prolificacy (1.9 vs. 1.9), although group WRS did not perform (P<0.05) as well as groups RS and EW for any measure of performance. In conclusion, the combination of hormonal treatment (FGA plus eCG) with weaning at 7 or 40 days pp, or restricted suckling, improves postpartum reproductive efficiency in Pelibuey ewes, demonstrating the inhibitory role of suckling on postpartum reproduction in this breed.
为确定哺乳对佩利布埃羊产后繁殖效率的影响，进行了两项实验。在实验1中，112只母羊在分娩时被随机分为两组：一组为无哺乳限制组（WRS），每天24小时哺乳，持续60天（n = 56）；另一组为断奶母羊组（WE），产后40天断奶（n = 56）。产后30天，所有母羊均注射前列腺素（PGF2α）并接受四种处理之一（n = 14）：T1，从产后30天起阴道内放置孕激素（FGA；40毫克），持续12天，同时注射马绒毛膜促性腺激素（eCG；300国际单位），直至取出FGA前两天；T2，FGA应用12天；T3，在产后40天再次注射PGF2α并于同日注射eCG；T4，仅在产后40天注射第二次PGF2α。在所有分析的特征中，WE组取得了最佳结果。在WE组中，最佳处理（P<0.05）为T1，发情母羊占85.7%，怀孕母羊占71.4%，产仔数为1.9。在WRS组中，T1组观察到最佳结果。在两组中，T4组取得了最低结果（P<0.05）。在实验2中，75只母羊在分娩后立即被随机分为三组（n = 25）：第1组为无哺乳限制组（WRS，同实验1）；第2组为哺乳受限组（RS；每天哺乳30分钟）；第3组为早期断奶组（EW：产后7天断奶）。所有母羊在产后30天均注射PGF2α，并接受相同的激素处理，即FGA应用12天，在取出FGA前两天注射PGF2α和eCG。在发情表现（96%对92%）、怀孕率（72%对76%）或产仔数（1.9对1.9）方面，RS组和EW组之间未观察到差异（P>0.05），尽管WRS组在任何性能指标上的表现均不如RS组和EW组（P<0.05）。总之，激素处理（FGA加eCG）与产后7天或40天断奶或限制哺乳相结合，可提高佩利布埃羊的产后繁殖效率，表明哺乳对该品种产后繁殖具有抑制作用。
