Ledezma-Torres Rogelio Alejandro, Sánchez-Dávila Fernando, Rodríguez-Miranda Diana Aimé, Luna-Palomera Carlos, Grizelj Juraj, Vázquez-Armijo José Fernando, López-Villalobos Nicolás
Universidad Autónoma de Nuevo León, Facultad de Medicina Veterinaria y Zootecnia, Posgrado Conjunto FA-FMVZ, General Escobedo, CP 66050, Mexico.
Universidad Autónoma de Nuevo León, Facultad de Agronomía, Posgrado Conjunto FA-FMVZ, Laboratorio de Reproducción Animal, Unidad Académica Marín, Marín, CP 66700, Mexico.
Arch Anim Breed. 2022 Jul 20;65(3):259-265. doi: 10.5194/aab-65-259-2022. eCollection 2022.
The objective of this study was to determine the effect of the weaning method on lamb stress, body weight, sexual behavior, and semen quality of Saint Croix male lambs. The present study was carried out during the late spring and summer of 2018 in the northeast of Mexico. Sixty male lambs born as twins or triplets (3.2 0.6 kg birth weight) and weaned at 60 d of age (19.21 1.8 kg weaning weight) were divided into two weaning methods: complete separation from the dams (CS; the lambs were moved to a pen that was at 500 m of distance from the dams) and separation with contact from the dams (SCD); the lambs were physically separated by a steel mesh that prevented the lambs from having the possibility of sucking milk from their mothers, but they maintained permanent visual and auditory contact. Cortisol levels were determined 3 d before and 7 d after weaning. Lambs were evaluated as 3-month-old lambs for sexual behavior and semen quality for 9 weeks. The effects of the weaning method (M), week (W), and the interaction M W were significant on body weight and cortisol levels ( ). The SCD lambs had higher cortisol levels at 3, 5, and 7 d after weaning than CS lambs ( ). The CS lambs had higher body weight during the first 4 weeks after weaning than SCD lambs ( ). The weaning method had no effect on scrotal circumference, sexual behavior, and semen quality traits, except for progressive sperm motility, being better for the lambs that were completely separated ( ). The results from this study show that complete separation of lambs and ewes at weaning is an effective method to reduce lamb stress and improve lamb growth after weaning, but it did not have long-term effects on sexual behavior and semen quality of Saint Croix male lambs.
本研究的目的是确定断奶方法对圣克罗伊岛雄性羔羊应激、体重、性行为和精液质量的影响。本研究于2018年春末夏初在墨西哥东北部进行。60只出生时为双胞胎或三胞胎（出生体重3.2±0.6千克）且在60日龄（断奶体重19.21±1.8千克）断奶的雄性羔羊被分为两种断奶方法：与母羊完全分离（CS；羔羊被转移到距离母羊500米的围栏中）和与母羊分离但保持接触（SCD）；羔羊通过钢丝网进行物理隔离，这使得羔羊无法从其母亲那里吸奶，但它们保持着永久的视觉和听觉接触。在断奶前3天和断奶后7天测定皮质醇水平。将羔羊作为3月龄羔羊评估其性行为和精液质量，为期9周。断奶方法（M）、周数（W）以及M×W的交互作用对体重和皮质醇水平有显著影响（ ）。断奶后3天、5天和7天，SCD羔羊的皮质醇水平高于CS羔羊（ ）。断奶后前4周，CS羔羊的体重高于SCD羔羊（ ）。断奶方法对阴囊周长、性行为和精液质量性状没有影响，除了渐进性精子活力，对于完全分离的羔羊更好（ ）。本研究结果表明，断奶时将羔羊和母羊完全分离是一种减轻羔羊应激并改善断奶后羔羊生长的有效方法，但对圣克罗伊岛雄性羔羊的性行为和精液质量没有长期影响。
