Koenig J L, Stormshak F
Department of Animal Sciences, Oregon State University, Corvallis 97331-6702.
Biol Reprod. 1993 Dec;49(6):1158-62. doi: 10.1095/biolreprod49.6.1158.
Cytogenetic characteristics of ova surgically recovered from 19 first-estrous (pubertal) gilts were compared with those from 24 third-estrous gilts. Mean percentage recovery of ova was 82.1 +/- 2.9%. A total of 159 and 203 ova from first- and third-estrous gilts, respectively, were evaluated. Gilts at first and third estrus ovulated more mature ova (metaphase I-II chromosomes visible) than immature ova (germinal vesicle stage through prometaphase stage), but the percentage of immature ova in gilts at first estrus was greater than in those at third estrus (33.1 vs. 24.1%, p < 0.06). Percentage of mature ova with a normal haploid complement of chromosomes was similar in gilts at first and at third estrus (52.7 vs. 47.5%, p > 0.10). Percentage of hyperploid ova did not differ between first- and third-estrous gilts (10.8 vs. 5.9%, respectively); however, estimated frequency of nondisjunction appeared greater for gilts at first than at third estrus (21.6 vs. 11.9%, p < 0.10). These data suggest that ova of first-estrous gilts are inferior in quality compared to those of cyclic gilts.
将从19头首次发情（青春期）后备母猪和24头第三次发情后备母猪手术采集的卵子的细胞遗传学特征进行了比较。卵子的平均回收率为82.1±2.9%。分别对来自首次发情和第三次发情后备母猪的159枚和203枚卵子进行了评估。首次发情和第三次发情的后备母猪排出的成熟卵子（可见中期I-II染色体）比未成熟卵子（生发泡期至前中期）多，但首次发情后备母猪中未成熟卵子的比例高于第三次发情的后备母猪（33.1%对24.1%，p<0.06）。首次发情和第三次发情的后备母猪中具有正常单倍体染色体组的成熟卵子比例相似（52.7%对47.5%，p>0.10）。超倍体卵子的比例在首次发情和第三次发情的后备母猪之间没有差异（分别为10.8%和5.9%）；然而，首次发情的后备母猪中非整倍体的估计频率似乎高于第三次发情的后备母猪（21.6%对11.9%，p<0.10）。这些数据表明，与发情周期的后备母猪相比，首次发情后备母猪的卵子质量较差。
