Reddy P R, Siegel P B
Poult Sci. 1976 Jul;55(4):1518-30. doi: 10.3382/ps.0551518.
Two experiments were conducted to study oviposition patterns and ovarian activity at various physiological ages in S15 and S16 generation pullets from lines selected bidirectionally for high (HWS) and low (LWS) juvenile body weight. The fixed periods of lay for random samples of pullets from the date of first egg were 20, 40, 60, and 80 days in the first experiment and 40, 80, 120, and 160 days in the second experiment. HWS pullets matured significantly earlier than LWS pullets in both generations. The frequency and the percentage hen-day production (%HDP) of defective eggs were significantly greater in the HWS than LWS line in both generations. Delayed sexual maturity did not significantly change the pattern of defective egg production for a fixed period of lay. In the HWS line the %HDP of defective eggs progressively increased until about 40 days of lay and tended to decline thereafter, while in the LWS line the percentage decreased from 20 to 40 days and then stabilized. The frequency of normal unbroken eggs to 80 days of production did not differ among lines either in the S15 or S16 generation. When measurements were extended to 160 days of lay in the S16 generation HWS pullets produced significantly more normal eggs than LWS pullets. Possible effects of ovarian activity on the egg production pattern during the laying cycle are discussed. There was a significantly higher incidence of internal laying and atrecia of the growing follicles in the HWS than in the LWS pullets. Ovarian activity, evidenced by the number of developing and ruptured follicles, was significantly greater in the HWS than the LWS line, as was the incidence of ova developing in pairs. Product moment correlations and multiple regressions among the measurements of ovarian activity were calculated within lines. In the HWS line, 62.5% of the variation in %HDP of defective eggs could be accounted for by the %HDP of normal eggs and the number of developing follicles while in the LWS line these variables accounted for only 7.29% of the variation in %HDP of defective eggs.
进行了两项实验，以研究双向选择高（HWS）和低（LWS）幼雏体重品系的S15和S16代小母鸡在不同生理年龄的产卵模式和卵巢活动。在第一个实验中，从第一枚蛋之日起，对随机抽取的小母鸡样本的固定产蛋期为20、40、60和80天；在第二个实验中为40、80、120和160天。两代中，HWS小母鸡均比LWS小母鸡成熟得早得多。两代中，HWS品系中次品蛋的频率和母鸡日产蛋率（%HDP）均显著高于LWS品系。性成熟延迟在固定产蛋期内并未显著改变次品蛋的生产模式。在HWS品系中，次品蛋的%HDP在产蛋约40天前逐渐增加，此后趋于下降；而在LWS品系中，该百分比在20至40天内下降，然后趋于稳定。在S15或S16代中，各品系到80天产蛋时正常无破损蛋的频率没有差异。当在S16代中将测量延长至160天产蛋期时，HWS小母鸡生产的正常蛋显著多于LWS小母鸡。讨论了卵巢活动对产蛋周期中产卵模式的可能影响。HWS小母鸡中内部产蛋和生长卵泡闭锁的发生率显著高于LWS小母鸡。以发育中和破裂卵泡的数量为证据的卵巢活动，HWS品系显著高于LWS品系，成对发育卵子的发生率也是如此。在品系内计算了卵巢活动测量值之间的积矩相关性和多元回归。在HWS品系中，次品蛋%HDP的62.5%的变异可由正常蛋%HDP和发育卵泡数量解释，而在LWS品系中，这些变量仅解释了次品蛋%HDP变异的7.29%。
