本研究调查了肉鸡孵化时间和拉动时间对随后的生活性能的影响。在试验1和2中,孵化卵分别从29和30周龄的Ross308的商业肉鸡饲养员群中获得。鸡蛋在2个相同的固定剂中连续2天孵育。在两个试验中,鸡蛋的一部分(9,600),在布景的第一天孵化,被分配到延迟拉(DP)治疗,和鸡蛋的另一部分(9,600),在设置的第二天孵化,被分配到正常拉(NP)治疗。孵化期分为3个孵化时间组,小鸡在早期(478到490小时)被归类为孵化,中间(490至496小时),或后期(孵育496至510小时)。在基于NP设定日期的510小时孵育时,所有小鸡都被转移到肉鸡研究屋。在2个小鸡拉时间处理×3个孵化时间组中,分别在试验1和2中饲养了7,200和8,400只小鸡。DP和NP处理之间的主要差异是DP组的孵化机中额外的24小时保持期。因此,在NP治疗中放置小鸡BW高于DP治疗(P<0.001)。然而,这个优势消失了7天,并且DP和NP处理在41d时的平均BW没有差异。小鸡拉动时间在41d时不影响饲料消耗或饲料转化率(FCR)。类似于拉动时间,孵化时间不影响BW,41d时的饲料消耗量或FCR。然而,41天的死亡率和欧洲生产效率指数(EPEI),观察到孵化时间×牵拉时间相互作用(P<0.001)。与NP治疗中早期和中期孵化的雏鸡相比,孵化后期雏鸡的死亡率更高,EPEI更低,而对于DP治疗的小鸡来说,死亡率和EPEI在孵化时间组之间没有差异.这些数据表明,DP治疗,在最佳条件下将小鸡在孵化机中再保持24小时,产生较低的初始BW,伴随着经过41天的补偿性体重增加,由于在孵化机中的保持时间,现场表现没有差异(P>0.05)。总的来说,孵化后不久将孵化的雏鸡送到肉鸡舍,增加了它们的死亡率,并对它们的生活表现产生了负面影响(通过EPEI衡量),与在孵化机中孵化(50小时)后将早期孵化的雏鸡保持相对较长的时间不同。
This study investigated the effects of broiler chick hatching time and pull time on subsequent live performance. Hatching eggs were obtained from commercial broiler breeder flocks of Ross 308 at 29 and 30 wk of age in trials 1 and 2, respectively. Eggs were incubated in 2 identical setters on 2 consecutive days. In both trials, portion of the eggs (9,600), incubated on the first day of set, were assigned to delayed-pull (DP) treatment, and the other portion of the eggs (9,600), incubated on the second day of set, were assigned to normal-pull (NP) treatment. The hatching period was divided into 3 hatching time groups, and chicks were classified as hatching in the early (478 to 490 h), middle (490 to 496 h), or late period (496 to 510 h of incubation). At 510 h of incubation based on the NP set date, all chicks were transferred to a broiler research house. A total of 7,200 and 8,400 chicks within 2 chick pull time treatments × 3 hatching time groups were raised in trials 1 and 2, respectively. The primary difference between the DP and NP treatments was an additional 24 h holding period in the hatcher for the DP group. Therefore, chick BW was higher at placement in the NP treatment than in the DP treatment (P < 0.001). However, this advantage disappeared by 7 d, and the average BW did not differ between the DP and NP treatments at 41 d. Chick pull time did not affect feed consumption or feed conversion ratio (FCR) at 41 d. Similar to pull time, hatching time did not impact BW, feed consumption or FCR at 41 d. However, for mortality and European Production Efficiency Index (EPEI) at 41 d, a hatching time × pull time interaction was observed (P < 0.001). Mortality was higher and EPEI was lower in late hatch chicks than in chicks hatched early and middle in the NP treatment, whereas for chicks in the DP treatment, mortality and EPEI did not differ among the hatching time groups. These data indicated that the DP treatment, which held the chicks for an additional 24 h in the hatcher under optimum conditions, produced a lower initial BW accompanied by a period of compensatory weight gain through 41 d, and no differences (P > 0.05) in live performance occurred due to the holding time in the hatcher. Overall, sending the late hatched chicks to the broiler house shortly after hatching increased their mortality and negatively affected their live performance (as measured by EPEI), unlike holding early hatched chicks for a relatively long time after hatching (50 h) in the hatcher.