ABSTRACT An experiment was conducted with broiler breeder females (up to 30 wks of age) to study the effect of body weight (BW) at 5 wks on BW uniformity, livability, and skeletal development and strength. At 5 wks of age, 160 females were randomly selected within a flock of 1,988, and they were reared without grading. Among these 160 females, the 40 with the lowest BW (Light Non-Graded, LNG) and the 40 with the highest BW (Heavy Non-Graded, HNG) were studied. LNG females, compared to HNG, had a higher BW coefficient of variation (CV) from 10 to 25 wks (P ≤ 0.05). At 25 wks, mortality of the LNG females was higher (20.0% vs. 2.5%, P = 0.027); they had shorter tibias (P ≤ 0.05), and a tendency to lower-tibia breaking strength (P = 0.085) and elastic modulus (P = 0.072). At 5 wks, their alkaline phosphatase was lower (2781 UI vs. 3839 UI, P = 0.023), and taking together 5 and 10 wks their osteocalcin was also lower (976 ng vs. 1239 ng, P = 0.029). Results indicate that without grading in rearing, light females had lower BW uniformity, lower livability, shorter and less resistant tibias than heavy females.

中文翻译：

---

体重对肉种鸡雌性均匀度、存活率、骨骼发育和力量的影响

摘要 用肉种鸡雌性（最大 30 周龄）进行了一项实验，以研究 5 周龄时体重 (BW) 对 BW 均匀性、存活率以及骨骼发育和强度的影响。在 5 周龄时，从 1,988 只鸡群中随机选择 160 只雌性，不进行分级饲养。在这 160 只雌性中，研究了 40 只体重最低（Light Non-Graded，LNG）和 40 只体重最高（Heavy Non-Graded，HNG）。与 HNG 相比，LNG 女性在 10 至 25 周期间具有更高的 BW 变异系数 (CV) (P ≤ 0.05)。在 25 周时，LNG 雌性的死亡率较高（20.0% 对 2.5%，P = 0.027）；他们有较短的胫骨（P ≤ 0.05），并且倾向于降低胫骨断裂强度（P = 0.085）和弹性模量（P = 0.072）。在第 5 周时，他们的碱性磷酸酶较低（2781 UI 对 3839 UI，P = 0.023），5 周和 10 周后，他们的骨钙素也较低（976 ng vs. 1239 ng，P = 0.029）。结果表明，在饲养方面不分级的情况下，与体重较重的雌性相比，较轻的雌性具有较低的体重均匀度、较低的成活率、较短且抵抗力较低的胫骨。