Department of Animal Science, College of Agriculture and Natural Resources, Razi University, Kermanshah, Iran.
Department of Animal Science, Faculty of Agriculture, Lorestan University, Khorramabad, Iran.
Vet Med Sci. 2024 Sep;10(5):e1527. doi: 10.1002/vms3.1527.
The study of growth traits is of interest to many animal scientists, regardless of specialization, due to the economic importance of growth rate, mature weight and other related traits.
This study aimed to compare six non-linear models for describing the growth of Lori-Bakhtiari sheep.
In order to collect weight data, 85 lambs (41 males and 44 females) were reared from birth to 140 days of age, and their growth patterns were recorded by measuring their body weight at 10-day intervals. Various mathematical functions, including the negative exponential, Brody, Gompertz, Logistic, Morgan-Mercer-Flodin (MMF) and Weibull, were used to model the relationship between body weight records and age.
The results showed that the MMF and Gompertz models provided the best fit to the body weight data, whereas the negative exponential model exhibited the worst fit. In all models, the asymptotic weight of male lambs was higher than females. The research also revealed differences in growth patterns between male and female lambs. Overall, females had a lower absolute growth rate than males, but they reached their peak growth at an earlier period, and their growth rate declined faster.
The differences in growth patterns between males and females indicate the importance of analysing male and female data separately when describing growth. As a result, Gompertz model can be recommended to Lori-Bakhtiari female and male lamb breeders to determine more accurate growth traits. In addition, it should be considered that feeding male and female lambs separately according to absolute growth rate values may increase growth performance.
生长性状的研究对于许多动物科学家都很重要，无论其专业方向如何，因为生长速度、成熟体重和其他相关性状的经济重要性。
本研究旨在比较六种非线性模型来描述 Lori-Bakhtiari 绵羊的生长。
为了收集体重数据，从出生到 140 天，共饲养了 85 只羔羊（41 只雄性和 44 只雌性），并通过每 10 天测量一次体重来记录其生长模式。使用了多种数学函数，包括负指数、Brody、Gompertz、Logistic、Morgan-Mercer-Flodin（MMF）和 Weibull，来模拟体重记录与年龄之间的关系。
结果表明，MMF 和 Gompertz 模型最适合体重数据，而负指数模型表现最差。在所有模型中，雄性羔羊的渐近体重均高于雌性。研究还揭示了雄性和雌性羔羊之间生长模式的差异。总体而言，雌性羔羊的绝对生长率低于雄性，但它们更早达到生长高峰，且生长速度下降更快。
雄性和雌性之间生长模式的差异表明，在描述生长时，分别分析雄性和雌性数据的重要性。因此，Gompertz 模型可以推荐给 Lori-Bakhtiari 雌性和雄性羔羊饲养者，以确定更准确的生长性状。此外，应考虑根据绝对生长率值分别饲养雄性和雌性羔羊，以提高生长性能。
