本文旨在拟合我国主要品种肉牛的生长曲线，优化体重预测模型。

基于国家畜禽养殖数据中心和国家肉牛遗传评估中心收集的22个肉牛品种近6万条体重记录，本研究利用Gompertz、Logistic、Bertalanffy和Brody等四种非线性模型拟合生长发育曲线，估计模型中相应的参数，并分析了11个肉牛品种间24月龄背膘厚和眼肌面积的差异，挖掘品种特性，为后期育种选种工作提供正确的理论依据。

根据模型拟合度及实际生长发育规律，为主要肉牛品种的公畜和母畜拟合了体重预测模型并估计相应参数。总的来说，各品种从初生到成熟体重呈逐增态势，整体上趋近“S”型曲线，12月龄之前增速较快，18月龄后增速减缓；公畜与母畜的发育趋势基本一致，但品种间存在一定差异，如和牛公畜前期发育速度高于安格斯牛，和牛母畜前期发育速度低于安格斯牛。结合24月龄背膘厚和眼肌面积比较，肉用型品种相较于兼用和地方黄牛品种在成熟体重和发育速度上有优势，而一些地方黄牛品种，如文山牛、渤海黑牛和南阳牛有不错的脂肪沉积能力，郏县红牛、晋南牛和三河牛表现出优良的高价值牛肉产率。

本研究为我国主要肉牛品种的公畜和母畜提供了较为准确的体重预测模型，并且发现我国一些地方黄牛品种体型较小，但有较高的高价值牛肉产率。

This research was conducted to fit growth curves for, and optimize body weight prediction models of, the main beef cattle breeds in China.

Based on more than 60,000 records of 22 cattle breeds collected by the National Center of Beef Cattle Genetic Evaluation, four non-linear models, namely Gompertz, logistic, von Bertalanffy and Brody, were used to fit growth curves, estimate the corresponding parameters and analyze the difference in back fat thickness and loin eye area among 11 beef cattle breeds at the age of 24 months. These models were used to determine breed characteristics and provide an accurate theoretical basis for future breeding programs.

According to the R^2 and actual growth laws, the optimal weight prediction models were selected for male and female cattle and the corresponding parameters were estimated. Overall, the body weight of each breed gradually increased from birth to maturity, approaching the “S” curve. The growth rate was faster before 12 months of age, and then gradually decreased after 18 months of age. The growth trend of male and female cattle was essentially the same, but there were certain differences between breeds; for example, Wagyu bulls showed higher growth rates in early stages than Angus, and Wagyu cows showed lower growth rates in early stages than Angus. Meat-type breeds had advantages in mature weight and growth speed compared with dual purpose and local cattle breeds. When compared for back fat thickness and loin eye area at the age of 24 months, some local breeds such as Wenshan cattle, Bohai Black cattle and Nanyang cattle had greater fat deposition, and Jiaxian Red cattle, Jinnan cattle and Sanhe cattle were superior in meat production.

This study provides more accurate weight prediction models than were previously available for bulls and cows of the major beef cattle breeds in China. Although some local cattle breeds are small in body size, they have the potential to produce high-quality beef products.