The objective of this study was to compare the ability of Basis spline (B-spline) models and five non-linear functions (Richards, Brody, Von Bertalanffy, Gompertz and Logistic) to describe the growth of females of a beef cattle breed and predict cow mature weight (A). Random regression models that included animal variation within function parameters were fitted using mixed model procedures. Comparisons were made among these functions for goodness of fit, standardised residuals and biological interpretability of the growth curve parameters. The B-spline function showed the best goodness of fit and within non-linear functions, the Richards and Von Bertalanffy functions estimated bodyweight at different periods accurately. The method of fitting the residual variance that provided the best goodness of fit in the model was the constant plus power variance function. The Richards function was found to be the best non-linear function and was compared with the B-spline function to predict mature weight. When the A parameter was estimated using fixed effects, it had a low correlation with the actual mature weight of the cow and the use of this estimate yielded no more gain in predictive accuracy of mature weight than the use of average breed mature weight. When A was estimated using fixed and random effects, it had a moderate correlation with actual mature weight for the B-spline and Richards functions. The use of both types of effects to estimate the maturity index reduced the error compared with the use of average mature weight, especially for the B-spline function, which is recommended as the best function to describe animal growth and predict mature weight.

中文翻译：

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更正：比较 B 样条和非线性函数来描述生长模式和预测雌性肉牛的成熟体重

本研究的目的是比较 Basis 样条（B 样条）模型和五个非线性函数（Richards、Brody、Von Bertalanffy、Gompertz 和 Logistic）描述肉牛品种雌性生长和预测的能力母牛成熟体重（A）。使用混合模型程序拟合包括函数参数内的动物变异的随机回归模型。对这些函数之间的拟合优度、标准化残差和生长曲线参数的生物学可解释性进行了比较。B样条函数表现出最佳拟合优度，在非线性函数内，Richards和Von Bertalanffy函数准确估计了不同时期的体重。在模型中提供最佳拟合优度的残差方差拟合方法是常数加幂方差函数。发现理查兹函数是最好的非线性函数，并与 B 样条函数进行比较以预测成熟体重。当使用固定效应估计 A 参数时，它与母牛的实际成熟体重的相关性较低，与使用平均品种成熟体重相比，使用该估计在成熟体重的预测准确性方面没有更多的提高。当使用固定和随机效应估计 A 时，它与 B 样条函数和理查兹函数的实际成熟权重具有中等相关性。与使用平均成熟权重相比，使用这两种效应来估计成熟度指数减少了误差，尤其是对于 B 样条函数，