1992 年 13 巻 1 号 p. 15-24
Data of 44 lactations for Holstein cows sampled weekly in 8 prefecture experimental farms were used to compare two models of the lactation curves: the Wood model of y = a tb e-ct and the McMillan model of y = d (1—e-g (t-h) ) e-ft (t>h). The mathematical models of Wood and McMillan were fitted to the results for individual cows by a non-linear least square method. The results obtained were summarized as follows:
(1) The standard deviations for all parameters of the Wood model were less than those of the McMillan model.
(2) The McMillan model fitted the data better than the Wood model except four cows with respect to AIC (Akaike's Information Criterion).
(3) Highly significant correlations were found between several parameters of the Wood model and the McMillan model: a, b, c of th Wood model and d of the McMillan model, c of the Wood model and f of the McMillan model, and, b, c of the Wood model and g of the McMillan model.