Empirical Percentile Growth Curves with Z-scores Considering Seasonal Compensatory Growths for Japanese Thoroughbred Horses.
Percentile growth curves are often used as a clinical indicator to evaluate variations of children's growth status. In this study, we propose empirical percentile growth curves using Z-scores adapted for Japanese Thoroughbred horses, with considerations of the seasonal compensatory growth that is a typical characteristic of seasonal breeding animals. We previously developed new growth curve equations for Japanese Thoroughbreds adjusting for compensatory growth. Individual horses and residual effects were included as random effects in the growth curve equation model and their variance components were estimated. Based on the Z-scores of the estimated variance components, empirical percentile growth curves were constructed. A total of 5,594 and 5,680 body weight and age measurements of male and female Thoroughbreds, respectively, and 3,770 withers height and age measurements were used in the analyses. The developed empirical percentile growth curves using Z-scores are computationally feasible and useful for monitoring individual growth parameters of body weight and withers height of young Thoroughbred horses, especially during compensatory growth periods.
Comparative Agricultural Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
Tomoaki
T
Onoda
The Japan Bloodhorse Breeders' Association, 4-5-4 Shinbashi, Minato-ku, Tokyo 105-0004, Japan.
Ryuta
R
Yamamoto
JRA Facilities Co. Ltd., 4-5-4 Shinbashi, Minato-ku, Tokyo 105-0004, Japan.
Kyohei
K
Sawamura
Hidaka Training and Research Center, Japan Racing Association, 535-13 Nissha, Urakawa-cho, Hidaka, Hokkaido 057-0171, Japan.
Harutaka
H
Murase
Hidaka Training and Research Center, Japan Racing Association, 535-13 Nissha, Urakawa-cho, Hidaka, Hokkaido 057-0171, Japan.
Yasuo
Y
Nambo
Hidaka Training and Research Center, Japan Racing Association, 535-13 Nissha, Urakawa-cho, Hidaka, Hokkaido 057-0171, Japan.
Yoshinobu
Y
Inoue
Equine Research Institute, Japan Racing Association, 321-4 Tokami-cho, Utsunomiya, Tochigi 320-0856, Japan.
Akira
A
Matsui
Comparative Agricultural Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
Takeshi
T
Miyake
Comparative Agricultural Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
Nobuhiro
N
Hirai
Thoroughbred horses; body weight; percentile growth curves; withers height