Publication | Open Access
A summary of growth rates of Thoroughbreds in Kentucky
81
Citations
0
References
1996
Year
Over a three year period (1993, 1994, and 1995), a total of 350 Thoroughbred colts and 350 Thoroughbred fillies in Central Kentucky were weighed monthly on a portable electronic scale through 1B months of age. Wither height and cond tion score were also measured in about half of the foals. In order to estimate mature body size ln these horses, 472 brood mares were weighed 60 to 90 days after foaling. In addition, 25 Thoroughbred breeding stallions were also welghed. The average body weight of the brood mares equaled 570 kg and the average weight of the stallions equaled 580 kg. At 14 days of age, colts and fillies weighed an avege ol77.7 and 76.1 kg and had average heights of 107.3 and 106.3 cm, respectively. Colts were heavier and taller than fillies throughout the study and at 490 days averaged 9.9 kg heavier (427.8 kg vs 418.0 k9) and 1.6 cm taller {153.4 cm vs 151.8 cm). The greatest difierence in condition score between sexes occurred at four months of age when the fillies had an average score oi 6.48 and the colts had a score of 6.0. Compared to March foals, foals born ln January and February were 6.8 kg ighter at 14 days of age. They remalned smaller, by as much as 15.3 kg at 72 days of age, until about I months of age when they averaged about the same as the March foals. April and lvay foals were larger at 14 days of age than March foals, and rernained sllghtly heavler unt | 6 months of age. Average daily ga n between the four groups was similar until about 7 months of age. ADG averaged 1.5-1.7 kg/d during the first month and declined linearly to about .70-.80 kg/d at 7 months of age. After 7 months of age, ADG tended to be more variable and by 12 months, ADG was very different between the difierent months of birth. Foal growth rates were reduced during the winter months, regardless of when the foals were born and increased during April and May of the foal's yearling year. Growth rate ln these yearlings was more a function of season of the year than age.