Bodyweights and growth rates of spring- and autumn-born Thoroughbred horses raised on pasture.
Abstract: To examine the growth of spring- and autumn-born Thoroughbred foals raised on pasture. Methods: Bodyweight and growth rates were measured in pasture-raised Thoroughbred horses, born in either spring (n=56) or autumn (n=7), from birth to approximately 13 and 17 months of age. Results: Birthweight tended to be lower in autumn- than spring-born foals (54.4, SD 7.92 kg vs 57.3, SD 5.90 kg; p=0.08). Between birth and 6 months of age, there was no difference in growth rate at equivalent ages between horses born in spring and autumn. Spring-born horses, which were weaned in the autumn, had lower post-weaning growth rates than autumn-born horses that were weaned in the spring. At time of the late yearling sales (March-April) in the Southern Hemisphere, unadjusted mean bodyweights of autumn-born horses (379.3, SD 24.8 kg) were lower (p=0.017) than those of the spring-born horses (437.2, SD 35.3 kg), although values in the autumn-born horses were all within two standard deviations (SD) of the mean of the spring-born animals. When adjusted for the covariates of birthweight and gender, the difference between spring- and autumn-born horses at that time was not significant (p=0.25). Conclusions: Some autumn-born foals could be marketed for late yearling sales in the Southern Hemisphere, on the basis of bodyweight. Furthermore, they might also be competitive in the Northern Hemisphere industry (sales or racing), as they would be competing against horses of the same official age.
Publication Date: 2005-10-13 PubMed ID: 16220125DOI: 10.1080/00480169.2005.36568Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research investigates whether the season of birth affects growth rates and body weights of Thoroughbred horses raised on pasture. The results suggest no significant difference in early growth rates between spring and autumn-born foals, but identified potential variations in post-weaning growth rates and yearling bodyweights.
Methodology
- The study involved tracking the body weight and growth rates of two groups of Thoroughbred horses raised on pasture.
- The first group consisted of 56 horses born in spring, while the second group included 7 horses born in autumn.
- Both groups were tracked and measured from birth till they were approximately 13 and 17 months old respectively.
Results
- The birth weight of foals born in autumn was found to be slightly lower than those born in spring, although the difference was not statistically significant.
- In the first 6 months from birth, the growth rates of the spring-born and autumn-born horses did not significantly differ.
- However, after weaning, spring-born horses showed slower growth rates compared to those born in autumn, which were weaned in spring.
- By the time of the late yearling sales in the Southern Hemisphere, autumn-born horses, on average, weighed less than spring-born horses. However, the weights of the autumn-born horses were within two standard deviations of the mean weight of the spring-born horses.
- Upon adjusting the results for birthweight and gender, the differences found between spring- and autumn-born horses were not statistically significant.
Conclusions
- Despite some differences in weight and growth rates, autumn-born foals could still be marketed for late yearling sales in the Southern Hemisphere based on their body weight.
- These foals could potentially compete in the Northern Hemisphere industry, against horses of the same official age, whether in sales or racing.
Cite This Article
APA
Brown-Douglas CG, Parkinson TJ, Firth EC, Fennessy PF.
(2005).
Bodyweights and growth rates of spring- and autumn-born Thoroughbred horses raised on pasture.
N Z Vet J, 53(5), 326-331.
https://doi.org/10.1080/00480169.2005.36568 Publication
Researcher Affiliations
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 11222, Palmerston North, New Zealand.
MeSH Terms
- Animal Feed
- Animal Nutritional Physiological Phenomena
- Animals
- Animals, Newborn / growth & development
- Birth Weight / physiology
- Body Weight / physiology
- Female
- Horses / growth & development
- Horses / physiology
- Longitudinal Studies
- Male
- Poaceae
- Seasons
- Sex Characteristics
- Weaning
Citations
This article has been cited 4 times.- Takahashi Y, Takahashi T. Seasonal fluctuations in body weight during growth of Thoroughbred racehorses during their athletic career. BMC Vet Res 2017 Aug 18;13(1):257.
- Onoda T, Yamamoto R, Sawamura K, Murase H, Nambo Y, Inoue Y, Matsui A, Miyake T, Hirai N. Empirical Percentile Growth Curves with Z-scores Considering Seasonal Compensatory Growths for Japanese Thoroughbred Horses. J Equine Sci 2013;24(4):63-9.
- Onoda T, Yamamoto R, Sawamura K, Inoue Y, Matsui A, Miyake T, Hirai N. Empirical Growth Curve Estimation Using Sigmoid Sub-functions that Adjust Seasonal Compensatory Growth for Male Body Weight of Thoroughbred Horses. J Equine Sci 2011;22(2):37-42.
- Balazs CL, Morello-Frosch R. The Three R's: How Community Based Participatory Research Strengthens the Rigor, Relevance and Reach of Science. Environ Justice 2013 Feb;6(1).
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