Mild Winter Weather: Affect on Horses

It is well-accepted that the foal losses and other problems seen in several states in the spring of 2001 were triggered by environmental factors, meaning weather. Farmers and livestock managers have known for years that weather conditions affect the health and welfare of their animals in various ways. The mild weather seen in Kentucky and other states early this winter potentially could cause problems with young, growing horses.

Joe Pagan, PhD, owner of Kentucky Equine Research, was able to provide information in the spring of 2001 during the mare reproductive loss syndrome scare when it was suggested that foals weren't gaining weight normally. From records kept on various farms and compiled over several years, Pagan was able to show that foals in 2001 were gaining weight at a normal rate.

The mild weather early this winter in Kentucky and other states, however, could leave foals open to growing too fast because the grass has maintained nutrients longer into the season. Farm managers who don't weigh their weanlings and have not reduced concentrate feeds accordingly could have young horses at risk of developmental orthopedic disease.

Pagan developed software based on the average growth of 350 colts and 350 fillies in Kentucky that allows anyone to compare an individual young horse's growth curve to that average.

"We're noticing foals growing too fast because of the weather and the grass," said Pagan. "Without weighing the foals, it is difficult for a manager to know to cut back on their concentrate feed since the foals don't appear too fat."

That fast growth rate could lead to physitis or other developmental orthopedic diseases.

Pagan reminded managers and owners that if energy is reduced in the weanling's feed, it is important that the nutrient levels (vitamins and minerals) be maintained to ensure proper growth.

Questions for Pagan can be directed via e-mail at or by calling 859/873-5663.

About the Author

Kimberly S. Brown

Kimberly S. Brown was the Publisher/Editor of The Horse: Your Guide To Equine Health Care from June 2008 to March 2010, and she served in various positions at Blood-Horse Publications since 1980.

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