What Was Causing Foal Abnormalities?

Q. I have bred and raised 142 Morgan foals since 1976. During that time, we've had eight foals born with a very similar set of problems--contracted front tendons, an underbite, lethargy, hypothyroidism, and/or mental deficiency. We tried bottle feeding, making a sling to hold them up to nurse, and putting plaster of Paris casts on their front legs, but our success rate was low. In 1994, a veterinarian suggested a mare supplement that happened to contain selenium. The four mares that were stalled and received the supplement had normal foals, and the four mares that were kept on pasture and didn't receive the supplement had foals with these clinical signs. We have not had any foals with this clinical signs since 1994, could this be because of the selenium?

Harvey Sawatzky, British Columbia, Canada

A. I couldn't find anything about the prognathia (underbite) related to selenium in my files. The flexure deformities and weakness that you mentioned could have been related to selenium. However, there are also toxic plants that can cause such deformities in foals. In British Columbia, Canada, it could have been caused by lupine or locoweed. The fact that the affected mares were on pasture, whereas the others were not, might also be significant.

About the Author

Sarah Ralston, VMD, PhD, Dipl. ACVN

Sarah L. Ralston, VMD, PhD, Dipl. ACVN, is a professor in the Department of Animal Sciences at Rutgers' School of Environmental and Biological Sciences, specializing in equine nutrition. Her research has focused on the effects of diet on metabolism, behavior, and the development of orthopedic disease in young horses, and she has additional interests in nutritional modulation of stress, metabonomics (the study of metabolic responses to drugs, environmental changes, and diseases), and pasture management. Previous research highlights were the pioneering work she did in nutrition for geriatric horses and post-surgical colics while at Colorado State University in the 1980s and the discovery of the correlation of hyperinsulinemia with development of osteochondrosis in young Standardbreds.

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