HOW A MARE’ S OBESITY MAY AFFECT HER FOALS

New research from France shows that a mare’s obesity can have negative health consequences for her offspring.

A study conducted at the experimental unit of the French Institute of Horses and Equitation by researchers of the National Institute of Agronomical Research within University of Paris—Saclay assigned 24 mares to one of two groups---obese or normal ---at the time of artificial insemination. The obese mares had a body condition score (BCS) of 4.25 or greater (on the European BCS scale of 1 to 5) and the normal group had a BCS of 4 or less.

The researchers monitored each mare’s weight, as well as various metabolic parameters, throughout the gestation period. The data showed, not surprisingly, that obese mares were more insulin resistant than normal mares and also that they were more likely to have elevated blood levels of a protein called plasma serum amyloid A (SAA), which is an indicator of lowgrade inflammation.

After the foals were born, researchers monitored their size and weight and conducted regular testing for SAA and various metabolic hormones. When the foals were 6, 12 and 18 months old, they were given a glucose tolerance test (to analyze their glucose and insulin metabolism) and examined for osteochondrosis, a musculoskeletal disease that has been linked to diet.

The researchers found that all of the foals grew at roughly the same rate, but those from obese mares had higher blood levels of SAA at 6 months of age, indicating chronic low-grade inflammation. In addition, these foals were more insulin resistant at ages 6 months and 18 months compared to the youngsters from normal mares. What’s more, at 1 year of age, offspring of obese mares were significantly more likely to be affected by osteochondrosis than were their peers from normal dams.

These differences cannot be attributed to genetics alone, says Pascale ChavattePalmer, DVM, PhD. “In our groups, there were two full sisters---one obese and one normal--and otherwise the genetics were very widely distributed between groups,

The researchers say it’s likely that the health status of the dams influenced the health of their foals.