Genetics of Laminitis in Ponies Studied

Researchers have estimated the heritability of laminitis in dairy cattle to be between 0.1 and 0.15, although the mode of inheritance has not been determined. A 2005 study in Virginia examined the heritability of grass founder in an inbred herd of Welsh and Dartmoor ponies.

The researchers traced the pedigrees of 257 ponies born from 1933 to 2002 back up to 10 generations. Ninety-five ponies (36.7%) were reported to have suffered laminitis. Nearly half of the affected ponies had a parent that was recorded as laminitic, and increased severity was noted when a pony’s sire and dam had both suffered laminitis.

Involvement of a dominant gene would mean that 100% of cases needed to have an affected parent, but the researchers postulated that the number was reduced by incomplete recordkeeping during previous generations of the pony herd and ponies that had a genetic predisposition to become laminitic, but didn’t experience environmental factors that could trigger clinical disease.

The development of a test to identify ponies with a genetic predisposition to laminitis would help the owners and managers of these ponies to maintain them carefully in order to reduce the incidence of the disorder.

Read more from Advances in Equine Nutrition IV.