Could ponies prone to laminitis be the equine equivalent of overweight humans who eat too many pies?
A preliminary study in Britain found no compelling evidence in a preliminary study to suggest that laminitis-prone ponies were necessarily greedier than ponies without a history of the debilitating hoof condition.
Jo-Anne Murray, from the University of Glasgow Veterinary School, and R. Harrison, from the University of Edinburgh’s Royal (Dick) School of Veterinary Studies, used 16 ponies under the care of the British charity World Horse Welfare in Norfolk. Eight of the ponies had a history of laminitis and the other eight were considered clinically normal.
The researchers, writing in the journal Livestock Science, said one possible factor behind triggering laminitis was grazing intake.
Whilst some studies had looked at grazing intake in healthy animals, there had been little comparison made between animals with and without a history of the condition, they noted.
The pair set about examining the grazing intake of the 16 animals. The ponies were all British native breeds and were mature animals maintained at grass 24 hours a day.
The study was carried in July, during the northern summer, over 12 days.
All the animals were grazed under identical conditions.
For ethical reasons, all the ponies were grazed in pastures where herbage mass was low to minimise the risk of the laminitis-prone ponies coming down with the condition.
The grass height was 1-2cm and the yield per hectare was calculated at 124kg of dry matter.
Manure samples were collected from the eight clinically normal horses as well as the eight predisposed to laminitis and their grazing intake was calculated.
Murray and Harrison found that the dry matter intakes per kilogram of bodyweight for all the ponies were low.
There was no significant difference in dry matter intake between the two groups of ponies, which was found to be 4.43kg per day for the clinically normal ponies and 4.25 kg for the laminitis-prone animals.
The mean dry matter intake per kilogram of bodyweight per day was 1.32 percent for the clinically normal ponies and 1.62 percent for the laminitis-prone animals.
The researchers noted that while there was a 20 percent difference, there was a greater variability of dry matter intake within the laminitis-prone group, with intakes ranging from 0.81 to 2.36 percent of bodyweight.
The low dry matter intake values found in the study were attributed to the overgrazed nature of the pasture used in the study – something they said was unavoidable due to the welfare issues associated with grazing laminitis-prone horses on good grazing pasture.
“Further work is required with a larger study population grazing pastures with greater herbage mass,” they noted.
A preliminary study of grazing intakes of ponies with and without A history of laminitis
R. Harrison, J.M.D. Murray
The abstract can be read here.