Many an obese horse has been labelled “lazy” or “gluttonous,” but new research from North Carolina State University suggests that, when allowed to make their own choices, most overweight horses do not eat more than their lean peers, nor are they less active.
The study focused on 10 mature horses divided into an “obese” group---six horses with body condition scores above 7, and a “lean” group of four horses with body condition scores of 4 or 5. Over a 25-day period, both groups made the transition from grazing pasture to free-choice hay. Then, for the next 11 days, their hay intake and metabolic state were closely monitored.
In addition, fecal samples were collected to determine dry-matter digestibility and gross energy digestibility, and the horses wore heart-rate monitors with GPS trackers that collected data that could be used to calculate each horse’s energy expenditure. Blood samples were also taken regularly for analysis.
Reviewing the data, the researchers found no significant differences in the energy intake and expenditures between the obese and lean groups. In fact, the obese horses were active—interacting with other horses or moving—for longer periods and spent less time eating than did the lean horses.
These findings, say the researchers, suggest that when horses are on free-choice forage, obesity does not appear to be related to excessive food intake or reduced activity but is more likely associated with metabolic factors not measured in this study.—Gulsah Kaya Karasu, DVM
References: “Voluntary energy intake and expenditure in obese and lean horses consuming ad libitum forage,” Journal of Equine Veterinary Science, December 2018