Obese horses get a bum rap say researchers

When allowed to make their own choices, fat horses do not eat more than their lean peers and they get just as much exercise.

Many an obese horse has been labelled “lazy” or “gluttonous,” but 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. This, the researchers say, suggests that underlying metabolic conditions may contribute to equine obesity.

The experiment

Researchers found that obese horses were active—interacting with other horses or moving—for longer periods and spent less time eating than did the lean horses.

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, the researchers closely monitored their hay intake and metabolic state.

In addition, the researchers collected fecal samples to determine dry-matter digestibility and gross energy digestibility. The horses also wore heart-rate monitors with GPS trackers that collected data for calculations of each horse’s energy expenditure. The researchers also took blood samples regularly for analysis.

The findings

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.

Click here to read how your horse’s herd status may contribute to obesity.

These findings, say the researchers, suggest that when horses receive free-choice forage, obesity does not appear to be related to excessive food intake or reduced activity. Instead, it’s 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

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