Equus – August 2019

28 EqUUS 498 AUTUMN 2019

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 pe-

riod, 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 close-

ly 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 en-

ergy expenditure. Blood

samples were also taken

regularly for analysis.

Reviewing the data,

the researchers found no

signifi cant 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 fi ndings, say the

researchers, suggest that

when horses are on free-

choice forage, obesity does

not appear to be related to

excessive food intake or re-

duced activity but is more

likely associated with meta-

bolic factors not measured

in this study.---Gulsah Kaya

Karasu, DVM

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SURPRISING

FINDINGS ABOUT

OBESE HORSES

References: “Voluntary energy intake and expenditure in obese and lean horses consuming ad

libitum forage,” Journal of Equine Veterinary Science, December 2018

NOT THEIR FAULT: Research suggests that metabolic factors,

rather than excessive food intake or lack of exercise, may

be responsible for obesity in some horses.