A look at feeding practices
In three separate studies with large groups of horses examined by private practitioners, Cohen and colleagues studied the
association of feed and feeding practices with colic.
In one study of more than 1,600 animals, 821 were treated for colic, while an equal number had other conditions. The types
of concentrates and hays fed to horses with colic were similar to that of the controls – oats to roughly half of each group;
a 12 percent sweet feed to about 30 percent of each group; and a 14 percent sweet feed to approximately 17 percent of each
Coastal Bermuda hay was fed to an equal amount of each group; about 82 percent of colic (672/821) and control (669/821) animals;
alfalfa to about 32 percent of each group; and about 9.5 percent of each group were fed other hays. Therefore, there were
no significant differences or alliance with any feed to colic or non-colic horses.
What was significant was change in diet.
"History of any recent change in diet was determined for 1,607 horses (807 with colic and 800 control horses), and a recent
change in diet was found to be significantly (P <.0001) greater among horses with colic (19.7 percent) than among control
horses (4.9 percent)," Cohen explains.
In a subsequent study (1,030 pairs of colic and control horses), also done at Texas A&M, Cohen and colleagues found that "colic
horses were significantly less likely to have been fed on pasture than were control horses."
Of horses fed different feeds, colic (532) and control (563) were fed sweet feed; fed oats, colic (411), control (386); fed
pelleted concentrate, colic (193), control (183); a mixture of sweet feed and pellets, colic (46), control (38); fed corn,
colic (20), control (22); and those fed extruded feed, colic (9), control (12). Again there were no differences due to concentrate
type that was fed.
Similarly for type of hay fed: There were no differences between the colic and control groups – alfalfa hay, colic (204),
control (201); coastal or Bermuda grass hay, colic (753), control (736).
Like the previous study, diet change again was significant, but of all the changes – concentrate to hay, one grain to another
and one hay to another, changes in amounts of hay and/or grain – "only change of hay was significantly associated with colic."
Of dietary supplements fed (vitamins, minerals, proteins, fats), none of them, nor their amount, was associated with colic.
Another study by Cohen and colleagues of 182 matched pairs of colic and control horses showed similar results. Of 165 horses
fed sweet feed, about 50 percent experienced colic; those fed pellets, there was no difference in colic incidence; for those
fed oats (136), 72 were colic cases, 64 control, and of those fed other grain, 30 horses, half were with and without colic.
Feeding >2.7 kg oats was allied to increased colic incidence. Change in concentrate/grain fed was again a source of colic.
"A change in the type of grain or concentrate fed during the two weeks prior to examination (e,g., from pellets to sweet feed)
significantly increased the risk of colic." The study also stated, "Horses with no grain intake appeared to be protected from
colic, compared to those fed grain or concentrate on a daily basis."
Of 244 horses fed coastal or Bermuda grass hay, an equal number were colic and non-colic cases; alfalfa hay, also even. It
was assumed that 6 flakes of hay per day was considered free-choice, and it was shown that consuming >2 flakes per day of
hay other than coastal, Bermuda or alfalfa was associated with increased incidence of colic. Switching to a different type
of hay was not found to be associated with colic, though horses that were recently fed a change in amount of hay was.
Various aspects of feed and feeding have been linked with increased colic risk.