The effect of a hay grid feeder on feed consumption and measurement of the gastric pH using an intragastric electrode device in horses: A preliminary report



Reasons for performing study

Obesity and gastric ulceration are highly prevalent in horses. Management modifications for preventing squamous gastric ulceration include frequent feeding and free access to pasture; however, these practices may predispose horses to obesity.


To compare the percentage of hay consumed, intragastric pH and horse activity between feeding from the ground and a hay grid feeder.

Study design

Crossover experimental study.


A pH electrode was inserted into the stomach to record the intragastric pH for 48 h. Horses received 1% of their body weight in grass hay twice a day. Horses were assigned to be fed from the ground or a commercial hay grid feeder for 24 h and then switched to the opposite protocol for an additional 24 h. Horses were continuously video-recorded and the percentage of time spent eating or drinking, walking or standing, and lying down were calculated. Two point data were compared by paired t test and pH over time was compared by repeated measures ANOVA.


Horses consumed significantly greater amounts of grass hay when fed on the ground compared with a hay grid feeder (n = 9; P<0.001). There were no significant differences between the groups for mean intragastric pH values (n = 6; P = 0.97), mean intragastric pH over time (n = 6; P = 0.45) the length of time the pH was below 4.0 (n = 6; P = 0.54), and the percentage of time horses spent eating or drinking (n = 9; P = 0.52), walking or standing (n = 9; P = 0.3), or lying down (n = 9; P = 0.4). Within each group horses spent more time eating during the day compared with the night (n = 9; hay grid feeder P = 0.003; ground feeding P = 0.007).


The hay grid feeder studied may be used to reduce the amount of hay ingested by horses without reducing the time horses spend eating.