Low Starch Feeds For Spooky Horses
Although we know anecdotally that some horses seem to be more reactive to being fed a higher starch diet there has been surprisingly little scientific research carried out into this matter.
One study, conducted in 2015*, investigated the reactivity of horses when fed a lower starch diet vs a higher starch diet. Eight horses, of mixed breeds, age and gender, were split into two groups of four. For the first 28 days, one group were fed the lower starch diet which consisted of hay and alfalfa with a starch level of 2%, and the other group were fed the higher starch diet which consisted of hay and a cereal-based, compound mix with a starch level of 22%. Both diets provided the same energy intake. For the second 28 days, the groups swapped diets.
On days 0, 7, 14, 21 and 28 of each of the two study periods, the horse’s behaviour and heart rate were measured whilst they were taking part in a novel stimulus test. The novel stimulus test took place in a large indoor school and consisted of two different assessments. The first assessment was a handling test in which the horses were led to a curtain of red and white strips of plastic and could make their way through the curtain in their own time. The time it took for the horse to go through the curtain was recorded. In the second assessment, the horse was loose in the school and allowed to eat from a feed bowl. White noise was then played behind the feed bowl and the time taken for the horse to come back to the bowl and start eating again was recorded.
The results showed that, compared to the horses on the lower starch diet, horses fed the higher starch diet showed higher average and maximum heart rates during the handling test, although there was no significant difference in the time taken to go through the curtain. When the white noise was played during a meal horses on the higher starch feed showed more interruptions in eating and higher heart rates.
The results of this study indicate that if you have a horse that is spooky or reactive, feeding a lower starch diet may help to alleviate some of these behaviours.
*Bulmer, L., McBride, S., Williams, K. and Murray, J.A. (2015) ‘The effects of a high-starch or high-fibre diet on equine reactivity and handling behaviour.’, Applied Animal Behaviour Science, 165, pp.95-102.