WHEN HORSES CHEW they crush their food via the lower jaw moving from side to side. The lips may pluck the grass from the pasture, or pull hay from a haynet, but the tongue then flicks it towards the back of the mouth where the molars do their crushing work. Chewing to prepare the food for digestion stimulates salivary secretion — and saliva also contains bicarbonate — to buffer stomach acid, and this may promote satiation (a feeling of fullness) as well as reduce the risk of developing gastric ulcers.
Vitally, because horses have only one stomach, this chewing needs to be as effective as possible in order for the rest of the digestive system to work efficiently. Interestingly, horses change their chewing pattern according to the fibre levels in their feed.
My study, believed to be the first to focus on chewing rate on a 50% straw-based forage ration, has shone a spotlight on horses’ chew time and consumption rates. The remit was to investigate feeding oat straw in a haylage diet, exploring the effects not only on those chew time and consumption rates, but also onweight and bowel movements, all of which are intended to aid understanding when it comes to feeding overweight and obese horses.
The study also aimed torestriction levels, may help to support gastric ulcer-prone horses. Researchers believe that these develop as a result of the restricted forage rations that are often fed to obese horses. Improving psychological wellbeing by satisfying a horse's behavioural need to chew and consume forages slowly throughout the day was also an important consideration for the present study. The preliminary results suggest that oat straw provided at 50% of the forage ration may indeed induce weight loss, reduce passage rate (the speed at which food passes through the gastrointestinal tract), slow consumption — indeed, therewas a statistically significant decrease in consumption rate after just aweek of feeding this diet—and alter chewing behaviour. In fact, adding oat straw into a forage diet may be an important part of improving the welfare of horses with low-energy requirements.
