Increasing browsing behaviour

By 

Rachel O'Sullivan MSc RNutr

At this time of year horses tend to spend longer than usual stabled, and with the very wet winter we have had this year many horses are currently stabled 24/7. Horses are designed to eat for up to 18 hours per day and, when grazing, will selectively forage on a wide range of different grass species. This browsing behaviour is often limited for the stabled horse who are usually only provided with one type of forage.

A study conducted in 2005* set out to investigate the behaviour of horses when presented with a single forage vs multiple forages when stabled. Nine horses were used in the trial and they were kept at grass overnight and stabled for eight hours during the day (07.30 – 16.30). The horses were randomly allocated into two groups, one group started with the Single Forage diet and the other started with the Multiple Forage diet. Each trial period lasted 7 days, with a 2-day acclimatisation period. The Single Forage treatment consisted of 6kg of hay tied in a haynet at the front of the stable. The Multiple Forage treatment consisted of 3 long chop forages (hay, ryegrass haylage, ryegrass & timothy haylage) and 3 short chop forages (molassed dried alfalfa, molassed dried grass, unmolassed dried grass) totally 5.5kg. The long chop forages were placed in haynets tied at the front of each stable and the short chop forages were placed in bucket underneath the haynets.

In order to record the horse’s behaviours cameras were set up at the back of the horse’s stables. Horses were presented with forage at 09.30 and again at 15.30 which allowed for both morning and afternoon behaviour assessment to occur. The horse’s behaviour was recorded as being either FORAGE, SEARCHING or REMAINING. FORAGE behaviour was chosen if the horse was seen to be sniffing, manipulating, biting, chewing or ingesting any of the forage options. SEARCHING behaviours were recorded if the horse was seen to standing looking over stable door or moving around the stable. REMAINING behaviours were recorded if horses were seen to do any other behaviour, such as drinking, urinating, defecating or performing stereotypic behaviours.

The results showed that horses on the Multiple Forage treatment performed significantly more FORAGE behaviours and for longer periods. They also showed and significantly less SEARCHING behaviours. Stereotypic weaving behaviour was only seen on the Single Forage treatment.

browsing pie chart

The researchers concluded that horses have a drive to forage and exhibit ‘sensory-specific satiety’ where the horse becomes satiated by one food type but is still motivated to consume others. If this occurs in stabled horses who are only fed one forage type the motivation to continue to forage will increase and the horse may start to display redirected forms of searching behaviour such as box walking, weaving, wood chewing, crib biting etc. By offering our stabled horses multiple forage options we can decrease the likelihood of this occurring, helping to stimulate natural foraging behaviours and help to support forage intake during increased stabling.

*Thorne, J.B., Goodwin, D., Kennedy, M.J., Davidson, H.P.B. and Harris, P. (2005) ‘Foraging enrichment for individually housed horses: practicality and effects on behaviour.’, Applied Animal Behaviour Science, 94 (1-2), pp.149-164.

 

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