Horses in an Australian study showed a limited adventurous spirit when it came to trying unfamiliar forages.
Even when placed on a diet that provided only 80 percent of their recommended daily intake, horses seemed only marginally more interested in trying new foods.
The researchers from the University of New England in New South Wales and Australia’s national science agency, the CSIRO, wanted to find out if the energy intake of horses affected their willingness to select unfamiliar forages.
Horses seemed to reject most of the novel forages based on odour before sampling food, Mariette van den Berg and her colleagues reported in the journal, Livestock Science.
The researchers said while it has been shown that diet selection by equids can be influenced by nutritional factors, it remained unclear how diet choices by horses were influenced when faced with a choice between a novel and a familiar forage.
Twelve adult mares were used in the study. They were kept in yards during feeding and were housed in two groups in barren paddocks when not feeding.
The experiment lasted for eight weeks.
For the first three weeks each of the horses was fed either a low energy diet that comprised 80 percent of their recommended daily intake or a high energy diet that amounted to 120 percent of their recommended daily intake. For the fourth week all the horses received a maintenance diet before they switched diets for the next three weeks.
All of them were placed back on a maintenance diet for the eighth week.
In the third and seventh weeks, their feed preferences were assessed across three days, during which they were presented with two food choices in buckets, one of which was always a familiar feed.
The familiar feed was either oaten or lucerne chaff, while the novel feeds assessed were bamboo, tagasaste (tree lucerne), willow and saltbush leaf chaff.
Horses showed a greater preference for the familiar feed, the researchers found. They found no difference between intake of the novel feeds between the low-energy and high-energy diet groups.
They found there was a higher acceptance of the novel feeds on Day 1, which subsequently declined for both diet groups over the next two days.
The horses on low-energy diets made marginally more visits to the novel feed bucket than the high-energy group, they found.
In the eighth week, when on a maintenance diet, the horses were given a final preference test in which all the feed choices were laid out in buckets in a checkerboard design.
Among the novel forages, the horses showed a greater acceptance of willow, bamboo and saltbush compared with tagasaste.
The researchers concluded that energy did not appear to be the main determinate for diet choice by horses.
“The mechanisms involved in diet selection by horses need further clarification,” they wrote.
Does energy intake influence diet selection of novel forages by horses?
M. van den Berg, C. Lee, W.Y. Brown, G.N. Hinch.
The abstract can be read here.