Researchers from the University of Melbourne, Australia, and the WALTHAM Centre for Pet Nutrition in the United Kingdom examined[i] how much weight obese ponies and horses lost when fed all the hay they wanted (ad-libitum). They also looked at weight loss when forage was restricted.
Twelve obese animals were used in this study: 4 Standardbreds, 4 mixed-breed ponies, and 4 Andalusian-cross horses. For the first 20 weeks, they were all fed hay, ad-libitum. During the next 12 weeks, their hay intake was restricted to 1.25% of body weight.
Results:
Obese Standardbred horses lost significant amounts of weight over 20 weeks when fed ad-libitum hay. Their average Henneke Body Condition Score (BCS) improved from 7.2 to 5.3. The pony and Andalusian groups also lost weight, though not as dramatically: average BCS decreased from 8.0 to 7.0. During the next phase when hay was restricted, all groups lost even more weight.
Implications for your horses:
The results of this study reveal that overweight horses and ponies, even breeds known for difficulty with insulin resistance, lose weight when allowed to eat hay ad-libitum (available all day and all night). However, it is likely that these animals would have experienced even more weight loss had several factors been addressed:
• The study lasted only 20 weeks. There was weight loss, but more time is needed, especially for ponies and insulin resistant horse breeds.
• The hay had not been analyzed for its sugar and starch content. Had it been confirmed that these horses were consuming hay with ESC + Starch levels less than 10%, the results would likely have been even more favorable.
• There was no dietary supplementation to alleviate inflammation. Body fat releases inflammatory cytokines which promote more fat storage. Obese horses benefit from dietary addition of omega 3s and antioxidants.
• The horses were housed and fed individually. The stress of confinement and isolation creates a hormonal response that promotes fat storage.
During the second phase of the study, where hay was restricted to only 1.25% of body weight, there was greater weight loss. This is to be expected, but at great cost. Forage restriction damages the horse’s ability to maintain a normal weight and subjects him to oxidative stress, causing harm to many tissues and metabolic processes. The researchers do not have a sequel to this study. If they had, they may have found that the animals who endured forage restriction became more severely insulin resistant, as well as developed leptin resistance.[ii]
Juliet M. Getty, Ph.D. is an independent equine nutritionist For more information www.GettyEquineNutrition.com
