Written by Andrea D. Ellis, PhD, MRSB
The natural body-cycle of nearly all mammals who have evolved in temperate climates with four seasons involves a period of undernourishment during the winter months followed by an abundance of food during late spring and early summer. The hormone body clock has adjusted to this and we now know that horses, for example, produce less appetite hormones during the winter, in order to protect them from hunger feelings, while the hormones increase in late summer/early autumn to encourage them to put on body fat to survive a harsh winter (Dugdale et al., 2011).
Keeping our horses on a high plane of nutrition during the winter could be counter productive, especially if they are going to put on weight during the summer months out on grass, and then do not have the chance to loose this during the winter. Studies have shown that a reduction in feed intake during the winter leading to a body-condition just below what we would ‘class’ as ‘good/ideal’ can actually protect against underlying metabolic conditions which contribute to the development of laminitis.
So any excess body condition from the summer should be lost during the winter period. This can be achieved through continuing to turn out on grass for as long as possible and not automatically increasing feed in the winter or putting on lots of warm rugs. Forage should be supplied as required to maintain body weight with a good quality vitamin mineral supplement. To check the requirements for this, get your forage analysed and consult with a nutritionist.
Overweight?
If you have a horse which is a particularly good ‘doer’ then restricting feed intake while trying to increase exercise is the best option. The author generally advises the following guidelines:
Replace and/or increase, replace, reduce (Ellis, Unequi Ltd):
1) Replace: first replace concentrates with forage
Increase: exercise, gently and slowly over time
2) Replace: – then replace high energy forage with low energy forage – e.g. younger cut haylage with late cut hay or even mix in a little straw chaff (a guide can be the measure of water soluble carbohydrates in your forage)
3) Reduce: reduce forage intake – this may include providing a poor pasture paddock or strip-grazing to reduce grass intake or even bringing horses in onto a sand arena or indoor group housing; reducing conserved forage intake while still helping horses to spend enough time on feed intake behaviour is important. Here a slow feeder can help. Only reduce forage below the recommended 2% of BW in DM if 1 and 2 have not worked. It may be advisable to consult your vet when doing this. Latest recommendations are not to reduce forage intake below 1.25% of BW in DM (Harris et al., 2017).
Remember to introduce any novel feedstuff (e.g. straw) very slowly over a period of several weeks. Some horses will avoid eating straw so mixing it into their hay will slow their feed intake behaviour as well. Avoid very fast weight loss, gently does it – allow 3 weeks between each step. Some internal body-fat may be broken down, which is hard to see externally.
Find out more about how you can restrict calories whilst keeping your horse busy chewing.
Underweight?
Some horses, however will loose bodyweight faster during the winter and are more high ‘maintenance’ in the winter. Especially old horses for example, need some special care in the winter. If weight loss is unexpected or out of character always consult a veterinarian and have a quick health check (teeth, worms etc.). Older horses may need to be checked for metabolic disorders. Allowing ad libitum access to forage and improving the quality of forage is a first step to take. Also ensure that the teeth are checked regularly. In older horses, dental conditions or loss can lead to forage not being chewed well, and in this case feeding chopped forage and wetting down forage will help. Horses which are just a little harder to keep weight on, can benefit from a small feed in addition to forage. Alfalfa pellets, which still contain some aspects of forage goodness can be useful step before moving onto concentrates containing sugar and starches. Soaked sugar beet pulp should be fed at an inclusion rate of maximum 2 kg wet feed (soaked at a ratio of around 4 water to 1 pellets, or according to manufacturers recommendations). Addition of vegetable oil of around 100ml can also help maintain condition. Sometimes switching from hay to good quality haylage may be all that is needed to help maintain bodyweight.
So the main take home message is – do not worry about a little ‘natural’ weight loss of your equine friends in the winter and immediately compensate with higher feeding. For aged horses or when the weight-loss does not balance out, consult your vet and a nutritionist.
References:
Argo, Curtis, Grove-White, Dugdale, Barfoot, & Harris. (2012). Weight loss resistance: A further consideration for the nutritional management of obese Equidae. The Veterinary Journal, 194(2), 179-188.
Dugdale, A.H.A., Curtis, C., Cripps, P., Harris, P.A., Argo, C.McG., 2011. Effect of season and body condition on appetite, body mass and body composition in ad libitum fed pony mares. The Veterinary Journal 190, 329–387.
Harris, P.A., Ellis, A.D., M.J.Fradinho, A.Jansson, V.Julliand, N.Luthersson, A.S.Santos and I. Vervuert. 2016. Feeding conserved forage to horses: recent advances and recommendations; Animal Science, Animal (2017), 11:6, pp 958–967
Lindberg JE 2013. Feedstuffs for horses. In Equine applied and clinical nutrition (ed. RJ Geor, PA Harris and M Coenen), pp. 319–331. Elsevier, Amsterdam, The Netherlands.
Longland AC, Byrd BM. 2006. Pasture nonstructural carbohydrates and equine laminitis. J Nutr;136. 2099S–2102S.
Ringmark S, Roepstorff L, Essén-Gustavsson B, Revold T, Lindholm A, Hedenström U, Rundgren M, Ögren G and Jansson A 2012. Growth, training response and health in Standardbred yearlings fed a forage-only diet. Animal 7, 746–753.
