February 2016 - Feeding horses under cold conditions
Cold winter periods affect the nutritional requirements of the horse, and especially the energy requirement. The ideal situation for the horse is to have time to adapt gradually to cold ambient temperatures. This period of acclimatization allows for the growth of a thick winter coat and a reasonable cover of fat. In addition, if the horse can access shelter from wind and rain/snow, it may remain comfortable outdoors during cold periods without having to wear rugs. However, proper feeding and access to temperate water is mandatory in this situation.
Responses to cold conditions.
The horse responds to cold conditions in several ways. Typical behavioral responses include turning their tails against the weather, gathering together in groups, and seeking out any kind of shelter. They also increase their feed intake and eating time. When the temperature falls below what is called the Lower Critical Temperature (LCT), metabolical and physiological responses are triggered that produce the extra heat needed to maintain normal body temperature.
Lower Critical Temperature (LCT).
The LCT is defined as the ambient temperature at or below which the horse increases its metabolic rate to produce more heat in order to maintain normal body core temperature. A horse’s individual LTC under given conditions will also be influenced by wind chill, precipitation (rain or melting snow), relative humidity, acclimatization, body condition (fat/thin) and density of hair coat. In addition, young horses are less cold tolerant than mature horses.
There are many tables presenting LCT values for different types of horses. If offered shelter from wind and precipitation, acclimatized adult horses can be comfortable in temperatures down to -15 oC or even lower. For young horses the LCT is typically in the range 0 to -10 oC.
Heat is produced by muscle contractions (shivering or voluntary physical activity), and in most chemical reactions. In the hind-gut (caecum and colon), the microbial fermentation of fibrous feeds produces a lot of heat. Consequently, feed intake and type of feed will also influence the body’s heat production.
The most efficient way of increasing the production of heat during cold periods is to increase the amount of roughage in the rations, as the high fibre content will stimulate microbial fermentation in the hind-gut and hence help increase heat production. Digestion of concentrate feeds produces far less heat compared to roughages. Consequently, it is often advised to let horses have free access to roughage when kept outdoors during winter. As long as the horses do not grow too fat, this is regarded as a well-documented feeding practice.
Under cold conditions, water intake can fall too low. This can decrease feed intake and increase the risk of colic. It is therefore strongly advised to provide horses with constant access to temperate water (at least 7 to 10 oC). It may be a good idea to get heated water containers as there are several brands on the market to choose from.
When using PC-Horse to compose your rations, you will always be in control of the amount of roughage in the rations and be able to optimize roughage content when needed.
This article was originally written by Dr. Day Austbø.
Copyright: PC-Horse International - Norway 2015
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