by Clair Thunes, PhD Equine Nutritionist
It is official, winter is here and with it the challenges in horse keeping unique to the season. One of the most common challenges is to maintain condition. When we think of winter we often think of weight loss especially in our senior horses. Too often weight loss seems to occur out of nowhere. But, most often it is a gradual loss that occurs right under our noses. Often we don’t become aware until there has been significant weight loss. With careful management and attention to detail preventative steps can be taken.
Your winter nutrition plan starts now with an assessment of your horse’s current condition and diet, a review of the work you are doing, and hope to be doing over the winter, and how your horse is kept, and is going to be kept in the coming season. All these factor into your horse’s dietary needs.
Maintaining condition is all about energy balance. When energy in equals energy out, body condition is maintained.
This means that if the energy content of the diet you feed your horse exactly meets your horse’s energy requirement it will maintain a constant weight. This is called being in energy balance – it is a state of equilibrium. Being in equilibrium is the key to good nutrition and some would say life in general. Conversely, if the energy in the diet is less than the horse’s energy requirement the horse will lose weight, and if the dietary energy is greater than the requirement the horse will gain weight as fat. The same is true for humans, it is the basic rule of energy metabolism.
Knowing this, the question then becomes, what factors affect a horses demand for energy? These factors include; reproductive state (pregnancy, lactation), level of activity, age, overall health status, and weather (ambient temperature, wind chill, humidity). A horse’s lowest energetic state is called maintenance and applies to horses and ponies that are not in work, are not pregnant or lactating, are in good health and do not have to deal with major climatic demands.
Dietary maintenance energy requirements differ by the size of horse as obviously it takes less energy to maintain a Shetland pony than it would a hack. For example, a 200kg (440lb) pony has a maintenance requirement of 6.7 Mcal per day compared to 16.7 Mcal per day for a 500kg (1100lb) horse. Assuming an energy density of 2.2 Mcal per kilogram (which is typical of many grass hays) their Mcal for maintenance approximately equals the number of kilograms of hay needed per day to meet that requirement.
Each time you add a factor such as work, your horse’s energy demand increases, and therefore to remain in energy balance, the diet must include more energy or the horse will lose body weight and condition. As mentioned above, weather can be such a factor. Cold weather requires that a horse burns more energy to keep warm, and therefore less energy is available to maintain other functions unless dietary energy intake is increased to compensate. This is one reason why horses tend to lose weight over the winter.
So how do you know if your horse is in energy balance? The best way is to assess a horses body condition and fat deposition is through use of a body condition scoring system. This involves manually palpating and visually assessing certain areas of your horses body that are known to be locations of fat deposition, namely; the loins, ribs, tail head, the side of the wither and neck and behind the shoulder. By running your hand over these areas and paying attention to what you feel, you gain a much more objective sense of your horses overall fat cover. This is particularly important in the winter when a horse’s hair coat can be long and give the illusion that the horse is in good weight when in fact they are not.
A 10 point scale is used on a frequent, monthly, basis to allow constant assessment of body condition over time. Details of the 10 point condition scoring system and methodology can be found below.
The best thing you can do to insure that your horse comes out of the winter in the condition you want them to be in is to insure they go into winter in good condition, and then provide enough energy in the diet to meet requirements. During the colder winter months, horses have to expend extra energy to keep warm and that means that the maintenance requirement increases.
Older horses are generally less efficient at both digestion and thermoregulation and so are more susceptible to extremes in temperature. They will therefore need a diet that is more easily digestible and may require intervention earlier than their younger counterparts to stay warm. Young horses especially those under a year of age are also less able to handle cold weather in part due to the large amounts of energy that are being utilised for growth. They should be provided with good shelter and ample access to good quality hay.
Fat acts as an insulator and so a modest covering of fat going into the winter will actually help your horse use less energy to keep warm. Plus, should the dietary energy levels fall below their requirement they can burn their fat stores as an energy source until the dietary energy levels increase. This is potentially useful for horses who need to lose weight, and mirrors horses in the wild that lose weight over the winter and regain it in the spring when the grass returns and weather warms up.
The key is not to lose so much weight that an undesirable condition results. The horse that condition scores now at a 5 or 6 is going to have an easier time staying warm and maintaining a desirable body weight than the horse that goes into the winter with a score of 4. As a general rule, to raise the condition score of a horse from a 4 to a 5 over a 90 day period requires an increase in energy intake per day of about 25%. So our 200kg pony from earlier would need 8.4 Mcal each day and our 500kg horse would need 20.9 Mcal per day over the 90 day period. Of course there are those horses who have to work intense jobs over the winter who are typically maintained at a lower condition score such as race horses and they will require particularly close management to insure that they do not drop too much condition.
Should you find yourself needing to put extra weight on your horse the first step is to increase the amount of forage being fed. In cold weather this has the added advantage of helping maintain body temperature as fermentation in the hindgut generates heat. In some cases even with plentiful forage either the horse will not consume enough or perhaps digestion is not as efficient as it could be and weight gain remains an issue. In this situation a more energy dense feed can be added to the ration such as HYGAIN® Micrbeet or HYGAIN® Fibressential.
High in soluble fiber, HYGAIN® Micrbeet provides energy at a level between good quality hay and grains. HYGAIN® Fibressential is an excellent fiber source with enhanced levels of digestibility making it a great choice for senior horses with poor dentition. Other good choices of feeds for weight gain include fat supplements such as HYGAIN® Tru Gain. With a fat content of 20 percent, Tru Gain increases the calorie content of the diet without fizz. If looking for a high calorie feed the extruded grains in True Care are more readily digestible in the small intestine making it an excellent choice for hard keepers and senior horses whose digestive tract may not be working as efficiently as they once did. It is possible to successfully maintain body condition in the winter even with a hard keeper, but it takes a close eye and constant assessment. Implement a monthly plan of body condition scoring your horse so you can catch changes in body condition and take action sooner rather than later to avoid undesirable weight loss in the winter months.
Free Fact Sheet on The 3 Step Weight Gain Strategy for your horse