WSVMA Annual Conference Equine Nutrition Spokane Convention Center Spokane, Washington October 1-3, 2010 Steve Duren, PhD Performance Horse Nutrition, Weiser, ID
Stephen Duren, MS, PhD, PAS Performance Horse Nutrition Weiser, ID Biography: Dr. Stephen Duren is an equine nutritionist based in the United States. As a consulting equine nutritionist, Dr. Duren works with horse farms and feed manufacturers throughout the world including LMF Feeds in the Western United States. Dr. Duren owns the consulting company Performance Horse Nutrition. Contact Email: sduren1@mindspring.com
FEEDING NEGLECTED HORSES Stephen Duren, MS, Ph.D., PAS Performance Horse Nutrition Weiser, Idaho 83672 USA Starvation or malnutrition in horses can be caused by intentional neglect, ignorance, economic hardship of owner, disease, dentition, pecking order, parasites, or seasonal variation in availability of feed. Remarkably, horses can lose 30% or more of their body weight and still survive. Horses in this condition will have very little muscle mass and will be very weak. Refeeding neglected or starved horses requires special attention and a sound nutrition program to return them to a proper body condition. Even with the best of care some horses won t survive, especially horses that have lost 50% or more of their body weight. When a horse is fasted, the body starts to breakdown stored fats and carbohydrates to use as energy to maintain life. When these stores are depleted the body starts to derive energy from the breakdown of protein. Initially the body breaks down protein from muscle causing muscle wastage. However, this utilization of protein is not specific to skeletal muscle and can also breakdown protein from vital organs such as the heart and gastrointestinal tract. The lack of nutrition also depletes the body of vitamin, mineral and electrolyte stores and leads to a state of salt and water intolerance. Body Condition Score Neglected or starved horses are generally in poor body condition. To quantify the condition of horses, a body condition scoring (BCS) system is utilized. The most widely accepted scoring system is the 1-9 system of Henneke and coworkers (1983). This system is used to determine the fat stores by visually evaluating specific areas of the body such as the neck, withers, tail head, ribs, shoulder, pelvic area and back. A horse with a BCS of 3 or less is considered underweight, a BCS of 4-6 is considered ideal, a BCS of 7-8 is considered overweight and a BCS greater than 8 is considered obese. The following is a written description of the Henneke body condition scoring system with illustrations put together by the Japan Racing Association.. 1
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Re-Feeding Syndrome 3
Neglected or starved horses that are being reintroduced to feed occasionally suffer from refeeding syndrome. Re-feeding syndrome occurs when a fasted horse eats a meal (generally high in carbohydrate); insulin is released and causes glucose to be absorbed into the body cells, but is also draws the electrolytes magnesium and potassium out of the bloodstream and into body cells. The starved horse doesn t have an adequate store of these electrolytes and their depletion can lead to heart, respiratory or kidney failure and subsequent death. These horses will also retain salt and water resulting in severe swelling. Generally the effects of re-feeding syndrome will be seen between 3 and 5 days after the first meal, and many horses die within a few days after starting a feeding program. Re-feeding syndrome can occur regardless of body condition in horses that have been fasted for more than 5 to 10 days. Feeding the Neglected Horse The first step in re-feeding the neglected or starved horse is to determine the reason for the weight loss. This veterinary evaluation will determine the presence of a medical condition resulting in weight loss. If the horses weight loss is the result of a medical condition, this condition will need to be corrected to facilitate weight gain. On the other hand, if the reason for weight loss is neglect, economics or ignorance this also must be noted to successfully plan a refeeding program. The re-feeding of a starved or neglected horse can be broken down into four phases. These phases are days 1-3, days 4-10, days 10-14 and day 15 and beyond. The following outline will provide feeding guidelines during the four re-feeding phases. Phase 1- Days 1-3 Equine nutrition research has shown the safest way to start a feeding program for a starved horse is to offer small frequent meals of high quality alfalfa hay. For our example, assume a mature horse with an ideal body weight of 1000 pounds. This horse may have lost between 30% and 50% of its ideal weight. Start the feeding program by offering one pound of alfalfa hay every 4 hours. The amount of alfalfa offered per day for the first three days of re-feeding is a total of 6 pounds. This is far below the horses energy requirement, but most feeding problems with starved horses are the result of feeding too much too soon. Alfalfa is better than other types of hay because of its high composition of quality protein, but also the major electrolytes. Because alfalfa hay is very low in sugar content, there are minimal effects in regard to insulin response. Follow this feeding program for the first three days and provide fresh, clean water at all times. If it is an older animal with poor or missing teeth, it may be necessary to feed an alfalfa hay pellet or cube that must be soaked and made into a mash prior to feeding. The horse should not be fed any grain during this stage of re-feeding. Phase 2 Days 4-10 If the horse tolerates the Phase 1 feeding program with no diarrhea or other problems, keep increasing the amount of alfalfa hay fed and decrease the number of feedings. From day 4 4
through 10, the horse should be gradually adapted to being fed 4 lbs of alfalfa every 8 hours. This provides a daily intake of 12 lbs of alfalfa. This is a twice the amount of hay that was being fed initially to the starved horse. Follow this feeding program for days 4-10 and provide fresh, clean water at all times. If it is an older animal with poor or missing teeth, it may be necessary to feed an alfalfa hay pellet or cube that must be soaked and made into a mash prior to feeding. The horse should not be fed any grain during this stage of re-feeding. Phase 3 Days 11-14 If the horse tolerates the Phase 2 feeding program with no diarrhea or other problems, the amount of alfalfa can be increased again. During this stage of feeding we attempt to get the horse to consume 2% of its body weight in alfalfa hay. This hay should be divided into two equal feedings. Depending on the appetite of the horse, this amount of alfalfa should be easily consumed throughout the day. The feeding rates for horses with different body weights are shown below. Current Weight of Horse Total Amount of Alfalfa per 24 hours 600 lbs 12 lbs 700 lbs 14 lbs 800 lbs 16 lbs 900 lbs 18 lbs Follow this feeding program for days 11-14 and provide fresh, clean water at all times. If it is an older animal with poor or missing teeth, it may be necessary to feed an alfalfa hay pellet or cube that must be soaked and made into a mash prior to feeding. The horse should not be fed any grain during this stage of re-feeding. Phase 4 Day 15 and beyond After two weeks, the horse can be fed twice daily with the total amount of alfalfa hay provided equal to 2.5% of the initial body weight. These feeding amounts are shown below. Current Weight of Horse Total Amount of Alfalfa per 24 hours 600 lbs 15.0 lbs 700 lbs 17.5 lbs 800 lbs 20.0 lbs 900 lbs 22.5 lbs After 14 days introduction to pasture can begin with an hour of pasture access for three to four days. Gradually increase pasture time over a period of 10 to 14 days and then daily or 24- hour access can be allowed. Also, if alfalfa hay is not readily available and another type of hay is more available or economical, the horse may be gradually changed to another type of hay over the next two weeks so that alfalfa hay no longer is fed after four weeks into the feeding program. 5
Grain Feeding The horse s digestive system is designed to digest fiber from hay and pasture. However, grain concentrates offer a more calorie dense feed and provide the horse with nutrients to repair tissues. Starting at day 15, add a small amount of protein, vitamin and mineral pellet. This pellet will add the essential nutrients that have been depleted from the body. This low inclusion supplement will help protect the digestive system from upset often caused by large meals of grain. A good protein, vitamin and mineral pellet to utilize with alfalfa hay is LMF Super Supplement (A). This product is designed to be fed at a rate of 0.1 lbs of LMF Super Supplement (A) per 100 lbs of body weight. For the body weights of the horses utilized in the previous example the amount of LMF Super Supplement (A) that should be fed is as follows. Current Weight of Horse Total Amount of LMF Super Supplement (A) 600 lbs 0.6 lbs 700 lbs 0.7 lbs 800 lbs 0.8 lbs 900 lbs 0.9 lbs The dietary adequacy of this diet is shown below. In this example the horse is eating 2% of its body weight in alfalfa hay along with 0.1 lbs of LMF Super Supplement/100 lbs of body weight. Finally, the horse has access to a plain white iodized salt block. At 21 days discontinue the LMF Super Supplement (A) and begin to add a more calorie dense grain concentrate. The LMF Primetime (A) is a pelleted grain concentrate that will facilitate weight gain. LMF Showtime (A) is a non-pelleted grain concentrate that will also help horses gain weight. Begin by feeding only one pound of grain concentrate twice daily. Gradually increase the amount of grain by adding one pound per day until feeding 0.5% of the horse's body weight daily. The dietary adequacy of this diet is shown below. 6
Feeding this amount of grain and plenty of hay will allow for a slow and gradual weight gain. Bringing a starved horse to normal body condition will take three to six months, depending on the level of weight loss. Incorporating commercial feeds that contain high amounts of fat will be beneficial as fat is the most dense form of calories that can be fed to horses (1 cup of oil is approximately equal to 2.5 pounds of cereal grains when considering energy content). 7