by Krista Schole, BSc Ag
It seems that many of us fall into the trap of believing whatever we hear about feeding horses.
That’s why, for the second time in seven years, Dr. Bob Coleman and Dr. Lori Warren tackled the myths and wives’ tales surrounding the feeding of horses at the 25th anniversary of the Horse Breeders & Owners Conference in Red Deer, AB, January 12 to 14.
The first myth deals with the use of protein in the equine diet and some of the commonly held “truths” out there.
First off, protein is not an energy source, but is used to grow and repair muscle tissue. That means it won’t provide calories, but instead provides the building blocks for growth in young horses and for muscle and tissue repair in exercising horses.
Low protein in a growing horse’s diet can decrease its overall feed intake and retard skeletal development.
Drs. Coleman and Warren also stressed that protein will not cause Developmental Orthopedic Disease (DOD) in horses because an increased protein diet does not increase the growth rate.
Instead, DOD can be linked to nutritional factors like increased levels of sugar, starch, and fat as well as genetics, excessive or restrictive exercise, and trauma.
A horse being fed a limited amount of mature, stemmy grass hay without grain or supplements sets the stage for long-term damage according to Dr. Warren, as it will reduce growth rate, disrupt bone growth and development, and lead to repeated episodes of DOD.
A good diet for a DOD horse is a reduced-calorie diet including free-choice access to good quality hay, grass or grass/alfalfa mix, and a protein, mineral, and vitamin supplement.
The keys are to gain control over what the horse is consuming in calories and reduce the sugar, starch, and fats that will increase growth rate without reducing the protein, mineral, and vitamins that a horse needs for proper growth and development.
Another topic discussed was the feeding of grain. Does your horse really need it? Dr. Coleman suggested three things to look at when making that decision. It will depend on the horse, the feed available, and your management.
Many people realize that their horse does not require grain in its diet. However, for those horses that do require grain, it is used as a source of calories from sugar and starch. In order to maximize digestibility, Dr. Coleman recommends selecting a starch that is more digestible to avoid digestive upset.
Less digestible starches are processed in the hindgut instead of the small intestine and this leads to digestive upset. Grain that has been processed, especially barley and corn, are considerably more digestible.
Dr. Coleman recommends no more than 5 lbs of grain per meal. That equates to 2.0 g of starch per kg of body weight. And, in reality, a horse needs to be slowly adjusted to a dietary change, so adding or subtracting grain “cold turkey” can also lead to digestive upset.
Selecting the right grain mix can be a challenge and both speakers suggested that horse owners consider their animal’s needs and the forage being fed before making a decision.
Read the feed tag on the grain mixes carefully, take the percentages listed, and multiply them by the amount fed. That will give the most accurate value of the minerals and vitamins present in your horse’s diet.
It is important to watch the calcium-phosphorus ratio, but don’t worry if the ratio is higher than the optimal 2:1. Research has shown no negative effects in mature horses up to a ratio of 8:1 calcium to phosphorus.
Dr. Warren indicated that your best bet is to meet the NRC requirements and keep the ratio in mind during supplement selection. For example, for grass hay choose a 2:1 supplement and for alfalfa hay choose a 1:1 supplement to most effectively balance the ratio.
Hay treated with proprionic acid has been a hot topic and both speakers stated that proprionic acid occurs naturally in a horse’s digestive tract so it doesn’t upset the digestive balance. They believe that horse owners avoid hay treatment because of the bad connotation of the word “acid.”
Dr. Coleman indicated that current research shows that horses on diets of treated hay versus untreated hay had the same dry matter intakes. It was interesting to note, though, that during this same research, horses chose untreated hay over treated hay when given the option.
Treating the hay allows producers the opportunity to bale the hay with more moisture, which can lead to moldy, dusty hay without the proprionic acid treatment.
Currently, the number-one issue with performance horses is lameness; the number-two concern is respiratory challenges. Dr. Warren suggests that respiratory challenges may move into the top spot if horse owners are not more careful with their feeding management.
