Behaviorists often say that the desire for food is stronger than the desire for sex. This is a half-truth; the desire for food is only stronger than the desire for sex when you are starving-at least it's that way for stallions. It it is our job as managers of breeding stallions to be sure that our horses are not forced into having to make a choice. We want to continuously provide all the necessary nutrients so that the stallion is inclined to choose sex every time it is offered and his fertility is not hampered by any lack of nutrition. A proper balance of nutrients is the basis of the true aphrodisiac.

Recognizing the importance of nutrition to reproductive productivity invariably brings up the following question: How do the nutritional requirements change for the sexually active male? Unfortunately, there is no concise answer to this question because every stallion is an individual and variation among horses is great. Still, finding the correct answer for your stallions is paramount to maintaining sound management practices and sometimes the conclusions may even surprise you.

I began to appreciate the uniqueness of individualized nutritional needs when my continued exposure to higher education conditioned an attitude toward testing and measuring. One breeding season my research animal became a mature Quarter Horse stallion with a book of thirty mares that had to be bred in ninety days. After calculating a well balanced diet that was to be fed at a constant amount over the course of the breeding season, I made plans to record his weight every seven days.

The first week of breeding season went exceptionally well; the horse covered a mare every single day. At the end of the week, I weighed the horse and was very surprised to .learn that the stallion had gained weight. To my astonishment, this trend continued, and by the end of the ninety days the horse had gained nearly one hundred pounds. Looking back at the behavior of this stallion during breeding season, it was easy to see that he became more sedentary as he settled into the routine of the breeding season. He was caught and bred at the same time each day and I usually found him in his stall, quietly waiting. His behavior was very different during the offseason. The stallion spent most of the time out in his paddock running and cavorting around-obviously burning more ATPs (energy) and needing more feed to maintain his weight.

In another instance, my research animal was an older Thoroughbred stallion on whom breeding seemed to have the opposite effect. This horse was fairly quiet and manageable during the nonbreeding season, but once mares started to come in to be serviced he became increasing rowdy and nervous, constantly pacing his stall or running the fences of his paddock.

During the off-season, this stallion maintained a relatively constant weight on ten pounds of grain and fifteen pounds of hay. During the active breeding season, doubling the daily grain ration to twenty pounds still did not curtail the weight loss. Only the end of the breeding activity fixed that.

Even though these two horses represent extremes, they illustrate that the nutrition necessary for breeding and sperm production can be secondary to the nutritional needs determined by the way the stallion adjusts his lifestyle to the breeding season-the physical and mental stress that he puts himself through. This fact holds true even in a more natural environment. Some stallions turned out with a band of mares present a very tranquil scene. As long as no other male tries to interfere with their herd, stallions such as these are content to graze along, breeding the mares as they become receptive and letting the boss mare handle herd politics. On the other hand, another stallion may be constantly searching for trouble, disciplining mares and worrying about intruders. It is obvious that the nutritional needs for these horses with such diverse dispositions would be different. With these diversities in mind, let's discuss the basic nutritional components that might be manipulated in order to create diets to fit the individualized needs of various types of stallions.

ENERGY

The main consideration in maintaining homeostasis for a hyperactive breeding machine is energy. There are two ways to provide the overly active stallion with more energy so that he won't loose too much weight during the breeding season. The first choice is usually to increase the amount of grain that is fed. Since the grain portion of the diet has more energy per pound than hay, this increase will result in higher energy totals for the day.

The limiting factor with this method is the horse, himself. The average horse will eat somewhere between twenty-five to thirty pounds a day; for safe digestion, at least ten pounds of this total feed consumption should be roughage (hay). This sets the maximum grain ration at twenty pounds a day.

For horses that still loose weight and can't be safely pushed to eat any more, a second option is available: Increase the amount of energy per pound of grain. There are two common ways to achieve this goal:

1. Add more high-energy grains like corn and barley to the grain mixture, or

2. Supplement with fats or oils up to 10 percent of the grain ration weight.

Historically, flaxseed or linseed meal were the supplements of choice to provide glossy hair coats and better condition. While both of these additives do have a fairly high energy content, they are relatively expensive. Today there are cheaper, if not better, sources of energy available, such as corn oil and fats, which have been treated so that they are not as likely to become rancid and therefore are more palatable.

VITAMINS

Wheat germ oil has long been a favored supplement for breeding stallions since it supplies both additional energy and contains a large amount of vitamin E-the vitamin that has received a lot of press because of its association with improved sexual performance. Actually, in horses not suffering from a deficiency of vitamin A or vitamin E, there does not appear to be any increase in reproductive performance from the overfeeding of vitamin E, either from wheat germ oil or from other sources (megavitamin therapy).

Adequate dietary amounts of vitamin A and vitamin E are necessary for the maintenance of the tissues in the reproductive system. These requirements are supplied in most standard horse rations and usually do not require supplementation. This is also true of other vitamins such as the B complex water-soluble vitamins associated with protein synthesis and blood building.

PROTEIN

Protein is an important part of any ration. Having an adequate supply of the essential amino acids is as important for the breeding stallion as it is for the competitive athlete. While linseed meal and flaxseed are also recognized as concentrated sources of protein, they do not provide high-quality proteins-that is, they are not good sources of the type of proteins normally lacking in the diet of the horse. Today, soybean oil is acknowledged as the protein supplement of choice. It is an inexpensive and high-quality source of concentrated protein.

Determining an adequate level of protein for the breeding stallion is related to his age and activity. The younger, more active stallion needs a higher level of protein than the more mature, less active one. For stallions eating ten pounds of hay (containing 10 percent protein), it is reasonable to expect that their total protein requirement would be met by feeding a good 12 to 14 percent protein grain ration.

Feeding the stallion during breeding season boils down to the same good nutritional management considerations that apply to the feeding of horses year-round: a proper level of energy, an adequate amount of quality protein, mineral, and vitamin concentrations that meet the requirements of the species, and plenty of fresh water. Since animals do vary, the requirements for these nutrients also change, and it takes the eyes of a good horseman to adjust the ingredients to satisfy varying needs.

And, yes, good horsemen see things differently. Some stud managers feel that a stallion should go into breeding season slightly overweight to compensate for an expected weight loss due to the increased activity. This is just another way of supplying energy to the active stallion. Other horsemen feel that a stallion should be maintained at a slightly overweight condition before, during, and after breeding season because they are selling the services of their stallion that is based, in part, upon his appearance. To most livestock people, a little fat is beautiful and this image makes the horse more marketable.Then, too, there are those horse persons who believe that the trim, fit animal is healthier and the health of the horse is the most important consideration. These caretakers maintain that the diet should only replace the energy being used and should not cause fat to be laid down.

The fact is, all these opinions can be correct. It is simply a matter of which management system is in operation and what the farm's priorities are. In actuality, under the care of conscientious horsemen who supply a balanced diet to their charges, a stallion's reproductive productivity is not likely to be hindered or enhanced by nutrition except, perhaps, in the case of the older male.

Maintaining stallions that are beyond middle age oftentimes requires adjustments to prolong longevity and fertility. Horses, like people, show a great deal of individual variation in the aging process-the mechanisms controlled in large part by genetics and influenced by environment. Even though we cannot control the genes, we can sway them somewhat through manipulation of the environment. Stress reduction can be accomplished through identification of factors that seem to cause discomfort to specific stallions. Heat, cold, too much rain, or too little rain are simple stressful situations that can be modified through the use of fans, heaters, blankets, and stalls.

Advancing age also affects nutritional factors in a variety of ways that contribute to common geriatric conditions. For example, constipation is a familiar problem in human aging, but in the horse, it can lead to major colic problems that may result in surgery or even death. As with humans, fiber in the diet is one of the more common preventative measures. A 20 percent bran ration or feeding hot bran mashes helps to improve movement in the gastrointestinal tract.

Coupled with constipation is the inability to chew coarse feeds. A stallion in his declining years (somewhere between eighteen and twenty-eight) will often develop gaps between his molars. Add to this the worn-down surfaces of very short teeth and the older horse has trouble chewing and swallowing those feeds usually given him. These problems can be overcome by either feeding a pelleted ration or soaking the grain ration in water. Pelleted feeds require very little chewing and soaked whole grains are also easier to swallow-both factors that will ultimately increase the available nutrients for the older horse.

Although little is understood about the maintenance of epithelial tissue, it is another area of geriatric concern. Skin and the reproductive tract are both made of epithelial tissue. The same minerals, vitamins, and proteins that make vivacious, healthy-looking skin contribute to maintaining a productive reproductive tissue. Both vitamins A and E have long been known to be important biological catalysts in this process. Normally, the horse's body makes vitamin A from a closely related precursor, carotene. However, in some older animals, the ability to either make or use this vitamin becomes somewhat impaired. Vitamin injections or oral supplementation ( e.g., cod liver oil and wheat germ oil) may offset this problem.

Excerpt from The Stallion: A Guide for Breeders and Handlers by Dr. Jim McCall