Although breeding is obviously a natural function for stallions, fertility levels don’t have to be left to genetics and luck alone.
For instance, it’s important to take care of routine dental work, worm counts and worming, as well as other veterinary issues a few months before breeding season. A good tip is to try to avoid annual vaccinations during or in the lead-up to breeding season.
Breeding is hard physical work for a stallion, and they need to be as fit as possible. Nutritionists estimate that the calorie and nutritional requirements of a stallion during breeding season are equivalent to a horse in moderate work. Moderate work is defined as a horse performing 3 to 5 hours per week of walking (30%), trotting (55%), cantering (10%) and skill work such as low-grade jumping, dressage or cutting (5%).
Providing some fitness work over winter can help prepare your stallion for the rigours of the breeding season, especially if he has a full book of mares to cover.
Most stallions will lose weight during breeding season because they spend less time relaxing and more time being alert and moving which uses more calories than they may actually be consuming.
Feeding stallions who lose weight during breeding season: If you know your stallion loses weight during breeding season, it is a good idea to allow him to gain a little additional weight over winter so that he has a slightly heavier body condition score (but is not overweight) before breeding begins.
It can be valuable to establish a routine so that stallions are not distracted during feed time. Limit movement of horses around the property at feed time and avoid serving mares or having mares arrive or leave at this time of day.
If the stallion is also in work or training during breeding season, lighten the work-load especially if he is losing body condition.
As so you will read so often, the basis of any good equine diet is roughage, whether the horse is stabled or at pasture. Ensure your stallion has free-choice access to adequate grass or grass hay, especially if he is kept in a yard or stable during breeding season. Providing a fresh source of grass or grass hay with a high content of leaf and minimal stalks or seed stems helps to meet the stallion’s protein and energy (calorie) requirements.
Supplementing with lucerne hay is also a good way to add essential lysine to the diet, but limit lucerne intake to 30 percent of the total forage intake to avoid excessive dietary protein and calcium.
When choosing your grain or energy source, consider how much time and energy you’re willing to put into preparation. Whole oats can be fed raw, but other cereal grains such as barley, sorghum, corn and wheat should always be fed in a cooked form. You can boil them or buy steam-flaked, pelleted or micronised. You may wish to avoid the cooked grains with added molasses – just check the labelling on the bag. Some super fibres require soaking (but it doesn’t take long) and whole lupins are also best soaked to soften the seed coat.
Stallions prone to gastric ulcers should avoid cereal grains (e.g. corn, oats, wheat, rice, barley) and by-products (millrun, bran, pollard) in their diets. Choose calorie sources high in digestible fibre (‘super fibres’) such as beet pulp, legume hulls or copra, or legume grains (e.g. lupins, chickpeas).
If you’re using a premixed feed, choose one formulated for working horses or stallions rather than a brood mare feed as the mineral and protein levels will be better suited to your stallion’s requirements.
Another handy hint is that vegetable oils are a good way to increase the energy density of the diet and help maintain weight, especially when giving large hard feeds. (Read more about how to choose the right oil to feed your stallion in the section on oils below.)
If your horse needs more than two or three kilograms of hard feed (or more than one or two kilograms for a pony) to maintain weight, it’s much better to split the amounts into multiple smaller feeds given over the day, to keep their diet as close to their natural grazing habits as possible. Adding an extra feed per day can be a useful tip to help your stallion maintain weight over the breeding season.
Feeding stallions who have to watch their weight: The hardest part about helping horses lose weight is to ensure they are able to eat all the time, but at the same time not consume too many calories.
The best way to be certain of how much energy (calories) your stallion is consuming is to control all intake by using a yard and feeding low-calorie hay. The only way to be sure of the calorie content in hay is to send a sample to a laboratory for testing. If this is not possible, try to select grass hay which was cut from more mature, stalkier plants as the energy content is likely to be lower (native, teff or rhodes grass hay are good examples). Soak hay for a half an hour in hot water or an hour in cold water then drain before feeding it in a slow feeder haynet to remove some calories but be careful of mould growth during hot weather if it’s not eaten within a few hours.
If you are also providing grazing time, a couple of hours grazing time in the early morning when the plant’s energy stores are at their lowest is good practice when limiting pasture to a pony or overweight horse. A grazing muzzle could also be used to increase his ‘safe’ grazing time each day.
Choosing vitamin and mineral supplements for stallions: Even if your stallion is grazing the best grass in the world, grown on the best soils in the land, he will need supplementary vitamin E and some minerals (usually magnesium, copper, zinc, iodine and selenium and in many cases, calcium or phosphorous as well) to top the diet to optimal levels and balance mineral ratios.
I can’t stress enough that mineral balance is critical. It is surprisingly common for horses to be lacking in essential minerals due to imbalance with other competing minerals, even when the diet provides more than the recommended daily intake (RDI) of each mineral. Poor mineral balance will negatively impact on feed use efficiency and can reduce fertility.
Supplementing stallions with selenium and primary antioxidants such as superoxide dismutase sourced from melon extract has been shown to improve the quality of fresh, cooled and frozen semen. But be careful not to double dose on selenium through different feed sources as this is one mineral where toxicity can occur even with fairly low levels of selenium.
Boosting fertility with Omega-3 Fatty Acids: Omega-3 Fatty Acids are a type of dietary polyunsaturated fatty acid that can be used to effectively assist in the general and respiratory health of breeding stallions. But some forms of omega-3 are more effective as a supplement than others.
Scientific research has demonstrated that marine-sourced forms of omega-3 (EPA and DHA) are even more potent than plant-based omega-3 fatty acids (ALA). DHA levels are especially high in sperm cells. Research shows that daily supplemention with 10 to 20 grams of marine-sourced DHA per 100 kg bodyweight improves the quality of cool-stored stallion semen and provides better tolerance of sperm to freezing. Stallions with marginal fertility may benefit most from DHA supplementation.
Vegetable oils such as rice bran, canola and sunflower and oils contain some ALA, but most contain much higher levels of omega-6 fatty acids. Therefore, stallions being fed vegetable oils such as rice bran or sunflower oil will need significantly more omega-3 supplementation than horses relying on grains for energy. Horses on high grain diets, and those reliant on hay and chaff for roughage will need more omega-3 supplementation than horses grazing green grass.
Good nutrition is the basis for stallion health fertility: Take advantage of scientific knowledge and have a nutritionist review your stallion’s diet prior to breeding season for optimal fertility. I would also recommend that mare owners ensure optimal nutrition since this may minimize the number of mares returning for re-breeding after the first cycle.
Larissa Bilston (B.Agrsc – Hons 1) is an animal nutritionist.