Chapter 8 BREEDING MANAGEMENT OF THE WARMBLOOD STALLION
The Warmblood or show horse breeding stallion is somewhat unique compared with racehorse stallions and stallions shown at halter. The Warmblood stallion frequently competes at an increasingly competitive level from age 3 through 15 years or more. The breeding demands of Warmblood stallions frequently peak at the same time as the horse’s show career. It is not unusual for the Warmblood breeding stallion to be in a regular, daily training program, compete in numerous 3- to 7-day-long shows during the year, and be transported hundreds of miles during the course of the breeding and non-breeding seasons. Frequently, the Warmblood stallion is located at a training stable or small farm that is less well-suited for natural mating or on-farm artificial insemination. The use of fresh, cooled semen has become commonplace for the breeding of Warmbloods. The use of frozen semen has also been accepted by most Warmblood breed registries.
Ideal management of the Warmblood breeding stallion needs to be tailored to the individual horse with respect to his training schedule, show date commitments, transportation, adequacy of the farm and its personnel for breeding activities, and the stallion’s innate fertility.
The Warmblood breeding stallion should remain athletic and fit even if he has been retired from active competition. High-quality hay and pasture will meet the stallion’s energy and protein requirements in most cases. First or second cutting grass or first cutting grass-alfalfa mixed hay should be available to the horse throughout the day. This will maintain healthy intestinal function, minimize boredom, and reduce the incidence of undesirable stall behaviors. The addition of grain or a vitamin-and-mineral supplement may be necessary to balance the nutrients supplied by hay and pasture.
The feeding program for stallions will need to be evaluated for each horse. If the horse is actively training and competing, he may need to be on a higher plane of nutrition to accommodate his level of exercise. Stallions that are stalled for long periods each day may be more relaxed and content if fed small portions of the ration throughout the course of the day. Fresh water should be available 24 hours per day for all stallions.
A common problem in breeding stallions is excessive weight. Horse owners commonly increase feed intake, particularly grain, during the fall and winter to offset the nutritional demands of cold weather. Feed intake, again, may be increased at the onset of the breeding season. However, many of these stallions are kept indoors during the winter and may even be blanketed. These nutritional changes are usually unwarranted and predispose the horse to laminitis. It is recommended that stallions be weighed each month. An ideal weight for the horse should be determined and maintained with minimal fluctuation. The feeding program should be closely associated with an exercise program. Recent evidence would suggest that feeding docosahexaenoic acid (DHA)–enriched nutraceuticals would have a significant effect on the quality of fresh, cooled, and frozen stallion semen 2
Stallions should receive daily exercise. Horses retired from competition should be turned out in a safe paddock or small pasture every day for as long as possible. Most stallions will then remain more athletic and will be more content and satisfied when returned to their stalls. The turn-out protocol, however, will need to be designed for each horse based on paddock behavior, stall behavior, personality, farm breeding schedule, and physical needs or limitations of each horse. If individual stallions do not run and play when turned out, they may need to be exercised on a walking machine, lunged in-hand or free for 30 minutes per day, or ridden under tack or driven in a jog cart three or more times per week for 20–30 minutes per session. The goal of the exercise program is to keep the horse alert, athletic, and content.
When a new stallion is brought to a farm, the farm personnel should be informed about the horse’s habits concerning feeding and exercise during the previous month. Management should also be made aware of any physical limitations or conditions affecting the horse, such as prior history of laminitis, tarsitis, navicular syndrome, colic, and objectionable habits. If the new farm management is aware of a stallion’s propensity for behavior such as nipping, stall kicking, running the paddock fence-line, stall walking, or weaving, procedures for correcting some of these behaviors may be successful now that the horse’s environment has changed. However, some of these behaviors may also begin with the environmental changes. It may take a stallion 1–2 weeks to acclimate to a new farm, personnel, feeding schedule, and other horses.
Many stallion owners are reluctant to turn out stallions during inclement weather (e.g., rain, snow, wind, insect season, heat, or muddy conditions). The breeding farm will still need to allow these horses to exercise. During the heat of the summer, horses can be turned out overnight or after sundown to avoid insect feeding times. Most horses are not adversely affected by rain or snow, unless excessive. An alternative may be to exercise stallions in an indoor arena during severe weather. Blanketing the horse when turned out during bad weather may preserve coat condition. Inclement conditions may persist for many days, so farm managers need to weigh the risks of stall confinement with any risks of turn out. Some farms that stand stallions retired from competition may find that 24-hour-per-day turn out is best for the health of the stallion, provided the horse has access to a run-in shed.
The stallion should be dewormed at regular intervals based on farm needs. No adverse effects from anthelmintics, such as pyrantel pamoate,∗ fenbendazole,† ivermectin,‡ or moxidectin,§ have been noted in stallions. A frequently used interval for deworming horses is 8 weeks, with the dosage based on the horse’s weight. Continuous, daily feeding of pyrantel pamoate¶ has also been safely used in breeding stallions. Periodic examination of fecal specimens should be performed to monitor the efficacy of specific deworming compounds and intervals between treatments.
Dental examinations should be conducted on all stallions once per year, or as needed, for each horse. Floating and other dental procedures should be performed as needed to maintain normal mastication and dental arcade alignment. If tranquilization is needed to safely conduct dental examinations and procedures, promazine tranquilizers should not be used due to risk of penile paralysis.3,4
The stallion’s feet should be evaluated by a competent farrier at regular intervals of 6–8 weeks. Special needs of some horses may require more frequent hoof care. Stallions that receive adequate paddock turn-out usually require minimal hoof trimming. Some stallions need shoes on the front feet only, and some need them on all four feet. For safety reasons, many farms prefer to have stallions barefoot in the front feet during the breeding season unless shoes are necessary for the health of the horse’s feet. Hind shoes may be indicated for stallions that are used for live cover or that become sore-footed during the breeding season. Horses that have laminitis, hoof wall cracks, or flat soles may require regular shoeing to remain comfortable.
The vaccination program for Warmblood stallions should be similar to the immunization program established for the other horses on the breeding farm. Horse population density, age of the horse, degree of non-resident horse exposure, and incidence of specific diseases on a farm are important considerations in development of an immunization program for the stallion. In general, the stallion should be vaccinated against tetanus, eastern and western encephalitis, rabies, and West Nile virus. On many farms, the stallion should also be vaccinated one or more times during the year against the most recent serovars of influenza and rhinopneumonitis viruses. Other vaccines that should be considered on a given farm include botulism, Potomac horse fever (Ehrlichia risticii), and strangles. The efficacy of these vaccines should be judged in relation to the disease risk on a given farm. Encephalitis and Potomac horse fever usually occur in relation to insect- and tick-biting activity. Therefore, these vaccines should be given in late spring in most parts of the United States. However, immunization against the upper respiratory viruses and bacteria should be carried out prior to the onset of the breeding and show season when exposure to other horses will be highest.
Equine arteritis virus can be spread from stallions to mares via respiratory secretions and the semen.5,6 Approximately 30% of horses previously exposed to equine viral arteritis (EVA) continue to shed EVA virus in their semen. Some of these stallions continue to shed the virus in semen for life. EVA virus infection can cause upper respiratory infections and abortion. The virus from shedding stallions can be passed to seronegative mares during live cover or artificial insemination with fresh, cooled, or frozen semen. Therefore, it is recommended that all stallions to be used for live cover breeding or in an artificial insemination program be serologically tested for exposure to EVA virus before the onset of each breeding season. Stallions that are serologically positive to EVA virus should have an aliquot of semen submitted to an approved diagnostic laboratory to determine the presence or absence of EVA virus in the semen. If the stallion has EVA virus in his semen, he should not be used to breed seronegative mares. Seronegative mares, however, can be safely bred to a virus-shedding stallion following EVA vaccination of the mare. The seropositive stallion that does not shed EVA virus in his semen can be safely used to breed seropositive or seronegative mares without risk of inducing viral infection in the mare.
Seronegative stallions can and, in most cases, should be vaccinated against EVA (e.g., Arvac, Equine Arteritis Vaccine, Fort Dodge Animal Health, Ames, Iowa) before the onset of the breeding season and given boosters annually.5