Managing Herd Boars

Proper selection, care, and management of herd sires is an essential part of efficient pork production. For best results, boars should be kept healthy in a moderate flesh condition, maintained on a proper level of nutrition, not mated excessively, and provided with sufficient housing.

Several factors need to be considered when buying boars. These include performance testing information, health, and soundness. Purchase boars from seedstock suppliers who can provide you with superior animals as a result of their genetic selection and herd health programs. Seedstock suppliers should have a sound genetic improvement program which includes selection based on accurate and complete performance records that assess the genetic merit of economically important traits such as growth rate, feed efficiency, carcass merit, and reproductive performance. Emphasis should also be given to physical characteristics such as sound feet and legs.

Herd health is a major factor in efficient pork production. The planning and utilization of a superior herd health program cannot be overemphasized.

Purchase boars only from herds that have implemented comprehensive herd health programs. Seedstock producers should clearly define their herd health status and be willing to contact their veterinarian to answer any questions. Only purchase boars that are from brucellosis validated free and pseudorabies PRV qualified herds. In addition, only purchase animals that test negative to the Porcine Reproductive Respiratory Syndrome (PRRS).

Isolating boars for at least 30 days will allow disease in the incubation stage to exhibit symptoms. After isolation, retest animals for PRV and other diseases.

The code of fair practices recommended by the National Association of Swine Records is a good guideline to follow and is available from the purebred associations. The seller or consignor is responsible for settling all claims. All requests for adjustments should be made within a reasonable time after date of delivery to the buyer.

If a boar has had reasonable care and still fails to serve or settle sows, the seller should make a replacement to the buyer or refund the purchase price upon return of the boar in a healthy condition and satisfactory state of flesh. Often the seller will have the buyer sell the boar for slaughter and refund the difference in price.

Many individual seedstock suppliers have their own adjustment policy. It is recommended that both parties understand the sale adjustment policy before the transaction is completed.

Proper care in transporting boars will help prevent stress, injuries, and sickness. Some suggested guidelines are:

   1. Clean and disinfect the truck before transporting boars.

   2. In the winter, use an enclosed truck or trailer to prevent drafts.

   3. In the summer, keep boars cool enroute. Wet sand is good bedding to use in extremely hot weather.

   4. Make sure there are no nails or sharp objects in the truck or trailer that could injure the boars.

   5. Use a divider when hauling strange boars together in the same truck or trailer.

Sexual maturity or puberty is a gradual process. Some boars exhibit sexual development at about five months of age but are not ready for service. It is recommended that boars not be mated before they are seven months old. With increasing age, there is an increase in semen volume and in total sperm production.

It is desirable to obtain an estimate of a boar's fertility prior to the breeding season. The practice of test-mating young boars can save many dollars by detecting problem boars before the breeding season starts. A procedure to follow is:

Take a market gilt in heat to the boar and observe the boar for aggressiveness and desire to mate.

Assist the boar if necessary. Occasionally young boars will mount the front end of a gilt. If the boar does this, gently move him to the proper position.

Observe the boar's ability to enter the gilt. Check for a limp, infantile, or tied penis.

If possible, collect a semen sample and have it evaluated.

Semen that drains from the vulva after mating may be contaminated. Check the semen for sperm motility, concentration, volume, and morphology. If it is not possible to collect semen, observe the mated gilt to determine if she is pregnant before the actual breeding season starts.

Young boars must be used with caution. Hand-mate them once per day. Less often is preferred. If a mature boar is used two or three times during a single day, he should be given a day of rest.

Too frequent mating of boars can cause reduced fertility or temporary sterility. Other factors that may cause sterility are a low plane of nutrition, high body temperatures, disease, and injury.

Many young boars need to make adjustments when placed with a herd of gilts. If they have not been tested on market gilts earlier, they may have difficulty in locating and mating with gilts in heat, or they may not be completely functional.

Young boars should be hand-mated when first put into service. Fenceline contact with gilts or sows before use will often result in increased libido (desire to mate) in the young boar when he is used for breeding purposes.

Pen breeding requires low labor and lower cost facilities, but there are definite advantages for the hand-breeding system. There is less stress on the boars and the sows. It is easier to know the exact breeding date and you can ensure that each sow or gilt is mated twice when animals are hand mated. Breeding animals twice during the heat period will on the average increase conception rate by 10% and increase litter size by about one pig when compared to a single mating.

The maximum recommended number of services for a boar in a hand mating system are follows (this is only an estimate, as individual boars can vary):



Producers using the pen breeding system should use plenty of boar power. A ratio of 8 to 10 sows per boar is recommended for mature boars and 4 to 6 sows is recommended for each young boar (less than one year of age). However, a sow-to-boar ratio of 4 to 1 for mature boars and 2 to 1 for young boars is more feasible when sows are weaned in groups.

Alternating or rotating boars among pens should be considered. It helps prevent the possibility that a group of sows will not become bred because of a sterile boar.


Feeding Boars

Table 1 lists ten different recommended OSU boar diets using corn, sorghum grain, wheat, or a mixture of these grains. These diets can also be used for sows. The amount to feed per day will vary according to weight, animals conditions, and climatic conditions. During the nonbreeding period, four to seven pounds per head is often adequate. Consider increasing the amount of feed two weeks prior to and during the breeding season.

When using the individual mating system, pen boars separately in crates which are 28 inches wide x 7 feet long or pens 6 feet x 8 feet. Individual housing of boars eliminates fighting and riding.

Boars housed outside should have 20 square feet of dry sleeping space per boar plus an exercise area. It is advisable to keep boars in outside areas penned separately unless they are used in groups in a pen mating system. In this case, it is desirable to keep boars that are to be turned in with a group of sows penned together.

Research at the Oklahoma Agricultural Experiment Station in cooperation with the USDA has shown that boars subjected to high temperatures have a reduction in semen quality and will have a reduction in fertility rate for five weeks after the end of being exposed to increased temperatures. Females bred to boars that have been subjected to heat stress during the hot summer months may have decreased conception rates and smaller litter sizes. Decreased fertility can occur with as little as three days of heat stress. If boars are sick and have a fever for 2 or 3 days, semen quality and fertility will be reduced similarly to when boars are exposed to heat stress.

It is recommended that pork producers make every effort to keep their boars cool and comfortable during the summer months. Adequate shade for the boar in the summer is not enough. A fogging system under a shade built over a sand or concrete floor should be used when air temperatures are greater than 80 degrees F. For boars housed in confinement consider evaporative cooling or a thermostatically controlled dripping system.

Boars can be dangerous. They should always be handled with care and with proper equipment. It is never safe to keep a boar with tusks, which may injure the handler or other hogs. All tusks should be removed well in advance of the breeding season and every six months on a routine basis. Bolt cutters can be used to carefully remove boar tusks.