Reproduction and Genetics

A fundamental part of pork production is reproduction and genetics. With a good understanding of reproductive biology, producers and managers can maximize the reproductive performance of their herd. Penn State Extension has a wide range of resources on farrowing, sow management, swine estrous cycles, and much more.

Pig Reproduction Management

Successful pig reproduction management begins with the gilts. These young pigs can be brought to the farm after weaning. It’s important they are as healthy as possible and in good physical condition. An understanding of the sow’s estrous cycle means the reproductive success of the herd can be maximized. Being able to determine when sows and gilts are in heat helps small farmers synchronize farrowing and weaning dates. Whether a sow is in heat can be determined using body condition scoring.

Pigs are prolific breeders and a sow reared on a commercial farm usually has as many as seven litters before being culled. After their seventh litter, statistics show that productivity drops. When a sow is culled, their place in the reproduction plan is taken by a replacement gilt.

The time a sow spends on a farm is known as sow longevity. The aim of a commercial producer is to keep a sow on the farm as long as they are economically productive. To be able to do that, the sow’s well-being and health are of the greatest importance. The health of the boars also needs to be considered, as they are a crucial part of successful swine reproduction management.

Swine Breeding Systems

There are two main breeding systems hog farmers can use: Purebred breeding systems and crossbred breeding systems. To be considered purebred, a pig must meet certain requirements of the breed registry association. Crossbred pigs are preferred by most commercial swine producers because traits of a purebred pig are often enhanced as a result of crossbreeding.

Sow Farrowing, Nursing, and Weaning

Preparing for the birth of piglets in a herd starts long before the farrowing date. Breeding dates should be recorded because the sows need to be moved to a controlled environment for optimum success. Piglets, for example, need additional heat immediately after they are born.

Delivery time is fairly quick, with piglets arriving approximately every 15 minutes. Half will be born head first and the other half – tail first. Most sows give birth without any intervention, however, it’s always best to be on hand should anything untoward happen.

Newly born pigs will immediately seek out a teat for food. Nursing sows require a high-energy lactation diet because they have to provide for their growing litter and maintain their own well-being.

On a commercial pig farm, piglets are weaned before reaching 21 days of age. Smaller pig farmers, however, leave weaning until the piglets are at least 28 days of age. Weaning can take place successfully up to six weeks of age.