Breeding the hogs that will produce the choicest and tastiest meats, at an affordable price, is a complex and sophisticated process that is part high-tech DNA analysis and part good hereditary luck.
At Smithfield Foods, a team of geneticists in North Carolina spend their days examining pig characteristics to pinpoint which combinations of sows and boars will create the ideal market hog. As a commercial producer, Smithfield strives to reach several goals: elevating the health of the animals, improving the quality of our foods, and maximizing the efficiency of our production.
Our breeding program identifies the best traits for market hogs and carefully selects the best animals from each generation to be the parents of the next. To understand the process, it helps to visualize a pyramid. At the top of the pyramid are pure line breeding pigs, which have been selectively developed to have specific traits. Over several generations, one elite “parent” animal at the top of the pyramid will impact tens of thousands of progeny at the commercial level.
These pure line are unique breed populations such as Durocs. (Smithfield has its own proprietary Duroc line.) They are housed in remote, secure farms in Texas and North Carolina designed to minimize disease contamination. Biosecurity is a top priority and requires a commitment similar to many processes found in other intensively managed health facilities. For example, at the state-of-the-art nucleus compounds, all employees shower before entering the farm, wear designated uniforms, and adhere to a variety of other biosecurity practices while performing their daily routines.
At birth, each pure line animal is tagged with a unique bar code. All information about the animals is entered into a database to help the scientists zero in on the pigs that will yield the best offspring. Smithfield Premium Genetics will analyze approximately 100,000 breeding pigs annually across eight genetic lines.
For the growing pig, the scientists seek superior features such as growth rate, feeding efficiency (i.e., how much food it takes for the pig to reach market weight), and the marbling and texture of the meat once processed. On the mother’s side, important characteristics include reproductive efficiency (i.e., litter size and birth weight) and the mother’s ability to produce milk and raise healthy piglets.
The genetics team tracks a percentage of the offspring of the pure lines through the commercial operations to evaluate their growth performance, and then follows them through to the processing plant for analysis of their product value after slaughter. Each week, about 1,500 pigs are examined at our processing plants for features including leanness and tenderness. The information is recorded in a database that can trace an animal’s pedigree back as far as 15 generations.
Through careful selection, hog geneticists have been able to increase litter sizes from an average of 10 or 10.5 piglets per litter six or seven years ago to an average of 12 to 13 piglets today. Yet, while the number of piglets has increased, the average birth weight of close to three pounds has stayed the same, or even increased slightly—resulting in healthy, vigorous piglets. (Larger litters with smaller birth weights would have been considered a genetics failure.)
Over recent years, the Smithfield scientists have improved other traits as well. As one example, scientists were able to eliminate a gene—known as the Rendement Napole or RN gene—which caused low pH and water holding capacity in pork. On average, it takes approximately two years for a genetic advance to make its way through from the nucleus group to the market hogs.
Most pork companies purchase their breeding stock from an external company, but Smithfield benefits from an internal genetics team that can follow pigs from farm to processing.
The team is focusing on finding the genetic lines that will maximize efficiencies on the farms, particularly as the price of feed increases. They want to see which pigs utilize their feed most efficiently and still grow to healthy and productive weights. The team is also looking for more resilient breeds.
