Ribs! These Pigs Have More

Myora Farm, run by Jeff Braun, is garnering a bit of attention for its specific genetic trickery involving pigs. They’re selectively breeding for sows that can feed more piglets, but the way they’re doing it is unexpected. Instead of breeding for weight or litter size, they’re breeding for number of ribs, which is correlated to the milk output of the sow. So pigs can have different numbers of ribs?

Humans and pigs are similar in plenty of ways, but in the ribcage, things can diverge. Humans all have 12 pairs of ribs (fun fact: this was a controversial topic at first, because it was assumed men would actually have one fewer rib, due to the Bible story of Adam giving one rib to form Eve). But pigs can vary widely; studies indicate that the number of ribs in a pig varies based on breed.

Generally, the more ribs a pig has, the longer it is from snout to tail. An exceptionally long pig, like the American Landrace, can have 16 or 17 pairs of ribs. Lacombe pigs might have 13 or even fewer.

Studies have shown that pigs generally have acquired more rib pairs due to their relationship with humans; ever since the pig was domesticated, about 10,000 years ago, it has gotten more and more pairs of ribs compared to wild pigs in the fossil record. Braun finds a distinct relationship between number of ribs and milk output, which might in part explain why pigs have changed in this way. He says he can gain up to 30 percent more milk capacity, in addition to the more expected gains in the cuts of meat in that part of the pig’s body. And that’s beneficial because the more milk a sow produces, the faster its piglets gain weight and mature. Who knew?

Via ABC, image via Flickr user Martin Pettitt