People keep asking me what breed these piglets are. They are what my friend, Dominique refers to as "Farmer's Breed." They are a mix of several breeds, in this case we were told Large White, Duroc and Landrasse, but I think (judging from the markings of some of the piglets) that some Pietrain is involved. I'll double check and get back to you.
The sows are Large Whites. They are known to be good mothers and are also known to be quite large. Sometimes breeding sows are a mix of Large White and Landrasse because Landrasse are known for very large litters. The boars are usually a mixture of breeds like Duroc, Pietrain and Landrasse. Boars are bred to pass on optimal meat characteristics to the piglets, sows for their ability to have successful careers as mothers (as well as contribute to meat characteristics). All things being equal, you chose the sows with the heritage of having big litters with a high percentage of piglets that live into adulthood, usually having lots of nipples that produce copious milk helps.
It had never occurred to me you could selectively breed for more nipples. I guess this trait isn't as desirable in humans.
When piglets are first born, they are about a kilo each. They bulk up super quickly. The next time I go back to visit the Guenard facility, I'll try to shoot a picture of a piglet line up: newborn to weaned (at five weeks) in one week intervals. It's kind of crazy how visibly they grow even over a matter of hours. They are born not exactly skin and bones but close to it. As soon as they start nursing — which is instantly — they start to fill out, not just their tummies, but all over. After a couple hours of hanging with newborns I was struck by the thought that pigs are really efficient meat-making machines.
So what are little pigs made of? Mother's milk, I guess.