Sunday, March 11, 2018

Science and Miracles

Thanks to Grace Woodmansee for taking this photo! Despite all of the
lambing photos I've taken, I have very few of me assisting a ewe give birth.
Lambs at birth, like the offspring of most "prey" animals, are precocious; that is, they are quickly able to stand, nurse, and move off with their mothers. From an evolutionary perspective, this makes perfect sense. Sheep, especially lambs, are vulnerable to predators. Even before domestication, those females who had offspring who were on their feet and vigorous quickly were more likely to remain in the population and continue to reproduce. While domestication may have altered this ability to some extent, observant sheep breeders continue to include lamb vigor in their selection criteria (more on this below). As a shepherd myself, I have a tremendous appreciation for the evolutionary biology and genetics behind the ability of our lambs to get up and get going; I also find myself awestruck by the miracle of new life during each lambing season.

For the last 10 years, we have used an objective system to evaluate the maternal abilities of our ewe flock. Using the EZ Care system developed in the United Kingdom, we score each ewe at lambing on three criteria: lambing ease, maternal ability, and lamb vigor. Lambing ease assesses the ability of a ewe to deliver her lamb(s) unassisted. Maternal ability measures her ability to protect and keep track of her lambs (a ewe with twins, for example, must know how to count to two). Lamb vigor measures the ewe's ability to feed her lamb(s), as well as the lamb's precociousness. These traits significantly reduce our labor at lambing. A ewe must measure up to remain in our flock, and we only keep daughters of those ewes who measure up. An objective system like ours helps us avoid keeping a ewe simply because we like the way she looks - it helps us keep those ewes that perform well in our environment.

The foundation of our success with this system is the science of genetics. The traits that we're measuring are mildly heritable; that is, birthing ease, milking ability and maternal ability are at least partially inherited from one generation to the next. The environment, certainly, plays an important role - ewes on poor forage won't produce as much milk as ewes on good forage; however, the genetic predisposition to producing adequate milk is important, too.

Despite my understanding of the science behind these traits, I find myself marveling at the miracle of new life every year during lambing season. I find that I can understand the objective principles behind a ewe's ability to give birth, clean her lamb, and make sure that it nurses - and still stand in amazement while I watch it happen.

Part of this, I'm sure, is the fact that I directly participate in this process. On occasion, I have to help a ewe give birth. I'm often present when a lamb has its first taste of its mother's milk. Regardless, I don't think anyone - scientist or layman - can watch a ewe give birth; watch a newborn lamb shake the afterbirth from its ears; or watch an unsteady, 15-minute-old lamb find it's mother's teat for the first time - and not feel that they've just witnessed a miracle.

For me, this underscores the fact that scientific understanding and the miraculous are not mutually exclusive. My understanding of the "why" of sheep behavior doesn't diminish my sense of awe when I watch it in action. I've never understood the either-or perspective that permeates the debate between science and faith. Science, for me, is miraculous.

Here's a short clip of a lamb taking it's first meal - and here's a clip of a ewe delivering a lamb. You'll need Facebook to view them, I think.

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