Tuesday, October 26, 2010

Luxury Animals and Selective Breeding

This week, selective breeding appears to be invading my life. On Thursday, I received a catalog from Heifer International, a charity that does great work giving animals to the international poor to improve their diet and economic circumstances. Part of the program is that the gift of a goat/cow/sheep will create a self-replicating cycle of improvement as the animals give birth and the new animals are given or sold to other poor families. So imagine my surprise when Heifer asked me to send them $120 so they could send two female goats to a family in need.

This reminded me of a scene from The King and I, the Rogers and Hammerstein musical. The King of Siam decides to send a pair of male elephants to America to help President Lincoln win the Civil War. When Anna, a British schoolteacher, suggests that perhaps two male elephants would not provide Lincoln an army of elephants, the king agrees and decides to send two female elephants.

In the modern world, these are amusing errors. However, they represent a belief that modern people should understand the basics of breeding. Looking at our recent readings, I was surprised how suddenly modern-style selective breeding made an appearance. Walter of Henley, for example, barely gives any advice on how animals should be bred. Although he acknowledges pigs and sheep should be “sorted”, he gives no advice on how to pick out the better stock or how they could be induced to breed and produce better offspring 1. This is in context of relatively extensive discussions on the proper feeding, housing, and weaning of animals (particularly cattle). This distinction is particularly pronounced in the case of cattle, where Walter makes no mention of good breeding. Furthermore, he seems to be sure that oxen and horses must be bought, rather than taken from one’s own flock 2. Given his apparently large stock of cattle, why would Walter buy oxen unless he didn’t believe high quality oxen and horses could be created by selective breeding?

This sort of ignorance about the ability to create “better” animals (that produce more meat or milk or can work longer) through breeding high quality animals would be totally understandable in the middle ages. After all, genetics is a pretty difficult concept to intuit. However, farmers (particularly those of luxury animals like rabbits and carp) seem to have stumbled upon the importance of this process.

For instance, fish farmers began to introduce pike into their carp ponds. A few pike, which eat other fish, were placed in the pond with thousands of carp. These pike would naturally begin to eat the smaller carp. Originally (according to Mary J. Henninger-Voss), pike were added only right before the farmer intended to harvest the adult pike 3. Thus, any accidental newer offspring would be eaten and not end up mixed with the full grown pike going to market. Presumably some farmer realized this selection bias towards the largest fish could be useful all year round, as pike later became a normal fixture in ponds 4. These pike would eat the smallest fish, effectively engineering the survival and procreation of the biggest, fastest-growing fish.

Fish farmers also appeared to have (perhaps accidentally) cared about genetic diversity in their animals. We have numerous instances of pike being sent as gifts to stock neighbor’s ponds (and sometimes as many as five or more neighbors at a time!) 5. We also have many receipts of nobles buying carp to restock their own ponds 6. These traditions meant that new carp often came into the ponds (at least of nobles), refreshing the gene pool and preventing genetic inbreeding.

This is not to argue that fish farmers thought of what they were doing in terms of selective breeding or even that larger, healthier animals were a predicted result of these actions. Clearly, in the case of gift-giving, the status associated with the animal was important. Exchanges of sheep and cattle could also have produced healthier, more productive livestock too. However, it seems that giving a fellow lord a cow in the middle ages would be rather like me giving my roommate a vacuum for Christmas. Although the gift may be productive and helpful, it doesn’t have the same prestige and respect as a gift of an elite animal.

Rabbits offer similar evidence, although realization of the importance of selective breeding and the dangers of inbreeding appear to have been more out of necessity than by accident. In the early middle ages, Bailey states that warreners made a concerted effort to not overhunt the rabbits in order to maintain the existing communities 7. In terms of modern science, this makes very good sense – the rabbits that were better adapted to England survived much better than the average recent import. Thus, it was a good idea to let natural selection do its job and allow these adaptations to take over the rabbit population instead of “harvesting” all the rabbits that survived to adulthood each year and starting evolution over with a new “crop”.

However, by the late fifteenth century the trend had reversed. Warreners had established colonies and no longer needed to import rabbits to replace those dying from the harsh conditions. Instead, rabbits were dying of diseases that resulted from inbreeding 8! A lack of genetic diversity meant that if one rabbit was susceptible to a disease, the entire warren was likely to die. Warreners tried many strategies for fixing these disease issues (such as planting gorse to feed the rabbits), but some realized that the most effective strategy was to bring in new rabbits to breed with the existing warren 9. This strategy appears to have been achieved mostly by accident: unable to cure the current rabbits, many warreners seem to have decided to bring in more rabbits to be sure the lords would have enough rabbits on hand! (Imagine their delight when this solved the longstanding problem in the warren as well!)

My point, simply, is this: to modern readers, it sometimes seems like basic common sense or observation would lead farmers to selectively breed their livestock. However, this concept appears to have been almost entirely absent from the discussions of husbandry in the middle ages. However, initially either by accident, coincidence, or necessity, selective breeding became commonplace for at least two luxury livestock – the carp and the rabbit. It seems unlikely to me that this occurrence of selective breeding in two luxury animals came about by happenstance. Instead, the luxury status of the animal created the mechanisms that allowed for selective breeding (gifts, ponds, adding new stock to the old) while the fact these animals only had uses after their harvest and death meant that it was easier for farmers to identify the goals of this selective breeding (such as larger fish).

What do you think, fellow bloggers? Is this a reasonable explanation? Does another make more sense?

1. Walter of Henley, Husbandry, ed. and trans. Elizabeth Lamond (London: Longmans, Green & Co., 1890), p. 29.
2. Walter of Henley, p. 23.
3.Henninger-Voss, Mary J, "Carp, Cods, Connections," Animals in Human Histories: The 
Mirror of Nature and Culture (Rochester: University of Rochester Press, 2003), p. 7.
4.Christopher K. Currie, “The Early History of the Carp and its Economic Significance in England,” The Agricultural History Review 39.2 (1991): 97-107.
5. Currie, p. 103.
6. Currie, p. 103.
7. Mark Bailey, “The Rabbit and the Medieval East Anglian Economy,” The Agricultural History Review 36 (1988): 1-20.
8. Bailey, p. 10.
9. Bailey, p. 10.


  1. Sorry the formatting is so ugly (changing fonts, lines that stretch too long) - I'm not sure what the problem is or how to fix it. If anyone does, please feel free to go in and edit my post to make it pretty!

  2. Heifer International is distributing nannies (female goats) for a good reason. They are working under the assumption that the community to which they are donating these animals already possesses a billy (male goat), which can produce as many offspring as there are available nannies. As such, there is the possibility of each of the two nannies producing a kid, rather than only one nanny producing a kid (which is what would happen if you gave the community only a male and a female). In that case, you end up with two kids fathered by the same billy. Nannies also have added utility in that they can produce dairy products, which are a renewable source of food. The primary use of a billy is breeding. In general, it is always best to have more females than males because this will lead to a faster rate of population growth and prevent the males from fighting during the mating season.


    On your points about selective breeding, I think you are *greatly* underestimating its development and the sophistication of people in agricultural societies. We do not have many records or instructions for how to make breeding selections because it is, in your words, "basic common sense" to match your best animals together. Nobody needed to write instructions out for farmers because farmers knew how to do this and didn't need (and couldn't read) written instructions. Choosing breeding stock does not take any knowledge of genetics, it only takes the knowledge that offspring carry some mixture of the traits of the parents. How this occurred was explained in ways that seem patently ridiculous to us now, but it was a known fact that it did happen.

    The very fact that humans have domesticated and bred animals for literally thousands of years attests to this. Let's consider horses for a moment. Not only did humans domesticate the horse, we have managed to breed very specific types of horse for different types of environments. Consider the Arabian horse, the Mongolian horse (steppe pony), the Andalusian (descended from the Arabians but bred specifically for Spain), the Icelandic pony, the Belgian draft horse, and I could go on. Horses have been selected for their abilities as riding horses or as work horses, depending on what was needed. Long before genetics came about people were breeding excellent race horses as well. In any type of animal that is useful for food production we see huge variations in breed from long before the modern era. Although professor Fulton Brown has questioned the accuracy of tracing breeds back into the Middle Ages, it is definitely a sure thing that animals originating in places like Mesopotamia and Africa (which is where many of the common European/American livestock like cows and horses seem to come from) underwent a great deal of human driven modification before they were thriving in places like England and Iceland.

    Another thing that might surprise you is that humans were also able to domesticate and develop plant species. There are hundreds of varieties of apple, the same for corn, wheat, rice, etc.

    Essentially, my point is that selective breeding is and has been the bread and butter of farmers, not something that happened accidentally as people bred luxury animals.

  3. Breeding has definitely been going on since we began raising animals. Assuming they have been doing this selectively, why is it mentioned only in the cases of luxury animals? Because they were harder to take care of or breed? Because there was more interest in literature about them (or that the people involved were more likely to be literate)?

  4. I honestly do not see much (or any) evidence for *selective breeding* amongst luxury animals. You cite page 10 of the Bailey article (it is actually page 9, the pdf document is different from the journal pagination) for a discussion of problems with inbreeding in rabbits, solved when the warreners introduced more rabbits into their warrens. However, the section in question is a discussion of problems with a proliferation of rabbits out-eating the warrens food supply, along with some problems like liver flukes (a parasite), and murrain picked up from other animals like sheep. The warrens which were re-stocked "for the lord's greater profit" were low in population because of two extremely cold winters which apparently killed off much of the rabbit's food supply, hence the need to plant gorse.

    You also imply that warreners tried not to overhunt in order to enable natural selection, whether they realized they were doing this or not. However, Bailey seems to be arguing that warreners/lords were not able to cull their rabbits too much because the rabbits had a hard enough time adapting to the environment that unless a very high base population was maintained all of the rabbits would die. Bailey also discusses the extent to which the warreners artificially facilitated the rabbits, such as building burrows for them. This is the opposite of letting natural selection work.

    On the issue of pike and carp. First, the fact that people managing ponds added predators is good evidence for the argument that medieval people were aware of useful breeding practices. Remember, they started off by adding pike only when they wanted to harvest the carp. You don't add a predator to your crop just before you want to harvest it unless you realize what the effect is going to be. It doesn't take *that* much more thought to realize that this will work to eliminate the weaker fish in general. Also, the inclusion of pike is perhaps just as much meant to discourage overbreeding (ie, overpopulation) as it was to encourage larger fish (see currie's reference on page 105).

    I'm also not convinced that re-stocking was primarily about adding genetic diversity so much as it was again a measure intended to keep population up. Often when ponds are harvested commercially a large amount of the fish are removed, sometimes even by draining the water from a section of the pond and scooping the fish off the bottom.

    As far as farmers of other livestock knowing how to breed selectively, I've already given several reasons for why we should believe this to be the case. I'll add one more, standing by my (and your) assertion that this is basic common sense. Farmers had to decide which male animals to kill or castrate early on. Oxen, wethers, capons, and geldings are all missing their reproductive organs, for all the same reasons as goats as explained by TE above. Male animals were a liability, not an asset, except in so far as they offered breeding stock or some other useful thing (strength, as in oxen). Therefore farmers had to decide which animals to castrate and which to mate with their females. Do you really think that for the last 6,000 years pre-17th century or so farmers would not distinguish between their less and more valuable animals while doing this? Do you think that they were oblivious to the fact that new adaptations were developing that made the animals more successful in certain environments, or that one animal seemed to be more likely to be useful than another for a specific task? Farming is a process that takes much more thought, planning, and decision making than you seem to think, and the techniques used for it have been developed and passed down orally for thousands of years.

  5. Breeding is clearly a heated topic! I think, Hannah, that you do an excellent job raising a very important question. I think, too, that B.T.C. and T.E. are correct to point to evidence of selective breeding in the very fact of domestication, with or without explicit discussions in the books of husbandry. In the materials we read, Biddick's account of the management of the flocks and herds at Peterborough Abbey likewise seems to suggest a high degree of attention to the ways in which the animals are reproducing. Perhaps we should draw a distinction between breeding in order to enhance the overall healthiness of a population and breeding so as to select for particular traits (although, of course, healthiness might be one of these). I mentioned in class that there are trusts in England set up to maintain historic breeds of domestic animals. Typically, these breeds were selected for the kinds of things one would expect: hardiness in a particular climate or types of wool (in the case of sheep). But it is possible that farmers were also breeding in the sense that we tend to use the word now, to maintain particular lines. For efforts to maintain these historic breeds, see Cotswold Farm Park.