Conservation of Heritage Livestock is a complicated (and essential) endeavor. No one blanket recommendation can cover all of the situations that range from rescuing rare breeds from extinction to assuring that rare breeds have a good market demand that assures their future. While each situation is unique, they all do share some common concerns.
As with most of life, the devil is in the details. Issues of selecting heritage livestock for quality varies along a long continuous line. The various stops along the way are each appropriate for specific situations. The challenge for breeders of Heritage Shorthorns is to figure out where their own program and goals fit along that line.
At one extreme of this line is a point where immediate rescue is the most important issue, with expansion of a truly rare population overriding any other concerns. In that situation, selection has to be minimal or the genetic pieces for a sound future are likely to be lost. Very few breeds fit into this category, but certainly the Randall Lineback Cattle did when they were first rescued from that original group of two bulls and ten cows. At that point, anything alive had a contribution to make! Such extreme situations are rare, but occasionally a rare bloodline within a breed might fit into this general category.
Way over at the other extreme are the common production breeds, where quality and productive potential trump just about all other issues. This is taken furthest in dairy breeds, most notably the Holstein, where individual bulls can sire tens of thousands of calves. Intense selection for the desired qualities (milk production) has resulted in very productive cows, but an unfortunately narrow genetic base that is now starting to have consequences in general viability and longevity.
Looking at these extremes can teach a few lessons. At the one extreme (no selection) it is possible to assure decent genetic variation, but usually at the expense of production and overall quality. At the other extreme (high selection) it is possible to have productive high quality animals but for the breed to collapse in on itself through inbreeding depression.
For most breeds, and the Heritage Shorthorn is among these, it is essential to find a point where selection for quality can be balanced against the genetic structure of the population. One way to do this is to always practice selection for quality, but to always balance this with selection for genetic representation. For example, if a calf comes from well-represented family lines, then selection for quality should have a high priority. If a calf comes from lines that are very rare, then it is appropriate in some cases to relax the selection for overall quality a bit, but only for that generation.
There is an important warning, though. There is a category that can be called “rare for a reason.” These are bloodlines, animals, or even entire breeds that are just not all that productive, hardy, or well-made. In the case of entire breeds, this situation puts them at risk of extinction. In the case of bloodlines, there are still some potential strategies that might work to salvage the more positive aspects of their potential genetic contribution. One strategy is to blend a few of these rare bloodlines together, playing off the weaknesses of one with the strengths of another. Success might take a few generations, but the reward is the genetic contribution that comes from having these diverse genetics represented in the breed.
The goal of breeders should always be to have high quality animals, regardless of how rare the breed is. That goal always needs to be undertaken with a view towards the long-term future, and a healthy genetic structure is an essential part of that. When healthy genetic structure of the population goes along with attention to selection for quality, it is indeed possible for the end result to be high quality, sound, productive Heritage Livestock long into the future. Indeed, the Heritage Shorthorn is a great example of just what is possible, over centuries, when breeders pay attention to these very details.
Author Profile: Dr. D. Phillip Sponenberg
Dr. Phillip Sponenberg (DVM Texas A&M University, PhD Cornell University) is a Professor of Pathology and Genetics at the Virginia-Maryland Regional College of Veterinary Medicine. He teaches pathology, genetic resources, and small ruminant medicine. His interests in coat color genetics include several species, and have resulted in journal articles, book chapters, and books.
Phil’s breed conservation endeavors include being a technical advisor for the Livestock Conservancy since 1977. This work has been pivotal in saving several endangered livestock breeds, with a special emphasis on breeds that are uniquely American or those for which the USA holds the greatest genetic diversity. These efforts are complemented by a personal herd of Tennessee Myotonic Goats in a wide variety of colors. He is also an avid spinner, and appreciates natural fibers and their color array.