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Re:Why Alpaca Breed Standards? - 2006/07/15 03:52
I am writing to offer some of my thoughts relating to certification of male alpacas. In my view, the basis of any sort of certification program is its purpose--that is, what it is trying to accomplish. I can think of several different goals for certification programs, and all of these require lengthy, cumbersome, and expensive procedures in order to accomplish them.
One type of certification used for males of many species evaluates fertility and breeding soundness. The American Society of Theriogenology has developed breeding soundness criteria for a variety of domestic species and could easily develop such a protocol for alpacas. Their certification is designed to assure breeders and customers that certified animals are fertile, lack reproductive abnormalities, and lack obvious structural defects. It is a sort of assurance of baseline quality in a breeding animal. The examiners sift through a variety of characteristics, most of which are related to male fertility, by means of visual appraisal and laboratory examination. The result is that certified animals are assured to be reproductively normal. This sort of certification is useful for weeding out animals that are below par for reproduction and should therefore be removed from the breeding population.
The American Society of Theriogenology breeding soundness certification has been used to good effect by cattle and sheep breeders and has made a real difference in those species. Two advantages of this program are its convenience and objectivity: examiners are widely available throughout the country and are disinterested third parties. What this program fails to do is assess general genetic potential or quality, which are, I think, vital issues for alpaca breeders.
Any certification for genetic potential or quality is bound to be subjective and arbitrary because selection of a breeding animal involves the simultaneous consideration of hundreds of traits, and the examiners must agree as to which set of traits represents superior genetic quality. For example, I can think of a variety of desirable traits that I think represent a genetically sound alpaca. These are in no special order of priority and, of course, are colored by my philosophy and thinking on where the species should be headed. But each expert is going to have a unique view. If, however, we were able to develop an objective testing standard, rather than relying on an individual examiner's visual assessment, some objectivity would be possible.
Any certification program for breeding males by definition must screen for genetic defects, and again, the program would have to go well beyond visual appraisal to ensure that an animal does not carry them in an expressed state. My testing approach would be to require mating of males to their own daughters and then evaluate all the offspring. But to be 95 percent sure that the animal being tested does not have a deleterious recessive gene, we would need to evaluate at least twenty-three offspring. To say the least, this would be a fairly long and complicated process, and it is really the only way, currently available, to identify unexpressed genetic defects. Even under such a program there are two other problems. One is that the test is only 95 percent sure, so 5 percent of tested males could still have deleterious recessives. The other is that the test simplistically assumes that the genetic defects of interest are autosomal recessives, meaning that some defects will not be detected. Both issues are significant because some few certified males will go on to sire defective offspring. The lawyers will then get to decide if the certifying body or the owner of the sire is liable--or me, for suggesting the test in the first place.
Fiber traits also would be important in an alpaca certification program. Suri and huacaya would need to be considered separately because objective measures are necessarily different for them. The certification criteria could include minimum levels for fiber diameter, fiber diameter variability, staple length per unit time, fleece weight per unit time, and perhaps handle of fiber (but again, this is a subjective factor). Another possible consideration is fleece density, although fleece weight probably would be a satisfactory measurement of this trait.
Rather than a "straight" certification for fiber quality, a wiser method might be to group animals within year of birth and use percentile scoring. So, therefore, the fiber characteristics of a two-year-old male would be evaluated against those of all other two-year-old males, and his score would reflect his comparative standing in his age group. But even this method has an important disadvantage: not all animals in the gene pool would be tested and the results would be statistically flawed. I suppose that an aggressive program could require fiber evaluation for registration, but the anarchist in me says that this is way too constrictive.
General soundness, style, and conformation are also possible criteria in certification, but assessment for these would be subject to the whims of fashion and could degenerate into a game that some get to play and some do not, a situation damaging to any breed of livestock. Our goal should be to foster an environment in which all breeders can participate fully and evenly because it is good for the long-term development of the gene pool. A superior animal in a small herd, owned by someone with insufficient economic resources to pursue certification, may actually have very significant potential for the improvement of the gene pool. Such animals need to be identified and used widely for the good of the gene pool, and any certification program that does not actively seek them out is likely to overlook them.
Alternatively, we could simply track instances of defects, but that would require honesty on everyone's part despite the potential economic damage that compliance could bring. The current registry could track occurrences much as the dairy cattle industry tracks each and every defect in calves sired by artificial insemination. This method is useful because it detects, at a relatively early stage, the occurrence and transmission of defects and keeps track of the animals producing them. A problem with this approach is what to do with all of the information, since some defects are going to eventually be proven to be genetic while others are not. This system, if very public, could easily label individuals as passing on defects that were not indeed genetic and for which the animal in question is not responsible.
Even in the event that a defect is proven to be genetic, it is important to remember the general way in which defects pass from generation to generation: A known carrier will pass the defective gene only to half of its offspring. The offspring are therefore more likely to carry the gene than the population as a whole, but about half of them do not carry the defective gene at all. If an identification program is public, these noncarriers produced by a carrier parent are very likely to be mistakenly stigmatized and, as a result, not used to their potential.
In summary, any worthwhile certification program would be very cumbersome to formulate and manage. And any worthwhile program must be objective. If the goal of certification is indeed to foster the wider use of desirable animals, we must define desirability, and that is by nature a subjective decision. Who decides? Who gets to decide on who gets to decide?
D. Phillip Sponenberg, DVM, PhD
ARI Journal, Summer/Fall 1996
Emphasis added
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Interesting article, expecially in light of the BS debate (or is that BS-BS?)
John Merrell
Gateway Farm Alpacas
Alpaca, a natural elegance... |
