Breeding Values In Alpaca
Phenotype is at least 50% environment, nurture and husbandry. Add that to Mendel’s
laws of inheritance, which states that dominant genes express themselves and recessive genes
hide from view, and you begin to understand why phenotype is a poor guide to breeding value.
If we are to breed for elite alpacas, we must have a dependable method of determining which
animals will pass on superior traits in predictable fashion. Simply analyzing an alpaca’s
phenotype as a guide to the animals breeding value is an entirely ineffective improvement
strategy. It is a fact that assessing an alpaca’s phenotype to determine its breeding value is the
least reliable method of selection.
Pedigrees document ancestors beautifully but are only of marginal assistance when being
used to identify alpacas that will breed true. The great-grandsire of any given alpaca contributes
1/8th of his genes to the total genetic makeup of the grandson. Selection based on pedigree as the
sole selection criteria, assuming a 30% heritability factor, is from 38 to 55% accurate
(Understanding Animal Breeding, 2000, Richard Bourdan). This means if you use the pedigree
to make breeding decisions you will be right about 50% of the time. When you add the
measurement of individual phenotypic traits—records for fleece density, micron count, staple
length and so on-- to your analysis the accuracy of selection increases to about 65%. However,
if you add the production records of the parent’s progeny to the analysis your ability to predict
improvement increases to near 100%. There is simply too much that a pedigree does not tell you
about an alpaca.
The critical flaw in using pedigree to select and breed alpacas is that the information
most useful to the breeder, from a genetic improvement perspective, is not on the pedigree. ARI
pedigrees 1) do not record an alpaca’s phenotypic performance statistics; 2) do not identify
siblings or progeny; and 3) do not identify prepotency or breeding value. Relying on a pedigree
as an effective way to select superior breeding stock is based more on myth than fact.
Craig Wheaton-Smith made the following observation about the use of pedigree in
.
