Selection for parasite resistance in goats
In fall 2011, Lincoln University (in Missouri) began a divergent selection program for parasite resistance in goats. Researchers assigned 146 mixed-age Boer and high-percentage Boer does to one of two divergent selection lines: low parasite resistance and high parasite resistance. Does were mated to unrelated Kiko bucks, selected for either high or low resistance, from buck tests in Oklahoma and Maryland. After this, lines were closed and selection was from within lines.
Various genetic parameters were calculated from the population. The heritability estimate for fecal egg count (FEC) was determined to be 0.13 ± 0.07. In the scientific literature, heritability estimates for FEC for goats range from 0.02 to 0.33. Heritability of packed cell volume (PCV) was determined to be 0.06 ± 0.04, which is lower than other estimates reported. The heritability of FAMACHA© score was determined to be 0.11 ± 0.08. There are no estimates for FAMACHA© for goats in the scientific literature.
Genetic correlations between FEC and PCV and between FAMACHA© scores and PCV were slight, while the genetic correlation between FEC and FAMACHA© was large and positive. Genetic correlations between the various parasitological measurements are scarce in the literature for goats.
Conclusion: Results indicate that parasite resistance may be lowly heritable, regardless of parasite indicator traits measured. Heritability estimates for parasite related measurements in the current study were similar to previous estimates reported in literature and suggested that selection progress may be possible, but slow.