The Effect of Initial Assignment of Parent Population Boer Does into High and Low Parasite Resistance Groups on Subsequent Doe Parasite Resistance, Survival Rate, Reproductive Efficiency, and Kid Performance and Survival Rates – 2 Year Summary

Abstract Text:

In the United States, goat numbers have increased by about one-third in the past decade because of their economic value as efficient converters of low-quality forages into quality meat, milk, and hides for specialty markets.  However, goats are more susceptible to internal parasites than other types of livestock.  Therefore, the objective of this study was to evaluate the effect of initial assignment of parent population Boer does into high and low parasite resistance groups on subsequent doe parasite resistance, survival rate, and reproductive efficiency, and kid performance and survival rates.  Parasite resistance Expected Progeny Differences were used to rank and sort mixed age Boer does (n = 146) into one of two selection lines:  1) high line (HL; n = 74) to be selected for high resistance to internal parasites or 2) low line (LL; n = 72) to be selected for low resistance to internal parasites.  High line and LL Boer does were mated to corresponding HL and LL Kiko bucks to produce crossbred Kiko × Boer progeny for two consecutive y.  After initial allocation, fecal egg counts, FAMACHA^© scores, and packed cell volumes were measured periodically on all does and were utilized to determine if an animal required deworming.  For does, number of times dewormed, survival rate, kidding date, litter size, and kid weaning weights were similar (P ≥ 0.27) across lines.  Kidding rates and kid birth weights were greater (P ≤ 0.04) for LL compared with HL; however, HL does weaned more kids (P ≤ 0.05) compared with LL does.  A sex effect (P ≤ 0.01) was observed for kid birth and weaning weights, where male kids weighed more compared to female kids.  Therefore, after two y, initial assignment of parent population Boer does to high and low parasite resistance lines had no effect on subsequent doe parasite resistance or survival rate, but mixed effects on doe reproductive efficiency, kid performance, and kid survival rates; however, these findings represent short-term effects from an ongoing, long-term selection study.

Keywords: Boer, Kiko, Parasite Resistance