Resistance of Djallonké sheep to <i>Haemonchus contortus</i> under artificial challenge

Abstract

Gastrointestinal parasitism is a major constraint for small ruminant production. Coupled to the development of drug resistance in parasite populations, it is of high interest to identify animals with tolerance to nematode infections. In this study we evaluated Djallonké and Sahelian sheep resistance to Haemonchus contortus infection in Burkina Faso by challenging a total of 35 lambs (21 Djallonké and 14 Sahelian). Five weeks following deworming, a single dose of 5,000 L3 infective larvae of H. contortus were inoculated to each lamb. Body weight (BW), fecal egg counts (FEC), packed cell volume (PCV) and FAffa Malan CHArt (FAMACHA) eye scores were recorded at days 0; 28; 35 and 42 following artificial infection. The body weight between days 28 and 42, the FAMACHA scores, PCV, FEC and lnFEC28-lnFEC35 were significantly correlated. Mean BW of Djallonké did not change significantly throughout the experiment while a significant loss of weight (p=0.04) was observed in Sahelian sheep. There were no breed effects on PCV, FEC and lnFEC (p>0.05), while effects of sex and measurement time on PCV and FAMACHA scores were significant (p<0.05), i.e., in Djallonké the FEC declined from 3945.14 to 3235.71 from days 28 to 35, and remained constant thereafter. The results of this study indicate that Djallonké breed is able to maintain its body weight despite the parasite burden. Together with the high variability found in FEC and PCV, Djallonké breed might be considered in selection program for internal parasite resistance.

Keywords: Haemonchus contortus, Sheep, FaffaMalanChart, Parasitism, Burkina Faso.