Grazing schedule and antihelmintic effect over gastrointestinal parasite burden in small ruminants

Abstract

To evaluate the effect of the grazing schedule and an anthelmintic over gastrointestinal parasite burden, in Saltillo, Coahuila, México (25° 21’ LN y 101° 2” LO) Murciano Granadina and Boer does (n= 83) and Dorper sheep (n=20) no pregnant and no lactating, regularly dewormed with ivermectina, they form two groups: A) grazing during the morning, n= 51 (9:00-13:00 h) and grazing during the afternoon, n= 52 (13:00-17:00 h). These two groups were subdivided en two; at the starting of the study one of them received a shot of levamisol 10% injectable 1 mL per 20 kg BW and the other group received a saline solution as placebo. The principal effects were: grazing schedule (morning vs afternoon) and anthelmintic (with vs without); the response variables were: the number of eggs per gram of feces (EPG) transformed by log 10 (n+1), packed cell volume (PCV) or hematocrit, Body condition score (BCS) and FAMACHA. The grazing schedule affected (P<.0001) EPG with 316.4 and 215.9, EPG transformed for the morning and afternoon grazing; so, EPG was affected (P= .02) by the anthelmintic with 239.8 and 292.5 EPG for animals with and without anthelmintic respectively. PCV was no affected (>.05) by the principal effects: it was obtained 19.33 and 20.82 for morning and afternoon grazing schedule; 20.85 and 19.30 % for animals with and without anthelmintic respectively. BCS was different (X2= .04) in the grazing schedule favoring the afternoon grazing schedule, but no the anthelmintic doses. FAMACHA was not different with the principal effects. The afternoon grazing schedule and the anthelmintic favored in diminishing EPG. It is suggested not utilize the same active principle in anthelmintic drugs.