Comparison of two grazing systems in the infestation with gastrointestinal nematodes of hair sheep

Abstract

THIS STUDY WAS AIMED TO COMPARE THE GASTRO-INTESTINAL NEMATODE INFESTATION OF HAIR SHEEP UNDER TWO GRAZING SYSTEMS (A, B) IN HUMID TROPIC. TWO GROUPS WITH 17 PELIBUEY EWES EACH WERE COMPARED DURING TWO PERIODS (SEPTEMBER-NOVEMBER AND DECEMBER- JANUARY). AS WELL AS A THIRD PERIOD (FEBRUARY-APRIL) WITH 10 EWES PER GROUP. GROUP A WAS SUBJECTED TO CONTINUOUS GRAZING, WHEREAS GROUP B FOLLOWED A ROTATIONAL GRAZING SCHEME, IN THIS, EWES WERE ALLOWED TO GRAZE ONLY FOR FOUR DAYS IN A ROW PER PLOT AND EACH PLOT HAD A 28-DAY NON GRAZING PERIOD. BLOOD AND FECAL ANALYSIS WERE CARRIED OUT EVERY FIFTEEN DAYS, WHILE BODY CONDITION, COLOR OF THE PALPEBRAL MUCOUS MEMBRANE AND BODY WEIGHT OF THE ANIMALS WERE ALSO MEASURED EVERY FIFTEEN DAYS. ADDITIONALLY, THE AMOUNT OF GRASS BOTH OFFERED AND REJECTED WAS MEASURED. COUNTS OF NUMBER OF NEMATODE EGGS PER GRAM OF FECES (EPG) WERE TRANSFORMED TO LN (EPG 1) AND THEY WERE STATISTICALLY ANALYZED WITH THE SAS GLM PROCEDURE, AS WERE THE REMAINING VARIABLES. THE LOWEST COUNT OF NEMATODE EGGS PER GRAM OF FECES (601.79 ± 1 664.94) AND THE LOWEST PERCENTAGE OF HAEMONCHUS SP (64.1) WERE OBSERVED IN CONTINUOUS GRAZING, IN COMPARISON WITH THE ROTATIONAL GRAZING GROUP (709.4 ± 1 945.9 EPG; 74.0%). ON THE OTHER HAND, THE VALUES FOR HEMATOCRIT, BODY CONDITION AND COLOR OF THE PALPEBRAL MUCOUS MEMBRANE WERE HIGHER IN ROTATIONAL GRAZING (0.31 ± 0.04; 3.7 ± 0.07 Y 3.9 ± 0.6) THAN IN CONTINUOUS GRAZING (0.30 ± 0.05, 3.4 ± 0.6, 3.8 ± 0.7).