Response to selective deworming in sheep of different breed types under continuous grazing in the humid tropics

Abstract

The aim was to evaluate the response under a selective deworming program of Pelibuey (PB, n=12), Katahdin (KT, n=12), Pelibuey x Katahdin (PB:KT, n=15) and Pelibuey x Dorper (PB :DP, n=15) ewes under continuous grazing on the excretion of eggs per gram of feces (HPG), live weight (LW), body condition score (BCS), level of anemia (FAMACHA), hematocrit (Hto), hemoglobin (Hb ) and deworming frequencies. The variables were evaluated by means of an analysis of variance considering as treatment the racial groups (PB, KT, PB:KT and PB:DP) through the four evaluation periods with repeated measures (days 20, 48, 76 and 104) in time and their interactions. The deworming frequencies of the sheep in each category were analyzed using contingency tables and Chi-square tests. HPG values ​​were higher (p<0.05) for ewes from the PB and PB:DP breed groups compared to KT and PB:KT ewes. In contrast, PB and PB:KT ewes showed higher levels (p<0.05) of Hto compared to KT and PB:DP ewes. However, the Hb levels found were similar between the racial groups evaluated. The accumulated total proportion reveals that PB:DP ewes were the ones that most required (p<0.05) to be dewormed at least once (32.8%). No significant differences were found between the PB, KT and PB:KT racial groups. According to the indicators of LW, BCS, Famacha, HPG, Hto, Hb and proportion of dewormed animals during the evaluated period, the sheep of the PB:KT breed group observed the best behavior. Therefore, the adequate choice of the best genotype for grazing conditions combined with a selective deworming program can contribute significantly to the control of gastrointestinal nematodes.