IMPACT OF DEWORMING AND BODY CONDITION SCORE ON CONCEPTION IN NELORE COWS

Abstract

Reproductive efficiency is one of the main indicators of productivity in beef cattle production and is influenced by nutritional, health, and management factors. The present study aimed to evaluate the influence of anthelmintic treatment and Body Condition Score (BCS) on the conception rate of Nellore cows subjected to Fixed-Time Artificial Insemination (FTAI). The experiment was conducted at Fazenda Pedra Branca, located in the municipality of Três Barras do Paraná, Paraná State, Brazil, using 75 multiparous Nellore cows distributed into three experimental groups: a group treated with fenbendazole, a group treated with a combination of doramectin and levamisole hydrochloride, and a control group. BCS was evaluated at the beginning of the reproductive protocol, when anthelmintic treatments were also administered, and pregnancy diagnosis was performed by transrectal ultrasonography 30 days after insemination. The overall pregnancy rate at 30 days was 77.3%. Pregnancy rates according to anthelmintic treatments were 68.0% for the fenbendazole-treated group, 80.0% for the group treated with doramectin combined with levamisole hydrochloride, and 84.0% for the control group, with no statistically significant difference among treatments (p = 0.372). Regarding BCS, pregnancy rates ranged from 70.0% to 100.0% among the scores evaluated, with no significant association between BCS and pregnancy outcome (p = 0.902). Under the conditions evaluated, administration of anthelmintic drugs at the beginning of the FTAI protocol and differences in BCS did not significantly influence the conception rate of multiparous Nellore cows.