The experiment was conducted at a commercial
beef cattle farm in west-central Brazil
(19◦5730S/54◦0104W) on January, 2005. The heifers
were maintained on Brachiaria brizantha pasture with free
access to mineralized-salt and water. Nelore (Bos indicus;
n = 180) heifers ranging between 24 and 32 months of age
were examined by transrectal ultrasonography for presence
or absence of a corpus luteum (CL). All procedures,
including injections, FTAI, and ovarian ultrasonography
were performed preserving the animal welfare state.