Application of PGF at the moment of fixed-time artificial insemination in crossbred beef cows.

Although studies have shown positive effects of gonadotropin releasing hormone (GnRH) or prostaglandin F (PGF) at the moment of fixed-time artificial insemination (FTAI) in the conception rate (CR) of cattle, its effects on treatments based on progesterone (P4) and estradiol benzoate (EB) is still not conclusive. The objective of this study was (1) to evaluate the effect of a PGF analogue at FTAI in the CR of crossbred beef cows submitted to a 11d FTAI protocol based on P4 and EB; and (2) to describe the CR between PGF-treated and control cows in different body condition scores (BCS) and parity categories. Crossbred (½ Nellore and ½ Angus) beef cows were submitted to a synchronization protocol and randomly assigned into 2 groups: Control (n = 163), at FTAI cows received 2 mL of saline solution as a placebo, and PGF (n = 163), at FTAI cows were treated with PGF analogue (10 mg of dinoprost tromethamine).