Comparison of 2 gonadorelin formulations and 2 luteolytic agents on pregnancy rates in beef cattle synchronized with a 5-d CO-Synch + CIDR program

Abstract

Improving reproductive performance in beef cattle is paramount to maximize beef operations productivity and sustainability. Gonadotropin releasing hormone (GnRH) and luteolytic agents (dinoprost tromethamine and cloprostenol sodium) are commercially available to be used in synchronization programs to allow timed artificial insemination (TAI) of cattle. Recently, a Synchronization Pack™ (Parnell) containing a combination of cloprostenol sodium and gonadorelin acetate was approved by the Food and Drug Administration to be used in TAI synchronization programs in both beef and dairy cattle. However, little research-based evidence on the pregnancy rates that can be achieved in beef cattle using these hormones is available. The objective of the present study was to compare the effect of 2 gonadorelin formulations and 2 luteolytic agents (PGF) injected as part of a 5 day CO-Synch + CIDR program on fixed TAI (FTAI) pregnancy rates (PR) in beef cattle.