311 - Administering a Bovine Appeasing Substance to Beef Heifers During an Estrous Synchronization Protocol and Its Impacts on Temperament and Pregnancy Rate

Thursday, June 30, 2022

9:20 AM – 9:35 AM CT

Location: Oklahoma City Convention Center, 209 A/B

Presenting Author(s)

Nicholas W. Wege Dias

PhD candidate
Department of Animal and Poultry Sciences, Virginia Tech
Blacksburg, Virginia

Author(s)

Stefania Pancini, n/a

PhD Candidate
Virginia Polytechnic Institute and State University - School of Animal Sciences
Blacksburg, Virginia
GG

Guillermo Goncherenko

Visiting Scholar
Department of Animal and Poultry Sciences, Virginia Tech
Blacksburg, VA
JC

John Currin, Dr.

Clinical Associate Professor
Department of Large Animal Clinical Sciences, Virginia Maryland College of Veterinary Medicine
Blacksburg, VA
SC

Sherrie Clark

Interim Department Head
Department of Large Animal Clinical Sciences, Virginia Maryland College of Veterinary Medicine
Blacksburg, VA
JS

Jamie L. Stewart

Assistant Professor
Department of Large Animal Clinical Sciences, Virginia Maryland College of Veterinary Medicine
Blacksburg, VA
RC

Reinaldo Cooke

Professor
Department of Animal Science, TAMU
College Station, TX
Vitor Rodrigues G. mercadante, DVM, MS, PhD

Associate Professor
Department of Animal and Poultry Sciences; Department of Large Animal Clinical Sciences, Virginia Tech
Blacksburg, VA

Abstract: This experiment evaluated the impacts of administering a bovine appeasing substance (BAS) to Bos taurus (angus crossed) beef replacement heifers at the initiation of an estrous synchronization (TAI) protocol on their temperament and pregnancy rates. A total of 348 heifers at four locations were stratified by body weight (BW); reproductive tract score (RTS), and temperament score [TS; average of exit velocity (EV) and chute score (CS), determined at the day of initiation of TAI) and assigned to receive BAS (IRSEA Group, Quartier Salignan, France; n = 173) or placebo (water; CON; n = 175). Treatments (5 mL) were topically applied to the nuchal skin area of each heifer at the initiation of the TAI protocol. Within location, heifers were allocated to pens (6 pens per treatment; pen being the experimental unit) and received a free-choice total mixed ration during the duration of the experiment. Temperament (EV, CS) was assessed three times (days 0, 7 and 9) during the TAI protocol by the same trained technician. Pregnancy rate was determined by ultrasonography between days 45 and 55 post TAI. Heifer BW (379.5±5 kg), RTS (3.8±0.06), CS on days 0, 7 and 9 (2.33±0.06, 2.08±0.04, and 1.91±0.04, respectively), and EV on days 0, 7 and 9 (1.35±0.03, 1.28±0.03, and 1.39±0.03 m/s, respectively), and estrus expression prior to TAI (40.2±5.9%) were similar (P>0.10) between treatments. Pregnancy rate to TAI differed among locations (P< 0.05); however, it was not affected by treatment (39.7±8.2% and 41.0±3.7% for CON and BAS, respectively), with no treatment by location interaction. In conclusion, administration of BAS to beef heifers at the initiation of a TAI protocol did not alter temperament, measured as CS and EV, and failed to increase pregnancy rates.