Improvement of conception rate on Hanwoo; The key hormones and novel estrus detector

Young Hoo Joo; Seung Min Jeong; Dimas Hand Vidya Paradhipta; Hyuk Jun Lee; Seong Shin Lee; Jeong Seok Choi; Hyeon Tak Noh; Hong Hee Chang; Eun Joong Kim; Sam Churl Kim

doi:10.5187/jast.2021.e122

Improvement of conception rate on Hanwoo; The key hormones and novel estrus detector

J Anim Sci Technol. 2021 Nov;63(6):1265-1274. doi: 10.5187/jast.2021.e122. Epub 2021 Nov 30.

Authors

Young Hoo Joo¹, Seung Min Jeong², Dimas Hand Vidya Paradhipta^{2

3}, Hyuk Jun Lee², Seong Shin Lee¹, Jeong Seok Choi², Hyeon Tak Noh², Hong Hee Chang^{1

4}, Eun Joong Kim⁵, Sam Churl Kim^{1

2

4}

Affiliations

¹ Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 52828, Korea.
² Division of Applied Life Science (BK21Four), Gyeongsang National University, Jinju 52828, Korea.
³ Department of Animal Nutrition and Feed Science, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia.
⁴ Department of Animal Science, Gyeongsang National University, Jinju 52828, Korea.
⁵ Department of Animal Science, Kyungpook National University, Sangju 37224, Korea.

Abstract

Two field experiments were conducted to improve the conception rate of Hanwoo cow. The first experiment aimed to investigate the physiological condition of Hanwoo cows on estrus, including metabolic profiles and body condition score (BCS). The second experiment investigated the effect of a novel estrus detector on the artificial insemination (AI) conception rate for Hanwoo cows. For the first experiment, 80 Hanwoo cows (2.5 ± 0.10 of parity), approximately one month before estrus, were housed in 16 pens and offered the experimental diets twice daily with free water access. The BCS were recorded, and blood was collected from the jugular veins just before AI. The collected blood was used to measure physiological conditions, such as metabolite and hormone levels. For the second experiment, each cow was equipped with a neck-mounted estrus detector collar, which had a sensor connected through the internet. Approximately one month before estrus, three hundred sixty Hanwoo cows (2.4 ± 0.21 of parity) were assigned into groups with or without W-Tag collar treatments. The animals were managed the same as in the first experiment. The pregnancy rate reached 55% in the first experiment. The concentration of luteinizing hormone (LH) was higher (p < 0.012; 1.56 vs. 1.08 ng/mL) in cows that were not pregnant (NPG) than in cows that were pregnant (PG) after AI. The BCS and other concentrations of metabolites and hormones in the blood were not different in both NPG and PG cows. The ranges of estrogen, LH, and follicle-stimulating hormone for PG cows were 11.9 to 39.0 pg/mL, < 0.25 to 1.98 ng/mL, and < 0.50 to 0.82 ng/mL, respectively. In the second experiment, cows with the estrus detector had lower days open (p < 0.001; 78.1 vs. 84.8 d), insemination frequency (p < 0.001; 1.26 vs. 2.52), and return of estrus (p < 0.001; 70.9 vs. 79.1 d) than those in cows without the estrus detector. In conclusion, the present study indicated that lower LH concentration just before AI potentially increased the pregnancy rate of Hanwoo cows. Furthermore, the application of estrus detectors to Hanwoo cows could improve the conception success rate for AI.

Keywords: Artificial insemination; Conception rate; Estrus detector; Hanwoo cow; Luteinizing hormone.