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2026 Vol.53, Issue 2

Animal

Environmental factors affecting services per conception in Hanwoo cows
Shil Jin1*
,
Sung-Sik Kang1
,
Hyoun Ju Kim12
,
Yonghwan Kim13
,
Hanwool Do1
,
Jeong Il Won1
,
Jun Kyu Son1
1Hanwoo Research Center, National Institute of Animal Science, Pyeongchang 25340, Korea
2Planning & Coordination Division, National Institute of Animal Science, Wanju 22365, Korea
3Department of Animal Resources Science, Kongju National University, Yesan 32439, Korea
*Corresponding Author
1 June 2026. pp. 99-110
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Abstract

Services per conception (SPC), i.e., the number of artificial inseminations (AIs) required for conception, is a key reproductive indicator in cattle. We quantified SPC in Hanwoo cows and evaluated the primary environmental sources of variation, focusing on the insemination setting. After quality control, 1,141 AI-to-calving records from the Hanwoo Research Center were analyzed; only normal single-calf calvings were retained, and records requiring ≥ 5 AIs were excluded. Cows were classified into either the hormone-treated group (HT), or the natural estrus group (NE). Differences in SPC across factors were tested using linear models and analysis of variance (ANOVA). SPC was lower in HT than in NE (1.38 ± 0.756 vs. 2.06 ± 0.785; p < 0.001). In HT, inseminator effects were significant (p = 0.026), whereas parity, AI year, and season were not (p > 0.05). In NE, primiparous cows had a lower SPC than multiparous cows (p < 0.001); the SPC was higher in March - August than in September - February (p < 0.05). Overall, the environmental sources of variation in SPC were not uniform across insemination settings, with parity and seasonal effects evident mainly under natural-estrus-based AI. Given the low heritability of reproductive traits and the strong influence of management and contemporary group effects on SPC, analyses of Hanwoo cows should account for insemination settings and systematically adjust for key environmental factors to avoid biased genetic effect estimates.

Keywords
environmental effect
Hanwoo
reproductive trait
service per conception
References
1

Baruselli PS, Ferreira RM, Colli MHA, Elliff FM, Sá Filho MF, Vieira L, de Freitas BG. 2017. Timed artificial insemination: Current challenges and recent advances in reproductive efficiency in beef and dairy herds in Brazil. Animal Reproduction 14:558-571.

10.21451/1984-3143-AR999
2

Berry DP, Wall E, Pryce JE. 2014. Genetics and genomics of reproductive performance in dairy and beef cattle. Animal 8:105-121.

10.1017/S1751731114000743
3

Bó GA, Baruselli PS. 2014. Synchronization of ovulation and fixed-time artificial insemination in beef cattle. Animal 8:144-150.

10.1017/S1751731114000822
4

Chang YM, Andersen-Ranberg IM, Heringstad B, Gianola D, Klemetsdal G. 2006. Bivariate analysis of number of services to conception and days open in Norwegian Red using a censored threshold-linear model. Journal of Dairy Science 89:772-778.

10.3168/jds.S0022-0302(06)72138-5
5

Choi SB, Lee JW, Choy YH, Na KJ, Kim NS. 2005. Estimates of parameters for genetic relationship between reproductive performances and body condition score of Hanwoo cows. Asian-Australasian Journal of Animal Sciences 18:909-914.

10.5713/ajas.2005.909
6

Choi TJ, Lee SJ, Park JE, Lim D, Cho YM, Park B. 2018. Analysis of environment effects on the carcass traits Hanwoo cows using ultrasonic measurement. Korean Journal of Agricultural Science 45:66-73. [in Korean]

10.7744/KJOAS.20180014
7

Colazo MG, Mapletoft RJ. 2014. A review of current timed-AI (TAI) programs for beef and dairy cattle. The Canadian Veterinary Journal 55:772-780.

25082993PMC4095965
8

Diskin MG. 2018. Review: Semen handling, time of insemination and insemination technique in cattle. Animal 12:s75-s84.

10.1017/S1751731118000952
9

Eum SH, Park HR, Seo J, Cho SK, Kim BW. 2016. Analysis of environmental effects affecting reproductive traits of primiparous and multiparous Hanwoo. Korean Journal of Agricultural Science 43:369-378. [in Korean]

10.7744/kjoas.20160039
10

Irikura N, Uematsu M, Kitahara G, Osawa T, Sasaki Y. 2018. Effects of service number on conception rate in Japanese Black cattle. Reproduction in Domestic Animals 53:34-39.

10.1111/rda.13049
11

Jin S, Kang SS, Won JI, Kim HJ, Jang SS, Kim SW. 2024. Analyzing environmental factors influencing the gestation length and birth weight of Hanwoo cattle. Journal of Animal Reproduction and Biotechnology 39:121-130.

10.12750/JARB.39.2.121
12

Jin S, Won JI, Park B, Kim SW, Kim UH, Kang SS, Lee HJ, Moon SJ, Park MS, Lim HT, et al. 2023. Genetic diversity analysis of the line-breeding Hanwoo population using 11 microsatellite markers. Korean Journal of Agricultural Science 50:363-372. [in Korean]

10.7744/kjoas.500302
13

Kang SS, Cho SR, Kim UH, Kim Y, Lee SD, Lee MS, Kim E, Won JI, Jin S, Kim HJ, et al. 2024. Pregnancy rate in Hanwoo cows after timed artificial insemination using different sperm concentrations. Journal of Animal Reproduction and Biotechnology 39:40-47.

10.12750/JARB.39.1.40
14

Kim BH, Lee SK, Kim IH, Kang HG. 2009. The effect of parity and calving seasons on the reproductive performance of Korean native cows. Journal of Embryo Transfer 24:127-130.

15

Kim IH, Jeong JK. 2018. Risk factors limiting first service conception rate in dairy cows and their economic impact. Asian-Australasian Journal of Animal Sciences 31:519-530.

10.5713/ajas.18.029630208696PMC6409448
16

Kim UH, Chung KY, Lee SH, Ryu IS, Kang HS. 2014. Case report on improvement of reproduction rate in Hanwoo farms. Journal of Embryo Transfer 29:7-12. [in Korean]

10.12750/JET.2014.29.1.7
17

Kwon DJ, Lee SM, Kim DH, Oh JD. 2019. Analysis and evaluation of reproductive performance of Korean native cattle (Hanwoo) in Jeonbuk Province. Journal of Agriculture & Life Science 53:113-121. [in Korean]

10.14397/jals.2019.53.3.113
18

MAFRA (Ministry of Agriculture, Food and Rural Affairs). 2023. Livestock improvement goals. Public Notice No. 2023-3. [in Korean]

19

Pursley JR, Mee MO, Wiltbank MC. 1995. Synchronization of ovulation in dairy cows using PGF2α and GnRH. Theriogenology 44:915-923.

10.1016/0093-691X(95)00279-H
20

R Core Team. 2024. R: A Language and Environment for Statistical Computing. Ver. 4.4.2. Austria: R Foundation for Statistical Computing.

21

Rizos D, Carter F, Besenfelder U, Havlicek V, Lonergan P. 2010. Contribution of the female reproductive tract to low fertility in postpartum lactating dairy cows. Journal of Dairy Science 93:1022-1029.

10.3168/jds.2009-2605
22

Sasaki Y, Uematsu M, Kitahara G, Osawa T. 2016. Reproductive performance of Japanese Black cattle: Association with herd size, season, and parity in commercial cow-calf operations. Theriogenology 86:2156-2161.

10.1016/j.theriogenology.2016.07.007
23

Setiaji A, Oikawa T. 2020. Genetics of heifer reproductive traits in Japanese Black cattle. Asian-Australasian Journal of Animal Sciences 33:197-202.

10.5713/ajas.19.011831208175PMC6946956
24

Souza AH, Ayres H, Ferreira RM, Wiltbank MC. 2008. A new presynchronization system (Double-Ovsynch) increases fertility at first postpartum timed AI in lactating dairy cows. Theriogenology 70:208-215.

10.1016/j.theriogenology.2008.03.014
25

Van Bebber J, Reinsch N, Junge W, Kalm E. 1997. Accounting for herd, year and season effects in genetic evaluations of dairy cattle: A review. Livestock Production Science 51:191-203.

10.1016/S0301-6226(97)00058-4
Information
  • Publisher :Institute of Agricultural Science, Chungnam National University
  • Publisher(Ko) :충남대학교 농업과학연구소
  • Journal Title :Korean Journal of Agricultural Science
  • Journal Title(Ko) :농업과학연구
  • Volume : 53
  • No :2
  • Pages :99-110
  • Received Date : 2026-01-22
  • Revised Date : 2026-03-09
  • Accepted Date : 2026-03-10
  • DOI :https://doi.org/10.7744/kjoas.530201
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