Lee Jae-Gu, Seo Jeongwoo, Alam Mahboob, Song Hyungjun, Lee Seokhyun, Cho Joohyeon, Dang Chang-Gwon, Lee Joonho
Animal Breeding and Genetics Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea.
GeneApps Co., Ltd., Seoul 06105, Korea.
Anim Biosci. 2025 Jan;38(1):33-40. doi: 10.5713/ab.24.0455. Epub 2024 Oct 25.
In Korea, dairy cattle breeding programs have historically prioritized productive, conformation traits, leading to positive improvements, yet reproductive traits have lagged in development. This study was conducted to develop the breeding program of key reproductive traits in the Korean dairy cattle population.
Utilizing data from 7,596 farms and over seven million observations, we conducted quality control to rectify manual entry errors and selected traits in line with international genetic evaluation standards. Traits analyzed included heifer conception rate (HCR), interval from calving to first insemination (CF), cow conception rate (CCR), interval from first to last insemination (FL), and days open (DO). Genetic parameters were estimated using a single trait animal model for HCR and a multiple lactation animal model for CF, CCR, FL, and DO, considering contemporary group of herd-insemination year, insemination month, and monthly age as fixed effects.
Results showed low heritability estimates, ranging from 0.007 to 0.035 across different traits and lactations. Theoretical reliability appears to be low on average due to the influence of heritability, but it showed sufficiently high reliability in some sires (over 0.8). In terms of genetic and phenotypic trends, capacity for reproductive traits declined for a long time until around 2014. In recent individuals, improved trend can be found.
This study addressed the critical need for enhancing reproductive efficiency to complement the existing breeding goals, thereby supporting sustained economic viability in the dairy industry. The results underscore the need for improved data quality and methodological adjustments for reproduction records to enhance the genetic evaluation of dairy cattle in Korea.
在韩国，奶牛育种计划历来优先考虑生产性能和体型性状，取得了积极进展，但繁殖性状的发展滞后。本研究旨在制定韩国奶牛群体关键繁殖性状的育种计划。
利用来自7596个农场的700多万条观测数据，我们进行了质量控制以纠正人工录入错误，并选择符合国际遗传评估标准的性状。分析的性状包括小母牛受孕率（HCR）、产犊至首次输精间隔（CF）、母牛受孕率（CCR）、首次输精至末次输精间隔（FL）和空怀天数（DO）。对于HCR，使用单性状动物模型估计遗传参数；对于CF、CCR、FL和DO，使用多胎动物模型，将牛群输精年份、输精月份和月龄的同期组作为固定效应。
结果显示，不同性状和胎次的遗传力估计值较低，范围在0.007至0.035之间。由于遗传力的影响，理论可靠性平均似乎较低，但在一些公牛中显示出足够高的可靠性（超过0.8）。在遗传和表型趋势方面，直到2014年左右，繁殖性状的能力长期下降。在最近的个体中，可以发现改善的趋势。
本研究满足了提高繁殖效率以补充现有育种目标的迫切需求，从而支持乳业的持续经济可行性。结果强调需要提高数据质量并对繁殖记录进行方法调整，以加强韩国奶牛的遗传评估。
