Earticle

초록

영어

Presently, the first pregnancy age of dairy heifers attended National Dairy Herd Improvement Program (NDHI) in Korea has increased, and more research have been requested to evaluate the possibility of decreasing the first pregnancy age of dairy heifers. Accordingly, this study was investigated the effects of the month of age at the first service and pregnancy on the reproductive efficiency of Holstein heifers. For these, the reproductive performance of heifers was analyzed by evaluating the effects of first insemination service at 12-14 months of age (12 month old), 15-16 months of age (15 month old), 17-19 months of age (17 month old), and > 20 months of age (20 month old) in Holstein heifers. The service numbers per conception in the first insemination months were 1.85±1.22, 1.59±0.77, 1.58±0.72, and 1.76±0.97 times at 12, 15, 17 and 20 months of age, respectively. The conception rates in the first service were 51.2, 57.8, 54.8, and 52.9% at 12, 15, 17 and 20 months of age, respectively. The conception ages were 453.2±78.9, 512.1±75.9, 590.1±98.0, and 713.0±74.5 days in the heifers serviced firstly at 12, 15, 17 and 20 months of age, respectively. There was significantly difference in the conception age among groups (p<0.05). The cumulative conception rates in the heifers serviced firstly at 12, 15, 17 and 20 months of age were 51.21, 57.8, 54.8 and 53.0% by the first service, 29.8, 30.1, 32.3, 23.5% by the second service, and 19.0, 12.1, 12.9 and 23.5% by the third service, respectively. The service numbers per conception in the first pregnancy months were 1.31, 1.55, 2.0, 2.05 times at 12, 15, 17 and 20 months of the first service age, respectively. The service numbers per conception in the 12 and 15 months of age were significantly lower than those in the 17 and 20 months of age (p<0.05). The rates of repeat-breeder were 6.0, 11.3, 22.0, and 41.0% in the heifers serviced firstly at 12, 15, 17 and 20 months of age, respectively. These results demonstrate that first pregnancy of Holstein heifers should be conducted at 15 months of age, because the age at first pregnancy in heifers can be substantially influenced through implementation of reproductive management and performance.

목차

ABSTRACT
 Ⅰ. 서론
 Ⅱ. 재료 및 방법
  1. 공시동물
  2. 공시재료
  3. 초수정 및 초임월령
  4. 조사방법
 Ⅲ. 결과 및 고찰
  1. 초수정월령에 따른 수태당 수정횟수
  2. 초수정월령에 따른 첫수정시 수태율
  3. 초수정월령에 따른 초임일수
  4. 초임월령에 따른 누적수태율
  5. 초임월령에 따른 수태당 수정횟수
  6. 초임월령에 따른 저수태우의 발생율
 Ⅳ. 요약
 사사
 Ⅴ. REFERENCES

저자

• 백광수 [ Kwang-Soo Baek | 농촌진흥청 국립축산과학원 ] Corresponding author
• 윤현상 [ Hyun-Sang Yoon | 한국종축개량협회 ]
• 이왕식 [ Wang-Shik Lee | 제주대학교 생명공학부 ]
• 안현숙 [ Hyun-Sook Ahn | 농촌진흥청 국립축산과학원 ]
• 기광석 [ Kwang-Seok Ki | 농촌진흥청 국립축산과학원 ]
• 김태일 [ Tae-Il Kim | 농촌진흥청 국립축산과학원 ]
• 채현석 [ Hyun-Seok Chae | 농촌진흥청 국립축산과학원 ]
• 김남영 [ Nam-Young Kim | 농촌진흥청 국립축산과학원 ]
• 조인철 [ In-Chul Cho | 농촌진흥청 국립축산과학원 ]
• 박남건 [ Nam-Geon Park | 농촌진흥청 국립축산과학원 ]

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