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Embryo transfer has been used in Japan for several years to produce bulls and cows of high genetic value, to produce beef calves from dairy cows. The average size of Japanese cattle farming is not very large. An efficient embryo transfer program is important to facilitate adoption of these technologies in the field. The fixed‐time embryo transfer programs allow for systematic embryo transfer under field conditions. The objective of this paper was to evaluate the practical utility of fixed‐time embryo transfer programs in cattle under field conditions. Two fixed‐time embryo transfer programs were used for dairy or beef cattle: 1) the ovysync program and the 2) progesterone and estradiol program. 1) Ovysync Program Dairy cattle (cows, n = 146; heifers, n = 107) were randomly allocated to a natural estrus control group (cows, n = 63; heifers, n = 47) or an ovulation synchronization (ovysync) group (cows, n = 83; heifers, n = 60), which was treated with an intramuscular (IM) injection of 100 μg GnRH at a random stage of the estrus cycle. Seven days later, the cattle received PGF2α (Cows; 25 30 mg) or PGF2α analog (Heifers; 0.5 mg) to regress the corpora lutea (CL). Forty‐eight hours later, the cows and heifers received a second injection of 100 μg GnRH. Embryo transfer was carried out 6 or 7 days after the second GnRH injection. There were no differences in the proportion of acceptable embryo transfers in the control (cows, 81.0%; heifers, 91.4%) and ovysync groups (cows, 83.1%; heifers, 91.7%). Pregnancy rates did not differ between groups. 2) Progesterone and Estradiol Program All beef heifers and beef or dairy cows received CIDR and estradiol benzoate (EB, beef heifers and cows, 1 mg; dairy cows, 2 mg) IM on Day 0, PGF2α at the time of CIDR removal (beef heifers and cows, Day 7; dairy cows, Day 8), 1 mg EB IM on Day 8 (beef heifers and cows) or 9 (dairy cows). Embryo transfer was carried out on Day 16 (beef heifers and cows) or Day 17 (dairy cows). The pregnancy rates were 80.0% (12/15) for beef heifers, 46.7% (7/15) for beef cows and 68.4% (13/19) for dairy cows. These results suggest that both fixed‐time embryo transfer programs can be effectively applied to cattle programs under field conditions.

저자

• O. Dochi [ Rakuno Gakuen University, Ebetu, Hokkaido, Japan ]
• T. Nishisouzu [ Rakuno Gakuen University, Ebetu, Hokkaido, Japan, Pressent address: Kumamoto Dairy Co‐Operative Association ]
• M. M. Yamaguchi [ Rakuno Gakuen University, Ebetu, Hokkaido, Japan ]
• M. Moriyosh [ Rakuno Gakuen University, Ebetu, Hokkaido, Japan ]
• S. Takahashi [ Rakuno Gakuen University, Ebetu, Hokkaido, Japan ]
• H. Koyama [ Rakuno Gakuen University, Ebetu, Hokkaido, Japan ]

참고문헌

발행기관

간행물

표지보기 관심저널 등록

• 간행물명

  발생공학 국제심포지엄 및 학술대회 [International Symposium on Developmental Biotechnology]

• 간기

  연간

• 수록기간

  2004~2018

• 십진분류

  KDC 527 DDC 636