Pregnancy per AI differences between primiparous and multiparous high-yield dairy cows after using Double Ovsynch or G6G synchronization protocols》.pdfVIP

Theriogenology 79 (2013) 1065–1070 Contents lists available at SciVerse ScienceDirect Theriogenology journal homepage: Pregnancy per AI differences between primiparous and multiparous high-yield dairy cows after using Double Ovsynch or G6G synchronization protocols S. Astiz a, *, O. Fargas b a Dpto. Reproducción Animal (INIA), Madrid, Spain b VAPL S.L., Barcelona, Spain a r t i c l e i n f o a b s t r a c t Article history: The objective of the present work was to determine the optimal protocol for timed AI on Received 19 November 2012 high-yield dairy cows. The pregnancy per AI (pregnancy/AI) arising from 7805 first timed Received in revised form 18 January 2013 artificial inseminations on 27 dairy farms in eastern Spain was examined after use of the Accepted 25 January 2013 Double Ovsynch (DOv; N ¼ 6783) or G6G (N ¼ 1022) synchronization protocols. Parity number, farm, prostaglandin analogue, and season (hot or cool) were examined for their Keywords: possible association with postsynchronization fertility (in terms of pregnancy/AI). Mean Double-Ovsynch pregnancy/AI overall was 36.1 8.4%, with no significant differences between the DOv or G6G Dairy cow G6G protocols (36.3 8.3% vs. 34.8 9.1%). However, parity and synchronization treat- Primiparous ment resulted in a significant interaction (P ¼ 0.03). When DOv AIs (N ¼ 6783) and