Factors affecting the success of resynchronization protocols with or without progesterone supplementation in dairy cows
Factors affecting the success of resynchronization protocols with or without progesterone supplementation in dairy cows
- 대한수의학회
- Journal of Veterinary Science
- 제16권 제1호
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2015.03121 - 126 (6 pages)
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The objective of this study was to investigate factors that influence the success of resynchronization protocols for bovines with and without&nbsp;progesterone supplementation. Cow synchronized and not found pregnant were randomly assigned to two resynchronization protocols:&nbsp;ovsynch without progesterone (P4) supplementation (n = 66) or with exogenous P4 administered from Days 0 to 7 (n = 67). Progesterone&nbsp;levels were measured on Days 0 and 7 of these protocols as well as 4 and 5 days post-insemination. Progesterone supplementation raised the&nbsp;P4 levels on Day 7 (<i>p</i> < 0.05), but had no overall effect on resynchronization rates (RRs) or pregnancy per artificial insemination (P/AI).&nbsp;However, cows with Body Condition Score (BCS) > 3.5 had increased P/AI values while cows with BCS < 2.75 had decreased P/AI rates&nbsp;after P4 supplementation. Primiparous cows had higher P4 values on Day 7 than pluriparous animals (<i>p</i> = 0.04) and tended to have higher&nbsp;RRs (<i>p</i> = 0.06). Results of this study indicate that progesterone supplementation in resynchronization protocols has minimal effects on&nbsp;outcomes. Parity had an effect on the levels of circulating progesterone at initiation of the protocol, which in turn influenced the RR.
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