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The Induction of a Secondary Corpus Luteum on Day 12 Post‐Ovulation can Delay the Time of Luteolysis in High‐Producing H olstein Cows
Author(s) -
SaintDizier M,
Legendre AC,
Driancourt MA,
ChastantMaillard S
Publication year - 2014
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/rda.12401
Subject(s) - luteolysis , corpus luteum , ovulation , luteal phase , estrous cycle , andrology , endocrinology , medicine , pregnancy , zoology , biology , hormone , genetics
Contents Luteolysis before the time of maternal recognition of pregnancy is one cause of low fertility in high‐producing dairy cows. The objective of this study was to assess whether induction of a secondary corpus luteum ( CL ) late in the luteal phase would delay the time of luteolysis. Twenty high‐producing H olstein cows were synchronized to ovulation ( D ay 0) with the O vsynch protocol and received h CG (1500 IU im) on D ay 12. Corpora lutea formation (as evaluated by ultrasonography) and plasma P 4 concentrations were monitored from D ays 4 to 36. hCG treatment induced the formation of one secondary CL ( CL 2) in 11 of 20 cows (55%) from the dominant follicle (mean diameter: 14.2 ± 0.9 mm) of two‐wave (3/11) and three‐wave (8/11) cycles. The maximal diameter of the CL 2 (23.3 ± 1.9 mm) was reached approximately 6 days after h CG treatment and was correlated with its structural lifespan (p < 0.01). Cows that formed a CL 2 after h CG had higher mean plasma P 4 concentrations on D ay 14 (+4.5 ng/ml) and D ay 18 (+3.0 ng/ml) compared with cows without CL 2 (p < 0.05). The structural regression of CL 2 begun approximately 8 days after that of the CL 1, and the median time at which the first drop in circulating P 4 levels occurred was later in cows that formed a CL 2 than in those that did not ( D ay 26 vs D ay 18; p < 0.01). Thus, the induction of a CL 2 by h CG on D ay 12 might reduce the risk of premature luteolysis in high‐producing dairy cows after insemination.