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Luteal Characteristics and Progesterone Production on Day 5 of the Bovine Oestrous Cycle
Author(s) -
Green MP,
Mann GE,
Hunter MG
Publication year - 2007
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/j.1439-0531.2006.00836.x
Subject(s) - luteal phase , ovulation , estrous cycle , endocrinology , medicine , incubation , corpus luteum , lactation , biology , andrology , chemistry , ovary , follicular phase , hormone , pregnancy , biochemistry , genetics
Contents In this study we have examined luteal function in non‐lactating and late lactation dairy cows on day 5 of the cycle, during the period of the post‐ovulatory progesterone rise. Comparison of luteal progesterone content and in vitro synthetic capacity with circulating plasma progesterone demonstrated that circulating progesterone concentration is a function of total luteal activity rather than the activity of individual units of tissue. Incubation of luteal tissue in vitro demonstrated stimulatory activity of LH and IGF‐I, and to a greater degree IGF‐II, on luteal progesterone synthesis. Finally the study showed no effect of double ovulation on luteal function. Occurrence of double ovulation in 35% of animals was not associated with any difference in luteal function or plasma progesterone concentrations.