Plasma levels of luteinizing hormone, estradiol and androstenedione in sows with inadequate plasma progesterone.

The authors report the profiles of luteinizing hormone (LH), estradiol (E2), progesterone (P) and androstenedione (A) in some female pigs with altered plasma hormonal levels. Twenty cycles are described and 19 out of them are characterized by low plasma P in luteal phase of different etiology, at least as measured by hormone concentrations. The following disorders are observed: a) possible impairment of follicular maturation; b) impaired LH secretion in presence of too high E2; c) low LH base-line values; d) inadequate luteal phase; e) short luteal phase; f) heat disorders. An attempt is made to correlate the altered hormonal profiles with the high rate of summer conception failure in sows.