Gonadotropic and ovarian hormone response in dairy cows treated with norgestomet and estradiol valerate.
Injection of estradiol valerate in conjunction with receiving a norgestomet ear implant (Syncro-Mate-B) reduced plasma progesterone (P<.001) and FSH (P<.02) and increased estradiol (P<.01) in postpartum cows during the treatment period. Occurrence of LH and FSH peaks (P<.05) varied between 12 and 48 hr following removal of SMB implants and estrous behavior was minimal. FSH was strongly correlated to LH and was inversely related to progesterone in untreated cows and to estradiol in treated cattle. Syncro-Mate-B suppressed luteal activity and peak gonadotropin release during treatment and elicited variable endocrine and behavioral response following treatment.
Barnes
M A
MA
Department of Dairy Science, Clemson University, Clemson, South Carolina 29631, USA.
Kazmer
G W
GW
Bierley
S T
ST