Prolactin and growth hormone responses to photoperiod in heifers.
D000818:Animals; D002417:Cattle; D003624:Darkness; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D008027:Light; D010507:Periodicity; D011374:Progesterone / Q000097:blood; D011388:Prolactin / Q000097:blood*
D011374:Progesterone; D011388:Prolactin; D013006:Growth Hormone