title: Serum melatonin concentrations during different stages of the annual reproductive cycle in ewes.
mesh_terms: D000780:Anestrus; D000818:Animals; D002940:Circadian Rhythm; D004971:Estrus; D005260:Female; D008027:Light; D008550:Melatonin / Q000097:blood*; D011247:Pregnancy; D012756:Sheep / Q000097:blood / Q000502:physiology*; D013997:Time Factors
chemical_list: D008550:Melatonin