title: Gamete physiology and timing of ovulation and fertilization in dogs.
abstract: Ovulation in most bitches occurs between 48-60 and 72 h from the onset of oestrus. The eggs are ovulated as primary oocytes and are not capable of being fertilized until about 60 h after ovulation when they undergo the first meiotic division to become secondary oocytes. By this time the ova have descended through two-thirds of the oviduct. Ova are fertilizable from the time of undergoing the first meiotic division at 60 h after ovulation until about 108 h after ovulation, i.e. for a period of about 48 h. The period during which the spermatozoa remain capable of fertilization in the female reproductive tract is thought to be about 5 days. The mating period during which conception is possible is thus about 7 days from the onset of oestrus.
authors.affiliation: Department of Reproduction, Nippon Veterinary and Zootechnical College, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tsutsui
mesh_terms: D000818:Animals; D004285:Dogs / Q000502:physiology*; D004971:Estrus; D005260:Female; D005306:Fertilization / Q000502:physiology*; D008297:Male; D010060:Ovulation / Q000502:physiology*; D010063:Ovum / Q000502:physiology*; D010066:Ovum Transport / Q000502:physiology; D013084:Sperm-Ovum Interactions; D013997:Time Factors