Ovulation without cervical stimulation in domestic cats.
Progesterone was measured by radioimmunoassay of serum collected at monthly intervals for 9 months (April-December) in 24 adult female American short-hair cats (age 2.5-11 years, mean 7.4 years); 20 cats were intact, and four were ovariohysterectomized controls. One of the 20 intact queens was ovariohysterectomized after 7 months, when pyometra was diagnosed. Cats could see and hear one another, and could see and hear male cats housed individually in the same room. Direct contact with other cats was prevented. Tactile stimulation of the cats' hindquarters and perineal regions by handlers was avoided. Serum progesterone concentration > or = 4.8 nmol l-1 was defined as evidence of ovulation. This concentration was exceeded in seven of 20 intact queens (35%) at one or more occurrences of non-coital ovulation; there were 13 such occurrences in all (1-3 per queen). Serum progesterone concentration ranged from 0.2 to 103.4 (mean 14.09 +/- 2.0) nmol l-1 in these seven cats, and was significantly greater than concentrations in the other intact and neutered cats. In the remaining 13 intact and four ovariohysterectomized cats, serum progesterone concentrations ranged from 0.2 to 3.2 (mean 1.24 +/- 1.46) nmol l-1. These data suggest that, at least as far as cats housed in proximity to one another are concerned, intact female cats do not always require cervical stimulation to induce ovulation.
Lawler
D F
DF
Department of Pet Nutrition Research, Ralston Purina Company, Checkerboard Square, St Louis, MO 63164.
Johnston
S D
SD
Hegstad
R L
RL
Keltner
D G
DG
Owens
S F
SF
D000818:Animals; D002415:Cats / Q000502:physiology*; D003307:Copulation / Q000502:physiology*; D005260:Female; D007044:Hysterectomy; D010052:Ovariectomy; D010060:Ovulation / Q000097:blood / Q000502:physiology*; D011374:Progesterone / Q000097:blood; D011863:Radioimmunoassay
D011374:Progesterone