Feline Pregnancy
In feline reproductive management, understanding the intricacies of the reproductive cycle is paramount. Queens are seasonally polyestrous, with cyclicity linked to photoperiods, where exposure to 14 hours of artificial lighting can induce and sustain cyclicity, while a decrease to 8 hours prompts anestrus. As induced ovulators, queens require coital stimuli for ovulation, with spontaneous ovulation observed in a subset, influenced by the proximity of an intact male and increased body weight.
Gestation in felines averages 65.6 days, with notable breed variation. Implantation occurs approximately 14 days post-fertilization, with palpable deciduomata by day 21.
Diet during gestation demands increased protein intake, with arginine, lysine, and tryptophan being critical. An optimal diet comprises a minimum of 32% protein and 18% fat to support the queen's weight gain, which should be between 12-38% of pre-pregnancy weight.
Progesterone, pivotal for maintaining pregnancy, peaks between days 13 and 21, subsequently declining to baseline by day 65 post-mating. The luteal phase, if not followed by pregnancy, leads to pseudopregnancy lasting about 40-45 days, with a subsequent inter-estrus interval of approximately 17±4 days. Extended progesterone exposure due to mating with sterile or subfertile toms can induce uterine pathology, adversely affecting fertility.
Ultrasonography plays a crucial role in gestational management. Initial detection is feasible as early as 10 days post-mating with embryonic visualization by day 17. Structural developments like the urinary bladder and stomach can be discerned around day 30, kidneys by day 39, and bowel by day 40. Gestational age estimation via ultrasound relies on measurements such as inner chorionic cavity diameter early in gestation and biparietal diameter later on. The deep portion of the foetal diencephalo-telencephalic vesicle becomes measurable between days 35 to 58. Accurate parturition prediction is attainable with species-specific formulae applied to these ultrasonographic parameters.
REFERENCES:
Johnson, AK. Normal Feline Reproduction. The Queen. Journal of Feline Medicine and Surgery (2022) 24, 204-211.
Root, MV. Clinical management of pregnancy in cats. Theriogenology 66 (2006) 145-150.
Beccaglia, M. Determination of gestational time and prediction of perturbation in dogs and cats: an update. Reprod Dom Anim 2016; 51: 12-17.
Davidson, AP. Pregnancy Determination in Dogs and Cats. Merck Veterinary Manual.
