Male (n = 6/group) and female (n = 6/group) kittens were gonadectomized at 7 weeks (prepuberally) or 7 months of age (postpuberally), or left intact. Lateral radiographic projections of the right forelimb were made from 4 months of age until the distal radial physis was closed, or 24 months of age. In males, distal radial physeal closure was delayed in both groups of gonadectomized animals, compared to intact males (p < 0.01). In females, proximal radial physeal closure was significantly delayed in prepuberally gonadectomized animals (p = 0.02), and distal radial physeal closure was significantly delayed in both groups of gonadectomized animals, compared to intact animals (p < 0.01). Final radial length (females p < 0.01, males p = 0.01), and age and radial length at time of the growth plateau (p < 0.01) were significantly increased in all gonadectomized animals. Age at gonadectomy had no effect on age and radial length at time of the growth plateau. No puberal growth spurt was observed in any of the cats.
Concentrations of estradiol, progesterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prolactin in serum from 6 bitches bled daily for at least 45 days before the onset of proestrus, during proestrus and estrus were determined by radioimmunoassay. Mean concentrations of estradiol in serum were high early in the sampling period (20 to 46 pg/ml) and appeared to decrease prior to the onset of proestrus (8 to 19 pg/ml). There were sporadic increases in serum concentrations of LH throughout the sampling period in each bitch. Five of the 6 bitches sampled had increased serum concentrations of LH following the low mean concentration of estradiol just before the onset of proestrus. Mean concentrations of FSH were highest during anestrus (240 to 294 ng/ml) and near the time of the preovulatory surge of LH (297 ng/ml) and were lowest during proestrus (131 to 200 ng/ml). The mean concentration of progesterone for the 6 bitches remained at less than 1.0 ng/ml throughout late anestrus, but increased to greater than 1.0 ng/ml the day of the maximum mean concentration of LH (preovulatory LH surge). Mean concentrations of prolactin were variable throughout the sampling period and demonstrated no consistent pattern among bitches. The results of the current investigation suggest that neither the canine ovary nor pituitary are quiescent during anestrus. The bitch appears to have sufficient FSH present during anestrus for follicular growth. Serum concentrations of LH appear to increase prior to the onset of proestrus when concentrations of estradiol are lowest, possibly inducing a new follicular phase. Progesterone and prolactin do not appear to be involved in the termination of anestrus in the bitch.
The Golden Retriever Lifetime Study (GRLS) is the first prospective longitudinal study attempted in veterinary medicine to identify the major dietary, genetic and environmental risk factors for cancer and other important diseases in dogs. The GRLS is an observational study that will follow a cohort of 3000 purebred Golden Retrievers throughout their lives via annual online questionnaires from the dog owner and annual physical examinations and collection of biological samples by the primary care veterinarian. The field of comparative medicine investigating naturally occurring disorders in pets is specifically relevant to the many diseases that have a genetic basis for disease in both animals and humans, including cancer, blindness, metabolic and behavioural disorders and some neurodegenerative disorders. The opportunity for the GRLS to provide high-quality data for translational comparative medical initiatives in several disease categories is great. In particular, the opportunity to develop a lifetime dataset of lifestyle and activity, environmental exposure and diet history combined with simultaneous annual biological sample sets and detailed health outcomes will provide disease incidence data for this cohort of geographically dispersed dogs and associations with a wide variety of potential risk factors. The GRLS will provide a lifetime historical context, repeated biological sample sets and outcomes necessary to interrogate complex associations between genes and environmental influences and cancer.
Reproductive performance in a feline research colony of 14 queens is reported. Average estrous length in 38 cycles was 5.8 +/- 3.3 days, with a range of two to 19 days. Estrous length in 23 bred cycles was not shorter (p greater than 0.05) than in 15 nonbred cycles, suggesting that induction of ovulation does not decrease estrous length. Pregnancy rate in 23 bred cycles was 73.9%. Gestation length averaged 66.9 +/- 2.9 days with a range of 62 to 71 days (n = 15). Average parturition length was 16.1 +/- 14.3 hours (n = 7), with a range of four to 42 hours. Litter size ranged from one to five kittens, with an average of 3.7 kittens per litter (n = 15). Percent mortality by eight weeks of age was 29.1%, with 4.7% stillbirths.
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