Serum progesterone levels and pregnancy rates in Great Basin porcupines
Sweitzer, R.A.; Holcombe, D.W.
Journal of Mammalogy 74(3): 769-776
ISSN/ISBN: 0022-2372 Accession: 033362182
We used serum concentrations of progesterone to estimate age-specific pregnancy rates of porcupines (Erethizon dorsatum) in the Great Basin Desert of Nevada during 2 years. Pregnancy status based on serum progesterone was verified from abdominal palpations, lactation, and locations with offspring. Progesterone concentrations for pregnant porcupines consistently were gtoreq 4 ng/ml throughout gestation, while progesterone levels of non-pregnant females never exceeded 2.5 ng/ml during the same period. As results suggested that serum progesterone was a reliable indicator of pregnancy, progesterone levels then were used to assess pregnancy rates in two populations. Results were that one of 13 juveniles, 100% of 2 and 3 year olds, and 90% of animals gtoreq 4 years old were pregnant. The breeding season was from September to November, and the average lactation period was 126 +- 4 days.