Approximately five to eight percent of domestic rams demonstrate a sexual attraction
towards other rams, directing no sexual behaviors towards estrous ewes. It has been
observed that these male-oriented rams (MORs) have a greater abundance of prolactin
mRNA than female-oriented rams in the medial preoptic area of the anterior
Sheep are seasonally polyestrus, which means they do exhibit estrus and ovulation during the short daylight (breeding season) and do not during the long daylight (nonbreeding season). To stimulate the ewes to ovulate during the nonbreeding season, various hormonal treatments have been used. PG-600 contains both equine chorionic gonadotropin and...
These studies examined the role of perinatal androgen
in the development of neuroendocrine and behavioral
characteristics of gray-tailed voles, Microtus
canicaudus. When mature, females exhibited alternating
vaginal smear patterns or persistent vaginal
cornification; estrogen and progesterone concentrations
were not correlated with vaginal smear patterns. Corpora
lutea were not observed in...
A major goal of conservation biology is to elucidate the population genetic
structure in threatened species and assess the relative importance of the
evolutionary forces that shape that population genetic structure. I conducted three
studies in the declining amphibian Rana cascadae to assess levels of population
genetic differentiation and the...
Our objectives were to determine 1) the concentration of prostaglandin
F2α (PGF2α) in whole and extended bovine semen, 2) if concentrations of
prostaglandins in extended bovine semen are correlated to fertility, and 3) if PGF2α
administered at the time of artificial insemination would improve conception rate.
Concentration of PGF2α tended...
Most vertebrates exhibit seasonality in many life history traits. Such seasonal rhythms are temporally organized via the transduction of environmental cues (e.g., photoperiod, temperature) into appropriate endocrine signals. However, among ectothermic vertebrates that undergo continuous winter dormancy, temperature is the only environmental cue available for synchronizing seasonal rhythms. Most intriguing...