EFFECT OF THE ESTRUS CYCLE ON COXOFEMORAL JOINT LAXITY

A few investigations in the 1960's were performed to document the effe ct of exogenous oestrogens on development of hip dysplasia. These proj ects concluded that oestrogen administration caused a significant incr ease in hip dysplasia. Additionally, the Orthopaedic Foundation for An imals (OFA) has recommended that bitches should not have hip evaluatio n for certification during oestrus, due to the possibility of increase d coxofemoral joint laxity. The purpose of this project was to determi ne if physiological fluctuations of oestrogen and progesterone through out the oestrus cycle significantly affected coxofemoral joint laxity. Nine bitches were evaluated through a single oestrus cycle. Although significant fluctuations of oestrogen and progesterone occurred throug hout the phases of the oestrus cycle, neither statistically nor clinic ally significant changes in coxofemoral joint laxity were documented.