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Updated: Aug 8, 2026

Rodent Estrous Cycle Monitoring Utilizing Vaginal Lavage: No Such Thing As a Normal Cycle
Published on: August 30, 2021
Variation in estrus-related odors in the cow and its dependency on the ovary
M Dehnhard1, R Claus, S Pfeiffer
1Universität Hohenheim, Institut für Tierhaltung und Tierzüchtung, POB 700562 D-7000 Stuttgart 70, Germany.
Abstract:
Urine samples were collected from 10 cows during the estrous cycle (Day 0=day of observed estrus) and investigated for pheromone activity using a quantitative rat bioassay. Pheromone activity in this assay was given in impulses/45 sec. Progesterone was measured in milk fat to verify the stage of cycle. The maximal response of rats was found on Day -1 (20.0 +/- 3.5 impulses/45 sec; x +/- SEM), and impulse rates were clearly higher (P
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