Four consecutive experiments were conducted to design and establish the effectiveness of different protocols for induction and synchronization of oestrus and
ovulation in
mice. Results showed that the highest synchronization degree and the highest
fertility rates were obtained using two
intraperitoneal doses of 0.5 mug of cloprostenol, three days apart, plus a single
subcutaneous dose of 3 mug of
progesterone coincidentally with the first injection of cloprostenol. Of the main advantages of the new method, we have to highlight the short time elapsed for appearance, and the high degree of synchronization of oestrus and
ovulations (almost 100% of the animals responding to the treatment in 48 h; 78.4% with
fertile mates at 24 h), plus the high
fertility rate obtained after a programmed mating (100%). Overall, these yields are superior to those obtained by classical methods based on the use of male
pheromones; hence the proposed protocol arises as an adequate alternative for reproductive management in
mice.
