1. the period in the estrous cycle of female mammals immediately before estrus, characterized by preparation for ovulation
Usage: veterinary; biology

Examples

• The veterinarian explained that the dog was in proestrus and would likely enter heat within a few days.
• During proestrus, hormone levels begin to change in preparation for the breeding cycle.
• The mare showed signs of proestrus behavior, becoming more restless than usual.
• Researchers monitored the cattle during proestrus to study reproductive patterns.
• The proestrus phase typically lasts several days before true estrus begins.
• Blood tests confirmed the cow was in proestrus based on her hormone levels.