Use of Mount Detectors Plus Chalk as an Estrous Detection Aid for Dairy Cattle

Abstract

Two experiments were conducted to determine effectiveness of mount detectors plus chalk as an estrous detection aid. Of 33 Holstein cows receiving more than one mount during continuous observations, three separate 30-min detection periods by a herdsman detected 20 (60.6%) of these cows in standing estrus. Use of either mount detectors, chalk, or mount detectors plus chalk indicated 31 (93.9%) of these cows in estrus. There were no false positives with estrous detection by the herdsman. Mount detectors and chalk had 28 and 38 false positives, respectively, compared with three false positives with the mount detectors plus chalk. Cows on three Holstein farms were assigned to treatments as 1) control, 2) cows with mount detectors, 3) cows with chalk, or 4) cows with mount detectors plus chalk. Based on 21-d estrous periods, treatments 1 to 4 resulted in 42.5, 56.6, 44.0, and 63.8% of estrous periods detected, respectively. Overall, cows not becoming pregnant on treatments 1 to 4 were 32.0, 23.0, 20.3, and 12.0%, respectively. Both cows with mount detectors and cows with mount detectors plus chalk had fewer days to second estrus than control cows and cows with chalk. Cows with mount detectors plus chalk had fewer days to conception than controls and cows with mount detectors. Cows with chalk had greatest days to conception. © 1986, American Dairy Science Association. All rights reserved.