Aggressive attempted escape behavior during head-lock restraint reduced reproductive performances in Holstein heifers

Abstract The objective was to determine associations between behavior during head-lock restraint and reproductive performance in dairy heifers. Behavior of 817 Holstein heifers from four farms was evaluated at feeding (Days 0 and 7) while restrained in a self-locking stanchion. All heifers were assigned a body condition score (BCS; 1, emaciated to 5, obese) on Day 0. Heifers were timed-inseminated on a maximum of three occasions to determine impact of behavior for first service pregnancy per AI (FS-P/AI) and cumulative P/AI (C-P/AI). Ovulation was synchronized with an Ovsynch synchronization protocol for first service and thereafter either Ovsynch and/or prostaglandin F 2α -based protocols. More heifers displayed calm escape behavior (P  P P P P P