Reproduction, Events and Management | Control of Estrous Cycles: Synchronization of Ovulation and Insemination

Abstract

Current nutritional and production management systems for dairy cattle have substantially increased milk production. However, reproductive efficiency has declined for the dairy industry. Systems of reproductive management offer means to improve herd reproductive performance, and major advances have been made in synchronization of ovulation in both lactating dairy cows and heifers. Advancements in reproductive management strategies for timed insemination encompass the following: use of a Presynch–Ovsynch program with Ovsynch started 10–12 days after completion of Presynch; optimized timing of gonadotropin-releasing hormone injection (+56 h), and timed artificial insemination (+72 h), after prostaglandin injection (0 h) in an Ovsynch protocol; alternative resynchronization strategies based on stages that cows are diagnosed nonpregnant (i.e., pregnancy-associated glycoproteins in blood, ultrasound diagnosis, or palpation per rectum); and short-term use of a progesterone insert during 5 days as applied to an 8-day Co-synch program in dairy heifers. These various programs require the producer, veterinarian, and reproductive management staff to understand the underlying principles and impacts of hormonal manipulations of the ovarian cycle and require a high level of protocol compliance. Functional and efficient computer record programs are essential to implement such reproductive management programs. Reproductive management systems provide the infrastructure to quantify the effects of nutritional, health, and physiological interventions on pregnancy rate.