Effects of Compensatory Gain on Success of a 7-day Co-Sync+CIDR Artificial Insemination Protocol in Beef Heifers

Angus heifers born in the spring of 2014 (n=38) were used to evaluate the effects of compensatory gain on the pregnancy status using a 7-day Co-Sync+CIDR® estrous synchronization protocol followed by a fixed-timed artificial insemination (FTAI) procedure. The heifers that were kept at the Management Instruction and Research Center (MIR group) were managed to a limited level of nutrient availability and experienced limited growth rate after weaning. Then the MIR group was placed in feeding pens to obtain an accelerated rate of gain to capture the compensatory gain phenomenon. Heifers concurrently managed at a collaborator herd in Fredericksburg (FRED group) were allowed access to oat forage, self-limiting supplementation, and free choice sorghum hay through the entirety of the project to suffice nutrient demands, not limiting growth rate. It was observed that even though differences in growth rate were significant, there was no difference in the pregnancy status from the FTAI.