We all know big birth weights can be disastrous in a first-calf heifer program because of increased labor and death loss. However, there is a hidden cost associated with big birth weights that few ranchers have considered.
Birth weight is highly correlated to a calf’s gestation period. Studies have shown big calves have longer gestation periods. We’ve personally seen instances where big 90-pound calves have gestation periods that are 20 days longer than 70-pound calves. I have heard of gestation periods in other herds that are as much as 10 days longer yet.
The hidden cost associated with a longer gestation period is in the cow’s inability to get bred back on time. It’s nearly impossible for a cow with an extra-long gestation period to have a calf every 12 months because there simply aren’t enough days in the year.
Based on the standard 283-day gestation period for beef animals, our start date at PCC Headquarters this year was May 16th. Because of the calving ease (short gestation) that has been bred into our cattle, we were half done with our calving on that date. That’s amazing! We have always preferred calves that do most of their growing on the outside of the cow.