Dystocia .03-.15 Adapted from Mao, I.L. 1984. National Invitational Workshop on Genetic Improvement of Dairy Cattle. Wisconsin p. 34. Although reproductive traits have low heritability, progress can be made. Because the heritability estimates for reproductive traits are low, environmental influences dominate the genetic influence.
Management plays a key role in determining the animal's performance for a given reproductive trait.
Cows may not be bred quickly in an attempt to increase production records. Many studies have shown this to be the single most costly management error in dairy herds. Recently, the genetic relationship between reproductive performance and milk yield has been examined. Some researchers have reported a decline in days open as milk yield increased. It appears that reproductive efficiency can be maintained at an acceptable level as long as management is excellent.