Genetic parameters for handling and milking temperament in Danish first-parity Holstein cows

The human-animal relationship in dairy cattle is reflected in the trait "temperament" in breeding programs and is mainly based on observations by farmers. However, farmers' knowledge of an individual cow's temperament decreases with an increased herd size, and this has been the case in many countries during the last decades. The aim of this study was to investigate if temperament recorded by classifiers and automatic milking systems is heritable, and estimate the genetic relationship with farmer-assessed temperament. Farmer-assessed temperament is defined as the overall assessment of the individual cows' temperament at milking and handling. Data on handling temperament were recorded by Danish classifiers from October 2016 to April 2017 on a 1 to 9 scale specially designed for this purpose. Data from automatic milking systems were recorded from January 2010 until April 2017, where connection time and number of attachments per teat were classified as milking temperament traits. Estimated heritabilities were relatively low for handling temperament (0.13) and farmer-assessed temperament (0.10). For milking temperament traits, connection time showed higher heritability than number of attachments per teat (0.36 and 0.26, respectively). The genetic correlation between farmer-assessed temperament and handling temperament was highly favorable (0.84). The genetic correlations between handling temperament and the 2 milking temperament traits, connection time and number of attachments per teat, were low (-0.02 and -0.10, respectively). Moderate genetic correlations were estimated between farmer-assessed temperament and connection time (-0.29) and between farmer-assessed temperament and number of attachments per teat (-0.37). The genetic correlations and heritabilities suggest a basis for further investigations of the possibility of including handling or milking temperament traits (or both) in the breeding program for temperament in dairy cattle.