| With the use of an automatic milking system dairy cows can be milked more frequently than twice a day. The objective of this study was to examine milking intervals of the fetched dairy cow and to estimate genetic parameters for milking frequency of dairy cows milked within an automatic milking system. The data consisted of 141, 927 daily records from 953 primiparous cows on 14 farms in Ontario and Quebec. A two-trait random regression animal model was used for estimation of (co)variance components for 24h milk yield and 24h milking frequency. Heritabilities for the 24h milking frequency and 24h milk yield ranged between 0.02 and 0.08 and 0.14 and 0.20, respectively. Genetic correlations between 24h milk yield and 24h milking frequency were highest at the end of lactation (0.80) and lowest in mid-lactation (0.27). Producers should select cows with a high milk yield if they are concerned about fetching cows. |
