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Published online by Cambridge University Press: 23 November 2017
Fertility has been shown to have an unfavourable genetic relationship with milk production in Holsteins so continued selection for milk production will exacerbate the decline in fertility in the absence of information on daughter fertility. The only way to reverse this genetic trend is to breed dairy cows additionally for fertility. But dairy farmers have historically had no access to fertility information when they purchase semen. It is therefore vital that fertility is included in selection programmes and that farmers can choose to inseminate their cows with semen from bulls with a positive predicted transmitting ability (PTA) for daughter fertility. Although of low heritability, fertility traits have been shown to have sufficient genetic variation and have recently been made available nationally for the Holstein-Friesian breed (Wall et al., 2003). The aim of this study was to investigate the feasibility of estimating fertility indices for Ayrshire (AYR), Guernsey (GUE) and Jersey (JER) dairy cows.