Age at first calving in UK Jersey cattle and its associations with first lactation 305-day milk yield, lifetime daily milk yield, calving interval and survival to second lactation.

Background: The association between age at fist calving (AFC) and production, fertility and survivability in Jersey heifers requires evaluation and comparison with published literature on Holstein heifers.

Method: Lactation records from 7256 pedigree Jersey heifers were grouped by AFC. Analysis comprised mixed effects multivariable regression modelling and binary logistic regression modelling.