Fig 1.
Age at first calving of UK Holstein and Holstein-Friesian heifers.
Distribution of age at first calving (AFC) for pedigree Holstein and Holstein-Friesian milk recorded heifers calving in the UK between 01/01/06 and 31/12/08.
Fig 2.
Age at first calving and first lactation milk yield.
Predicted means (± 95% confidence intervals) obtained from mixed effects multivariable regression modelling for first lactation (305-day) milk yield (kgs) by different age at first calving (AFC) class.
Fig 3.
Age at first calving and first lactation fat and protein yield.
Predicted means (± 95% confidence intervals) obtained from mixed effects multivariable regression modelling for first lactation (305-day) fat and protein yield (kgs) by different age at first calving (AFC) class.
Fig 4.
Age at first calving and recorded lifetime daily yield.
Predicted means (± 95% confidence intervals) obtained from mixed effects multivariable regression modelling for recorded lifetime daily yield (milk kgs) by different age at first calving (AFC) class.
Fig 5.
Age at first calving and first lactation somatic cell count.
Back-transformed predicted means (± 95% confidence intervals) obtained from mixed effects multivariable regression modelling for first lactation (305 day) log somatic cell count (cells/ml) by different age at first calving (AFC) class.
Fig 6.
Age at first calving and calving interval.
Back-transformed predicted means (± 95% confidence intervals) obtained from mixed effects multivariable regression modelling for calving interval (days) by different age at first calving (AFC) class.
Table 1.
Predicted probabilities (with 95% confidence intervals) of calving for a second time by Age at First Calving (AFC) class (months).