Research in Calf Weight Variance

Research conducted by Simon Archer, the Veterinary Innovation Solutions Pillar Head, helps the dairy industry to better understand the variance in calf birth weights and growth rates, and outlines solutions.

The aim of this research was to update reported estimates of birth weight and growth rate for UK Holstein-Friesian female dairy calves and to partition unexplained variance in calf weight up to 20 wk of age. – Research paper.

Raising calves as replacements contributes to the sustainability of the dairy industry but the targets set may be unrealistic, unachievable, and not applicable on all farms. Simon Archer’s research aims to explore the unexplained variability in the weight of calves aged up to 20 weeks.

The research shows the mean birth weight and growth rate estimates were consistent with the previous expectations. Calf growth rate generally varied between farms and the difference between farms was the largest determinate of the unexplained variance in calf weight from 66 days of age.

The variance partition coefficient (VPC) was highest at calf level and decreased with age and from 66 days of age VPC was higher at the farm level.

Simon’s research highlights that farm-specific targets should be used instead of the one size fits all approach. This research can be used to inform strategies to optimise the efficiency of calf rearing systems. Also, that management and environment on farms are important considerations in rearing calves.

The research Simon conducted resulted in a published paper, to read it, click here.