Comparison of ten Friesian strains in Poland for yield traits from first three parities.

Milk yield, fat yield, and fat percentage for the first three parities were compared for crosses of Friesian strains from Canada, Denmark, Israel, The Netherlands, New Zealand, Sweden, the United Kingdom, the US, and West Germany with Polish black-and-white cattle. Mixed model multitrait BLUP solutions for milk yield ranked Holstein strains (US, Canada, and Israel) and New Zealand Friesians higher than European Friesian strains for all three parities. Largest difference for milk yield between highest ranking US strain and lowest ranking Polish strain was 1002 kg for first lactation. Rankings for fat yield were similar to those for milk yield. For all three parities, the New Zealand strain ranked highest for fat percentage and the US strain lowest. Although rankings were consistent across parities for all yield traits, differences between Holstein and Friesian strains decreased as parity increased. Holstein strains maintained their superiority for milk and fat yields for all three parities despite difficult environmental conditions and a feeding regimen worse than in their country of origin.