Better fertility without compromise on production
Commenting on the
fertility of the ProCROSS, the study’s lead author, Dr Amy Hazel, said: “For
every parameter we looked at, the crossbreds were overwhelmingly better than
their Holstein herd mates.”
For example, the three-breed
crossbreds had significantly higher (+9% to +10%) first service conception
rates. They also had lower ages at first, second and third calving;
significantly fewer (-16.5) days open over three lactations; and their
advantage in days open increased to almost three weeks for their third
lactations.
The improved fertility of
the crossbreds has been achieved without any compromise to their milk
production.
When
converted to a lifetime daily yield (LDY) of kg fat + protein, the ProCROSS
cows produced 2,537 kg per day, only 1% lower than the 2,554 kg per day of their
Holstein herd mates.
“Lifetime daily yield of fat plus protein
is an important economic parameter, as it is influenced by a range of traits
including conception rates, return to peak production and survival, all of
which are influenced by the cow’s fertility,” continued Dr Hazel.
Following the three-breed cross on to the
next generation revealed there was no difference in weight of fat plus
protein between the third (Holstein-sired) cross of ProCROSS cattle and the
pure Holstein. All of the crossbred generations also produced milk with higher
percentages of fat and protein than their Holstein herd mates.