This article first appeared in our sister publication, Dairy Farmer.
Indexes are designed to rank cows and sires on their ability to breed profitable replacements. New Zealand has the BW (Breeding Worth), Australia has the BPI (Balanced Performance Index), Nordic countries have the NTM (Nordic Total Merit) and the United States uses the NM$ (Net Merit).
Indexes are created with the national herds’ environment, dairy system and herd goals in mind. In NZ a sire’s BW is based solely on ancestral information available in New Zealand Animal Evaluation Limited (NZAEL).
For many years international sires have struggled to get reliable representation on the NZ BW index due to the lack of ancestral information in NZ. This is beginning to shift as more farmers take to the benefits of these international sires and more data is introduced into the system.
Accurately predicting the performance of international sires on NZ pasture-based dairy systems is becoming easier with the introduction of Samen NZ’s gNZI (genomic NZ Index), Samen NZ’s Sire analyst Craig Mckimmie says.
“The gNZI is highly correlated to the BW with a few additions based on economic values and farmer-needs surveys,” Mckimmie says.
Samen NZ has been using a formula to compare and select international sires that will perform in the country for many years.
“Now we have international sires originally selected and marketed in 2019 on the New Zealand RAS list with a highly correlated and reliable gNZI figure to match.”
One of these exciting sires is ABS Jeronimo-P-ET, currently featured at No 15 on the Ranking of Active Sires (RAS) list and the highest ranking polled Friesian with a BW of 372 Rel 76% and a gNZI of 362 Rel 82%. Jeronimo P is a high achiever all around the world and first took the No 1 position on Australia’s BPI in 2017, continuing on to retain the No 1 position until late 2022.
Another exciting sire from Samen NZ currently featured on the Friesian RAS list is DE-SU 13050 Spectra-ET. With a BW of 323 Rel 75% and a gNZI of 337 Rel 90%, and boasting a moderate frame, extreme calving ease and high semen fertility, Spectre ticks a lot of boxes for NZ pasture-based dairy farms.
With the absence of NZAEL genomics, the gNZI is one of the best tools available to dairy farmers to evaluate overseas sires for use here in NZ pasture-based systems.
“What excites me most is the access we now have to incredibly high genetic merit polled sires. The gNZI has enabled us to work closely with a large range of suppliers to identify sires early on, and breed the bulls New Zealand dairy farmers are asking for.
“Leading from strength to strength, we are proud to be able to offer our clients commercial dairy sires that stand strong on both the world stage and here in New Zealand”.
Other notable up and coming sires from Samen NZ often have much higher gNZI figures and lower BWs but the importance comes from the reliability, as the gNZI index does in fact have a high correlation to the NZ BW.
An outstanding example of this is Bomaz ANZAC-PP-ET. With a gNZI of 525 Rel 68% and a BW of 201 Rel 7%, his gNZI is much higher than that of both Jeronimo P and Spectre, yet he has a lower BW and lower BW Rel%.
As NZ daughters come into profit locally, the system gains access to more data and our learned experiences shows that when this happens we see a rise in the BW and BW Rel% more in line with the gNZI and gNZI Rel%.
Anzac PP is notably the highest gNZI PP sire available and has extremely high components and production. The No 1 gNZI sire available from Samen NZ is Bomaz Perfect Pp-ET with a gNZI of 528 Rel 69% and a BW of 193 Rel 11%. Perfect Pp combines good US fertility data with extreme fat percentage and production figures.
With access to incredible sires like these and an index that fits NZ’s pasture-based systems, farmers can confidently utilise world-leading outcross genetics and build better herds that continue to drive herd longevity and overall profitability.
More: For further information about the gNZI and how Samen NZ’s international line-up of high-genetic-merit sires can benefit your dairy farm in NZ, contact your local Samen NZ representative.