With the introduction of genomics, the rate of genetic gain in dairy herds globally accelerated. New Zealand dairy farmers stand to gain more value than ever before from using overseas genetics in their herds.
Accurately predicting the performance of overseas sires has been a core focus for the genetics team here at Samen NZ. Being able to predict how animals perform in New Zealand herds, required that we developed a rigorous evaluation system now represented by the gNZI©.
When a sire is introduced into New Zealand, with no relationship to the existing bloodlines and without genomics and a sound broad reference population, the current system cannot identify sires that may have been exhibiting all the correct traits and indicators for New Zealand pasture-based dairy farms. Some sires could show up with very low or in some cases, negative BW's.
Once an overseas sire gets milking daughters on the ground here in New Zealand and becomes a proven sire, the BW becomes a fairer representation of his true genetic value. Often by this point in time the bull is no longer available, and the next generation of sires are already being marketed.
Our team has used regression equations to select a suitable group of sires for approximately seven years. By doing so, we have developed a formula to convert and predict how sires from Samen NZ's thirteen global suppliers, would convert on the New Zealand genetic evaluation system. Predicting the future Breeding Worth of those sires much more accurately with much higher reliability.
This formula has enabled us to narrow down the selection process from approximately six thousand sires to a much smaller selection of around three hundred sires. From this selection, our team then identifies sires that best fit New Zealand farmers. Focusing on those traits Kiwi farmers found most important in a recent survey, these include traits such as medium stature, high fertility, great udders, and high component production.
Utilising this formula in 2020 to select the genomic sires for the 2021 Samen NZ Breeding Guide, is now more relevant since the genomic sires from that catalogue have New Zealand daughter proofs. It is important to note that the formula used in 2020 went on to be the foundation of what is now the gNZI©. The methods used to calculate the gNZI© were published in the peer-reviewed scientific journal, the Journal of Animal Production Science in 2023.
For example, sire proofs as of 15/11/2024:
Denovo 15969 Atlantis-ET in the 2021 breeding guide had a Breeding Worth of -1/12% rel. As of 15/11/2024 has a Breeding Worth of 633/72%.
ABS Jeronimo Pp-ET in the 2021 breeding guide had a Breeding Worth of -107/26% rel. As of 15/11/2024 has a Breeding Worth of 413/87%.
FB 7683 Virtue Conforto-ET in the 2021 breeding guide had a Breeding Worth of -32/13% rel. As of 15/11/2024 has a Breeding Worth of 426/73%.
DENOVO 7921 Atrium-ET in the 2021 breeding guide had a Breeding Worth of 1/-22% rel. As of 15/11/2024 has a Breeding Worth of 410/94% rel.
The list of sires goes on and as these bloodlines are getting representation in the New Zealand genetic evaluation system, we are starting to see new sires coming to the market with stronger Breeding Worth due to linkage to these proven sires.
Finally, the New Zealand dairy industry has a reliable index to predict the breeding value of overseas Holstein genetics in their pasture-based farming operations. It has proven to deliver the most reliable predictions of a bull’s future Breeding Worth and simultaneously factors in medium stature, udder improvements, fertility, and component production. gNZI is unrivalled by other overseas or domestic companies in delivering a reliable prediction of a bull’s overall suitability for New Zealand.
Make gNZI your new selection tool, it is as easy as using the latest bulls in Samen’s fast forward packs.
A study outlining how gNZI is calculated has been published in a peer-reviewed scientific journal, the Journal of Animal Production Science.
