NRF x Holstein crosses have also been included in several trials.
Testing of NRF abroad is carried out mainly by foreign universities and research institutes, and many results have already been published in recognized international journals.
Tested under the same conditions
The background concerns prompting the trials abroad include the goals of improved fertility and health. Pregnancy rates, for example, have significantly declined during the last thirty to forty years in countries such as Ireland, the UK, and the US where Holstein is the predominant breed.
This poorer reproductive performance worries many dairy producers. Researchers in Ireland developed an early interest in trialing the NRF cow because Norway’s breeding program has a long tradition of including improved health and fertility as selection criteria, in contrast to programs in other countries. This interest has motivated independent researchers to compare NRF with other breeds, under identical conditions. Such scientific trials are essential in order to discover whether there are clear differences between the various breeds, as well as the extent of any such differences. This is important in order to be able to judge whether the development of the NRF breed is headed in the right direction.
Many trials and many animals
The first NRF calves were exported to Moorepark Research Centre in Ireland in 1999. These 30 animals were compared through several lactations with Holstein, Montbeliarde, Normande and Holstein crosses.
Another field trial was initiated in 2004 with 300 heifer calves from Norway, distributed across 45 Irish herds. This trial involves a comparison between pure NRF, pure Holstein and Holstein x NRF crosses, all in the same age group.
In 2000, 53 pregnant NRF heifers were exported to the Hillsborough Research Centre in Northern Ireland. These were compared with an equal number of pure Holstein animals. Around the same time, 230 heifer calves were also exported for a field trial which included 19 farms in Northern Ireland. In this case, 11–12 NRF animals were compared with an equal number of pure Holstein animals in the same age group.
A comprehensive crossbreeding trial with NRF/SRB has also taken place in California. Similar trials are also ongoing in other countries, but it is as yet too soon to present data from several lactations.
Clear results for fertility
Enough time has passed since the start of the first trials to have allowed for the collection of solid data on fertility and a range of other traits, through several lactations. The results from Ireland, Northern Ireland, and California clearly show that NRF and NRF x Holstein crosses have significantly better fertility than pure Holstein. This same conclusion can be drawn from studies both at research institutes and on dairy farms, regardless of how fertility is measured. As an example, the pregnancy rates after first insemination from the field trials in Northern Ireland are presented in Figure 1. Here we see clear and significant differences between NRF and Holstein in the various lactations.
Dependent on concentrated calving
Much of the milk in Ireland is produced from pasture-based systems. The producers are therefore extremely dependent on concentrated calving in February/March. This means that the cows have to come in heat at the right time after calving, and that they have to go back into calf in the course of a relatively short breeding season.
Therefore, Irish researchers use pregnancy within the course of a defined breeding season as one measurement of fertility. In a five-year study, they discovered that NRF cows had significantly greater chances of becoming pregnant during the breeding season than did Holstein cows. In addition, NRF performed better than the other breeds that were included in the trial.
Field trials in Northern Ireland also show significant differences between Holstein and NRF when it comes to the percentage of cows culled because of poor fertility. These figures were 28.5% and 11.8% respectively for the completed trial, which included animals through zero to five lactations.
What about herd life?
Fertility and disease are decisive factors for how long a cow can remain in a herd. Survival rate or herd life has been studied at Ireland’s Moorepark Research Centre, as well as in field trials in both Northern Ireland and Ireland. All of these studies show that NRF cows survive significantly longer than Holstein cows. For example, the median survival time for NRF was 1559 days after the first calving, compared to 1133 days for Holstein x Friesian cows on the farms in Northern Ireland. Corresponding results from the field trial in Ireland are presented in Figure 2.
NRF also performed better at Moorepark than the French breeds Montbeliarde and Normande.
Data from six large herds in California further show that crosses (Holstein x NRF/SRB) have much better survival rates than pure Holstein. The results on fertility and herd life make for pleasurable reading for anyone who has a soft spot for the NRF cow.
The trials abroad also produced positive results in the areas of production and health.
More profits with Norwegian Red crossbreds