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10 Jun 2020

VikingJersey - International Daughter Fertility Trendsetter

The breeding program for VikingJersey proves that it is possible to breed for high production and at the same time, have high genetic progress in reproduction traits.

Interbull study verifies the leading position of VikingJersey

The Interbull organization enables us to evaluate the genetic levels of daughter fertility in leading Jersey populations. Results are based on data from 13,000 daughter proven Jersey bulls born between 1981 and 2015. The genetic trends reflect the level of daughter proven bulls per birth year and population (country).

The results below are based on information from new daughter proven bulls, with daughter fertility data. The number of new bulls added per year, over the last years is: USA app. 200 bulls, New Zealand app. 150 bulls, Viking countries (DFS) app. 55 bulls, Australia app. 15 bulls and Canada app. 10 bulls.

Female fertility

In Figure 1 below, you can follow the genetic trend for what is considered the most important daughter fertility trait – the interval from first to last insemination for cows. This trait is of great economic value, as it is most important to get the animal pregnant as quickly as possible, when you have made the decision to start insemination.

The results clearly show the importance of including daughter fertility in a Net Merit index with a weight compensating for more than the negative effects of high progress in milk yield.

For VikingJersey, the relative weight on daughter fertility has increased over the last 25 years, enabling the breed to go from a stable situation to actually improving the daughter fertility in the population. None of the other populations have been able to change the negative trends.

When looking at heifer conception rate, the trend for North American bulls is stable, but when it comes to cow conception rate, it seems that only VikingJersey has a positive trend that clearly stands out.

When looking at April US proofs, the difference between populations is very clear. For CCR, the 10 best bulls are VikingJersey, for DPR, 8 out of 10 best bulls are VikingJersey and for HCR, 6 out of 10 best bulls are VikingJersey. Daughter proven VJ Gislev (JPI 136) is one of the bulls ranking high in all daughter fertility categories.

VJ Gislev - one of the best daughter fertility bulls worldwide

Production does not harm the impressive genetic daughter fertility trend

Below, the genetic trend is shown for production of kilos of butterfat and protein. In both cases, the genetic trend is nearly linear and very positive. So, if the production of solids increases, it doesn’t have a negative impact on the fertility. Note that the number of bulls is nearly the same as included in the fertility trend and that the numbers for Australia and Canada are very small.

High production and good female fertility at the same time

Daughter fertility has traditionally been among the most important traits in NTM, even the genetic level in the VikingJersey breed is high. The main reason for this is the fact that there is a strong negative genetic correlation between milk yield and daughter fertility traits (-20% for Jersey) and milk yield is the highest prioritized trait in the NTM index (35% of total weight).

As Table 2 shows, when these traits are combined in NTM it is possible to get genetic progress in these traits at the same time. The response when selecting for NTM is highest in longevity with 0.62, second is udder health with 0.56 and then production with 0.55 (55% of max. response). The response for daughter fertility is 0.32.

Table 2 Response in genetic progress in specific traits when selecting for NTM (source NAV)


Response in NTM



Udder health




Calving maternal


Youngstock survival


Daughter fertility


Genetic development is a long-term investment. Consistent focus on female fertility from generation to generation will steadily strengthen the fertility performance of your cows. Fertility performance is crucial for profitability of your dairy herd, decisions made today will have an impact on your bottom line in the years to come.

By choosing VikingJersey to improve your herd´s reproduction performance, your breeding strategy gets a highly reliable base. Daughter fertility index has been a part of the Nordic Total Merit Index (NTM) since the 1980s – that is 40 years of systematic data collection for daughter fertility. Today 95% of Jersey cows in Denmark contribute with registrations for daughter fertility.

Learn more about daughter fertility Daughter fertility