ABOUT DUTCH PROOF

ABOUT DUTCH PROOFS
NVI - Dutch Flemish Index;
NVI is the total performance index that is used in the Netherlands to rank the bulls according to
their genetic economic merit. NVI is the sum of Production, Durability and Health Traits.
Farmers around the world are looking for long lasting, high production cows. NVI is one of the
best tools to help with that quest.

Using NVI in a breeding programme will lead to:
• Improvement of production and durability;
• Lower culling rates, which means fewer replacements and thus a higher income;
• More fertile and healthier cows, which will have a positive effect on income and
consumer acceptance.

The current importance of the traits in NVI is;
INET (Milk, Kg Fat, Kg Protein) 33%, Longevity 20%, Somatic Cell Count 6%, Fertility 19%, Udder 11%,
Feet & Legs 11%.

Understanding Dutch Type proofs;
Understanding Dutch type proofs is not as difficult as you might think. The values and ranges of
the Dutch proofs maybe look different from what you are used to, but if you compare them to
US, Canadian and German proofs they are quite easy to understand. The graph shows the ranges
of the proofs in the four different countries. For example, a bull with a breeding value of 108 on
the Dutch scale is comparable with a US bull at +2.00 PTAT or a Canadian bull at +10
Conformation.

Relativity;
As you can see from the distribution of indexes, 95% of the bulls have breeding values between
92 and 108. This means that bulls with a proof over 108 represent the top 2.5% of the breed.

This principle applies to any of the Dutch type traits, both the linear and the composites, and
also to the Dutch proofs for management and health traits like Durability, Udder Health, and
Fertility.



Figure: Comparison of Type proofs

Longevity
High longevity means less culling, lower rearing costs and above all higher lifetime yields!
The average score for Longevity is 0 and is expressed in days. The standard deviation is 270 days.
• Bulls with a Longevity breeding value > 0 have daughters with high Longevity
• Bulls with a Longevity breeding value < 0 have daughters with below average Longevity

Every point Longevity above 0 increases the average longevity of the bull’s daughters with 0.5
days. So if the bull of your choice has a longevity of 500 days, this means that his daughters will
be on average 250 days longer in production!

Udder Health
Mastitis is one of the most significant health problems on dairy farms.
The positive effect of improving udder health are: less production lost, less undeliverable milk,
lower costs of treatment and labour, and also less involuntary culling.

The average proof for udder health is 100. A higher score means healthier udders and less
mastitis. Daughters from a bull with a breeding value of 104 for udder health, have 3 % less cases
of mastitis.

Somatic Cell Score is also an important indicator for udder health. In our evaluation-system it
means that if a bull has a somatic cell score proof of 104, his daughters will have 10.000 cells in
their milk less.

Fertility
Improving the herd fertility will result in higher milk revenue’s, lower insemination costs and
lower labour – and veterinary costs.

The average of the proofs for daughter fertility is 100. Using bulls with proofs of 100 or higher
means that their daughters will have a better than average fertility with shorter calving intervals
and higher pregnancy rates.

More specifically, if a bull has daughter fertility proof of 104, it means his daughters have a Non
Return rate that is 2.6 % higher, their interval calving 1st insemination is on average 3.8 days
shorter and their calving interval is 6.6 days shorter.