Breeding for improved fertility for over 40 years

Breeding for improved fertility for over 40 years

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A dairy farm begins with a calf, and a satisfactory female fertility is therefore an important part of any dairy business.

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This is advertiser content for VikingGenetics.

A dairy farm begins with a calf, and a satisfactory female fertility is therefore an important part of any dairy business. A cow needs a calf periodically to be able to re-start lactation and continue milk production while heifer calves are also needed to replace older cows.

Management strategies related to replacement of culled cows have changed over time.

Today, many dairy farmers use sexed semen to produce replacement heifers from the best cows/heifers and use conventional semen, usually in combination with beef semen for the remaining cows.

From a financial point of view, this is very positive as cow longevity is improving, which means cows have a longer useful life and the need for replacement heifers is lower than before. Besides, many dairy farmers know that it is expensive to raise heifer calves both for their own use and for selling.

In the Nordic countries we have been breeding for improved fertility for more than 40 years, even before the Nordic Cattle Genetic Evaluation (NAV) or VikingGenetics was created.

In the 1980s and 90s, the target was very much about increasing milk production which meant importing semen, mainly from North America.

Due to the negative genetic correlation between milk production and female fertility this led to a decline in fertility, both phenotypic and genetic, which soon became a practical problem on dairy farms.

Breeding strategies were then changed, and more bulls were selected from pedigrees with an increased focus on fertility and at the same time avoiding some international pedigrees with poor fertility-related performance.

The effect of this change was most evident in Holstein where a rapid increase in genetic levels has been observed until today. A similar trend can be observed in Jersey and the red breeds but at a lower level because these in general have better fertility than Holstein.

Figure 1 shows genetic trends for fertility in Holstein, based on the Interbull fertility index. Shown here is the comparison of Nordic (DFS) bulls with bulls from other countries. The effect of the change in breeding strategy for fertility mentioned can be clearly seen from the year 2000. The trend is similar for all countries, but the Nordic Holstein bulls remain at a higher genetic level.

Figure 1: How VikingGenetics bulls (DSF) compare with bulls from other countries.

Figure 1: How VikingGenetics bulls (DSF) compare with bulls from other countries.

Accurate breeding values for fertility as a target

With regards to fertility, it is easy to conclude that VikingGenetics bulls are highly sought after on the world market. The reason for this success is very much the focus on fertility.

For example, for Holstein the weighting given to fertility in the Danish total merit index, the S-index, was 0.18 in 1989, later increased to 0.26. When NTM was introduced in 2008 the weighting for fertility was increased to 0.41. This was subsequently adjusted to 0.36 in 2019.

Accurate breeding values are the key to achieving a big genetic progress in fertility. The Nordic countries have a long tradition of extensive and accurate registration of inseminations.

This included collecting registrations and insemination of each bull planned for an insemination, together with accurate dating and recording of calving, registration of reproductive disorders and elimination of genetic defects etc.

This is advertiser content for VikingGenetics.

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