A dairy farm begins with a calf, and 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 the 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 it used to be. What´s more, many dairy farmers now know that it is expensive to raise heifer calves both for their own use and to sell.
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 were created, breeding values for fertility were being calculated in the Nordic countries.
In the 1980s and 90s, the target was very much about increasing milk production, which meant imported 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.