Each progeny tested Norwegian Red sire is evaluated on the basis of 200 daughters. This ensures genetic progress for low heritable traits such as health and fertility.
Fertility has been included in the net merit index for Norwegian Red since 1971, and health traits since 1978. Photo: Elly Geverink
Production
Production in the best herds exceeds 10.000 kg, with the top cows milking more than 16.000 kg. Growth traits are also included in the index, and young sires for progeny testing have a growth rate of approximately 1.4 kg/day. Fully-grown cows have a live weight of 550-600 kg.
Health traits
Health traits have been included in the net merit index since 1978. Currently mastitis and other diseases (in particular ketosis) are included in the breeding programme. Although these are low heritability traits, progeny testing based on a high number of daughters provides a selection index with high accuracy. Progeny testing for mastitis is currently based on approximately 300 daughters.
Figure:
Positive genetic trends for health, fertility and production - simultaneously
Fertility
Fertility has been included in the net merit index since 1971. The selection index for fertility is currently based on non-return rate of heifers and first lactation cows. The genetic trend for fertility is positive, the average 60 days non-return rate in the population is 73,4 per cent. Progeny testing for fertility is currently based on approximately 260 daughters.
Calving ease
Calving ease has been included in the selection programme since 1978. Norwegian Red is characterised by a low frequency of calving difficulties. Less than 2 per cent of the calvings are reported as having major calving difficulties. Stillbirths are also included in the index, and figures show that less than 3 per cent of the calves are stillborn.