NRF heifer Credit: Randi Therese Garmo

For 35 years, fertility, health and utilisation potential have been an integral part of the breeding programme of Norwegian red cows (NRF). A PhD research project at The Norwegian School of Veterinary Science has demonstrated the connection between selection, energy intake and ovarian activity in Norwegian red cows and has come to the conclusion that NRF cows have a good fertility rate and are well adapted to the requirements of milk production in both ecological and conventional dairy farming.

Randi Therese Garmo has researched the fertility of NRF cows in both conventional and ecological herds in different parts of Norway. The primary objective of "good fertility" is that a cow calves once a year. To reach this goal, the cow must become pregnant again three months after calving. Garmo discovered a high pregnancy rate in NRF after the first insemination, both in cows (61%) and heifers (70%).

In order to produce a calf once a year, a cow must start to ovulate soon after calving, to increase the chances of again becoming pregnant by insemination. Garmo found that cows bred solely with a view to high milk production start ovulating later than cows that have been bred for fertility in addition to milk production. The study also shows that unknown factors other than energy balance alone influence and result in lower fertility in cows bred solely for high milk production.

Cow: Ovarium with Corpus luteum Credit: Henry Moore, Pathways to pregnancy and parturitition, 2005

Even though ovulation recommences after calving, several factors may prevent the cow from becoming pregnant again. After ovulation, a yellow body (Corpus luteum) is formed where the egg once was and this sometimes remains for a long time, with the result that the length of time between two heats is longer than normal. In NRF cows, the occurrence of prolonged yellow bodies was found to be low, while cows that have this problem have a higher risk of being inseminated while on a "false" heat and therefore do not become pregnant. Prolonged yellow bodies occur more often in cows that start ovulating again soon after calving, thus showing that breeding solely to achieve early ovulation can have unfavourable effects on the way ovulation functions.

Garmo's comparison of fertility in conventional and ecological farming showed that fertility was good in both cases and that there was no difference between the cows in the two types of dairy farming. This contradicted studies from 10 years ago, which came to the conclusion that cows in ecological farming suffered from a lack of energy, which in turn led to reduced fertility rates. In recent years, cows on ecological farms have been fed with more concentrates and this is probably why there is no longer any difference in the fertility rates of ecologically and conventionally reared cows.

Cand.med.vet. Randi Therese Garmo presented her doctoral thesis on 14th January 2010 at The Norwegian School of Veterinary Science (NVH). The thesis is entitled: "The Significance of Sustainable Breeding and Management Programs on Reproductive Performance in Norwegian Red Cows”.

Biographical data
Randi Therese Garmo grew up in Lom in Norway and completed her education at The Norwegian School of Veterinary Science in December 2003. She carried out her doctoral research at ProdMed, NVH, and is currently at NVH's ambulatory clinic.

Contact information:
Randi Therese Garmo
Tel.: +47 22 59 74 91
Mobile: +47 992 94 512
Email: randi.garmo@nvh.no

Magnild Jenssen, Information Consultant, NVH
Tel.: +47 77 66 54 01
Mobile: +47 957 94 830
Email: magnhild.jenssen@nvh.no