A calving interval of 12-13 months has long been considered the most economically advantageous for dairy cows. However, for some cows, extending the calving intervals can be beneficial. This is shown in a new thesis from SLU.
Extending the calving interval means a longer period between the demanding transitional phases of gestation, calving and starting a new lactation (milking period), which is significant for both individual cows and farmers.
In her doctoral research at the Swedish University of Agricultural Sciences, SLU, Anna Edvardsson Rasmussen investigated the possibility of implementing more flexible calving intervals by studying how milk production, animal health, and fertility are affected when the time until the next calving is extended. In the studies, the calving interval was extended to 16 months, and the cows were monitored during two lactation periods.
Anna Edvardsson Rasmussen’s conclusion is that extended calving intervals can be an alternative strategy for high-producing herds, as it better utilizes the fertility and high milk production potential of modern dairy cows.
Cows with extended calving intervals maintained the same amount of milk per day during the first lactation and increased the amount of milk per day during the second, compared to cows with traditional calving intervals. They also had lower milk production at the start, which is positive for udder health and animal welfare. Furthermore, the fertility of the cows improved; more cows became pregnant after the first insemination post-calving, and fewer inseminations were needed for the cows to become pregnant. The overall health status was good, and neither disease frequency nor culling rate was affected.
Read the full press release HERE