Shortening calving is therefore a financially rewarding ambition for beef herds. There are several ways to approach this ambition.
Management Targets
Ideally females should be calved in a Fat Score of 2.5 – 3.5. This means carefully managing pre calving nutrition. It also means that heifers or cows that are lighter in condition will take longer to recover before returning to oestrus.
For producers with lighter females, this could be addressed by increasing energy in the daily ration for lactating cows. It’s important to remember that once calving occurs, females’ energy intake doubles. This extra energy is often provided by metabolising fatness. So, producers with light cows should supplement to make the ration meet the increased demands for the females.
Selection Targets
While fertility is strongly influenced by environmental impacts – particularly nutrition, it is possible to select for those animals which are genetically suited to be more fertile and likely to conceive earlier.
This can be done through using selection tools such as the Days to Calving EBV and the Gestation Length EBV.
The Days to Calving EBVs are estimates of genetic differences between animals in the time from the start of the joining period (i.e., when the female is introduced to a bull) until subsequent calving. Lower, or more negative, Days to Calving EBVs are generally more favourable.
