Recording Days to Calving


Days to calving and its associate trait, gestation length, are important management traits which have been undervalued to date, mostly because of the complexity of recording natural service matings and transferring this information into a consistently usable format for submission.  Consequently, these two measures have tended to be very low accuracy.  In recognition of the importance of gestation length and days to calving as selection criteria, especially in both the dairy and commercial suckler herds, we have attempted to simplify the recording process in an effort to increase the number of breeders recording this information.  Additionally, the registration screen now gives the option to add a natural service date.



Reproductive performance is a key determinate of profitability in a beef cattle enterprise. Consequently, selection for improved reproductive performance should be an important consideration for all beef cattle producers. One major component influencing a beef enterprise’s reproductive performance is the fertility of the female herd. The job of a female in a beef producing herd is to conceive (preferably as early in the joining period as possible), carry a foetus during gestation, deliver a live calf and raise it until weaning, within every 12 month period of her breeding life. A female that does not do this is failing to do her job and eroding herd profitability. While many producers manage the reproductive performance of their female herd using different management strategies, in particular the culling of females that fail to get in calf, research has shown that female fertility is influenced by the genetics of the breeding herd. Consequently, Days to Calving EBVs provide a useful tool that breeders can use to improve the genetics of their females for fertility, in association with their routine management and culling strategies.


Recording Days to Calving Data

A spreadsheet has been prepared which can be downloaded from here. Your herd list can be populated by the Breedplan office, so please ask.  Disposals during the bulling period should be recorded as such, to include deaths, culls, sales, withdrawals from bulling group for any reason.  The second page should be used to record bulling groups, and has options for different sires having been introduced and their bulling periods.  The bulling group number is then recorded against each female on the first sheet, in column I.  At the end of the bulling period, please submit your completed worksheet to the Breedplan office for submission.


Figure 1. Days to Calving Spreadsheet – Data input