Calving Ease EBVs provide an estimate of genetic differences in the ability of calves to be born unassisted from two year old heifers. Calving Ease EBVs are calculated from three main sources of information, being calving difficulty scores, birth weights and gestation length records. Calving difficulty scores are by far the most important of these sources.

Why Should Calving Difficulty Scores be Recorded?

Calving difficulty can have a negative impact on the profitability of a herd as it can lead to increased calf, heifer and cow mortality, slower re-breeding performance and/or additional expense (which can be considerable) associated with increased labour and veterinary services.

While a number of studies have shown birth weight to be the most important genetic factor influencing calving difficulty, there are a number of additional genetic factors that also have an influence. These include calf shape, pelvic area and the calving “will” of the dam. Calving difficulty scores capture all of these factors, and therefore give beef breeders the opportunity to make more genetic improvement for ease of calving than is possible if selecting on birth weight alone.

Calving difficulty should be measured at birth using a 1-6 scale as per the table below.

* Note that a blank score will not be interpreted as “unassisted”. Instead, it indicates that calving difficulty was not scored.

What Considerations should be made when Recording Calving Difficulty Scores?

• If you are checking your cows regularly during calving (e.g. on a daily basis), it is reasonable to assume that any cow who calves without assistance between visits is unassisted (no difficulty), even if you did not see her calve.
• Calving difficulty scores should be recorded for all calves, and not just those that had difficult or easy births. Calving difficulty scores should also be recorded for stillborn/dead calves; this information is useful for calculating the Calving Ease EBVs of close relatives (e.g. sire and dam).
• If calving difficulty score is either blank or zero (0), it is interpreted as no score recorded NOT as a score of no calving difficulty (unassisted). All calves that are unassisted should be given a score of 1.
• There needs to be some level of calving difficulty in the herd for the calving difficulty scores to be used effectively by the BREEDPLAN analysis. That is, simply scoring all births in a herd with a calving difficulty score of 1 will not identify any genetic differences in ease of calving.
• As is also the case with birth weight, a birth management group should be recorded alongside the calving difficulty score if there have been different treatments of the females prior to calving that may have affected calving difficulty. For example, where cows have had different levels of feed availability prior to calving.
• When calculating the Calving Ease EBVs, calving difficulty scores of 3 and 4 are grouped together. Calving difficulty scores 5 & 6 are excluded from the BREEDPLAN analysis as these are considered non-genetic in origin.

How do I submit Calving Difficulty Scores?

Calving difficulty scores can either be submitted to your breed society when submitting your calf registration details or directly to your BREEDPLAN processing centre. Please contact staff at your breed society or your BREEDPLAN processing centre should you have any queries about how to submit this information.

For more information regarding how to record calving difficulty scores or Calving Ease EBVs in general, please contact staff at your BREEDPLAN processing centre.