Conception: It’s all about timing!

As we move through calving, our attention (hopefully) starts to focus on mating. While for most of us it is still 6 weeks away, our success depends largely on the combination of two factors – submission rates along with conception rates. Sadly, we are often most preoccupied with submission rates and accept that, if we have achieved the accepted gold standard of 90% submission rates in the first 3 weeks of mating, we have done a superb job, and all will be well! But will all be well, and have we done our best? First-service conception rates are notoriously disappointing and may range between 45% and 55%, with some doing better and some doing worse. The brutal truth is that the average cow only has approximately 35 days to get in calf if she is to calve at the same time each year, and, given first-service conception rates are on average sub 50%, most good cows get later and later each year before falling off the end as empties.

Non-cycling cow (NCC) treatments go some way to addressing this issue, but they really only address the one part of the problem which is submission. NCC programmes are great at submitting cows to first service but, as I have already stated, the conception rate

is poor. The second oestrus of a cow is by far more fertile than the first, so servicing cows on their second heat rather than their first should improve conception rates. A DairyNZ statistic suggests that the chance of conception increases by 18% for every cycle a cow has before the planned start of mating. So theoretically, anything we can do to ensure cows have cycled before the planned start of mating (so that their first service is to their second or subsequent ovulation) should enhance conception rates. It may mean treating non-cycling cows 3 weeks earlier, so that they are returning to oestrus with a second heat during the first week of the planned start of mating. Sounds crazy, or a new way of thinking? One thing is for certain – if we do what we have always done, we will continue to get the same result. Only if we dare to change our approach and look at different avenues can we achieve a different result. At Vetlife, we are continually striving to improve our offerings to provide optimal reproduction outcomes for you, the farmer. Talk to your Vetlife veterinarian today.

Ivan Holloway Vetlife