This 2019 spring was quite challenging so most with poor weather and cows not showing trong heats. This reflected in a below average submission rate and subsequently a lower than average conception rate.
The 6 week in calf rate (WICR) is the best indicator of how mating went for people as it gives everyone a set time period, whereas empty rates vary drastically depending on your mating methods (AI or bull) and mating period (with ranges between 9 weeks to 16 weeks). The 6 WICR is drawn from everyone who aged scanned this season. The overall median 6 WICR was 70%, with the mean being 69%. As discussed, we need to take the empty rate with a pinch of salt as there are huge variations on length and method of mating management.
The median empty rate was 9%, and the average being 11%. The table below shows the median values for the last 4 seasons, overall not a huge variation season on season, but bearing in mind that a variation of 1% is the equivalent of 3-7 cows depending on the size of the herd. With that in mind variations in percentages soon add up.
Finally, below is an interesting table from Dairy NZ and shows the change in conception rate depending on the time period from the date the cow calved to when she conceived. It shows how much relies on giving the cow that time needed to clear any post-calving endometritis and allow the uterus to remodel itself and prepare and be ready to maintain another pregnancy.
