By Brett Littler, Senior Land Services Officer, Livestock
With bulls out and about joining up with spring calving herds, I thought it time to remind producers that it is your choice how long the bulls stay in with the cows and that this has a big influence on a number of factors. A long joining means longer calving and an extended calving leads to:
- Greater chances of feed shortages.
- Greater variation in calf live weight and size (this was a major issue when early weaning during the drought)
- Less heifers reaching suitable joining weight to calve at 2 years. This can have several issues, including calving problems.
- Loss of potential income
So, what is the difference between extended and compact calving?
If we look at a 100-cow herd that has an 85% weaning rate, calves that grow at 0.9 kg/day and are weaned at 200 day after the start of calving.
In this scenario, if we compare a 15-week joining to a 9-week joining, then just by shortening the calving to 9 weeks we would get an extra 1,587 kg or 18.7 kg per calf. So, at $5.00 this equals $7,935 or $93.50 per calf
If you are a producer, then manage these cows to get more calving earlier in this 9-week period, lets say 70% in the first cycle and 20% and 10%in the following periods the benefit of this shortened calving period gets bigger. 2,551 kg or 30 kg per calf at $1.90 = $12,755 or $150 per calf.
I recommend a maximum joining period for cows of 9 weeks and heifers for 6 weeks and join heifers 3 weeks before the cows to allow first calf heifers a little more time to get them to join successfully.
It is your choice how long you leave the bulls in but I think now is the time to tighten up your joining period and put some pressure on your herds fertility.