Maximising Your Calving…
Joining Weights – For maximum joining rates the following targets are best used
Heifers: 275 kg or better. This varies for different breeds, but this is a good base to work from.
Mature Cows: 2½ – 3½ Condition Score. Studies have shown that when cows get below 2.5cs, then there ability to conceive begins to fall off dramatically.
Joining Period – New Zealand studies have shown that when trying to decrease the joining period to 2.5 cycles, the joining rates were dropping off considerably. The trend now is to join for 3 full cycles (9 weeks), thus getting the optimum number of cows in calf without the compromising the fertility of the herd.
Note: We are starting to see the fertility of flocks and herds go down where bulls / rams are left with cows / ewes for prolonged periods of time. While in the first couple of years, breeders are reporting greater numbers of calves over a twelve month period, the weaning numbers are now starting to decrease
Scanning – Cows should be scanned in the period 40 days to 105 days from the day that the bulls went with the cows. This time period allows for the 9 week joining period. This allows the best time for viewing the foetus as it has developed enough to be effectively seen but are not too large to impede view.
Post-Scan – Cows should be given enough feed to ensure that they can feed their calves and also get into the condition score of 2.5 – 3 to enable joining in the minimum possible time to ensure that the calving rate remains 1 calf per year average.
- By scanning 6 – 7 weeks after the bulls have been removed allows you to make decisions on what to do with the empties. The extra 4 – 8 weeks gained can save large amounts of feed which can go towards the more productive cows.
- Scanning is much easier on the cow than conventional pregnancy testing methods. (You don’t see her walking away with her tail in the air for 5 – 10 minutes after the scanning procedure).
- You are welcome to do other tasks (ie: vaccinating or back lining) at the same time as scanning providing you have the staff on hand to accomplish this.
Fat Scores and Pregnancy
As mentioned above, the condition of the cow has a major impact on her ability to get in calf again. The optimum is in the 2.5 – 3.5 condition score. The agnotes from Victoria has a graph showing the conception rates done at trials over a large number of years.