Advice for dairy farmers: Late calvers are often neglected part of the herd
The median calving date is March 10, but the optimum target for most farmers is February 20.
The average six-week calving rate is 55%; the ideal target is 80-90%, which only a minority of farmers achieve.
Pregnancy rates to first service are 52%; the target is 68%.
Submission rate is only 60% and the ideal target is 90%, but of course this is impossible for most herds with a scattered calving pattern.
Calves per cow per year are 0.85; the target is 0.95.
As we can see from these figures, there is a lot of room for improvement.
We know that some farmers are getting closer to the targets, but it is difficult where existing calving patterns are very scattered.
It can only be achieved by batch calving heifers at the start of the calving season, and adhering to best breeding practices.
Breeding of late calvers should be brought forward, by using hormone treatments.
Despite being somewhat off target, the breeding performance of the best farmers in Ireland is as good if not better than those in New Zealand and Australia. Some of the New Zealand breeding achievements are influenced by some unethical practices which may now be fading out.
ICBF has found a very close relationship between herd fertility index and herd fertility performance.
Most farmers are now using bulls with high fertility indices, and this is promising for the future.
Late calvers are very often the neglected part of the herd.
This is mainly due to a poor understanding of the feed intake and energy requirement of these animals — probably the main reasons why it is often so difficult to get late calvers back in calf.
During a few weeks before calving and for the first 10 weeks of lactation, the intake of cows is significantly reduced and there is a severe risk that these animals will go into negative energy balance.
Peak milk yield usually occurs at six weeks after calving, while peak feed intake does not usually occur until 10 to 12 weeks after calving.
Therefore these cows need extra concentrates to avoid negative energy balance which delays them going back in calf.
The problem is worse with over-fat cows.
Even on good quality grass, the intake of late calvers will be about 20% less than early calvers for the first six weeks, and they need extra supplementation.
Almost one third of our cows calve after late March, and they are in a vulnerable position now.
Ideally, when they are 35 days calved, they should be put on a synchronisation programme with fixed time AI from short gestation bulls.
This practice has been very successful in tightening up the calving practice on some farms, and reduces the necessity of culling due to late calving.
Most late calvers do not get any special treatment, and they calve later and later until they are eventually culled.
This is a huge loss to farmers, and they should take all the necessary steps to reduce the problem.
- Record keeping is an essential element of a good breeding programme.
The first step is carrying a pocket notebook to record everything happening on the farm such as heats, body condition, cows off-form or passing dirty discharge, grass supply etc.
Information on the notebook regarding breeding such as calving dates, pre-service heats, service heats, and bulls used, should be transferred to a wall chart where it can be conveniently checked.
Wall charts are available from breeding societies.
Some farmers use a computerised system but even with that, a well-kept wall chart staring at you is very useful.
Data on the wall chart can be analysed during the year to check breeding performance.
Cows not showing heat, and calved 30-40 days may need veterinary examination or a wash-out.
