Breeding is about to get under way for suckler herds calving from mid- to late-February through to late April.

Where farmers are breeding home-reared replacements with the aim of calving down at 24 months of age, there needs to be a final call on which animals are heavy enough to serve.

Well-developed heifers meeting target breeding weight increase the chances of animals coping with the physical demands of calving at 24 months and going back in-calf again.


Under-developed heifers will cycle and hold to the bull. But they are usually too small when calving, unable to cope with the demands of rearing a calf and normally don’t go back in-calf.

These negatives understandably see farmers abandoning the idea of calving at 24 months in subsequent years.

After a late turnout to grass, there will be farmers with a lot of heifers below target breeding weight.

Tight selection

Therefore, before breeding starts, weigh potential replacements and make a final call on which animals are suitably developed to breed.

The old rule of thumb where heifers weigh at least 60% of mature cow weight when breeding starts is a good guide to work to.

If the average cow in the herd weighs 750kg, heifers need to weigh at least 450kg when breeding starts. The next target is having heifers at 90% of mature cow weight by calving time.

Do not be swayed by a 'favourite' heifer that is under-weight, simply because of nice colour markings. These animals are more likely to cause problems next spring after calving, even if served to easy calving bulls.

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