Almost 50% of NZ dairy heifers are more than 5% below target calving weight.

Using the InCalf Gap Tool calculation, heifers that are 10% below target weight will lose $88/heifer and those 20% below lose $218/Heifer. The losses are caused by lower milk production, lower R3 6 week in calf rate, and more empty R3 cows.

The biggest risk of failure to achieve target weight gain is between 6-9 months old. This is due to poor quality summer pasture with lots of fibre that takes a few days to digest.

The next biggest challenge is around 18 – 22 months. These R2 heifers cope with summer pasture fine because they are big enough, but they are also pregnant. If the increased feed demand associated with pregnancy is not met this results in slower or no growth.

Ensure that individual weaning weights are done and recorded, and that calves going to the graziers are at least 100kg. Good, convenient times to weigh your calves at grazing are: 

• Jan / Feb. zinc bolusing.  Calves have been at grazing for several weeks – this is a good opportunity to check performance at the highest risk time, as pasture quality may not be that great. 
• March – May.  This is the end of the high risk time, grass is growing again unless there is a drought. A good time to do the six month booster lepto vaccination and trace element tests too. 
• September – October.  Pre mating is the first major target. If they are too light at this time, it may be a challenge to catch up, so an earlier weigh/intervention should have been done already. This is a good time to assess any nutritional interventions made during the summer. 
• April – June the following year.  These are R2 heifers returning to the farm. There should be a written agreement with the grazier that heifers will meet their targets at this point. This presents another opportunity to lepto vaccinate. 
• Pre calving.  The second and most important major target. This is the reality check: is the replacement program working or not? We would love to assist you with assessing your heifer weights and targets. 

If you can’t weigh your stock – we can! Electronic scales, a transportable crush and race are available. We can drench, tag, blood and liver sample, teatseal, vaccinate etc. as well, as required. It would be great to work with you to set up a scheduled weight assessment program so we can help your heifers perform to their potential!