Meeting heifer growth targets is vital to dairy farming success, a field day revealed.
On their first visit to the new North Otago heifer-grazing focus farm late last year, cattle owners and graziers were urged not to underestimate the importance of growth milestones.
A large crowd gathered at Foxhaven, a 145ha property run by Tony, Megan and Jared Fox northeast of Oamaru.
It was selected as a focus farm by DairyNZ and Beef and Lamb New Zealand, the only South Island property so far in their nationwide programme.
DairyNZ national heifer grazing strategy leader Sarah Dirks said an LIC study showed that on average, heifers were 10% behind growth targets at calving.
''Heifers are quite a demanding stock class,'' Ms Dirks said.
''If they're not gaining weight, you're losing.
''Targets are important. It can end in tears and tantrums if you don't agree on what you're aiming for.''
Liveweight breeding values were the most technical, industry-agreed way of setting targets, she said. The target had to be set with the end in mind - when the cow was 4 to 6 years old.
At 22 months, the animal should be at 90% of target. At 15 months, when it would be mated, it should be at 60%. At 6 months, it should be at 30% of target.
''If a calf is at 30% at 6 months, she's on track for puberty. At 12 months, she should start showing heats.''
That meant by mating time, at 60%, she would be on her third cycle.
''You get early-calving heifers and lower empty rates.''
Hitting targets was more important than achieving certain rates of growth, Ms Dirks said.
''There's nothing proven that growth rate matters.''
It depended on the breed and what the farmer was aiming for, she said.
''As a grazier, tell the farmer what you can give as a growth rate. Then the question is, how do you merge the two together when discussing it with the stock owner? It becomes about the start weight.
''You need to set a mature target liveweight and be working towards that.
''It is about the conception rate and milk production.''
A new paper from the Australasian Dairy Science Symposium showed that if the heifer started out behind, it could have an effect on milk production for five years, Ms Dirks said.
Graziers had to consider the value they were adding to the long-term sustainability of the dairy industry.
''It's about being on target, not just that bigger is better.''
Being on target was 60% at mating. If a heifer was 62%, she would drop out of the herd more quickly. If she was 53%, it was even worse, she said.
Suggestions from audience discussion groups at the field day included giving the grazier financial incentives for hitting growth targets, sending fewer stock, and buying in feed.
With the latter, the parties had to agree who paid for it. Ideally, calves would be on grass for two weeks before leaving the home farm.
Heifers also had to be on target when they arrived at the grazier's property.