New Zealand dairy statistics show about 13% of heifers that enter the herd won’t be back for a second season.
LIC research scientist Lorna McNaughton said a recent review of costs versus first season milk returns found each heifer hadn’t even paid for herself by the end of the first season.
Based on a cost of $1400-$1500 to rear a heifer from newborn calf to her first milking, and a first season’s milk production paid at $4.69/kg milksolids (MS), each heifer was still, on average, $117 short of breaking even.
“She needs to be in the herd, going through a second lactation, before she pays for herself,” McNaughton said.
The most commonly reported reason for not being there was reproductive failure or failure to get back in-calf at the second mating, not long after she joined the herd.
One of the greatest influences on reproductive performance of first calvers was how well she had been grown-out and whether she met target weights.
LIC’s latest research showed NZ dairy farmers and graziers appear to have heeded messages from LIC and DairyNZ about the importance of getting young stock to target weights, with many more animals at or above six, nine, 12, 15 and 18-month weight targets than there were just a few years ago.
But there were still improvements to make in getting more animals to their target weights.
The research also showed while there were improvements at the younger age targets it wasn’t the same story for heifers at 22 months. (Dairy Exporter, October 2015, p78)
Close to two-thirds of heifers were under target weight at 22 months.
DairyNZ targets were for heifers to be at:
- 30% of their mature bodyweight at six months
- 60% at 15 months
- 73% at 18 months
- 90% at 22 months
The incentives for achieving target weight were compelling, with analysis from the LIC database and DairyNZ research showing heifers that achieved 90% of their mature bodyweight by first calving produced more milk and stayed in the herd longer.
A heifer at 100% of her 22-month liveweight target would produce 35.4kg MS more in her first lactation than she would if she was at 80% of her liveweight target.
They were also likely to have a 5% better three-week submission rate and a 4% higher six-week in-calf rate.
At a $4/kg MS payout, each additional kilogram of liveweight at 22 months, between 80-90% of mature liveweight, would return about $1 in the first lactation.
Achieving the 15-month liveweight target would help minimise the incidence of non-cycling heifers at their first mating.
The first step in ensuring heifers got to weights was to know what their target weights should be and the next step was to weigh them – the more often the better.
Calculating individual target weights could be done using liveweight breeding values and adding it to 500 (the liveweight of an animal with a BV of zero).
So if a heifer had a liveweight BV of +12 her target mature body weight would be 512kg.
Alternatively this could be done for a line of similar heifers using the average liveweight BV of the line.
Frequent weighing, accurate recording of the data and assessment of where animals were at relative to their targets would give an early warning if growth rates weren’t where they should be.
Research based on data from LIC records showed the first winter and second summer could be risky, with growth rates falling below what was required to reach targets.
Those growth rates picked-up in spring but not enough to compensate for the other shortfalls.
Heifers therefore either needed to be heavier going into the first winter or be fed more through that period.
Setting out the requirements so graziers understood growth rates and target weights needed was important, as was regular monitoring of young stock by the dairy farmer.
Good communication was essential, particularly in heading off problems such as impending feed shortages on the grazier’s property.
It was easier to find solutions before the problem hit than to suddenly find heifers were all well-below weight targets.
Based on the latest data it was also important to integrate heifers into the herd carefully and watch their condition through the winter leading-up to their first calving.
