Keeping up the momentum with your heifers
As mentioned in their ‘What’s New’ article printed in August 2015, Handcock and McNaughton’s recent study noted that there has been a general lift both in liveweight recording of NZ dairy heifers in MINDA® and in the growth of heifers to 18 months of age over that last 3years.
That’s great news for the industry! It should result in more heifers reaching puberty by 15 months, getting in calf quicker and calving down earlier at first calving.
It was also evident that many heifers lost much of that growth advantage in the final 4 months before calving, resulting in 60% of heifers being more than 5% below target liveweight at 22 months.
The two researchers’ take home messages were:
So where might things still be going wrong?
The first thing to look at is nutrition – the amount and quality of the feed available to heifers. Although health issues can be a major challenge in some regions and herds over the summer and autumn period, the biggest risk to heifers not reaching live weight targets at calving is nutrition.
Having sufficient high quality feed on hand for those big hungry pregnant heifers to keep them maintained and growing is essential if you are to get them to weight targets at calving. It all comes down to monitoring and planning. Some things to consider are:
- Plan ahead – but be conservative with your feed budgets. Run a couple or three different versions of the feed budget. Compare best case scenario (fantastic summer and autumn) to worst case (summer dry, low pasture production and/or low summer crop yields, with a late autumn break). By knowing how worse case might look, you can look at developing potential contingencies if worse case were to happen.
- Monitor pastures, crops and supplementary feed inventories to ensure feed on hand will be sufficient to meet demand. Some winter crops are already below target in drier east coast areas. Early yield checks starting late March 2016 could be useful in order to give you an estimate of what final winter yields might look like.
- Include feed planning on the milking platform in May if the heifers are due home. They will compete with milking cows for pasture and supplements.
- Soil test and look for fertiliser opportunities including nitrogen to improve pasture and/or crop performance for late summer and autumn.
- Review numbers of heifer replacements. Are numbers too high? Could you be better off if you sold surplus heifers to improve per head performance of remaining animals?
- Pregnancy test the mated heifers early to remove empties if feed supplies are short.
- Monitor heifer weights regularly in MINDA weights to check they are keeping on track. Respond quickly to heifers not on track and make necessary feeding adjustments quickly as calving is fast approaching.
- Monitor trace mineral status. Low levels of copper and selenium have a tendency to reduce heifer live weight gains.
- Pay attention to the yearlings too; they’re at risk of falling behind through the same period. Don’t let them deviate so far below the target line that they are unable to get back to target by mating at 15 months. The closer you are to mating the closer to the target line you need to be.
Climatic extremes can affect feed availability and utilisation, and they usually occur somewhere in NZ every year! Don’t assume every year that pastures will always grow well and everything will be 100% perfect. Better for a little pessimism and contingency planning that is not needed, than being unable to feed heifers if pasture ends up scarce.
Set the scene for better production and reproduction with well managed heifers that meet target live weights when they enter the herd next spring. The next few months are crucial!