SPECIAL REPORT
Transition management - prevention better than cure Identify your at-risk cows before calving starts advises DairyNZ scientist Jane Kay. Sheryl Haitana reports.
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f more than 2% of a herd is having difficulty calving or going down with metabolic disorders, farmers need to reassess how they are taking their cows through the transition period, DairyNZ scientist Jane Kay says. The success achieved during the transition period will impact a cow’s milk production for the rest of the season, her health and ultimately her reproductive success. Often one of the main reasons a cow will exit the herd can be because of an unsuccessful transition period, she says. “It’s a short period, but it’s incredibly important.” Transition management is complicated, it can be impacted by the season, and farmers can hear mixed messages. It’s also difficult to dissect what the issue is when farmers are in the thick of calving and things are not going well. Ultimately, prevention is easier than cure and farmers need to be looking at their system and talking to their veterinarian and consultants to make sure they have a good plan in place. “There are practices we can put in place to reduce the risk of problems during that transition period. “Prevention is much more favourable than trying to treat cows with calving difficulties or down cows with milk fever or ketosis.” Ideally farmers need to identify at-risk cows in January or February, who are not on target to reach an ideal body condition score (BCS) by calving. Coming into calving, first and second calvers should be a BCS 5.5, and mixed-age cows 5.0. “Sometimes we forget about our three year olds, our second calvers. They are the ones who can have the poorest reproductive performance and struggle the most in the herd.” The other cows to watch out for are those who have had an ailment throughout the season, so might be more vulnerable, and any cows who have had metabolic 60
problems in the past. “We need to look after them, feed them well before calving. If we think they’re going to have a problem, a starter drench can be good to give them once they’ve calved. “Treat them with kid gloves, look after them, give them calcium after they’ve calved, make sure they have high energy feed after they’ve calved.’”
DairyNZ scientist Jane Kay is advising farmers to check their at-risk cows before the calving season starts.
PUT THEM ON A DIET On the flip side, if there are cows in the herd who have too much condition on them, they are also at risk and should be put on a slightly restricted diet the last few weeks leading into calving. “If we have animals that are 5.5 and above at calving, one of the recommendations is to restrict their intact 2-3 weeks before calving.” When talking about a restricted diet, it’s only reducing a cow’s energy levels slightly to get her body prepared, Jane says. “If we can restrict their energy intake by only about 1kg drymatter (DM), it primes up the liver to start to mobilise some body tissue. Then when she actually calves she’s much more able to cope with that challenge.” Straw or hay works well as a lower energy feed for cows to keep them full. “I’ve seen it work really well on a lot of farms, where they have cows that are over-conditioned and they’ve had trouble with Dairy Exporter | www.nzfarmlife.co.nz | August 2021
