Decisions made while drying off will influence next season's performance, and can have a huge impact on milk quality, cow condition, and reproductive performance. It could influence your ability to go to once-a-day milking next season, and any impact on calving spread could take years to correct.
Dry cows off sooner rather than later
In a high payout season, there's always temptation to milk on for just a little bit longer. But if cows don't have enough time to gain condition over the dry period, they risk dropping too much weight after calving, reducing their chances of getting back in calf on time.
Antibiotic dry cow therapy is designed to diffuse up through an udder full of milk, and cows producing under five litres (L) per day are likely to be dry in at least one quarter already.
Antibiotic dry cow therapy going into a dry quarter is less likely to work and can increase the risk of residue detection at the start of next season. Be conscious of any withholding periods; an early calving cow dried off late in the season could calve within her withholding period.
The optimal dry off date for each cow is influenced by her condition, expected calving date, current production level, and the available feed. This will be different for every cow in the herd and calculating that date will allow for better decision-making before and during the dry period.
Be prepared
Drying off a herd is a big job but will go more smoothly if you give yourself enough time, and resources. Think about what makes drying off difficult on your farm and what might make it easier. Do you have all the products/wipes/gloves/teat spray you'll need? Could you get some helpers? Could you dry the herd off in batches over several days?
Use the right product
Every time antibiotics are used there is a risk of creating resistant bacteria that can no longer be killed by antibiotics. A recently published study1 estimates resistant bacteria killed more people internationally in 2019 than AIDS and malaria combined. Agriculture accounts for 70% of all antibiotics used worldwide, and human health bodies are increasingly concerned about prophylactic antibiotic use in agriculture - the practice of pre-emptively treating animals before they get infections or to increase their growth rates.
Come dry off, most quarters of most cows are not infected and therefore, do not need to be treated with antibiotics. However, leaving them untreated increases the risk of new infection during the dry period, and an internal teat sealant is recommended for those low cell count cows. Internal teat sealants create a physical barrier that's only removed when the quarter is stripped out, meaning their protection won't run out during the dry period.
All cows should be treated with something while drying off, but only cows with a high cell count will benefit from antibiotics.
Pay attention to hygiene
Even with antibiotic dry cow therapy, there's a risk of introducing udder infection via an intramammary product, and some of those bugs won't be affected by the antibiotic. New Zealand research has shown the importance of staff training on reducing mastitis post dry-off, so make sure everyone involved has recent training on hygienic infusion techniques.
Wear gloves, keep tubes clean and dry, clean teats immediately before treating them, remove the cap cleanly, insert the tube the shortest distance needed, and teat spray once you've finished.
Managing risks in the early dry period
The most common risks for mastitis post dry-off come from two sources; bugs introduced while drying off due to poor hygiene, or environmental infections that flare up a few weeks later in cows still dripping milk.
It takes about two weeks for milk production to cease once milking stops, and it's important udders are kept clean over this time and cows are only fed maintenance to ensure production stops. Cows dripping milk have open teat canals and are at heightened risk of environmental mastitis, even if they've been treated with antibiotics while drying off.
Planning for next season
A successful dry off should set you up for good milk quality next season. To help farmers improve their milk quality Fonterra is offering free Milk Quality Improvement Visits with our field teams.
If you would like to know more about this service, head to nzfarmsource.co.nz/mq-service or talk to your Area Manager.
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1 Murray et al. Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis, The Lancet, Volume 399, Issue 10325, 2022.