Kia ora ,
The impact of Cyclone Gabrielle has left many farms in the upper North Island without power or with flooding and infrastructure damage.
It is likely that many cows will not be milked for some days to come. Farmers will be considering their options this late in the season and may look to dry off some cows early. Some herds will be in later lactation but the summer has been favourable, so milk production has generally held up.
Dairy NZ research has shown that mid-lactation herds can tolerate delays of
up to a week and, with careful handling, they can return to full or near-full milk production. If milkings are missed for up to a week, then cows should recover with the exception of very low producing cows ( <8-10L). The herd can be milked as soon as conditions allow and any cows that have started to dry off should be recorded and treated with dry cow therapy or teat sealant as required (see below).
If cows cannot be milked for a week or more, then drying off the whole herd may be the best option.
To help get cows and farmers through, we recommend:
- Feed cows as best you can. Reducing feed
quality or volume will start the drying-off process and it will be harder to get cows back to production, especially later in lactation. Access to clean water is also desirable but may not be realistic in flooded environments.
- Milking once a day is okay to start with. If you are sharing milking facilities with neighbours or more urgent things require time, you can afford to be flexible and milk once a day or twice in three days until twice daily milking is an option again.
- Udders are likely to be very dirty, especially at the first milking. If udders are covered in mud, then wash the udders thoroughly, let them drip dry, then wash just the teats again. If the udders are not badly covered in mud, just wash the teats. Be very
thorough with teat spray application after milking and ensure there is sufficient emollient in the spray to improve teat condition.
- In the Dairy NZ trials, a quarter of the cows not milked for seven days developed mastitis. The bulk milk somatic cell count (BMSCC) is likely to be high for two to five days after milking resumes depending on the period without milking. Strip the herd and check for mastitis every two days if possible to detect new mastitis cases early.
- Dry cow therapy/teat sealants are an important part of mastitis management. Once milking resumes, cows that return to production can be milked until final dry off date and treated as normal. Cows that do not produce much milk may have started to dry off. They can be treated based on
veterinary prescription but there is an increased risk of antibiotic residues if antibiotic dry cow therapy is administered to udders that have already started to involute.
- Cows requiring antibiotic dry cow treatment will have a long dry period which should reduce their residue risk early next lactation, as long as they are treated within a week of the last milking. Farmers should record the number of cows treated with antibiotic dry cow and extend their colostrum period by two days. If large numbers of cows are affected, QCONZ can test the first consignments next season for inhibitory substances before restarting supply. Communicate with your dairy company representative so they can help with your individual situation.
- Cows requiring teat
sealant can be treated at any time, but strict hygiene before administration is critical to prevent introduction of bacteria and severe mastitis.
- Talk to the dairy company and district or regional councils. They will have contingency plans for emergency disposal of milk and will be keen to help and advise on each farm’s individual situation.
- Look after yourself. If there are heavy demands on your time clearing away damage or sorting out problems, it may be worthwhile to miss a few milkings and sacrifice some production in the short term to allow you to cope better for the rest of the season.