DairyNZ research has shown that delays of up to a week can be tolerated by mid-lactation herds, and with careful handling they can return to full or near-full milk production.
Herds in early lactation are more problematic, but there may be the option of leaving calves on cows where shelter is available or reducing milking frequency for a short period of time.
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.
Keep feeding your herd well
Any sustained reduction in feed quality or volume will start the drying-off process and it will be harder to get cows back to full production (especially later in lactation), so feed cows as well as you can and ensure that they have access to clean water. Take care if feed type is radically changed.
When milking resumes
Remember that twice daily milking is not essential. If you are sharing milking facilities with neighbours or if more urgent things require time you can afford to be flexible and milk, say, once-a-day or twice in three days.
Ensure that cows are milked out completely
Resist the temptation to rush through milkings. Make sure cows are properly milked out properly to reduce the risk of mastitis developing.
Spray teats thoroughly
Stock are likely to be confined to smaller areas than usual and so udders will be dirty. Attention to hygiene is very important, and teats should be sprayed manually after each milking to ensure complete coverage.
Expect high SCCs for some days
SCCs typically take 2 to 5 days to fall below 400,000 cells/ml depending on the period without milking and the SCC of the herd prior to the changes in milking frequency.
Be vigilant with mastitis detection
In the DairyNZ trials, a quarter of the cows not milked for 7 days developed mastitis. Higher levels are likely in commercial herds. Vigilance is essential for the long-term health and productivity of the herd and for food safety.
Check SCC tolerances with your dairy company
In emergencies dairy companies are usually able to accept milk with higher cell counts. Fonterra for example will not penalise suppliers if SCCs are high in the first two consignments after an extreme weather event. Contact your area manager, field rep., or service centre.
Consult before dumping milk
Talk to district or regional councils. They will have contingency plans for emergency disposal of milk, and they will be keen to help and advise. What suits your situation will depend on volumes and facilities available and on soil conditions, etc. Options can include irrigation onto pasture or ploughed land, constructed ponds or trenches, and limited disposal to oxidation ponds.