The answer to the question of when to dry cows off depends on your plan for winter feeding and the trade-off between production this season and next season. Having said that, the rule of thumb is :

• Dry off any cows that are producing less than 5L and/or have a high SCC immediately.
• Minimum 42-day dry period to allow for udder repair and avoid limiting next season’s production.
  • For a 10th July calving that means drying off by 29th May.
  • But 95% of cows calve up to 12 days either side of their due date, so to adding another 12 days means dry off is 17th May for a 10th July calving.
• It takes 100 days to put 1 BCS on a cow with minimal supplement/crop fed during the dry period.
  • For 10th July calving (plus 12 days for calving spread) and cows at BCS 4, dry off before 20th March.
  • Yes, that date has been and gone already so if you missed it and have cows at BCS 4 or less, they will need supplementary energy to put on condition before calving.
  • Cows can’t gain BCS in the month before calving.

There are a couple of tools available to help guide your decision beyond the rules of thumb:

1. Infovet dry-off planning report

• This report takes your aged scanning data and a whole herd BCS to produce a list of cows to be dried off each week.
• The idea behind this report is planning to give every cow enough time to reach BCS target at calving (5.5 for first and second calvers and 5.0 for older cows).
• Talk to your vet if you would like to organise a herd condition score to be done, then we can produce the report with the click of a button.

2. DairyNZ milk on/dry off tool (https://www.dairynz.co.nz/tools/milk-on-dry-off/#)

• This tool is designed to test scenarios for milking on when feed is short and tries to answer two questions:

1. Do I have enough feed to keep on milking?
2. Is it profitable to keep on milking?

Talk to your vet or local DairyNZ area manager if you would like help to use this tool.