Published: 24 May 2019
Lesley Irvine, TIA
It is estimated the total cost of a clinical case of mastitis is $277 (Dairy Focus, 2013). Your dry-off strategy will have a big impact on the number of clinical cases of mastitis occurring at the start of the next lactation (or even during the dry period). Get your dry-off strategy right and it can save you a lot of money.
What is drying-off?
At the end of lactation, cows need a dry (not lactating) period to allow their udder to repair damaged tissue and rejuvenate. A dry period of a minimum of six weeks (42 days) is recommended. A dry period of eight weeks (56 days) is preferred. The length of the dry period will impact on the daily milk yields achieved during the following lactation.
The Countdown Farm Guidelines for Mastitis Control (2018) recommend the following strategies for drying off:
- Cows should be dried of when their production is between 5 and 12 litres per day. If production is higher than 12 litres per day, take steps (such as decreasing feed intake) to reduce milk production.
- Dry off abruptly; do not skip days and preferably do not skip milkings – milk out as usual at each milking until drying-off.
- Don’t leave cows in laneways or yards immediately after drying-off.
- Put cows in a dry, clean paddock (not heavily soiled with manure, no bare ground, no exposure to dairy effluent) for 3-4 days after drying-off. This paddock should be well away from the dairy and not near any cows still milking so cows don’t receive any stimulus that encourages milk let down.
- Continue the ‘maintenance only’ diet for another 3-4 days for cows that were producing 12 litres/day or more in the week before drying-off.
It is important to be realistic about how many cows can be dried-off at one time. To do a good job with Dry Cow Treatment, one person can only effectively handle 20 cows per hour.
Blanket vs Selective
Decide if you are treating the whole herd (Blanket Dry Cow Treatment) or part of the herd (Selective Dry Cow Treatment). If only treating part of the herd, Countdown recommends treating all cows with any individual cell counts above 250,000 cells/ml during the lactation, and any cow having had a clinical case of mastitis.
Hygiene is critical during Dry Cow Treatment – if care is not taken to make sure the teats, and particularly the teat opening, are clean, there is increased risk of infection. Treat all quarters of cows receiving Dry Cow Treatment except quarters that have been dried-off for some time in any cows milked as ‘3-teaters’. If a quarter is dry, absorption of the Dry Cow Treatment will be affected increasing the risk of antibiotic residue. Speak to your vet about possible options for these cows. Once you have finished treating the cow, make sure teat spray (or dip) is applied thoroughly to all teats.
Clearly mark cows that have been treated with antibiotics in case they make their way back into the milking herd. Create permanent records of cow ID, date and product details of all Dry Cow Treatments.
Internal Teat Sealant
Many farmers are now using teat sealant as part of their drying-off strategy. Teat sealant doesn’t contain antibiotics so will not cure existing infections. The role of a teat sealant is to prevent new infections occurring, especially in the early dry period and just prior to calving.
Research has shown teat sealant, either alone or used in conjunction with antibiotic Dry Cow Treatment, reduced the risk of clinical mastitis after calving by 29% when compared to cows only treated with antibiotic Dry Cow Treatment (Countdown Technote 14).
When cows treated with teat sealant only were compared to those who received no treatment, the use of teat sealant reduced clinical mastitis by 48% (Countdown Technote 14).
Keep dried-off cows away from the dairy and away from the milking herd moving to and from the dairy to avoid a milk let-down response. Observe dried-off cows daily for a week. Check for swollen quarters. If a cow has a swollen quarter, the cow should be checked manually for mastitis. Only strip the swollen quarter, don’t remove milk from the normal quarters. If mastitis is detected, treat as normal (e.g. with a lactating cow intra-mammary antibiotic). Strip the quarter out completely twice daily for the course of the treatment. For clinical cases that occur in the first week after drying-off, re-treatment with Dry Cow Treatment is advised (consult with your vet). If a cow is re-treated, make sure records are updated with the new withhold period.
For further information, the Countdown Farm Guidelines for Mastitis Control are a great resource and can be downloaded for free from www.dairyaustralia.com.au/Countdown. Dairy farmers can also receive a free hard copy of the guidelines by filling in the online order form or contacting Dairy Australia on 1800 004 377.
A snapshot of what some farmers are planning for drying-off this season:
Andy Jackman, milking 200 cows at Oldina (organic farm)
Cows are dried-off once milk production declines to 6-10 litres. Cow condition and a dry period of 7-8 weeks is also factored in. No specific dry-off treatments are given – neither antibiotics or teat sealant are used. Cows are provided with apple cider vinegar and minerals all year-round to promote a healthy immune system. When cows are dried-off they are put in a clean paddock and fed hay and pasture. They have ad lib access to a dry cow lick.
Gary Watson, milking 400 cows at Lileah (organic farm)
Cows are dried-off in batches of 100 at a time based on calving date and milk production. They are milked once-a-day and fed hay for a week prior to dry-off. Apple cider vinegar is put in the water trough. No antibiotics or teat seal are used. After dry-off the cows are fed a dry cow diet of pasture and hay.
Michael Palmer, milking 1000 cows at Sisters Creek
Cows are dried-off in batches based on calving date. The protein supplement in the concentrate mix is removed three days prior to dry-off. Cows are fed hay and water during the day and a restricted pasture allowance of a night. All cows in the herd are dry cow treated with antibiotics and teat sealed. Teat seal is used because cows are calved on a calving pad. Cows are milked and immediately dry-cow treated and teat sealed whilst still on the platform. After being dried-off the cows are fed hay and silage for several days with minimal pasture. They are moved to a clean area each day. Any cows being trucked to a run-off are taken there straight away, while they don’t have full udders. Heifers aren’t teat sealed.
Ronnie Mulder, milking 280 cows at Forest
Cows are dried-off based on calving date to give them a minimum 6-week dry period. First calvers in lower condition are dried-off earlier to give them extra time to put on condition. All cows are dry cow treated with antibiotics. In the past, a part-herd (selective) dry cow treatment strategy was used but last season this practice changed to whole-herd dry cow treatment and saw a big reduction in mastitis at the start of the season. All cows are teat-sealed. Heifers are also teat-sealed. This was also done for the first-time last season and the Mulders are happy with the results so will continue this practice. Heifers are teat-sealed in the (herringbone) dairy.
Stuart Burr, milking 400 cows at Ringarooma
Cows are dried-off based on production (8 litres) or calving date to give a 60-day dry period. Intake is limited to hay and water for a few days prior to dry-off. All cows are dry cow treated with antibiotics and then teat-sealed. Typically, only a row (40 cows) a day is dried-off. This helps to make sure everyone is focussed on doing a good job for all the cows. Heifers are also teat-sealed. This is conducted in a tipper crush.
Tim Salter, milking 1000 cows at Meander
Tim gets their vet to visit each year before dry-off to conduct a refresher session on dry cow treatment. This is to emphasise the importance of making sure the teat is clean and the correct techniques are used. Tim uses a part-herd dry-off strategy. This is based on the four herd tests that are conducted through the season. Any cows that had a cell count above 150,000 cells/ml or clinical mastitis are dry cow treated with antibiotics. All cows are teat sealed. Cows are dried-off in batches based on calving date to allow for a minimum dry-period of 60 days. No more than 200 cows are dried-off in a day to prevent operator fatigue. The amount of grain fed to cows about to be dried-off is reduced 5 days prior to dry-off. After dry-off, cows are fed a diet of just hay and water for two days and then pasture is gradually re-introduced.
Heifers are also teat-sealed. This is done on the rotary platform – they have used a tipper-crush but found it to be more labour intensive.