Dry cow management is a big topic right now. Part of the reason is because there is so much discussion about whether treating every quarter of every cow with an antibiotic dry cow treatment is a good idea. Another reason is that drying off is more complicated because average production has so steadily increased that farmers are drying off cows that are still producing a lot of milk. Yet another reason is that dry cow management is always evolving as new research and differing opinions get brought up and discussed.
Just recently, two veterinarians did a review of research on drying off to try to figure out what the research we have tells us about important parts of dry cow management. They wanted to see how much we know about the impact of high production on risks at dry off, the effectiveness of management to reduce production before drying off and the impact of dry off on the cow herself.
They started by looking at what we know about the changes that happen to the udder and to the cow’s drive to milk when we stop milking them gradually or abruptly. They also looked to see if there was much evidence of how effective some of the strategies to lower production have turned out to be.
There are two general approaches to drying off – abrupt dry off or gradual tapering in the last few days before actual drying off. According to surveys, farmers use abrupt drying cows off most often.
When you stop milking a cow, the cow’s stimulus to produce milk is reduced, but it takes time for the reduced stimulus to produce milk to have an effect. This is the reason why gradual rather than abrupt dry off might be better – less milk in the udder lowers the risk to the cow, reduces leaking and allows the cow to be more comfortable.
Some of the ways that have been investigated to taper off milking are to cut back to once daily milking for about a week before dry off. Numerous other more complicated alternatives have been investigated but most don’t look to be very practical in larger herds. One that may be feasible is to switch to once a day milking 5 days before planned dry off but not milk at all on the day before drying off. The milking schedule would be once a day on days 1, 2 and 3 before dry off, don’t milk on day 4 but then milk cows once on the day they are dried off.
Research trials on tapering lowered milk production by 20-47% in cows that had been producing more than 20 kg per day before tapering started. In fairness, most of those trials that investigated tapering also included changes to feeding or to the ration too. There were variety of feeding changes that were evaluated in different research trials but the overall objective was to reduce available energy and protein. So the impact on milk production was likely not just from changing how cows were milked.
Of course, even if you dry off cows abruptly, you can use nutritional changes to lower milk production before dry off.
After they finished their review, the researchers made the following recommendation: “Based on the findings of this review, gradual cessation of milking over several days before the final milking can effectively reduce milk yield at dry-off and accelerate mammary gland involution while maximizing cow comfort and welfare. Data from this review indicate a target production level of 15 kg/day of milk or less at dry-off.”
I was involved in a survey of dry cow management practices last fall. About half the farmers in the survey told us that they tried to reduce milk production before dry off. About half of those farmers had 15 kg or less as their target. The other half had 20 kg or less as their target.
Dr. Robert Tremblay is a veterinarian for Boehringer-Ingelheim and lives near Guelph.