Two weeks of once-per-day milking can clear up a high proportion of ketosis cases —although researchers are holding off on recommending the strategy pending further analysis of the financial drawbacks.
Dr. Stephen LeBlanc of the University of Guelph’s Dairy at Guelph research cluster provided an update about ongoing research at the recent South Western Ontario Dairy Symposium in Woodstock. He reported that his colleague, Dr. Todd Duffield, has been heading up the new study into ketosis and altered milking schedules.
Why it matters: Postpartum ketosis (or acetonaemia), characterized by a low energy balance, can knock back the timelines for dairy cows reaching peak milk production and for resuming reproductive activity.
LeBlanc began his talk by conducting a poll of symposium attendees about routine testing of fresh cows for ketosis. Nearly half of the respondents — who were handed “clickers” as they entered the room — are doing more than just the once-per-month milk testing offered by Lactanet —generally on a daily basis or even more frequently. But about a quarter are not testing at all.
Cows with ketosis are “burning fat off their back to support lactation,” he said. A bit of this is expected, and indeed is seen as positive. But cows that live through elevated degrees of ketosis have been shown to be more susceptible to metritis (inflammation of the uterus), to not be cycling at the time generally expected, and to not get pregnant as frequently when bred.
“Cows that are ketotic for two weeks, that really knocks back their reproduction.” Even if she recovered several weeks previously from the negative energy balance, “this has a long hangover.”
Milk, urine and blood tests are all effective, and all are available in a form with which most farmers would feel comfortable using. Although it certainly may be convenient to use Lactanet’s services, LeBlanc cautioned that if tests are only being done once per month, you’re going to miss some because many cows are only ketotic for two weeks and then recover.
“And we can do something about this. Good cow comfort and dry cow management is good prevention.”
Early treatment with propylene glycol has also been shown to be very effective at diminishing the amount of time a cow is ketotic. Additionally, about a third of these cases also show low blood glucose levels, meaning these cows will also benefit from an injection of Vitamin B-12.
So far, from Duffield’s study of post-partum cows put on 14 days of once-per-day milking, indications are that it has a very strong effect in first-calf heifers — it essentially cured all of the animals in the study, LeBlanc reported — as well as a lesser but still significant effect in older cows.
This strategy, however, represents a potentially large financial impact in terms of milk production, so Dairy at Guelph isn’t advising producers to try it at this point. They’d like to do some more work, perhaps with less severe alterations to the milking schedule or a shorter time period, to determine an optimal strategy for both cow health and economic impact.