January 26, 2023 at 3:26 p.m.
Organic herds utilizing nurse cows
Dr. Bradley Heins, professor of dairy management at the University of Minnesota-Morris, spoke about his research on calf raising systems Jan. 5 at a breakout session titled “Putting Dairy Research to Work.”
“How we raise calves is always a hot topic,” Heins said. “Getting out in front of it before the consumer demand is important.”
Heins began a study in the spring of 2020 to research dairy cattle nursing their young while being milked twice daily. As more funding became available, the study expanded to explore individual, pair and group housing as well.
In 2.5 years, the study has accomplished five sessions, raising almost 100 calves on their dams and about 60 calves each in the other three systems.
While raising calves with their mothers is taboo in the dairy industry, Heins found points of success in this portion of the project.
“Some people are worried that we bred the ability to raise their calves out of dairy cows, but this is simply not true,” Heins said. “We had cows that were 7 and 8 years old raising their calves for the first time.”
The cow and calf were given a few days to bond together before the cow and calf joined the rest of the herd either in the pasture during the grazing months or in the pack barn in the winter. Calves were weighed, vaccinated and tagged but then were otherwise dependent on their dam. Treatments were given as necessary. Every cow nursed her own calf and began milking twice daily three days after calving.
The nurse calves were only separated from their mothers during milking time.
At day four, all the calves across the study were offered starter. While the calves nursing had free-choice milk from their mothers, the calves in the individual, pair and group housing were fed 10 liters of milk a day.
“How much milk to feed calves is a topic continuously discussed,” Heins said. “I’ve settled at about 10 liters per day, because it is probably optimum from an economic standpoint and a growth standpoint.”
At 3 months of age, all the calves from across the study were weaned.
The study is now coming to a close and some of the first calves that nursed off their mothers are coming into milk themselves, and as they do, more data will be observed including behavior and production. The economics of the study will be complied within the next year.
Heins’ preliminary results from the study resulted in a few observations.
One of the most notable observations was that blood serum levels in the calves that nursed off their mothers were significantly higher than those in individual, pair and group housing groups. Heins said this may be due to the calves receiving all of the transition milk therefore absorbing more immunoglobulins than their counterparts.
“This goes against the conventional dairy mentality of trying to pull the calf away from the cow right away because you have to get colostrum in it,” Heins said. “The calf can figure out how to get it from its mother because it’s in its nature.”
Heins did not need to force feed any colostrum to the nurse calves throughout the study.
Heins also found the health of calves across the four systems were all relatively similar with no differences in calf mortality. He said calves in group housing have more incidents of scours but not a significant enough amount to make it a concern.
The study did shed light on the stressors of weaning.
While all the calves across the study expressed signs of distress while weaning, it was more notable in the nursing calves because the cows were also experiencing distress away from their calves.
“Through all of this, I learned that weaning is way more important than what we have given credit,” Heins said. “It’s stressful. These calves were stressed, but the cows were stressed a lot more.”
After weaning, many of the cows decreased in milk production, but after a few days, most of the cows returned to producing 60 pounds with the exception of a few younger cows.
Heins said he may continue working with nurse cows to identify ways to improve the weaning process.
As Heins weighs the variables of raising systems, he said group housing is his method of choice.
“I think farms should be raising calves in a group housing situation because calves can maintain growth and health in those systems,” he said. “I think that individual housing requires too much labor in today’s dairy industry, and nurse cow systems take a different form of management, so it may not be for everyone.”
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