Acidification Allows 24/7 Milk Access for These Calves

Mercer Vu Dairy of Mercersburg, Penn. is known for its innovation and can-do approach to dairying.

It’s that positivity and creativity that have allowed brothers Rick and Rod Hissong to grow the business from a few hundred cows to its current scope of 3,400 cows on two dairy sites, along with 5,000 acres of cropland.

Through that growth, the Hissongs have managed their pre-weaned calves in a number of systems. An expansion in the early 2000s included the decision to resume raising their own calves, after contracting services with a wet-calf grower for several years.

They used calf kennels and hutches, utilized a computerized feeder for a time, and also experimented with “grazer-style” group feeders dispensing pasteurized waste milk twice a day via nipple feeders on 55-gallon drums.

“We would drag those barrels into the pens we had, in pretty much any corner we could find on the farm,” Rod Hissong shared on a recent episode of the Center for Dairy Excellence “Cowside Conversations” podcast. “We liked the group feeding, but ventilation in some of those locations was not the best, and we realized we had to do something better.”

In 2015, the Hissongs built a new calf barn. They chose to stick with group housing and ad-lib feeding, but wanted to explore options other than the barrel feeders or computerized autofeeders. “When we had a computerized feeder, it worked great, but with 350-400 calves on milk, we would have needed to purchase and maintain several of those,” Rod stated.

They arrived at a configuration of 20 pens of 20 calves each, with 10 pens on each side of a central milk room. Waste milk is brought in from the dairy and fortified with a balancer to boost protein levels. It is then acidified and stored in a holding tank.

“From that tank, we pull milk into a loop that runs the entire length of the barn, so there is constantly milk circulating through the barn,” shared Rod. Calves access it via nipple boxes equipped with 6 nipples per pen. They are fed the ad-lib milk ration for 8 weeks, along with access to free-choice starter grain and water starting in their first week of life.

Hissong said acidification is key to minimizing bacterial growth in the milk as it is pumped through the system. “The milk comes over from the plate cooler at about 65°F. The holding tank in the calf barn has no refrigeration at all,” the dairyman noted.

He said the milk typically is in the system for only about a day. But they have tested milk that has been stored for 3 days, and still showed no bacterial growth, even though it is warmed to 85-90°F as it is circulated.

Over time, the Hissongs have adjusted the degree of acidification to arrive at the sweet spot between bacterial growth suppression and palatability. They’ve raised the pH level slightly, from about 3.5-4.0 to 4.5-5.0, which Rod believes has improved milk intake.

The system is not completely low-tech, because it is controlled by a programmable logic controller (PLC). In addition to agitating and pumping the milk, the PLC dispenses the acid treatment, so employees never have to handle the acid.

And while it is impossible to know how much milk each calf drinks, it’s hard to argue with the production success the Hissongs have had with the system. Their calves routinely gain about 2.0 pounds per day, with less than 1% mortality, about 10-20% treatment rate for pneumonia, and “next to no scours,” according to Rod.

The milk-feeding system at Mercer Vu Farms is thoroughly washed and sanitized three times a week, and every pen in the calf barn is cleaned and sanitized between groups of calves. Rod said colostrum management also is of utmost importance for keeping calves healthy, and they’ve fine-tuned their ventilation system to improve air quality in the barn.

Overall, the Hissongs are pleased with the labor-efficient, low-overhead, welfare-promoting, high-performance calf-rearing system that has evolved in their operation. “What works for us might not work for somebody else, but through trial and error, we’ve come up with an approach that we really like,” said Rod.

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