by Karl H. Kazaks
UNION GROVE, NC — After milk prices collapsed in 2009, Nathan Souther decided to make big changes.
“We either had to get bigger or get out,” he said.
In 2009 the dairy was milking about 450 cows. Today it milks 750 Holsteins (3x).
To accommodate the more than 50 percent increase in herd size, Souther switched to direct loading of milk, expanded his housing for fresh cows, and built a calf barn. He also started bedding with sand in 2011.
“We used to treat maybe one a week, now it’s maybe one a month.”
The incidence of coliform mastitis, however, didn’t immediately drop when Souther switched to sand. He suspects that was because he was getting wet sand. So he started stockpiling sand to let it dry before using it as bedding. After instituting that step, the dairy’s rate of coliform mastitis decreased.
At first, Souther wasn’t reclaiming sand. When he cleaned out the first lagoon (with a capacity of one million gallons) in his dairy’s series of lagoons, he pumped the liquid out five feet and had 300 loads of sand to haul out.
The dairy invested in sand reclamation equipment in 2012. They bought two single piston 7.5 hp pumps (with 16 in. discharge) and a sand-manure separator with a hydrocyclone for fine sand recovery. Since then, Souther estimates he’s been reclaiming at least 90 percent of the dairy’s sand.
“It’s a substantial savings,” he said.
The dairy has three fresh cow barns. One pump is for the two barns located side by side, while the other serves the third. Manure is scraped to a reception area, where it falls into a concrete pit through steel slats.
Adjacent to each collection pit is a pump house. Inside the houses, the Futuros slowly push the manure-sand mixture to the separator through underground eight-inch pipe.
The pumps are activated with a switch on the outside of each pump house. When the pit is empty, sensors notice and turn off the pumps. Two minutes later the separator also shuts down.
At the separator, water is added to the paste-like sand/manure conglomeration and the mixture is pulled up an augur. Much of the sand is separated through this action, with the augur pulling the sand out of the water and manure.
In this method of treating sand-laden manure, however, the very finest sand tends to remain in the water. It can be reclaimed by sending the water through a hydrocyclone, a device Souther has attached to his separator. With it, he figures, he captures about an additional 10 percent of the sand used on the dairy.
The system is effective and economical but it does involve practice to get used to. As Souther said, “I’ve had to learn how to use the equipment.”
For example, he modified the separator by adding a metal table to allow the pumped manure and water to mix more quickly, at a point where the water is still rapidly flowing. This helps break up the manure, Souther believes, and results in more consistent sand. The modified table has a screen, for catching objects like large rocks.
When it rains, Souther has learned to turn off his pumps. He’s found that when the manure mixture is too wet (as when processing manure in the rain), the sand will settle in the underground pipes between the pumps and the separator. To fix the blockage, he had to remove a heavy elbow between the pump and the pipe and then mechanically loosen the sand collected in the pipe.
“We jabbed it out by hand,” he recalled, with a group of people taking turns knocking the built-up sand with a length of one-inch PEX pipe.
So now when it rains Souther just scrapes and fills his pits but waits to operate the pumps until the rain has passed.
To accommodate runoff during this waiting period, Souther has built overflow channels for each of his collection pits. The channels lead to his series of manure lagoons.
“I’m a man of backups,” he said.
For example, he has a bypass whereby if the pumps fail he can move manure directly from the collection pits to the first lagoon. Sand will collect in the lagoon like it did before Souther bought the reclamation equipment, but at least the dairy will have a way to handle its manure.
“If I had to do it again knowing what I know now, I would build settling lanes,” Souther said.
With such a design, he figures, there would be fewer mechanical issues, because he would be treating mostly sand (from the settling lanes) rather than sand-laden manure. There would also be less labor, he calculates. As it is now, Souther runs his sand reclamation system about 18 hours per day.
“It’s labor intensive. I want something to be as simple and user-friendly as possible,” he said. “At some point I will try to design settling lanes,” and incorporate them into his current system.
But he’s glad that he’s made the strides he has with his dairy, from the expansion to the lesser incidence of coliform mastitis to economizing on sand purchases.
“You don’t know it ‘til you’ve done it,” he said.
Dairy also gains with new calf barn
As part of the post-2009 transformation of his dairy, Nathan Souther built a calf barn in the fall of 2011. The first heifers raised in the facility are just starting to calve and are already good producers.
“They’re milking good,” Souther said.
Before building the calf barn, Mountain View Dairy housed its calves in hutches. The purpose of investing in a calf barn was to have calves ready to produce during their first lactation, rather than diverting energy to growth.
With the first cohort of barn-raised heifers freshening at 21 to 24 months and weighing about 1,300 pounds, Souther is pleased with how he’s been able to meet that goal.
The facility currently houses about 80 calves. Young calves (up to two weeks) are kept in individual pens.
Above them are heifers separated by age into groups of about 20. The barn typically houses four such groups, though if the dairy were to grow, the barn could be adjusted to hold eight total groups, for a total of 160 to 200 calves.
The barn includes an indoor space where milk is treated with a GEA UV pasteurizer and then kept at 35 degrees in one of two 300 gallon milk tanks. Calf machines draw milk from the tanks and heat the milk on demand, with calves being able to draw up to two or three gallons of milk per day.
Since building the barn, Souther has also modified his feeding program, giving young heifers grower pellets once they leave the barn (post-weaning).
“After giving them eight to 10 pounds of grain per day plus milk, when you switch them to three to five pounds of grain a day plus forage, sometimes heifers go backwards,” Souther said. The pellets help in the transition period as heifers get used to eating silage, and they “never go backward now.”
Of course, part of the reason for the heifers’ success is the dairy’s good deworming and vaccination program (which includes InforceTM for BRSV).
Overall, the calf barn was a significant investment. But to Souther’s figuring, investing in growing strong and healthy heifers is “only gonna make you more money in the end.”
Nathan Souther institutes sand reclamation as part of larger changes at Mountain View Dairy
by Karl H. Kazaks