“The problem with both is they are not delivering fresh air throughout the entire barn, and fans need to run 100 percent of the time,” he said.īut that’s not the case in the all-seasons design. However, Jones believes tunnel and cross ventilation have their shortcomings. Over the years, the standard naturally ventilated barn with open curtains and fans over the beds and feed rails evolved to include mechanical ventilation means. The all-seasons hybrid could mark the next generation of freestall barns.
Goat dairy barn design full#
He added, “Every extra hour in bed with a full rumen is now 5 pounds of milk.” Jones credits this increase to a barn environment that encourages cows to do their job: “Stand to milk, stand to eat and drink, and lay down.” Combined with other improvements, like reducing overcrowding and widening the main street to the milking parlor to 26 feet, the herd’s milk production increased from 80 to 85 pounds per day, topping at 108 pounds per day, in just six months. The prototype barn ventilation system has proven itself thus far by standing up to the weather extremes, from more than 20 days of zero or below temperatures last winter to a peak of 100 degrees last summer.
High-velocity/low-speed fans placed every 80 feet mix air and bring it down. Looking up to the roof, an overshot ridge allows warm air to escape the barn, and a controllable vertical curtain prevents precipitation and snow from entering. To enclose the barn, a curtain is lowered to cover the fans from the outside. When it dips below 10 degrees F, the exhaust is reduced down to four continuous air exchanges per hour, which is sufficient to successfully prevent manure from freezing in the barn. At 68 THI, the curtains automatically close and fans turn on to create positive ventilation with an air exchange rate of 40 exchanges per hour at 70 degrees, building up to 60 exchanges per hour by 80 degrees. The curtains are open and no fan power is needed. When the temperature-humidity index (THI) is under the heat stress threshold, the design leverages the advantages of natural ventilation. “We are not blowing the soaking water onto the feed,” Jones added. No fans are placed over the feeding area. Angled at 22 degrees, the fans blow onto the cows as they rest in head-to-head beds, and the air stream carries all the way to the feed lane to cool the backs of cows. The ratio is one fan for every four stalls. The arrangement includes 3-foot-diameter fans placed every 10 feet, running both lengths of a four-row freestall barn with 16-foot sidewalls. “It doesn’t matter where you are in the barn, every cow now has equally fresh air,” Jones said. The non-traditional fan array, coupled with thermostatically controlled curtains, work in tandem to provide appropriate air exchange and direct cool air delivery precisely where it needs to be – at the cow level. Jones worked with a northeast Wisconsin dairy family to implement the all-seasons hybrid prototype into both a new barn design and renovation of the farm’s existing buildings. On the coldest days of winter, manure does not freeze and during the hot, humid days of summer, cows don’t bunch or exhibit signs of heat stress. So far, in the first couple of barns that have been built or retrofitted with the design, that’s been achieved. Jones is calling this concept the “all-seasons hybrid” barn because it easily adjusts to temperature fluctuation throughout the year. “It’s positively ventilated part of the year, naturally ventilated the rest.” Gordie Jones, DVM, a partner in Central Sands Dairy in Wisconsin, and a world-traveling dairy nutrition, facilities, and cow comfort consultant. “The newest freestall barn we’ve come up with is a combination hybrid barn: natural and positive ventilation,” according to Dr. A novel barn ventilation design brings the two methods together to create a controllable environment with big-time cow comfort payoffs. When building a dairy barn, choosing between natural and mechanical ventilation can be a tough decision. Click here for Jones' PowerPoint presentation.
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