Greenberg Farms Ltd. is a fourth generation family farm. James (Jim) Greenberg, his wife Jackie, his sons Jeff and Jamie, and his daughter Janet all work on the farm. They are currently milking 500 cows on their dairy farm, and up until last fall were housing their cows in a converted machine shed with a manure pack system. It worked well except in the summer time, when the hot weather would cause mastitis problems with the manure. When the time came to construct a new dairy barn, Jim chose Structures Unlimited to complete the expansion.
Greenberg Farms had a large free stall barn when they were farming in a partnership in Michigan during the 70’s and in the summer time the barn got too hot. The steel building radiated too much heat, and while they had a lot of fans to circulate air, it just seemed to circulate the heat. The reason that they chose a Structures Unlimited building was that they were impressed with the results they had in their old manure pack system and converted shed as far as ventilation and health. “The Structures Unlimited buildings we had looked at were the lightest and best ventilated buildings of any that we had seen,” comments Jim. The biggest draw back to the bedded pack system is the cost of bedding, but by using a composting system they were able to reduce that. Instead, they aerate the pack twice a day while the cows are out grazing which in turn causes the bacteria to turn from anaerobic to aerobic.
In the autumn of 2006, they moved into the new Structures Unlimited building. They have had good herd health since they have been in the Structures Unlimited building and mastitis has not been a problem. The building is constructed with 6 foot (1.8m) concrete walls around the outside to accommodate the build up of the bedded pack. In this building, they have 3-4 feet (0.9m to 1.2m) of pack at the most and then the composting breaks it down decreasing the height.
Ventilation in the building is accomplished by a 16 inch opening under the eave of the building. This is equivalent in cubic feet of air transfer to 5 feet wide (1.5m) by 20 feet long (6.0m) ridge vents in every second bay of the building. “This is proven to give us more than adequate ventilation in the winter time with very little dripping from condensation, much better than metal buildings in my estimation,” suggests Jim. The pitch of the roof creates the natural ventilation that is not possible in a traditional barn. Most facilities have a slope equivalent to 4:12 while the Structures Unlimited building has a slope of approximately 6:12. Wayne Shroper, University of Minnesota Extension Services, has been working with compost bedded pack barns for about 6 years now. He comments that cow comfort is very important in these buildings, and a Structures Unlimited building has a lot of open area with excellent air movement and a lot of light coming in. “On a day like today where it is maybe 85°F(29°C) outside, it is considerably cooler in here,” states Wayne. “We have good fresh air movement.” This combined with the large volume of air space allows hot air to flow through the ridge vents in this large dairy barn.