May 21, 2009, Dublin, TX – A weeping-wall manure-settlement basin and
cross-ventilated dairy barns that work like huge swamp coolers were
just a few of the features showcased during the Southwest Dairy Day.
May 21, 2009, Dublin, TX – A weeping-wall manure-settlement basin and cross-ventilated dairy barns that work like huge swamp coolers were just a few of the features showcased during the Southwest Dairy Day.
More than 600 people and 70 agricultural business vendors attended the event, which was hosted by the Sierra Dairy and the Texas AgriLife Extension Service.
Owned by the Vander Horst family, the Sierra Dairy milks 3,500 cows twice daily; fresh cows, four times a day, with a production ranging from 57-65 pounds of milk per cow per day.
A state-of-the-art feature of the dairy tour was the weeping-wall manure-management system. A 3,500-cow dairy produces a lot of liquid and solid manure and it must be managed and recycled properly, said Dr. Saqib Mukhtar, AgriLife Extension waste-management engineer. The first step is to separate the solids from the manure slurry as it is flushed out of the barns. This allows recycling of the separated effluent to be reused for flushing manure alleys.
Some liquid-solid separation systems are energy intensive and require pumping of flushed manure from free-stall alleys to a mechanical system where the solids are screened out, then the effluent is conveyed back to a lagoon and recycled for flushing and irrigation, he said.
The weeping-wall system installed at Seirra Dairy uses a wide, long and deep sedimentation basin instead, and gravity does much of the work, he said.
The Sierra Dairy has two eight-foot deep weeping-wall systems. One has four chambers, with each chamber about 40-feet wide and 300-feet long. The secondary weeping wall consists of two chambers, each about 40-feet wide and 80-feet long.
“The chamber walls have weep holes in them that can be anywhere from a half inch to one inch, and the flushed manure from the barns is conveyed to these weeping-wall systems,” Dr. Mukhtar said. “The liquid goes into one or two chambers of the weeping wall.”
For this dairy, after solids separate out in the first weeping wall, the liquid is pumped from a small holding pond to the secondary weeping wall, he said.
“Then the effluent is conveyed back to the lagoons where it is used to flush manure from the barns,” he said.
Though the weeping-wall system was well-designed and a good fit for Sierra Dairy, despite what salesmen may tell, it's not for everyone, Dr. Mukhtar said.
“Not everyone needs one of these,” he said. “I can tell you this because I’m not selling these systems. I work for Texas AgriLife Extension, not for the manufacturer.”
Dr. Mukhtar is the lead organizer for the upcoming Texas Animal Manure Management Issues Conference, set Sept. 29-30 at Round Rock in Austin area. For more information on the conference see http://grovesite.com/tamu/tammi/.
Attendees were also treated to a bus tour of Sequoia Calves, which is touted as the only cross-ventilated cow barn in the U.S.
The facility has more than 1,000 calves under one roof that uses open ventilation.
Other barn designs use fans to move air lengthwise and the sides are left open or draped (also called open free-stall barns). Cross ventilation barns are closed on all four sides and the air is pulled through pads in which water flows, a large-scale version of what are commonly known as swamp coolers. The design means greater cow comfort as the blown air keeps the cows cooler and can reduce the negative effects of summer heat.
