Pouring concrete is a commitment. Once the bones of a dairy facility are constructed, there are only so many adjustments that can be made to improve cow comfort, employee safety and efficiency, and animal flow.
That’s why it’s so crucial when building a new facility or expanding an operation to not only give plenty of thought to current animal and staff needs, but to also consider what space and facilities you may need in the future. Planning your barn dimensions, stall layout, parlor size, and manure storage carefully helps animals thrive in the immediate future and provides your business with long-term flexibility.
The Dairyland Initiative at the University of Wisconsin-Madison helps farmers with facility design and improvement, and outreach specialist Courtney Halbach offered advice for sizing and designing new and expanded facilities in a podcast discussion.
Three main limitations
There are three major facility factors that limit a farm’s ability to expand, outlined Halbach: manure storage, parlor throughput, and holding area capacity. She provided guidance on calculations to use when sizing a new operation or facility so these don’t become your limiting resources, too.
Every lactating cow will produce about 150 pounds, or 18 gallons, of manure each day. Halbach said a useful rough estimate to determine how much manure storage you will need is to account for 1 million gallons of manure per year for every 100 cows. A typical recommendation is to have enough storage for six months of manure.
But manure handling depends on more than just quantity; bedding type also plays a significant role in which structure will work best. Organic bedding types like sawdust are generally easy to use with something like a gravity flow system. Sand, on the other hand, despite its many cow comfort benefits, is more complicated to handle. Halbach said you will want to consider a vacuum system, scrapers, augers, or flumes to get sand-laden manure out of the barn.
Since every cow will go through the holding area and parlor two or three times every day, they must be able to accommodate the desired cow flow. In addition to the number of employees in the parlor and your prep routine, parlor capacity is determined by the number of stalls in the parlor. To size parallel or herringbone parlors, Halbach said to first determine the number of cows you need to have milked per hour by dividing the number of milking cows by 7 (for 3x milking, factoring in one hour of clean up per shift) or 10.5 (for 2x milking).
Then, divide that number by how many parlor turns you will achieve to determine the number of stalls needed. “We suggest a minimum of four turns an hour so there’s plenty of time for cows to transfer to and from the pen,” Halbach noted.
In a rotary setup, your throughput will largely depend on the platform speed. If you have a 72-stall rotary parlor running at a platform speed of five seconds per stall, each rotation will take about six minutes. An average cow will need 1.5 minutes to be prepped and 4.5 minutes to milk out, which meets that six-minute time frame. However, if cows are producing more than 80 to 90 pounds of milk, or your rotation is shorter than six minutes, depending on the number of stalls or platform speed, you will be putting a cap on how much milk cows have time to let down.
We want the holding area to be designed so that cows are not overly crowded and subject to heat stress while waiting to be milked, but we also don’t want to split up groups if the holding area isn’t big enough, Halbach continued. This is often a limiting factor to herd growth because the holding area is landlocked in between the barn and parlor with little, if any, room to expand.
Halbach recommended providing at least 15 square feet per cow in the holding area. Building for 20 square feet per cow, or 125% of your largest group, offers more wiggle room now and for any future growth.
Typically, the width of the holding area is fixed depending on the width of the parlor, but the length is adjustable. Halbach described that a rapid exit parlor will be roughly 40 feet wide, a parallel will be 30 to 38 feet wide, and a single exit will only be 20 to 22 feet wide. After you determine how much square footage you need in the holding area, depending on your largest group, use those approximate widths to calculate how long the holding area needs to be.
Keep resting time available
On the individual cow level, the most important part of planning a dairy is getting pen size and stall layout right to encourage and protect resting time. We want to allow cows to have between 11.5 and 12.5 hours of resting time each day. After also factoring in eating, drinking, and standing time, Halbach said we are left with approximately three hours each day when a cow can afford to be away from the pen without sacrificing resting time. Sizing your groups appropriately plays a role in this time budget so cows aren’t spending excess time waiting to be milked. “When thinking about group size, we’re not just looking at size and design of the parlor, but how much time we’re going to allow out of the pen for milking,” she said.
Halbach outlined that finding your maximum group size requires math that is the reverse of the calculations used for parlor capacity. Multiply the number of stalls in your parlor by the number of turns you achieve per hour. Multiplying that group size by 7 (for 3x) or 10.5 (for 2x) gives you the maximum herd size your parlor can accommodate without sacrificing resting time. These calculations account for the fact that milking order is not random; some cows are habitually the last in their group to be milked. We want to stay under that three-hour threshold even for those cows, Halbach encouraged.
When planning the pen itself, she strongly recommended against stocking densities over 100%. If there is less than one stall for every cow, lying time goes down and displacements by boss cows go up. She cited a study that found when stocking density went from one cow per stall to 1.5, lying time was reduced from 12 hours per day to 10.5 hours. “When we reduce lying time like that, we see an increase in lameness down the road,” Halbach stated.
Overstocking also limits access to feed and results in lower milk production. Aim for at least 24 inches of feedbunk space per cow in milking pens and 30 or more inches in transition cow pens. Halbach shared research that showed cows visit the feedbunk mostly when fresh feed was delivered or when it was pushed up. If cows couldn’t access feed at that time, they didn’t go back and try later on. That means that if there is not room for about 80% of a pen’s cows to be eating at one time, cows are missing out on a meal. Halbach also noted that headlocks at the feedbunk prevent displacements more than a post and rail system.
Adding crossovers is one way to create more feedbunk space in a pen. Halbach recommended having a crossover every 25 stalls in a milking cow pen and making them at least 14 feet wide so one cow can be drinking and two can pass behind her. When locating waterers, plan for at least two per group and 3.5 inches of linear water space perimeter per cow in the pen.
Don’t forget to allocate enough space for sick cows, either. This pen will typically have to accommodate 1.5% to 3% of your herd, Halbach said. A bedded pack is ideal; plan for 100 square feet per cow. If the pen has stalls, keep the stocking density under 100%. Also ensure these cows have at least 30 inches of feedbunk space.
While we are largely locked in to the facilities we have once they are built, careful planning can help dairies start off on the right foot and even have room for future changes. In existing facilities, evaluating group sizes, parlor capacity, and cow flow with these recommendations is a way to analyze animal performance and efficiency.
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