As farms grow, rotary parlors have become more common on dairy farms, and their efficiency is directly tied to three factors, according to the Miner Institute’s president, Heather Dann. These have been identified as parlor size, rotation time, and milking duration.
In a recent study conducted by Cornell University researchers and reviewed by Dann in a Miner Institute Farm Report article, an individual cow’s willingness or unwillingness to step onto the rotary can impact overall cow flow and the efficiency of the milking process.
“Stall unoccupancy occurs when a stall in the parlor remains unoccupied during a rotation,” explained Dann. “The study was conducted on a 5,000-Holstein cow dairy where cows were milked three times per day in a 100-stall rotary parlor. The parlor rotated at a speed of 4.8 seconds per stall, with milking done by four milking technicians at specific stalls.”
The Cornell University researchers evaluated the impact of individual cows that caused recurrent stall unoccupancy, which they defined as a cow that caused a stall in front of her to stand empty for the turn more than 37% of the time she was milked. This number was an arbitrary one decided on for this study, and applied to 124 cows out of 4,486 that were tracked by the study.
“Cows in their first and second lactations were less likely to experience recurrent stall unoccupancy compared to those in their third or greater lactations,” Dann detailed. “This is likely due to the social hierarchy, where older cows tend to be more dominant and create larger clearance zones.”
Additionally, early-lactation cows had lower odds of leaving the stall open in front of them than those greater than 100 days in milk. Cows that had higher somatic cell counts or those that were diagnosed with lameness before, during, or after the study period were more likely to cause recurrent stall unoccupancy.
The Cornell University scientists indicated that more research could help define the point at which stall unoccupancy by an individual animal would cause biological and economic relevance to the farm, but that the current study can help identify cows that might be impacting efficiency.
Dann suggested that considering unoccupied stalls could help farms find their optimal rotation speed for the parlor, minimizing empty stalls while maintaining overall efficiency. Finally, she emphasized the importance of cow health and reducing the number of mastitis and lameness events for cows housed and milked in these barns.
