Is everyone familiar with the old adage that cows should stand for 30 minutes after returning from the parlor? For years, dairy farmers have been told to encourage cows returning from the parlor to remain standing to decrease the chance of intramammary infection. With intramammary infections often leading to mastitis and a subsequent $1.7 to 2 billion loss annually to the U.S. dairy industry, ensuring that the age-old practice of having your cows stand following milking has scientific merit is key. The thought behind ensuring that cows remain standing following milking lies in that 30 minutes of standing should provide sufficient time for the teat canal sphincter closure prior to coming in contact with the bedding material or stall. This closure will then reduce the chances of bacteria entering into the teat canal and potentially resulting in an intramammary infection. However, where does the 30 minute recommendation come from and more importantly does the time a cow needs to stand to reduce the potential for intramammary infection alter with farm management?
When comparing post-milking standing time in tie-stalls to freestalls, it’s important to consider the differences that may occur simply due to animal handling and facility differences. A Canadian study in 2010 found that the incidence of intramammary infections in those cows housed in tie stalls decreased when post-milking standing time ranged between 40 and 60 minutes. However, the same study found that when post-milking standing time increased to greater than 60 minutes, the incidence of intramammary infections, particularly those caused by environmental pathogens, increased.
A similar study completed in freestall facilities with automatic milk systems concluded that the incidence of intramammary infection for cows with post-milking standing times greater than 2.5 hours increased significantly.
Not only is it important to consider the impact of housing on post-milking standing time and intramammary infection, but also the effect of milking frequency. A recent study completed by Watters and collaborators in Eastern Ontario found that post-milking standing time was longer in free-stall dairy herds that were milked three times a day. Moreover, those cows that were encouraged to stand for 90 to 120 minutes after milking had a reduced incidence of intramammary infections.
If you want to give increasing post-milking standing time a try on your farm there are several low cost options. Decreasing the stocking density of your freestall may increase the post-milking standing time of your cows. A study conducted by the University of British Columbia in 2007 showed a 13-minute increase in post-milking standing time when the stocking density was decreased from 150 to 100%. In addition to increasing post-milking standing time, reducing stocking density may also reduce competition at the feed bunk which can result in increased post-milking standing time. Finally, increasing the frequency of feed push-ups, as well as fresh feed delivery, can increase post-milking standing time by enticing cows to the feed bunk directly following milking as well as reducing competition at the feed bunk during peak feeding times.
Reducing the incidence of intramammary infections cannot be achieved solely through increasing post-milking standing time. Proper milking procedures must still be followed in the parlor. Ensuring that your staff is milking clean and dry udders with properly maintained equipment is also essential to lowering the incidence of intramammary infection.
Source: William H. Miner Agricultural Research Institute
