Hoof health is crucial to a dairy cow’s overall well-being – and in turn milk production and the farm’s bottom line. Yet, through all the industry-standard approaches to proper hoof health, different seasons put greater pressure on hoof health in a dairy herd than others and call for a pivot in management. Summer heat is one of those times.
“Looking at hoof health data, we see an increase in problems one month after that first hot spell of the summer,” says Lee Erickson, dairy technical specialist with Zinpro Corporation. “That first hot spell is when we see the highest heat stress for dairy cows.”
Erickson spoke with Progressive Dairy editor Matti McBride in the Progressive Dairy Podcast episode “Managing hoof health in the heat.”
The great heat stressors
Implications of heat stress begin long before the dog days of summer.
Erickson says cows will start showing signs of heat stress when temperatures are as low as 68ºF, particularly when optimal barn ventilation is not occurring.
“What’s important is the heat and humidity index,” Erickson says.
When the heat index – or apparent temperature – reaches that threshold, cows do not eat and standing time greatly rises, which leads to an increase in lameness incidences. Erickson says until the animal’s core body temperature returns to normal, they will continue to stand on their feet and reduce feed intake.
“It makes me think of us doing cardio on the treadmill or running,” Erickson says. “Even after we’re done, we still feel hot. Cows are the same way. You have to look at the respiration rate, and anything north of 60 breaths per minute means the cows are still hot.”
Effects on the feet
Dairy producers are likely to see lameness rates increase following the bout of heat, particularly with non-infectious diseases such as toe and sole ulcers and white-line lesions. Those are indicative of poor cow comfort, such as overcrowding in cooler areas of the barn, excessive standing time or even changes in bedding, which all cause additional wear on the hoof, notes Erickson as examples.
“The goal would be to say no to overcrowding in freestall pens,” Erickson says. “I understand the economics of it, but overcrowding has a huge impact on behavior, on eating time, lying down time.”
Erickson stresses that if a pen is overcrowded and negatively impacting cow comfort, then those lactating animals are not reaching the recommended 12 hours of lying time, which is directly related to poorer hoof health.
If farm personnel notice an increase in infectious diseases, such as digital dermatitis (DD) or foot rot, action should be taken soon thereafter. Erickson says these conditions could be caused by a change in the footbath or another hygiene problem on the farm.
Both infectious and non-infectious diseases can be identified by weekly assessments of lameness.
“Ideally, we would have every cow on the dairy looked at once a week,” Erickson says. “We can do that with locomotion scoring and watching the cows walk.”
For large dairies, Erickson recommends having the same person tasked with identifying lameness, spending a couple of hours each day watching cows walk.
“That way, we can detect the early stages of lameness,” he says.
Remedies to combat heat stress
Hoof health challenges related to heat stress can be avoided with improved cow comfort that reduces heat stress incidences. Mitigation tactics include running sprinklers in the holding area and using water soakers where the cows are leaving the milking parlor. Erickson says consistent water application to soak the skin initiates evaporative cooling for the cow. It is also important to have proper airflow throughout the freestall barn.
“Cows associate darkness with cooler temperatures,” Erickson says. “Maybe the sidewall opened to the south for sunlight is causing the stall surface to get hotter. Put up the shade some so those outside rows stay cooler and encourage cows to lay down, creating healthier feet.”
Soft and level bedding applied daily will also promote lying time.
“There are three keys to get cows to lay down: air movement, soft and level beds, and the frequency of bedding on a daily basis,” Erickson says.
For producers perhaps designing a new barn build, the most crucial element they can consider to avoid lameness incidences is adequate airflow.
“We want to make sure there’s a lot of air moving above where the cows lay down, particularly where their head is,” Erickson notes.
Treating lameness as a special need
Heat stress adds a complicated layer to hoof health management, but it does not have to be a limiting factor in reaching good herd health and longevity. Erickson recommends caring for a lame cow the same way special-needs cows are cared for.
“On a dairy farm with a lame cow, we should see this lame cow as a special-needs cow,” he says. “We need to treat her in a different way than a healthy cow.”
Lame cows should be trimmed and appropriately treated, then placed in a pen that is not overcrowded. One week following the treatment, the hoof should be rechecked to ensure the lesion is healing properly.
“At that time, we might notice more loose hoof or necrotic tissue that needs to be removed to facilitate the cow recovering more quickly,” Erickson says.
Then, the cow should be rechecked in another five weeks. At that time, the treatment should have been effective, and the cow can return to the milking herd.
“Managers hear this and think this is a lot of work,” Erickson says. “It is a lot of work. If we’re rechecking after one week, then five weeks later, this gives the cow the best chance of recovery. We only get one chance to do it right, and we have to do all we can to facilitate healing.”
Of course, Erickson notes, the most effective way to manage lameness is to prevent it.
