Thanks to El Niño and an unpredictable stratospheric warming event that began in Siberia (see "El Niño Weakening"), this winter has been colder and wetter across much of the nation, increasing a number of stocker challenges.
In Mississippi, for instance, Justin Rhinehart says wet and muddy conditions across the state have changed production practices and early performance of winter-grazing stockers. The Mississippi State University beef cattle specialist says one result is more foot rot.
"It's relatively common to deal with a few cases of foot rot as winter mud accumulates, but the excessive amount of rain has left few dry places for cattle to loaf,” he says. That means more challenge to the bottom line both in performance loss and treatment costs.
He says a three-year Kansas State University study estimated that calves with foot rot gain 0.45 lbs./day less than calves without foot rot. “Aside from the decrease in gain, treatment of calves with foot rot can become expensive and take time away from other management practices. Even if most of the calves don't contract this disease, excessive mud decreases performance of grazing and backgrounded calves by requiring them to use more energy for maintenance and normal movement,” he says.
Though experts say too much lameness in cattle is misdiagnosed as foot rot and improperly treated, it's estimated to account for about 25% of lameness in cattle, say University of Arkansas researchers Jeremy Powell and Brett Barham.
In a 2008 article, the duo explained that foot rot is primarily caused by infectious bacteria called Fusobacterium necrophorum, a pathogen commonly found in the intestinal tract of cattle and in the soil.
"It's been shown to survive in the soil for up to 10 months. For infection to occur there must be a compromise to the integrity of the hoof. Moist or muddy conditions allow for the hoof and surrounding skin to soften, and then any abrasion by rocks, forage stubble, nails or wire could allow entry of the bacteria, resulting in infection. Incubation for this disease is approximately 5-7 days,” they said.
If not detected early, Rhinehart explains, “the condition is easily identified by severe swelling from the dewclaws and the top of the hoof that extends to between the toes, spreading them apart. Early detection, through close observation, is extremely important to improve the effectiveness of treatment. However, spotting a swollen hoof is even more difficult in deep mud. This scenario is further complicated by the mud because calves will be naturally slower moving, making it difficult to spot the early onset of a limp.
“Calves affected by foot rot will display other signs of illness similar to respiratory diseases, such as elevated rectal temperature and visual indications. When using visual appraisal, one of the most important signals of illness is appetite suppression. Some research has demonstrated that feed consumption of cattle exposed to disease begins to decrease 48 hours before increased body temperature is observed. The most effective time to observe the feeding behavior of cattle is when they are fed each day,” Rhinehart says.
Since it’s difficult to monitor daily feeding patterns in grazing cattle, he emphasizes the importance of monitoring cattle for gut fill.
“Most stocker operators or backgrounders have had experience treating foot rot and similar infections but regular consultation with a veterinarian will provide new information on improved protocols and insight into a wider range of experiences,” Rhinehart says.
Most treatment protocols include systemic antibiotics and cleaning the affected area. But if the infection has progressed to the point that much of the tissue between the toes is rotted, surgical removal might be necessary. "Early detection is the most important aspect of combating foot rot when preventive measures become difficult due to harsh environmental factors such as excessive rain,” Rhinehart says.
Barham and Powell note that preventive vaccines are available and should be considered with the input of your veterinarian. “Beyond treating the affected animal, attention may need to be given to the environment," they say. "If muddy conditions exist in the pasture – especially around hay rings, loafing sheds or mineral bunks – then scraping the muddy area or moving the bunk/feeder may need to be considered. Treated cattle may need to be kept in a clean, dry pen during recovery.”