Even though calves may have been on a backgrounding program for several months, it doesn't mean they are safe from subsequent health issues later on in the feeding period, explained Russ Daly, Professor and SDSU Extension Veterinarian, and Reid McDaniel, Assistant Professor and SDSU Extension Feedlot Specialist.
The Extension specialists outlined some possible health issues cattle producers should keep an eye out for, which may appear later in a backgrounding program.
Bloat, McDaniel explains, is one condition to be particularly attentive of following the introduction of calves to backgrounding rations. "In feedlot situations, frothy bloat is more common than free gas bloat," McDaniel said.
In frothy bloat, gas becomes trapped in tiny bubbles within the rumen fluid and pressure cannot be relieved through eructation, or belching. As pressure increases without relief, cattle may die of asphyxiation.
There are many contributing factors, McDaniel said, most of which are dietary in nature. "Particle size, grain type, and unmanaged diet adaptation can contribute to changes in the rumen microbial population, increasing the risk for frothy bloat and other metabolic disorders such as acidosis," McDaniel said.
In order to reduce sorting, McDaniel said rations should be mixed thoroughly and chop-length of roughages should be in the 1.5 to 2 inch range. "Sound bunk management is key to establish feed intake and reduce metabolic disorders," McDaniel said.
Proper use of approved feed additives or ionophores such as monensin, lasalocid, or laidlomycin and potentially probiotics, McDaniel said, can help alter rumen microbial activity in such a way as to decrease the incidence of frothy bloat.
He added that surfactants such as poloxalene, can also be offered in block form to help animals get through these issues, but nutritional management is key in reducing incidence of bloat. "Remember, sound nutrition is a key component to keep cattle healthy," McDaniel said.
Bovine respiratory disease complex (BRDC) tends to show up at a much lower rate later in the feeding period. However, Daly explained this doesn't mean that some of the same germs typically involved with "shipping fever" can't show up and cause problems in the later feeding period as well.
"In recent years, Histophilus somni, a common cause of BRDC, has been increasingly implicated in sudden death in the feedyard," Daly said. "Usually, these deaths occur in the absence of any visible pneumonia."
He explained that oftentimes, these mortalities are associated with bacterial damage in the heart muscle that results in a rapid onset of heart failure. "Anecdotally, clusters of these cases seem to occur especially after periods of bitter cold weather. Prevention of these infections is problematic. Vaccines are available to protect against disease caused by H. somni, but they are not always effective," Daly said.
Mycoplasma bovis is another bacteria commonly associated with BRDC that can pop up later in the feeding period.
"While Mycoplasma is a potential contributor to BRDC, its slow-growing nature means that it will often emerge long after the typical two-week post-arrival shipping fever period has passed," Daly said.
In addition to BRDC, Mycoplasma bovis can settle into the tissue around the leg joints, creating the appearance of swollen joints. As with Histophilus somni, vaccines are available to protect against Mycoplasma-related illness, but effectiveness is often lacking.
Early recognition of these cases, along with treatment with appropriate antibiotics, maximizes the chance of recovery in these animals.
"The list of ailments that could potentially affect calves later on in the backgrounding period is a long one," Daly said. "It's important to be able to sort out potential herd problems from individual animal issues."
He said working with a veterinarian to devise a plan to quickly perform post-mortem exams on any animal that dies during the feed period is important. Consult your nutritionist with concerns about feeding programs and management. "Rapid identification of problems can lead to rapid interventions and slowing down or stopping a herd problem in its tracks," Daly said.