Rightfully, we pay a lot of attention to newly-arrived or newly-weaned calves entering the backgrounding yard. We implement receiving protocols that include vaccinations, dewormers, and sometimes preventive medications in the feed or water. Finally, we institute “enhanced surveillance” during the first few weeks after arrival to quickly find calves in need of individual treatment. However, even though those calves may have successfully cleared the one-month hurdle post-arrival, subsequent health issues can still arise later on in the feeding period
Bloat is one condition to be particularly attentive of following introducing calves to backgrounding rations. In feedlot situations, “frothy” bloat is more common than “free gas” bloat. In frothy bloat, gas becomes trapped in the rumen fluid and pressure cannot be relieved through eructation. As pressure increases without relief, cattle often die of asphyxiation. There are many contributing factors, 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. In order to reduce sorting, 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 establishing feed intake and reducing metabolic disorders. Proper use of approved feed additives such as ionophores (e.g., monensin, lasalocid, or laidlomycin) and potentially probiotics, can help alter rumen microbial activity in such a way as to decrease the incidence of frothy bloat. 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 keeping cattle healthy.
Bovine respiratory disease complex (BRDC) tends to show up at a much lower rate later in the feeding period. However, that 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. Usually, these deaths occur in the absence of any visible pneumonia. 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.
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 2 week post-arrival “shipping fever” period has passed. 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 againstMycoplasma-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 Bottom Line
The list of ailments that could potentially affect calves later on in the backgrounding period is a long one. It’s important to be able to sort out what are potential herd problems from the individual animal issues. 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.