Author: ksubci

Cattle producers who manage newly-weaned feeder cattle recognize that calves that are castrated and dehorned, trucked, commingled with new pen-mates, and given a completely new diet – all near the time of weaning, are at high risk for bovine respiratory disease. Pneumonia or bovine respiratory disease (also known as BRD) can be caused by a combination of several factors. These factors are stress (shipment, mixing with new cattle, and diet change), viral infection, and bacterial infection. BRD is generally considered to be a disease of stocker or feedlot cattle that are trucked to a feeding facility, commingled with new animals, and exposed to new feed and water sources. Age is also a factor with recently weaned calves and light stocker calves having higher sickness and death risk than yearling cattle.  

Preconditioning programs aim to reduce the number of stressful situations that a feeder calf has to deal with as it is moved from the ranch of origin to a stocker or feedlot operation. Trucking and exposure to new animals is unavoidable in most situations, but other known stresses can be managed. Preconditioning programs have been designed by universities, pharmaceutical and biological companies, marketing groups, and integrated production chain alliances.  The overall target of decreasing the risk of BRD and other diseases is the same among different preconditioning programs, yet specific requirements can vary widely.  For example, preconditioning programs for cattle entering an all-natural program may differ from programs for cattle in a traditional management scheme.  Other examples include the utilization or prohibition of specific vaccines, dewormers, growth implants, feed additives, and feed ingredients. 

Castration and dehorning have been shown to severely decrease feed intake and gain and increase the risk of disease when done at the feedlot. If these stresses can be done earlier in life (<2-4 months of age), the negative effects are greatly reduced. Castration prior to shipment is one of the oldest and most common components of preconditioning programs.  Bull calves that are not castrated until they arrive at a feedyard or stocker facility have higher risk of illness and death and decreased performance relative to comparable steer mates.  Whether or not bull calves have been castrated is easy to tell, and castrated calves typically garner higher prices than comparable intact bull calves. 

Because viral diseases such as IBR (infectious bovine rhinotracheitis) and BVD (bovine viral diarrhea) are associated with BRD, vaccination programs to decrease the risk of infection with these viruses are key components of preconditioning programs. Vaccines directed against bacteria that are associated with BRD such as Mannheimia haemolytica, Pasteurella multocida, and Haemophilus somnus are included in some preconditioning programs, but not all. The challenge in developing the best vaccination strategy is to select the correct vaccines and to deliver them in the best fashion and at the correct times to create a response that will protect the calves. 

Weaning on the ranch of origin for 30 to 45 days is a component of many preconditioning programs.  Calves in these systems face relatively low levels of disease challenge because they are not trucked or commingled with new cattle during the stressful period immediately following separation from their dams and tend to have comparatively low risk of becoming sick.   

Preconditioning programs may also require that calves become accustomed to grain-based feeds fed in a feedbunk. The greatest risk for BRD occurs soon after arrival to the feedyard, and adequate nutrition in the first weeks is critical to allow the animal to overcome stress and disease challenges. Better feed intake in the arrival period is believed to be strongly influenced by familiarity with feeds other than grass or hay and by feeding behaviors other than grazing. Inclusion of a period allowing cattle to understand the procedure for eating from a bunk in the low-stress environment of their home ranch is a valuable component of a complete preconditioning program.   

Feeder calf nutritional status is difficult to evaluate visually, but body condition is often used as a gauge of previous management.  Preconditioning programs that incorporate weaning and feeding for a period of time may result in cattle with good flesh scores at the time of sale.  Fleshy cattle may be viewed as healthier, yet still garner a price discount because buyers will be unable to capture compensatory gains.  The goal is to find a balance between healthy calves with adequate nutritional status and the potential for rapid, efficient weight gains after the calves leave the ranch. 

Adding management such as dehorning and castration, vaccinating, weaning and starting on a grain-based diet are designed to reduce the risk of disease once an animal has left the ranch of origin, but these activities will increase costs for cow-calf producers. In order to benefit from these expenditures, producers must increase the income they receive for their calves (price ´ pounds). Preconditioned calves routinely receive a higher price than similar calves that have not been preconditioned, but net income includes not only the price received, but also the total weight sold and costs incurred; therefore, producers considering a preconditioning program should calculate the difference between their cost of weight gain and the increased value of the weight gain. Before determining the economic risks and rewards of preconditioning, several factors including the marketing method and timing, cyclical market fluctuations, fixed costs (overhead), variable costs (primarily feed), and the goals of the producer should be considered.  

Cow-calf producers may face obstacles to implement preconditioning management on their ranch due to lack of facilities and labor necessary to keep weaned calves on the farm, or from a reluctance to bear the health risks for post-weaning calves. In some areas of the country, raised or local feedstuffs are not available at a price that allows low cost of gain. These obstacles are legitimate reasons that some producers should not precondition their calves. To overcome these obstacles, producers must be able to utilize cost-effective weaning, working, and feeding facilities, obtain feed at a competitive cost, grow the calves at a high enough rate of gain to allow a low cost of gain, and sell the calves in marketing channels and to buyers that reward preconditioning. Another consideration that supports increased utilization of precondition by cow-calf producers is that beef production is shifting toward a consumer focus and new areas are achieving more attention including: individual animal identification, value-based marketing, animal health and welfare, food safety, as well as source, process, and age verification.  These changes in the beef industry are compatible with concepts of preconditioning management and should serve to generate further interest in preconditioning throughout the beef production chain. 

Calves running with their dams on grass pastures are considered to be at low risk for developing pneumonia because they are not facing any of the risks typically associated with bovine respiratory disease (i.e. trucking, commingling, diet change, etc.). However, every year, outbreaks of “summer pneumonia” in calves occur in some herds. The viruses and bacteria that are associated with summer pneumonia of suckling calves are very common and it is assumed that they are present in every herd of cattle. Therefore, these disease-causing germs are only a problem if they are able to multiply in the lungs to the point where they cause enough damage for the calf to show signs of illness.  

Even though the well-known stresses that often contribute to pneumonia in weaned calves are not present in suckling calves on pasture; stresses such as dust, temperature swings between afternoon highs and nighttime lows, or close contact with other calves are believed to increase the risk of summer pneumonia.  

Because cattle grazing pastures are not typically observed daily, the first sign of problems may be finding one or more dead calves with other calves showing signs of pneumonia such as rapid breathing, laying down and being reluctant to rise, and having a high rectal temperature. I recommend that a necropsy be performed on calves that are found dead in the pasture in order to look for signs of pneumonia or other potential causes of death. A number of other causes of loss in suckling calves such as: blackleg, sudden death caused by Clostridial perfringens, trauma, and digestive tract disease can be differentiated from pneumonia by a necropsy examination. In some situations, tissue samples may be sent to a diagnostic laboratory for further investigation.  

Calves that exhibit signs of pneumonia should be treated with injectable antibiotics to combat bacterial causes of respiratory disease. If treated early enough in the disease process, many calves are likely to recover; however, calves with advanced lung damage may not respond to treatment. If the pneumonia is caused by a virus such as bovine respiratory syncitial virus (BRSV), antibiotic treatment will not be a directly effective treatment. In addition to antibiotic treatment, young calves with pneumonia should be protected from weather extremes, dusty conditions, and poor forage – this may require moving them and their dam to a new pasture or grass-trap.  

Because a number of different bacteria and viruses can cause pneumonia in suckling calves, prevention is focused on: protecting calves from environmental stress, ensuring that adequate forage is available for the dam and calf, as well as maintaining good herd immunity with available vaccines. Some veterinarians recommend that herds with a history of summer pneumonia vaccinate young calves at “turn-out” or “branding time” with vaccines against the viruses IBR (infectious bovine rhinotracheitis), BVD (bovine viral diarrhea), PI3 (parainfluenza 3), and BRSV (bovine respiratory syncitial virus) as well as bacteria that are associated with pneumonia such as Mannheimia haemolytica, or possibly Pasturella multocida and Histophilus somni. The theory behind this strategy is that summer pneumonia is most likely to occur as the immune protection from the dam that the calf received in colostrum is declining and before the calf develops its own immunity to common pneumonia-causing germs. The specific vaccines that you should consider should be decided by working with your veterinarian to identify your risk and likely effectiveness of calf vaccinations. Following the label directions and working with your veterinarian will help guide the selection of the type and timing of vaccination to reduce the risk of summer pneumonia. 

It may not be possible to completely avoid the risk of an outbreak of pneumonia in suckling calves, but focusing on good overall health of the cows and calves by: meeting the herd’s nutritional needs, providing a good environment, and timely use of vaccinations in the cows and calves are important tools. If calves are affected with pneumonia while suckling their dams on summer range, they should be given the best possible care and treated with appropriate antibiotics. No one likes dealing with summer pneumonia of calves, but working to decrease the risk and being prepared to recognize and treat cases early are the best methods to be prepared to minimize losses.