We discuss getting and keeping this year's calf crop healthy.  Plus, updates on Beef imports and exports, new possible genetic defects, markets, recaps, sales and more on this all new episode of the Ranch It Up Radio Show. Be sure to subscribe on your favorite podcasting app or on the Ranch It Up Radio Show YouTube Channel. EPISODE 189 DETAILS BOVINE RESPIRATORY DISEASE (BRD), MANAGE IT NOW.  OVERVIEW OF BOVINE RESPIRATORY DISEASE COMPLEX Bovine respiratory disease (BRD), shipping fever pneumonia, or undifferentiated fever is a respiratory disease of cattle of multifactorial etiology with Mannheimia haemolytica and, less commonly, Pasteurella multocida, Histophilus somni ( see Histophilosis), or Mycoplasma bovis being the important bacterial agents involved. Viral pathogens may also be involved, such as bovine herpesvirus 1, parainfluenza-3 virus, and bovine respiratory syncytial virus. BRD has a multifactorial etiology and develops as a result of complex interactions between environmental factors, host factors, and pathogens. Environmental factors (eg, weaning, transport, commingling, crowding, inclement weather, dust, and inadequate ventilation) serve as stressors that adversely affect the immune and nonimmune defense mechanisms of the host animal. In addition, certain environmental factors (eg, crowding and inadequate ventilation) can enhance the transmission of infectious agents among animals. Many infectious agents have been associated with BRD. An initial pathogen (eg, a virus) may alter the animal’s defense mechanisms, allowing colonization of the lower respiratory tract by bacteria. BRD is most commonly associated with the transport and assembly of large groups of recently weaned calves into feedlots. Morbidity in these types of feeder calves often peaks within the first 7–10 days after feedlot arrival. Morbidity can approach 35%–50%, and case fatality is 5%–10%; however, the levels of morbidity and mortality strongly depend on the array of risk factors present in the cattle being fed. The use of broad-spectrum antimicrobials labeled for bovine respiratory disease is the primary treatment, with macrolides and fenicols most commonly used as first-line treatment. Prevention and control are achieved via vaccination programs, preconditioning, identification and treatment of subclinically infected animals, and biosecurity. Etiology of Bovine Respiratory Disease The pathogenesis of bovine respiratory disease involves a stress factor, sometimes coupled with viral infection, which results in suppressed immune defenses and the proliferation of bacteria in the upper respiratory tract. Subsequently, these bacteria colonize the lower respiratory tract and cause bronchopneumonia with a cranioventral distribution in the lung. Many of the bacteria and viruses involved are commensal organisms of the upper respiratory tract that can be isolated from a proportion of healthy animals. Multiple stress factors contribute to the suppression of host defense mechanisms in cattle. Weaning is a noteworthy stressor, and the incidence of this disease is highest in recently weaned calves. Transportation over long distances serves as a stressor; it may be associated with exhaustion, starvation, dehydration, chilling, and overheating, depending on weather conditions. Additional important stressors include passage through auction markets; commingling, processing, and surgical procedures on arrival at the feedlot; dusty environmental conditions; and nutritional stress associated with a change to high-energy rations in the feedlot. The individual viral and bacterial etiologies, clinical signs, lesions, and treatment are discussed under Viral Infections Associated with Bovine Respiratory Disease Complex in Cattle and Bacterial Pneumonia in Cattle with Bovine Respiratory Disease Complex. Viruses associated with BRD include: bovine herpesvirus 1 (IBR) bovine respiratory syncytial virus parainfluenza-3 virus bovine viral diarrhea virus bovine