Bovine respiratory disease (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. 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.
OTHER TOPICS IN THIS CHAPTER
Respiratory Diseases of Cattle
Overview of Respiratory Diseases of Cattle
Allergic Rhinitis and Enzootic Nasal Granuloma in Cattle
Sinusitis in Cattle
Necrotic Laryngitis in Cattle
Tracheal Edema Syndrome of Feeder Cattle
Bovine Respiratory Disease Complex
Enzootic Pneumonia of Calves and Shipping Fever Pneumonia
Viral Respiratory Tract Infections in Cattle
Bacterial Pneumonia in Cattle
Contagious Bovine Pleuropneumonia
Interstitial Pneumonia in Cattle
Acute Bovine Pulmonary Emphysema and Edema
Anaphylaxis in Cattle
Hypersensitivity Pneumonitis in Cattle
Diffuse Fibrosing Alveolitis in Cattle
Acute Respiratory Distress Syndrome of Feedlot Cattle
4-Ipomeanol Toxicity (Moldy Sweet Potato) and Perilla Ketone Toxicity (Purple Mint Toxicity) in Cattle
Toxic Gases in Respiratory Disease of Cattle
Vena Caval Thrombosis and Metastatic Pneumonia in Cattle
