Use of metaphylactic protocols based on the risk to develop bovine respiratory diseases in feedlot cattle

Abstract

Bovine respiratory diseases (BRD) affect production rates negatively because it compromise health and well-being of the affected animal. The hypothesis of this study was that the use of metaphylactic protocols based on the risk to develop BRD would reduce morbidity and pulmonary lesions. For this purpose, the aims of this study were to evaluate the effect of two metaphylactic protocols on the morbidity of feedlot cattle with a known sanitary history, occurrence of pulmonary lesions at slaughter, and the possible participation of Mannheimia haemolytica, Histophilus somni, Bovine alphaherpesvirus 1 (BoHV-1) and bovine respiratory syncytial virus (BRSV) in the development of BRD. An experimental study was designed in which 3,094 adult, male, cattle, were grouped according to the risk to develop BRD: a) group without metaphylaxis (n=2,104), low-risk animals; b) metaphylaxis group with oxytetracycline (n=789), moderate-risk animals; c) metaphylaxis group with tildipirosin (n=201), high-risk animals. All cattle were immunized against pathogens associated with BRD (BoHV-1, BVDV, BRSV, PI3). The morbidity for BRD was 8.2% (253/3,094); cattle within the moderate-risk group for BRD had the lowest frequency (6.1%), followed by high-risk animals with tildipirosin metaphylaxis (6.5%) and low-risk without metaphylaxis (9.1%) (P=0.019). At the abattoir, 1.2% of lungs with lesions were found. There was a difference (P=0.036) in the frequency of pulmonary lesions between healthy animals (1.1%) and those diagnosed with BRD (2.8%). Two agents associated with BRD were identified by PCR assays in the lungs (n=37) of cattle: M. haemolytica (16.2%) and H. somni (5.4%). In addition, concomitant infections involving these pathogens were identified in the lungs of two steers. These results demonstrate that the use of metaphylactic protocols, based on the risk to develop BRD, reduces morbidity and pulmonary lesions in affected cattle. Furthermore, pulmonary lesions were more frequent in animals with a history of BRD.

The Participation of a Malignant Catarrhal Fever Virus and Mycoplasma bovis in the Development of Single and Mixed Infections in Beef and Dairy Cattle With Bovine Respiratory Disease

“…In Brazil, information relative to the occurrence of BRD is limited when compared with studies from North America (25)(26)(27)(28) and Australia (29,30). Previous studies done in Brazil were designed to investigate a single (31)(32)(33)(34)(35)(36)(37) or several agents (2,16,(38)(39)(40)(41)(42)(43) associated with BRD. These studies focused on the molecular identification of agents, with and without the histopathologic diagnosis of the patterns of pulmonary disease.…”

Bovine respiratory disease in Brasil: a short review

“…Several studies done in Brazil have demonstrated concomitant action of respiratory agents of BRD (Baptista et al, 2017;Beuttemmuller et al, 2017;Magalhães et al, 2017;Tortorelli et al, 2017;Gaeta, Ribeiro, Alemán, Yoshihara, & Nassar, 2018;Oliveira & Pelaquim, et al 2020;Oliveira & Dall Agnol, et al 2020) using molecular identification with or without histopathological and immunohistochemical diagnoses. This trend of concomitant infections in BRD is evident in other countries such as in the USA (Fulton et al, 2009;Schneider, Tait, Busby, & Reecy, 2009;Taylor et al, 2010), Canada (Gagea et al, 2006;Booker, Abutarbush, Morley, Jim, & Pittman, 2008;Jim, 2009), and Australia (Cusack, McMeniman, & Lean, 2003;Moore et al, 2015;Hay et al, 2016).…”

“…The affected cattle suffer the effects of individual disease agents or more often by a combination of several pathogens (Fulton & Confer, 2012), so clinical evaluations must include the examination of several animals of the same farm (Caswell, Hewson, Slavić, DeLay, & Bateman, 2012). The DART system that evaluates the clinical signs (depression, appetite, respiratory, temperature) of pulmonary disease, is recommended for the clinical evaluation of animals with BRD (Wilson, Step, Maxwell, Wagner, & Richards, 2015), and has been used in several studies by our group Magalhães et al, 2017). However, the isolated use of clinical manifestations is not the best method to diagnose BRD (Fulton & Confer, 2012).…”

“…Control of BRD can best be accomplished by focusing on integrated programs of vaccination against pathogens causing BRD and improvements in nutritional status, especially for calves exposed to stress conditions. Among the prevention strategies, vaccination against the main causative agents of BRD plays an important role in feedlot cattle, since animals immunized animals and booster vaccination prior to entering the feedlot were found to be 2.5 times less likely to develop BRD than those that received vaccination when entering the feedlot (Magalhães et al, 2017).…”

“…In Brazil, a study using oxytetracycline and tildipirosin in metaphylactic protocols for prophylaxis of BRD demonstrated that these drugs were efficient in reducing both morbidity and lung lesions in feedlot cattle (Magalhães et al, 2017). Florfenicol has also been shown to be efficient in the metaphylaxis of BRD in feedlot cattle, reducing clinical manifestations and improving the development of the animals economically viable (Catry, Duchateau, Van de Ven, Laevens, & Opsomer, 2008).…”