Effects of Tilmicosin Treatment on the Nasopharyngeal Microbiota of Feedlot Cattle With Respiratory Disease During the First Week of Clinical Recovery

Abstract

While the nasopharyngeal (NP) microbiota is believed to be a key player in bovine respiratory health, there is limited published information about the change of NP microbiota associated with clinical recovery from bovine respiratory disease (BRD). The objective of this study was to evaluate the effect of tilmicosin treatment on the NP microbiota composition and diversity of BRD-affected calves during the first week of clinical recovery. Deep NP swabs were collected from diseased calves at the initial diagnosis of BRD, and again 7 days after the administration of a single dose of tilmicosin. As an experimental control, samples were collected from clinically healthy, pen-matched calves at the time of initial BRD diagnosis. In general, the NP microbiota from the control calves were more diverse than the NP microbiota from tilmicosin treated and BRD-affected calves. Principle coordinate analysis (PCOA) of Bray-Curtis and Jaccard dissimilarity also revealed that the overall composition of NP microbial communities in tilmicosin-treated calves closely resembled that of BRD-affected calves but differed significantly from pen-matched healthy calves. Overall, it appeared that there were only minor changes in NP microbial communities following tilmicosin treatment and, during the early phase of clinical recovery the NP microbiota in treated animals was disparate from that observed in healthy control calves. Understanding the potential impact of this prolonged recovery in mucosal microbiota would be important in optimizing the use of antimicrobials in health management programs in the feedlot industry.

Welfare of cattle during transport

“…Respiratory disorders, such as BRD, are caused by different bacterial and viral pathogens (Grissett et al., 2015) and have been associated with cattle of most ages (Earley et al., 2017; Cirone et al., 2019). Although studies of respiratory microbiota associated to BRD are actively ongoing, only a limited number of studies have been performed to investigate the longitudinal changes of the microbiota of calves diagnosed with BRD compared to healthy calves or its evolution after antibiotic therapy (Timsit et al., 2016; Zeineldin et al., 2020).…”

Bovine respiratory microbiota of feedlot cattle and its association with disease

“…Additionally, diseased animals often have altered eating habits, such as inappetence, are sometimes offered diets higher in roughages such as hay, and may also receive antimicrobials in their diet, which may also impact the respiratory microbiome. Moreover, there are multiple factors that affect the URT microbiota and eventual microbial shifts in newly weaned calves, including antibiotics, external environments, stress, and host immunity [ 11 , 15 , 105 , 106 ]. Recently, a study confirmed that a single injection of antibiotic including oxytetracycline and tulathromycin led to changes in the nasopharyngeal and fecal microbiota, and increased the relative abundance of several antibiotic resistance genes in these two communities later [ 28 ].…”

Metagenomics Reveals That Proper Placement After Long-Distance Transportation Significantly Affects Calf Nasopharyngeal Microbiota and Is Critical for the Prevention of Respiratory Diseases

“…Losing the balance of beef cattle’s nasopharyngeal microorganisms contributes to the morbidity and mortality associated with bovine respiratory diseases (BRDs) ( Holman et al, 2015 ; Zeineldin et al, 2017 ). Hence, the nasopharynx microbial community is regarded as the respiratory health situation indicator, especially BRD ( Qi et al, 2021 ; Zeineldin et al, 2020 ).…”