Investigation of Bovine Respiratory Disease in Dairy Calves in Bahri Locality, Sudan

Abstract

Bovine respiratory disease (BRD) is considered the major cause of economic losses in dairy and beef cattle production due to its high morbidity and mortality rates. Opportunistic bacteria are factors for the development of BRD. This study was aimed at investigation of BRD in dairy calves in Bahri locality, Sudan. The study was carried out during six months of the years 2019 and 2020. This simplified scoring system which used assessed six clinical signs.  When present, a specific number of points were assigned for each sign. A total score of 5 or higher classified an individual as a BRD case. Among 450 dairy calves investigated for presence of BRD, 40 calves (8.9%) were positive for the scoring system. Out of the 40 dairy calves positive for BRD scoring system, 24 (60%) were male calves. Out of 40 dairy calves positive for BRD scoring system, 25 (62.5%) 1 month old, 5 (12.5%) were 1.5 month, 4 (10.0%) were 2 months, 2 (5.0%) were 2.5 months and 4 (10.0%) were 3 months. Out of 40 dairy calves positive for the scoring system in Bahri Locality, 40 (100.0%) appeared nasal discharges, 31 (77.5%) eye discharges, 33 (82.5%) coughing, 25 (62.5%) difficult breathing, 13 (32.5%) fever and 29 (72.5%) Ear drop or head tilt. In this investigation a total of 43 bacterial isolates were obtained from 40 nasal swab samples collected from pneumonic calves in Bahri locality. The identified bacteria according to bacteriological examiations were: 8 S. aureus (18.6%), 3 S. epidermidis (6.9%), 2 S. chromogenes (4.7%), 5 Str. Pneumoniae (11.6%), 2 Str. uberis (4.7%), 3 K. pneumoniae (6.9%), 7 E. coli (16.3%), 6 Ps. aerogenosa (13.9%), 2 B. subtilis (4.7%), 2 M. variens (4.7%) and 3 M. luteus (6.9%). Staphylococci represented the predominant bacteria (30.2%) isolated from nasal swabs compared to other bacteria E. coli (16.3%), Streptococci (16.3%), Ps. aerogenosa (13.9%), Micrococci (11.6%) K. pneumoniae (6.9%) and B. subtilis (4.7%).