Bovine respiratory disease (BRD) is considered as one of the key health issues and is answerable for serious economic losses all over the world. This study aimed to determine a prevalence and proper treatment of Staphylococcus aureus and Pasteurella multocida isolated from calves had respiratory manifestations. Bacteriological examination of 45 nasal swab samples collected from respiratory manifested calves, revealed that 19(42.2%) and 13(28.9%) were S.aureus and P. multocida respectively. S. aureus and P. multocida displayed good sensitivity for gentamicin, ciprofloxacin and chloramphenicol, according to in-vitro antimicrobial susceptibility results.
Twenty calves, (3-5 month) were divided into 2 groups. Gr1: contain five of clinically healthy calves kept as a negative control group. Gr2: fifteen calves had respiratory manifestations and positive for S. aureus and P. multocida isolation (kept as positive control group), blood samples for hematological and biochemical studies were taken before treatment. Gr2 (diseased calves) sub divided into three equal groups (Gr3, Gr4 and Gr5) (five calves each). Gr3: were treated with Gentaprima® 1ml /25kg b.wt. I/M for 3 days. Gr4: were treated with Gentaprima® with the same dose+ MENTO-Z^® (1 ml/8 litre drinking water for 5 successive days) and Gr5: were treated with Gentaprima® with the same dose + Levamizole (single S/C injection at dose of 1 mg/50kg bwt).
From a bacteriological aspect, all swabs collected in 10^th day after treatment from groups (Gr3, G4 and Gr5) were negative for S.aureus and P. multocida isolation.
Hematological study concerning to RBCs count, Hb concentration and PCV% revealed significant decreases in diseased, 3^rd and 10^th days after treatment calves in compared with positive control group. Diseased calves showed significant decrease in PH, PO₂ and SO₂% while there were significant increase in PCO₂, tCO₂ and HCO₃ compared to control animals. At 3^rd and 10^th days post treatments PH, PO₂ and SO₂% recorded significant increase and PCO₂, tCO₂ and HCO₃ showed significant decrease in comparison with diseased group before treatment. In regard to phagocytic index and percentage showed significant decrease in diseased calves compared with control, meanwhile there were significant increase in phagocytic index and percentage in Gr4 and Gr5 at 3^rd and 10^th days post treatment in compared with diseased group.
Biochemical finding demonstrated significant increase in serum protein, globulin, glucose, AST and creatinine as well as haptoglobin and fibrinogen in diseased calves compared with control one. Marked improvement in the mentioned parameters in all treated groups at 3 days post treatment which returned to the normal level at 10 days post treatment compared with control one.