Effect of residual calf suckling on clinical and sub-clinical infections of mastitis in dual-purpose cows: epidemiological measurements.

The effect of residual calf suckling on sub-clinical (SM) and clinical mastitis (CM) in dual-purpose cows was assessed. Prevalence, incidence rate, and relative risk were determined from 30 cows allocated to two treatments: (i) residual calf suckling once after milking (RCS) and, (ii) no residual calf suckling (NRCS). The overall prevalence of SM and CM, at cow and at quarter levels was higher in NRCS cows (P<0.05). The incidence rate of CM for NCRS and RCS cows was 53 cases per 10,000 animal-days at risk, and eight cases per 10,000 animal-days at risk, respectively. Cows that did not suckle their calves after milking were 6.59 (3.15-13.93) times more likely to develop CM than cows which did suckle after milking. In both experimental groups, coagulase-negative staphylococci were the most frequently isolated pathogens, followed by Staphylococcus aureus and Pseudomonas aeruginosa. Eliminating the practice of residual calf suckling presents a high risk for development of mastitis in dual-purpose cows.