Effect of omitting post-milking teat disinfection on the mastitis infection rate of dairy cows over a full lactation

Abstract Fifty-six autumn calving Holstein-Friesian dairy cows were milked as one herd over a complete lactation. Right-sided teats were disinfected post-milking by submersing teats in a chlorohexadine solution, while teat disinfectant was omitted on left-sided teats. Milk samples were taken from individual quarters to measure SCC on thirteen occasions during the lactation. Mean somatic cell count was lower (P<0.01) in milk from disinfected compared to non-disinfected quarters over the full lactation. The number of clinical infections was also significantly lower (P<0.001) in disinfected compared to nondisinfected quarters. Omitting teat disinfection also resulted in a higher (P<0.01) number of non-haemolytic staphylococci and Staphylococcus aureus pathogens in those quarters compared to disinfected quarters