Abstract
This study aimed to assess the impact of S. aureus as well as Non-aureus Staphylococci and Mammaliicocci (NASM) subclinical mastitis-causing in the economic return in dairy herds. Data were gathered from the databases of five dairy herds located in the Agreste region of Pernambuco state, Northeastern Brazil, over a period of three consecutive months. A total of 155 mammary quarters from 155 healthy cows were categorized into the healthy group. Meanwhile, 257 mammary quarters from 187 cows that tested positive for either S. aureus or NASM were categorized into the infected group. The effect of mammary quarter infection in economic return was estimated using milk payment criteria on milk samples from healthy vs. infected cows based on a linear mixed model. Milk yield and milk price influenced the economic return, and both varied according to factors like herd, parity, stage of lactation, period of analysis, and the type of pathogen causing subclinical mastitis. There was a reduction in the average economic return caused by NASM infection (by 0.41 to 0.65 US$/cow/day) and S. aureus infection (by 0.25 to 0.36 US$/cow/day), when considering the effect of the pathogen over time for 1 and ≥ 2 infected quarters. Although no significant differences were observed in economic return between healthy cows and those infected with NASM or S. aureus, it is important to collect data on these pathogens for a more precise assessment of the economic impact of subclinical mastitis and for developing enhanced approaches for prevention and control.