Milk NAGase, CMT and antitrypsin as indicators of caprine subclinical mastitis infections

Abstract

Aseptic milk samples (962) from udder halves of 39 goats were collected sequentially for one lactation. After routine bacteriology, the samples were analyzed for California mastitis test (CMT), N-acetyl-β-D-glucosaminidase (NAGase), and antitrypsin. The prevalence of infected halves was 20.2%. All isolates belonged to staphylococci. All three inflammatory parameters showed elevated levels in the infected halves as compared to the healthy halves during the whole lactation period, with the exception of the colostral period. During the colostral period the infected halves gave lower values for NAGase and antitrypsin as compared to the healthy control halves of the same goats. Halves adjoining infected halves gave significantly higher values for CMT and NAGase as compared to healthy udders. Interhalf evaluation did not increase the diagnostic capacity of any of the three inflammatory parameters. Milk antitrypsin levels showed relatively less increase during subclinical staphylococcal infections than CMT and NAGase.