N-acetyl -β-D-glucosaminidase activity in cow milk as an indicator of mastitis

Abstract

Activity of lysosomal N-acetyl-β-d-glucosaminidase (NAGase) in milk has been used as an indicator of bovine mastitis. We studied NAGase activity of 808 milk samples from healthy quarters and quarters of cows with spontaneous subclinical and clinical mastitis. Associations between milk NAGase activity and milk somatic cell count (SCC), mastitis causing pathogen, quarter, parity, days in milk (DIM) and season were studied. In addition, the performance of NAGase activity in detecting clinical and subclinical mastitis and distinguishing infections caused by minor and major bacteria was investigated. Our results indicate that NAGase activity can be used to detect both subclinical and clinical mastitis with a high level of accuracy (0·85 and 0·99). Incomplete correlation between NAGase activity and SCC suggests that a substantial proportion of NAGase activity comes from damaged epithelial cells of the udder in addition to somatic cells. We therefore recommend determination of NAGase activity from quarter foremilk after at least six hours from the last milking using the method described. Samples should be frozen before analysis. NAGase activity should be interpreted according to DIM, at least during the first month of lactation. Based on the results of the present study, a reference value for normal milk NAGase activity of 0·1-1·04 pmoles 4-MU/min/μl for cows with ≥30 DIM (196 samples) could be proposed. We consider milk NAGase activity to be an accurate indicator of subclinical and clinical mastitis.

Amplified Fluorescence by ZnO Nanoparticles vs. Quantum Dots for Bovine Mastitis Acute Phase Response Evaluation in Milk

“…Decreased milk production yield, unsatisfying product quality and increased treatment costs are all proportionally correlated to the severity of the occurring BM [4,5]. The disease is classified as chronic, clinical and subclinical based on the induced pathogenesis [2,6,7]. The latter (>90% of BM cases) is difficult to detect due to the absence of any visible indications, as in the case of clinical BM (visual milk abnormalities, tissue swelling and redness, systemic illness, etc.)…”

“…Lactate dehydrogenase and N-acetyl-β-d-glucosaminidase (NAGase) are predominant indicators of BM, which correlate with the SCC levels found in milk [3]. These enzymes are released upon damage to or lysis of epithelial cells of the mammary gland, therefore representing augmented health status [1,6]. NAGase peripheral distribution in plasma increases (up to an order of magnitude) upon inflammation or infection with respect to healthy conditions [1,3,10,11].…”

“…NAGase peripheral distribution in plasma increases (up to an order of magnitude) upon inflammation or infection with respect to healthy conditions [1,3,10,11]. NAGase lysosomal activity is used to differentiate healthy quarters from all other inflamed statuses based on a fluorescence (FL) methodology developed by Kitchen et al [2,6,12]. Briefly, the method includes the specific lysosomal breakdown of 4-methylumbelliferyl-N-acetyl-β-d-glucosaminide (4-MUAG) substrate to fluorogenic products of 4-methylumbelliferone (4-MU) in alkaline conditions [6,12].…”

“…NAGase lysosomal activity is used to differentiate healthy quarters from all other inflamed statuses based on a fluorescence (FL) methodology developed by Kitchen et al [2,6,12]. Briefly, the method includes the specific lysosomal breakdown of 4-methylumbelliferyl-N-acetyl-β-d-glucosaminide (4-MUAG) substrate to fluorogenic products of 4-methylumbelliferone (4-MU) in alkaline conditions [6,12]. Despite the known advantages of the procedure, e.g., being simple, rapid and affordable, it suffers from low quantum efficiency and low sensitivity in differentiating subclinical cases [13].…”

S100 calcium‐binding protein A12 as a diagnostic index for subclinical mastitis in cows

“…Milk from cows with clinical mastitis (CM) generally contains >500,000 cells/ml (Guan et al, 2017;Smith, 1996;Sun et al, 2017). N-acetyl-β-D-glucosaminidase is used to measure cell damage, which is closely correlated with SCC and can be used to diagnose mammary gland infection (Guan et al, 2017;Hovinen et al, 2016;Williams, Marschke, Nottingham, & Kitchen, 1991). However, no single indicator can reflect all aspects of mastitis adequately.…”