Indicator Of Subclinical Mastitis Research Articles

Preliminary studies on the prevalence of Mycoplasma bovis mastitis in dairy cattle in Australia

A highly sensitive and specific PCR (MB-PCR) was used in preliminary studies to detect M. bovis in milk samples to investigate its association with high somatic cell count (SCC), an indicator of subclinical mastitis and one of the factors in down grading the quality of milk. A total of 186 and 167 herds were tested with 43% and 62% of herds positive for M. bovis in Victoria and North Queensland, respectively. The quarter milks from 52 cows with persistently high SCC were tested by MB-PCR and culture to investigate the association of M. bovis with major mastitis pathogens (MMP). M. Bovis was detected in 77% of cows of which 19% alone had M. bovis without any other bacteria, 17% had M. bovis in combination with major mastitis pathogens and 40% had M. bovis in combination with non-major mastitis pathogens. We believe that M. bovis is widespread in dairy cattle and has the potential to produce disease alone or to predispose the udder to disease caused by major mastitis and environmental pathogens. These studies have revealed a hitherto unrecognised high prevalence of M. bovis in dairy cattle in North Queensland and Victoria in Australia. These initial studies also give a clear association between M. bovis and elevated somatic cell counts.

Milk N‐acetyl‐B‐D‐glucosaminidase and Serum Albumin as Indicators of Subclinical Mastitis in the Camel

NAGase activity (NAGase) and serum albumin concentrations were determined in milk from 101 traditionally managed camels in the Sudan. NAGase, a lysosomal enzyme released from damaged epithelial cells as well as other somatic cells in milk, was recorded for quarter milk samples from camels (n = 353) using the fluoroscan method. NAGase activity in major pathogen-infected quarters was significantly (P < 0.05) higher than in minor pathogen-infected and non-infected quarters. Means for minor pathogen-infected quarters were also significantly higher than non-infected quarters. Concentrations of serum albumin, resulting from increased vascular permeability, in quarter milk samples (n = 320) were measured by the radial immunodiffusion test. Serum albumin content in milk was not affected by infection status of the quarter. There were, however, large variations in serum albumin levels and, to a lesser extent, NAGase values between samples in both infected and non-infected quarters. NAGase was more effective in predicting bacteriological status of the quarter than serum albumin.

Electrical Conductivity of Milk for Detection of Mastitis

The potential value of electrical conductivity of milk as a screening test for subclinical mastitis was evaluated. Conductivity of foremilk and of post-milking strippings from 368 quarters of 92 cows was measured. Infection status of quarters was determined by bacteriological analysis of strict foremilk samples. Infections were classified as by primary or secondary pathogens, depending on the importance of the isolated organism as a mastitis pathogen. Somatic cells were counted on foremilk samples.Milk conductivity increased with infection. Conductivity of postmilking strippings was higher than that of foremilk in samples from quarters infected by primary pathogens. By thresholds which correctly classified at least 90% of normal quarters, accuracy of identifying primary pathogen infections by absolute conductivity was 62.8 and 96.2% with foremilk and postmilking strippings. Differential conductivity and combination of absolute and differential methods also were evaluated with the latter being the most effective. Number of quarters with elevated conductivity of postmilking strippings tended to be higher when somatic cell count was greater than 500,000/ml in both normal and infected groups. Conductivity of milk seems to hold promise as an indicator of subclinical mastitis.

Oxidative enzymes in milk and their value as indicators of sub-clinical mastitis in the cow.

Oxidative enzymes in milk and their value as indicators of sub-clinical mastitis in the cow.