Indicator Of Mastitis Research Articles

Antibodies Against Staphylococcus Aureus Nuclease in Bulk Milk As An Indicator of Mastitis in Dairy Herds

Titres of staphylococcal antinucleases and cell counts in bulk milk samples were compared as indicative criteria of the mastitis situation in dairy herds. The correlation coefficients between the prevalence rate of mastitis and the antinuclease titre and cell count, respectively, were of the same order of magnitude. The incidence of clinical mastitis showed a better correlation to the antinuclease titre than to the cell count. When cell counts and antinuclease titres were combined a more reliable selection of herds with a possible mastitis problem was achieved. The antinuclease test is consequently recommended as a supplement to cell counting when screening bulk milk.

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.

Heritability Estimates of Udder Disease as Measured by Various Tests and their Relationship to each Other and to Milk Yield, Age, and Milking Times

Paternal half-sib heritability estimates of milk yield, number of quarters infected with mastitis organisms, and number of quarters showing abnormal milk were obtained from an analysis of milking and mastitis data of 2,865 Holstein cows. The within-herd heritability estimate for daily milk yield was 0.353 and that for the number of quarters infected with Streptococcus agalactiae 0.196. The heritability estimates for the number of quarters infected with organisms other than Streptococcus agalactiae, number of quarters infected, and number of quarters showing abnormal milk were all below 0.1.Within-herd correlation coefficients were calculated among daily milk yield, milking data, age, and mastitis indicators. Age, stripping time, and machine-on time were positively correlated with daily milk yield. Older cows had longer machine-stripping times and machine-on times than younger cows. Older cows also showed higher values for all indicators of mastitis.

129. The Chlorine Content of Milk as an Indication of Mastitis

1. The importance of a rapid and simple test for the diagnosis of mastitis in cows is a question which has attracted considerable attention on the part of many workers. One such test based on the determination of chlorine in milk by a rapid method has been advocated recently by Rosell.2. The authors of this paper have made a careful examination of this method and compared the results obtained on samples of milk with those given by other methods known to yield reliable and reasonably accurate results.3. The direct titration of chlorine in milk with silver nitrate solution, without the removal of proteins, invariably gives high results, and, moreover, a satisfactory end-point is difficult to obtain.

The Leucocyte Content of Milk as Correlated with Bacterial Count and Hydrogen Ion Concentration for the Detection of Mastitis

Summary This paper presents experimental data concerning the laboratory diagnosis of mastitis in cows. Aseptically drawn milk samples representing the individual quarters of each udder were used. The following conclusions appear valid: (1)Of all the laboratory methods used in this investigation, the leucocyte content of milk is the truest indicator of mastitis. (2)Bacterial counts on blood agar were more reliable for detecting udder infections than those on plain agar because plain agar often failed to produce distinct colonies from the organisms which were responsible for the infection. (3)Hydrogen ion determinations by the quinhydrone and Brom Cresol Purple methods correlate with other laboratory methods used to determine udder infections. The changes in reaction, however, are so slight, except in extreme cases, that the results are difficult to interpret. (4)The leucocyte count seems to be the most reliable index of udder infection, due to the enormous numbers of leucocytes encountered in milk from infected quarters, and the generally high leucocyte content of milk drawn from apparently normal quarters of the same udders. The fact that the leucocyte content of milk remains constant after it is drawn adds to its reliability. (5)Analysis of 758 leucocyte counts seems to warrant the conclusion that milk from normal udders usually contains less than 50,000 leucocytes per cc., whereas milk from infected udders almost invariably contains more than 100,000 leucocytes per cc.