EurekaMag.com logo
+ Site Statistics
References:
53,869,633
Abstracts:
29,686,251
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on LinkedInFollow on LinkedIn

+ Translate

Assessment of the loss in milk yield due to subclinical mastitis tested with electrical conductivity



Assessment of the loss in milk yield due to subclinical mastitis tested with electrical conductivity



Japanese Journal of Zootechnical Science 58(10): 827-832



The effects of subclinical mastitis on milk yield were studied by analyzing data on quarter-milk yields and data on mastitis tests. Six cows were milked for the experiment twice a month by using a separate quarter-milker for 4.apprx.6 months. The quarter difference of electrical conductivity (QdEC) or of the concentration of chloride (QdCl) was used as a criterion for subclinical mastitis, in place of the conventional cell count. The QdEC value of each quarter milk is the difference in conductivity between the lowest among 4 quarter-milks from an udder and that of the other quarters in an udder. The degree of subclinical mastitis of a quarter was expressed by the mean value of the QdECs. A decrease in milk yield in a quarter was expressed by the quarter-milk yield ratio. (R: %). This is the ratio of a sum of actual milk yield from an affected quarter to a presumed sum of milk yield which would be produced from this quarter if the quarter were healthy. The ratio R was calculated according to the following procedure on the basis of assumptions as described below. Each milk yield obtained by a series of milkings from a quarter was expressed as a percentage of the yield at the first milking time for the quarter. These milk yields in percent are denoted as the relative quarter-milk yield, (relative yield, yi). When the quarters in a udder and healthy, the relative yield of each quarter in an udder should change coincidentally from one milking to the next, notwithstanding that milk yields in weight differ or that yields diminish gradually, and the sum of the relative yields (%) for each quarter (.SIGMA. yi) is assumed to be equal in an udder. Therefore, when a cow has at least one healthy quarter in an udder, its sum of relative yield should represent the sum of all of the other quarters when they were healthy. Then, the quarter-milk yield ratio, R (%), which assesses the loss due to subclinical mastitis over a few months' period for a quarter, is calculated as a percentage of the sum of relative yield for a quarter (.SIGMA. yi) to the sum for the healthy quarter in an udder (.SIGMA. yn). The healthy quarter was chosen by comparing the mean of the QdEC for 4 quarters in an udder and the quarter with the lowest mean was selected as healthy. We found a negative, highly significant correlation between the mean of QdEC and the ratio R for 24 quarters in 6 cows; the correlation coefficient, r=-0.72, (P < 0.001). The relationship expressed by a linear regression equation was; y=- (2.556 .+-. 0.531) x + 99.724, where x is the mean of the QdEC (10-4 S), and y is R (%) for a quarter. From the equation it was assessed that a 2.6% reduction in milk yield occurs for every 1 .times. 10-4 S increase in the mean of QdEC in the affected quarters. A similar relationship was found between the quarter difference of chloride (mM) and the ratio R (%). The correlation coefficient was; r=-0.75. In this paper, we discussed an example in an assessment on the milk loss in a herd, where frequency distribution of the mean of the QdEC for all quarters of the cows in a herd was known.

(PDF emailed within 1 workday: $29.90)

Accession: 001533200

Download citation: RISBibTeXText



Related references

The efficacy of in line measurement of quarter milk electrical conductivity milk yield and milk temperature for the detection of clinical and subclinical mastitis. Livestock Production Science 30(3): 239-250, 1992

The electrical conductivity of milk for the detection of subclinical mastitis in cows: comparison of various methods of handling conductivity data with the use of cell counts and bacteriological examination. British Veterinary Journal 134(4): 308-314, 1978

Milk electrical conductivity in cows with subclinical mastitis. Journal of Dairy Science 81(SUPPL 1): 41, 1998

The electrical conductivity of milk as a diagnostic of subclinical mastitis. Occasional Publication, New Zealand Society of Animal Production 8(Dairy production from pasture): 114-115, 1982

Reliability of testing the electrical conductivity of milk in subclinical mastitis. Praktische Tierarzt 75(11): 987-988, 990, 1994

Electrical conductivity of goat milk in evaluating subclinical mastitis. Proceedings of the 3rd AAAP Animal Science Congress, May 6-10, 1985 Volume 2: 1272-1274, 1985

Influence of treatment of subclinical mastitis on electrical conductivity of milk before milking. Berliner und Munchener Tierarztliche Wochenschrift 113(11/12): 440-443, 2000

Comparison of electrical conductivity of milk with other indirect methods for detection of subclinical mastitis. Journal of Dairy Science 68(2): 449-456, 1985

Electrical conductivity and lactose content of milk as sensitive indicators of subclinical mastitis. Conference on resistance factors and genetic aspects of mastitis control, Jablonna, 2nd 5th October 1980: 67-87, 1980

Relationship between subclinical mastitis and changes in milk lactoperoxidase and electrical conductivity in dairy cows. Chinese Journal of Veterinary Science 16(4): 397-399, 1996

Detection of subclinical mastitis with a handy instrument by measuring the electrical conductivity of milk. Livestock Adviser 17(11): 27-30, 1992

Diagnosing subclinical mastitis in the cowshed by measuring the electrical conductivity of milk with a portable instrument. Monatshefte fur Veterinarmedizin 44(22): 788-789, 1989

Cowshed diagnosis of subclinical mastitis using portable unit for measurement of electrical conductivity of cow milk. Monatshefte fuer Veterinaermedizin 44(22): 788-789, 1989

On the electrical conductivity criteria to be used to detect compositionally abnormal milk due to presumed subclinical mastitis. Kieler Milchwirtschaftliche Forschungsberichte 37(4): 360-363, 1985

The use of electrical conductivity measurements for the detection of subclinical mastitis in single, normal milk samples. Tieraerztliche Umschau 51(4): 216, 219-220, 1996