Effects of an immunomodulatory feed additive on intramammary infection prevalence and somatic cell counts in a dairy herd experiencing major health issues

Data from 350 herds enrolled in the Norwegian Dairy Herd Recording System (NDHRS) were used to investigate the associations between the first two cow-milk somatic cell counts (SCC) test-days’ results after calving or the three last SCC test-days prior to drying off in the first lactation and the hazard ratio (HR) of clinical mastitis (CM) during the remaining first or the subsequent second lactation respectively. Altogether, 9519 first lactations and 6046 second lactations were included. Cox regression analyses adjusted for herd frailty effect were used. In the first lactation, SCC>40000 cells/ml on the first or second test-day was significantly associated with an increased risk of a CM event in the remaining first lactation. HR, compared with 10000 cells/ml, increased from 1·6 (1·4) for SCC of 40000–60000 cells/ml to 6·9 (4·2) for SCC >800000 cells/ml, when using the first (second) SCC test-day in the first lactation. Cows with a geometric mean of the three last SCC test-days between 50000 and 100000 cells/ml and between 401000 and 800000 cells/ml in the first lactation had HR of CM during the second lactation of 1·3 and 2·8 respectively compared with a reference group of 10000–20000 cells/ml. If a CM episode in the first lactation occurred, the HR for having a CM event during the second lactation was 1·5. There was a significant frailty effect which disappeared if the incidence rate of CM at herd level was included in the model.

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Use of somatic cell counts and California mastitis test results from individual quarter milk samples to detect subclinical intramammary infection in dairy cattle from a herd with a high bulk tank somatic cell count

Journal of the American Veterinary Medical Association ◽

10.2460/javma.2004.224.419 ◽

2004 ◽

Vol 224 (3) ◽

pp. 419-423 ◽

Cited By ~ 26

Author(s):

John R. Middleton ◽

David Hardin ◽

Barry Steevens ◽

Richard Randle ◽

Jeff W. Tyler

Keyword(s):

Somatic Cell ◽

Somatic Cell Count ◽

Test Results ◽

Intramammary Infection ◽

Somatic Cell Counts ◽

Milk Samples ◽

California Mastitis Test ◽

Cell Counts ◽

Bulk Tank ◽

High Bulk

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Genetic parameters for somatic cell count for three dairy breeds in the united kingdom (uk)

Proceedings of the British Society of Animal Science ◽

10.1017/s0308229600028944 ◽

1995 ◽

Vol 1995 ◽

pp. 128-128 ◽

Cited By ~ 1

Author(s):

R A Mrode ◽

G J T Swanson ◽

M S Winters

Keyword(s):

Somatic Cell ◽

Cell Count ◽

Genetic Parameters ◽

Management Practices ◽

Dairy Herd ◽

Economic Loss ◽

Clinical Mastitis ◽

Average Cell ◽

Somatic Cell Counts ◽

Cell Counts

Mastitis constitutes a major source of economic loss in the national dairy herd. Although good management practices can produce a major reduction in mastitis, there is considerable interest in the reduction of mastitis through breeding. Somatic cell counts (SCC) have been used as a way of indirectly measuring sub-clinical mastitis within a herd. Since 1991, average cell count is obtained for all herds and this is used to adjust milk payments.Milk recording organisations introduced a cow cell count service in 1990. The data are now available for the preliminary analysis of the usefulness of somatic cell counts. The objective of this study was to estimate genetic parameters for SCC for three major breeds in the UK.

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