DGfZ_24'11'03_Gerald Otto

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Christian-Albrechts-University Kiel Institute of
Animal Breeding and Husbandry
Investigations on somatic cell count in Swiss
dairy production systems
J.C. Bielfeldt1, R. Badertscher2, K.-H. Tölle1,
and J. Krieter1
1Institute of Animal Breeding and Husbandry,
Christian-Albrechts-University, Kiel,
Germany 2Swiss Federal Research Station for
Agricultural Economics and Engineering, Taenikon,
Switzerland
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Introduction

• 13 of involuntary cullings in Switzerland
• due to mastitis (Aeberhard et al., 1997)
• Somatic cell count (SCC) high genetic
• correlation(rg 0.8) to the susceptibility
• of mastitis (Dopp et al., 1998)

Analysis of fixed effects on SCC
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Data material

• Swiss Brown Cattle Breeders Association
• Monthly milk recording from 80,000 cows
• 1,674 farms (eastern central Switzerland)
• Information about the housing system
• Number of records 1,866,242
• January 1994 - May 2002
• SCS log2 (SCC/100,000) 3

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Data material
Characteristics of the data set
_
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Statistical analysis
Mixed model for SCS
Fixed effects housing system, zone,
calving age within lact.number Covariables
milk yield (kg), fat/protein (),
lactation day b0-b6 regression
coefficients Random effects herdyearseason,
animal
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Results
Least-square-means for SCS (n 1,866,242)
Zone
Housing system
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Results
Least-square-means for SCS (n 1,866,242)
2
3
gt3
1
Calving age in months (in column) within
lactation number
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Results
Lactation curves for SCS
Days in milk
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Discussion

• Clusters of risk factors with potential
• relationship to mastitis (Elbers et al., 1998)
• production indexes
• housing
• hygiene
• health disorders
• milking management
• milking machine

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Thank you for paying attention!
The authors thank the Swiss Brown Cattle
Breeders Association for preparatory work and
free supply of the data. The project was carried
out with the financial support of the Swiss
Federal Research Station for Agricultural Economic
s and Engineering Taenikon.