文档介绍：Seasonal changes in somatic cell content in milk of Polish Holstein-Friesian cows
Maciej Gierdziewicz
The Faculty of Animal Sciences
Agricultural University in Cracow
鲜奶吧
Somatic cells in milk
In cattle breeding, the number of somatic cells in milk (Somatic Cell Count - SCC)
is monly accepted indicator of subclinical mastitis.
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Healthy cow – SCC up to 100 000 /ml
SCC depends on lactation number:
1st lactation cow –
up to 35 000 /ml
2nd lactation cow – up to 50 000 /ml
3rd lactation cow – up to 60 000 /ml
Cow with (sub)clinical mastitis – SCC
500 000
5 000 000
50 000 000
?
Somatic cells in milk (2)
COUNCIL DIRECTIVE 92/46/EEC, 16 June 1992: Health rules for the production and placing on the market of raw milk, heat-treated milk and milk-based products
„[...]
CHAPTER IV Standards to be met for collection of raw milk [...]
A. Raw cow's milk
[...]”
COUNCIL DIRECTIVE 92/46/EEC 16 June 1992 (continued)
„Somatic cell count (per ml)
400 000 (b)
(b) Geometric average over a period of three months, with at least one sample a month, or, where production levels vary considerably according to season, method of calculating results to be adjusted [...]”
Rozporządzenie Ministra Rolnictwa i Gospodarki Żywnościowej z dnia 29 września 1999 r. (Polish regulations)
Wprowadzone w normie zmiany obejmują:
[...]
2. Ograniczenie ilości klas jakościowych mleka.
[...] klasa Ekstra, klasa I i klasa II
Wymagania szczegółowe dla poszczególnych klas mleka:
Ekstra: Komórki somatyczne   - liczba w 1 ml
(SCC/ml limit)→ 100 000
Transformation of SCC to SCS
Somatic Cell Count is very variable:
0-1-10-100- ... 10 000 000 - 100 000 000 ...
logarithmic transformation:
SCS - Somatic Cell Score
SCS = log2(SCC/100 000) + 3
SCC 6 250 12 500 25 000 50 000 100 000 200 000 400 000 800 000
SCS -1 0 1 2 3 4 5 6 ...
Selected references I. General
Svendsen M., B. Heringstad, 2006:
Somatic cell count as an indicator of sub-clinical mastitis. ic parameters and correlatio