香蕉牛奶.ppt

Seasonal changesin somatic cell contentin milk of PolishHolstein-Friesian cows
Maciej Gierdziewicz
The Faculty of Animal Sciences
Agricultural University in Cracow
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.
线电缆电力电缆低烟无卤电缆 p://
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/EEC16 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 Rolnictwai Gospodarki Żywnościowejz 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 referencesI. General
Svendsen M., B. Heringstad, 2006:
Somatic cell count as an indicator of sub-clinical mastitis. ic parameters and correlations wi