Plasma Vitamin E and Blood Selenium Concentrations in Norwegian Dairy Cows: Regional Differences and Relations to Feeding and Health

Table 1 Description of variables used in the main statistical calculations

Variable	Description
Analytical:
TOC	Plasma a-tocopherol concentration, μg/ml
SEL	Blood selenium concentration, μg/g
Obtained from the questionnaires:
DATE	Date of blood sample
YIELD	Daily milk yield of sampled cow at sampling time, kg
CONC	Daily amount of concentrates fed to the cow at sampling time, kg
REGSIL	Daily amount of regular silage fed to the cow at sampling time, kg
QUALSIL	Quality of regular silage fed to the cow, scale 1–4
BALE	Daily amount of baled silage fed to the cow at sampling time, kg
HAY	Daily amount of hay fed to the cow at sampling time, kg
STRAW	Daily amount of ammoniated straw fed to the cow at sampling time, kg
MIN	Daily amount of mineral supplement fed to the cow at sampling time, g
Obtained from the Norwegian Dairy Herd Recording System and the Norwegian Cattle Health Recording System:
CALVNUMB	Parity number*
CALVDATE	Last date of calving
COWMAST	The sampled cow was treated for mastitis** in the same lactation*
COWACMA	The sampled cow was treated for acute clinical mastitis in the same lactation*
COWPARES	The sampled cow was treated for parturient paresis in the same lactation*
COWKETOS	The sampled cow was treated for ketosis in the same lactation*
COWREPRO	The sampled cow was treated for reproductive disorders in the same lactation*
Calculated from other variables:
DAYSPP	DATE - CALVDATE
TOTSIL	REGSIL + BALE

* Class variable.
** Encompasses all recorded mastitis treatments, included treatments for acute clinical mastitis, subacute/chronic and subclinical mastitis.

ISSN: 1751-0147