DNA Extraction from blood and matrix samples
Blood samples of 128 healthy cattle aged 2−14 years were collected from
regions of southern Italy (Basilicata, Calabria, Campania). All animals
were pasture-free, except for 30 cattle from intensive livestock
farming. Blood samples harvested in ethylenediaminetetraacetic acid
(EDTA)-acid-containing vacutainers were obtained from healthy cattle at
public slaughterhouses. Total DNA was extracted using a DNeasy Blood &
Tissue Kit (Qiagen, Wilmington, DE, USA) according to the manufacturer’s
instructions. Furthermore, DNA was extracted from samples of grass hay
and maize silage (used as feed for cattle) obtained from intensive
livestock farming. The DNeasy plant Mini Kit (Qiagen, Wilmington, DE,
USA) was used for the extraction of hay and maize DNA, according to the
manufacturer’s instructions.