بررسی مقدماتی وضعیت آلودگی گله های گاوهای شیری به ویروس BVD در نمونه های شیر مخازن (Bulk Milk Samples) با استفاده از روش Nested RT- PCR

Bovine viral diarrhea virus (BVDV), a member of the Pestivirus genus, is an important pathogen of dairy cattle which can cause several clinical syndromes ranging from subclinical to sever disease such as early embryonic death, abortion, congenital defect or the birth of persistently infected (PI) calves which are immunotolerant to the agent. The objective of the present pilot study was to detect the presence of BVD virus in somatic cells from bulk milk samples by the use of a nested RT-PCR as a screening test. In total, the bulk milk of 18 dairy cattle herds in Mashhad suburb of Iran, covering 4105 milking cows were tested for BVD virus presence. None of the herds had been vaccinated against BVDV. RNA was extracted from somatic cells of bulk tank milk samples. Oligonucleotide primers were selected based on the 5′ untranslated region BVD virus genome. BVD virus was detected in 2 (11.1%) out of 18 industrial herds representing 742 milking cows. According to the high sensitivity and specificity of nested RT-PCR test, it is concluded that this invaluable procedure is less complicated and cost effective for detection of BVD virus as a reliable screening test in dairy cattle herds. This study revealed that, at least 11.1% of bulk milk samples examined were BVDV positive, indicating the presence of PI milking cows in dairy cattle herds in Mashhad suburb of Iran.

Keywords:

BVDV , Nested RT-PCR , Bulk milk