DETECTION OF BOVINE HERPESVIRUS 1 (BHV-1) INFECTION IN SEMEN OF INDIAN BREEDING BULLS BY POLYMERASE CHAIN REACTION AND ITS CHARACTERIZATION BY DNA SEQUENCING

Bovine herpesvirus 1 (BHV-1), the causative agent of infectious bovine rhinotracheitis (IBR), is considered to be the most common viral pathogen found in bovine semen. BHV-1 is associated with several clinical conditions, including infectious bovine rhinotracheitis, infectious pustular vulvovaginitis, balanoposthitis, conjunctivitis and generalized disease in newborn calves, causing great economic loss to the livestock industry. A total of 101 semen samples from breeding bulls of different Artificial Insemination Centres were screened for the presence of viral genome by employing PCR using two sets of primers viz., gB1/gB2 and gC1/ gC2 from gB and gC genes coding for viral envelope. Viral DNA was extracted from semen using QIAamp DNA Mini Kit and was then subjected to PCR. In gB gene based PCR, 47 (46.53 %) semen samples were found to be positive, producing an amplified PCR product of size 478 bp. While in gC gene based PCR, 43 (42.57 %) were found to be positive for presence of viral genome, producing an amplified PCR product of size 173 bp. In comparison of the efficacy of the primers, the results of these two primers were in agreement for 95 samples out of the 101 tested samples. Thus, both the primers can be applied effectively in detection of BHV-1 DNA in semen. In sequencing of gB-gene based PCR products, a consensus sequence of 459 bp was obtained. The sequences of field isolates matched completely with the sequence of BHV-1.1. Finally, the study revealed the presence of BHV-1 in the semen of breeding bulls of Gujarat. Thus, under the Sexual Health Control Programme proper measures must be taken at the State level for controlling BHV-1 infection. The bulls must be free from BHV-1 infection prior to use