Fecal Rotavirus Antigen in Diarrheic Calves of High and Average Producing Holstein Dairy Cows

The difference in genetic potential and specific and non specific immunity (genetic immunity) and other unknown factors in diarrheic calves of high and average producing Holstein dairy cows may affect the level of rotavirus infection in diarrheic calves. Over one-year period, based on a random cluster sampling design, 661 fecal samples from natural cases of diarrheic calves were taken in Fars province (Iran). The samples were taken from the 267 diarrheic calves of high (HPDCs) and 394 diarrheic calves of average producing Holstein dairy cows (APDCs). Samples were collected based on 5 percent of herd population in 4 geographical regions: North, West, East and South of Fars province (Iran). The herds were stratified into small (50-100 cows), medium (101-200 cows) and large size (>200 cows). Laboratoiy investigation consisted of a direct identification test for antigens of rotavirus. Age and Parity of the dam was also recorded. Diarrheic rotavirus infected HPDC calves in southern region of Fars province were at much lower risk (P<0.05) than APDC calves. All herds had HPDC and APDC rotavirus infected diarrheic calves in their population. When considering the effect of age and parity of dams, the diarrheic rotavirus affected APDC calves of younger cows (>2 to 3years) showed a higher rate of infection when compared to diarrheic HPDC rotavirus affected Holstein calves. The rate of rotavirus infection in diarrheic APDC calves in southern region of Fars province was highest when compared to other geographical locations. There was a significant difference between the prevalence of rotavirus infection in diarrheic HPDC and APDC calves of Southern region (P<0.05). There were no differences among the occurrence of rotavirus infection in diarrheic HPDC and APDC calves of different herd size groups. Our results revealed that there are differences of rotavirus infection in diarrheic HPDC and APDC calves.