In this study, the efficacy of a combination rotavirus, coronavirus/Escherichia coli vaccine (Kolibin RC) in a dairy herd of Mashhad suburb was evaluated. Thirty pregnant cows were selected and randomly sub-divided in two groups. Cows in one group (15 head in total) were vaccinated 6 weeks before calving and again 3 weeks later (no significant adverse reaction were noticed), cows in the other group (15 head in total ) were left as unvaccinated controls. After calving, colostrum was collected from each cow and stored at 4°C separately until used for feeding calves. The quality of colostrum was assessed by use of colostrumeter which measured specific gravity. Blood samples were taken from jugular vein at 48 hours and weekly intervals for measuring hematology indices and serum total protein, albumin and serum protein electrophoresis. At each time, weight, length, heart girth and height of calves were measured. Also disease occurrence and weight gain were recorded for the one month of life. The results were analysed with statistic package SPSS 9 (t-test). P<0.05 was considered as significant. There were no significant differences between groups for hematology indices, total protein,serum protein electrophoresis concentration, disease occurrence and performance records. These results indicated that vaccination (Kolibin RC vaccine (of the dams during pregnancy were not helpful in reducing the incidence of neonatal diarrhea in new born calves in this herd.

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