Objective of the present study was to determine calving
parameters in eighteen large dairy herds of Holstein
Friesian in Tabriz. Data analysis showed that the mean
gestations length were 276.69 ± 6.29, 279.54 ± 8.55 and
271.38 ± 7.34 days in multipara cows and twining
pregnancy respectively. Percent of premature birth were
24.14% in twining (28 cases out of in 116 births), 9.61% in
heife...
