D
AYS OPEN (DO) is considered one of the most important parameters used to determine the
reproductive performance of dairy buffalo farms. It is known as the duration between calving
and the next pregnancy, minimizing this period helps control the calving interval and thus the
reproductive efficiency of the buffalo farms. So, the aim of this study was to apply the Poisson
regression model to determine factors influencing days open (DO) in dairy buffalo farms, by
evaluating several parameters such as calving seasons, parity, 305- day milk production, lactation
length, Age at first calving (AFC), age at first service (AFS), calving interval (CI), and evaluating
how days open affect the subsequent reproductive indices. A total of 1388 buffaloes were collected
from reliable records of large dairy buffalo farms. These buffaloes calved during the period extending
from 2003 to 2015. The results of this study revealed that the important factors for DO were
uniparous parity (P=0.03), calving seasons, calving interval, age at first calving, 305-day milk yield
and lactation length (P ≤ 0.001). The reproductive measurements of CI, AFC, and N/C showed
significant difference at the level of days open groups (P ≤ 0.001). Subsequently; they considered
good indicators for evaluating fertility in dairy buffalo farms.