This study was performed on 1480 productive records collected from private farm of Holstein
Friesian cows. In addition, collections of 70 milk samples for the measurement of somatic cell count
(SCC). This study aims to evaluate the effect of some non-genetic factors (days in milk (DIM), peak
milk yield (PMY), dry period (DP), calving interval (CI), parity, and season of calving) on total milk
yield (TMY), and studying the effect of305-day milk yield (305-DMY), peak milk yield (PMY),
days in milk (DIM), parity and season of calving on mastitis in Holstein Friesian cows. All data
were analyzed by general linear model (GLM) using SAS software ver.9.1.3. The current results
revealed that DIM and parity had a significant effect on TMY, where the highest milk yield was
obtained when DIM were more than 357 days and in the 3rd lactation season. Season of calving
showed a significant effect on occurrence of mastitis, where the highest incidence of mastitis was
recorded for spring calvers. |
