Effects of Milking Frequency on Milk Production and Composition of Holstein Cows during Their First Three Lactations

The objective of this study was to investigate the effect of milking frequency (two times daily vs. three times daily) on the 305-d lactation milk, fat and protein yield and fat and protein percentage of Holstein dairy cows in Morocco. Data analyzed were 31400 records collected between 2009 and 2016 on 14272 cows raised in 194 herds. The frequency of milking had significant effects (P<0.05) on 305-d milk, fat and protein yield as well as fat percentage. The milk, fat and protein yield and fat percentage were higher by 265.1 kg, 13.3 kg, 5.8 kg, and 0.3 g/kg, respectively, i.e. 3,79%, 4.78%, 2.40%, and 0.75%, respectively, for cows milked thrice than those milked twice daily. However, the frequency of milking did not influence protein percentage (P>0.05). The interaction between parity and milking frequency was not significant (P>0.05) for any studied trait. Based on the results of this study, it can be concluded that increasing milking frequency increased milk, fat and protein yield as well as fat percentage regardless of parity. However, the additional milk yield obtained might not compensate for the cost of the labor generated by the extra milk-ing.