Lactation Order Effects on Milk Production in Romanian Black and White Cows from Timiş County

Researches were carried out on 988 normal lactations of Romanian Black and White cows from the actual active population raised in Timiş County. Six groups of production were formed according to the lactation order: 1st, 2nd, 3rd, 4th, 5th, and 6th and over. For each group, the averages and dispersion indices were calculated, and the differences between groups were statistically tested. The highest production was obtained by cows in the 6+ lactation, 4979.2 kg milk with 3.921% fat and 3.26% protein, and the lowest in the first lactation 4455.4 kg milk with 3.944% butterfat and 3.195% protein. Milk production in the first lactation was significantly lower (p<0.05) than that produced by cows in the second, fifth and sixth lactations, by 495.9 kg milk and 16.98 kg protein; 477.9 kg milk and 17 kg protein; and 523.8 kg milk and 19.97 kg protein, respectively. Also, cows in the second lactation produced more (p<0.05) by 353.8 kg milk and 10.61 kg butterfat than cows in the third lactation.