The yield and quality of milk on the farms using conventional milking systems and twice a day milking in comparison with the farms using conventional or automatic milking systems and three times a day milking

The objective of this study was to compare milk parameters during lactation months on farms using automatic (ALS) and conventional milking systems (PLS). The highest milk yield per cow (30.1 kg) was obtained on 3x PLS farms, whereas cows on 2x PLS farms produced 7.7 kg less milk. Milk yield of the cows on ALS farms (24.8 to 26.3 kg) was between that of 2x PLS 2 and 3x PLS farms. On Robot 1 ALS farms the milk yield of cows was by 1.5 kg higher compared to Robot 3 ALS farms (24.8 kg). Milk yield increased until the second month of lactation on all the farms, and decreased subsequently. The difference in milk yield between 2x and 3x PLS farms increased until the third month of lactation, whereas it was by 8.8 to 9.9 kg higher in 3x PLS until the ninth month of lactation, and decreased subsequently (8.6 to 9.4 kg). All ALS farms showed more uniform results. Higher milk yield resulted in lower milk fat (r = –0.36) and milk protein (r = –0.42) content. The highest somatic cell score (SRS) (3.81) was found in the milk obtained from 2x PLS, whereas increased milking frequency decreased SRS by 0.48. Milk SRS was the lowest (2.88) on Robot 1 ALS farms, and the highest on Robot 2 (3.66) ALS farms. Irregular milking on ALS farms did not cause higher SRS of milk, compared to PLS. Increase in milking frequency resulted in higher milk yield and lower SRS, milk fat and milk protein content, whereas ALS and PLS farms showed similar trends. Decrease in milk yield was linear during lactation.