MILKING CHARACTERISTICS IN DAIRY-COWS OF DIFFERENT BREEDS FROM DIFFERENT FARMS AND DURING THE COURSE OF LACTATION

Milking characteristics were studied in 106 cows belonging to four breeds, and housed in four farms. Cows were either milked without any, or after a 1-mm pre-milking udder stimulation. Milk yields were not influenced by pre-milking stimulation, whereas average and peak milk-flow rates were tendentially greater with than without stimulation, resulting in shorter milking times. However, the time spent on pre-stimulation was never completely compensated for by faster milking. Bimodal milk flow, indicating delayed milk ejection, was seen in about 70 % of milkings without stimulation and in only 13 % of SI x RH on the FRS farm also after pre-stimulation. The size of the mammary cisternal cavities on ultrasound, and most of the evaluated milking characteristics, were not different between farms and breeds. Milk yield, milking time and average flow rate decreased during the course of lactation. Total and main milking times were generally shorter with than without stimulation. Average flow rate was always numerically higher with than without stimulation, but was only significant in late lactation. The time to reach peak flow rate was similar with and without stimulation in early lactation, and was significantly and progressively prolonged without stimulation in mid and late lactation. The interruption of milk-flow increase in bimodal milk-flow curves was prolonged during the course of lactation. Increasing effects of pre-stimulation on milking characteristics towards the end of lactation are indicated.