Effect of liner life, working vacuum and pulse ratio changes on milking performance and physico-mechanical properties of liner

Vacuum and pulse ratio are important working parameters affecting milking performance of milking machines. In addition, the design and composition of the materials in the milking machine are other major factors affecting the performance characteristics of the teat. The aim of this study is to determine the effects of changes in working vacuum and pulse rate on milking performance and physical and mechanical properties of teats. The research was carried out in Bursa Uludag University, Faculty of Veterinary Medicine, Research and Application Farm dairy cattle milking facility. The milking system is a herd management facility with 8 milking units of 2x4 herring type. The farm is milked 3 times a day and on average 68 Holstein cows are milked. After the removal of cows with missing observations for one or more milking in the trials, 52 available cows were evaluated. In the research, imported rubber long type rubber liner (Liner 20 M type) was used. Milking system vacuum 41, 44 and 47 kPa, pulsator pulse ratios 60:40, 65:35 and 70:30 were selected, working vacuum and pulse ratio changes were made. The measurements were made in four periods, four different milking life of the liners (new, 1250, 2500, 3500 milking). Milking observations were made for 9 days with a total of 27 milking per cow. At the end of the 9-day experiments of each period, one set of liners were removed from the milking facility and analysed for their physical and mechanical properties. During the experiments, milk yield, peak and average milk flow rates, milking duration, milk yield in the first 2 minutes of milking and milk percentage in the first 2 minutes of milking were analysed from the herd management program. According to the results of the experiment, the milking yield increased as the pulse chamber ratio increased in the life of each tread. However, as the tread life increases, milking yield decreases. The highest milking pulse ratio was found at 70:30 pulse ratio of the newly installed product. While milking durations decreased in each milking life, peak and average milk flow rates, milk yield and percentages increased in the first 2 minutes, but declines occurred as the rubber liner aged. The interaction of vacuum level and pulse ratio was found to be significant for milking duration, peak milk flow rate, milk yield and percentage rates in the first 2 minutes, but not for milking yield and mean milk flow rate. Average and peak milk flow rates, milk yield and percentage in the first 2 minutes increased with each increasing vacuum level and pulse ratio, and milking duration decreased.