EVALUATION OF 50 50 AND 70/30 PULSATION RATIOS IN A LARGE COMMERCIAL DAIRY-HERD/

An experiment was conducted in a large commercial dairy milking 1350 H olstein cows in Florida to investigate the effects of 50:50 or 70:30 p ulsation ratios on milking parlor performance, milk production, and ud der health. The experiment used a reversal design in which the two pul sation ratios were tested over four 2-mo periods in nearly identical d ouble-11 herringbone milking parlors. Analysis of milking parlor perfo rmance measures of cows milked per hour, milk harvested per hour. parl or turns per hour, and parlor cycle time revealed a small increase in milking parlor performance for the 70:30 pulsation ratio. Milking with the 70:30 pulsation ratio increased cows milked by 4.1 cows per h, in creased milk harvested by 38.3 kg/h, increased parlor turns by .2 turn s per hr, and decreased parlor cycle time by .4 min compared with the 50:50 pulsation ratio. Average milk production per cow per milking did not differ between the two ratios. Udder health indicators of clinica l mastitis incidence, cows culled for mastitis, or bulk tank SCC were not different because of pulsation ratio.