Evaluation of an experimental milking pulsation system for effects on milking and udder health.

This study was to test whether cows milked by an experimental pulsation method differed from cows milked with conventional pulsation milking in somatic cell count (SCC), intramammary infections (IMI) defined by milk bacteriological culture results, teat end condition, or milk flow rate. The study design was a 1-yr trial with a completely randomized block crossover. Holstein cows were blocked into 15 pairs of contemporaries. Both cows from each pair were milked with experimental pulsation and with conventional pulsation for 6 mo, in reverse order from each other. The SCC (217,000/ml) of experimentally milked cows was not significantly different from SCC of conventionally milked cows (175,000/ml). Mean milk flow rate was 5.2 lb/min (2.4 kg/min) for experimentally milked cows and 5.3 lb/min (2.4 kg/min) for conventionally milked cows, not significantly different. Differences among the experimentally and conventionally milked cows, respectively, in new (13.5 and 12.7%), chronic (12.9 and 8.9%), and negative (73.6 and 78.4%) quarter culture results were not significant. New IMI per 100 d of lactation were 1.50 and 1.46, and chronic IMI per 100 d were 1.85 and 1.27, for experimentally and conventionally milked cows, respectively. These IMI rates were not significantly different between pulsation types. There were more new Staphylococcus aureus IMI associated with conventional pulsation, but overall cases of Staph. aureus were similar between the two types of pulsation. Teat end scores for the experimentally and conventionally milked cows, respectively, were good (6.5 and 11.7%), intermediate (68.2 and 66.9%), and poor (25.3 and 21.4%), not significantly different. These results support previous studies, which have found that except for complete failure of pulsation, differences in pulsation characteristics apparently have little effect on milking and udder health.