Effects of ketoprofen on milk ejection curves in chronic cows

The presence of a mastitis induces an inflammatory status that, very likely, have an influence on milk ejection curve, in addition to the changes in milk yield The very few studies analyzing the relationship between udder health status and milk ejection curves suggest that mastitis lead to a decrease of duration of plateau phase, increase of duration of descending phase and increase in frequency of overmilking. Recently, non-steroidal anti-inflammatory molecules (NSAID) gained interest in mastitis therapy being a potential alternative to antibiotic treatment, specifically when the expected cure rate is very low such as in chronic mastitis cases. There are no available data on the possible mechanism explaining the effect of NSAIDs on milk ejection curve, but there is evidence, at least under field conditions, that anti-inflammatory treatment positively affects milk ejection curve. To specifically investigate the effects of NSAID on milk ejection curve characteristics, a controlled field study was designed to compare milk ejection curve in chronic mastitis cows treated with NSAIDS or not treated (controls). Chronic cows were identified by the Farmer Association monthly individual cows SCC evaluation. Inclusion criteria were the following: SCC >400.000/ml in the last two monthly records and no blind quarters. The herd veterinarian assigned cows randomly to the treated or not treated group once they were enrolled in the study. The treatment protocol was 15 ml of ketoprofen (Dinalgen 15%) IM every Monday and Thursday for 4 weeks. Milk flow curves of the whole udder and of each quarter were registered with a continuous electronic milk flow meter (Lactocorder, WMB, Switzerland) and by Vadia™ (Biocontrol Sa, Norway) that logs vacuum during milking at 4 points in the milking cluster. At the end of the study, 582 records for cows were included and for each milking 110 different parameters were collected, for a total of 64,020 data points. In our knowledge, this is the first field trial assessing the influence of anti-inflammatory treatment on milk ejection curves in cows with chronic mastitis. The statistical analysis showed that treatment significantly influenced among the others: milk yield, milking period, time to maximum milk flow, average milk per minute, time of stripping phase, vacuum short milk tube overmilking and bimodality frequency. The result of this study support the hypothesis that chronic mastitis have a significant influence on milk ejection curves. This influence is not only related to a decrease in milk yield but also affects milking duration and the overall milking process. The changes in milk ejection observed in diseased animals start a vicious cycle that increases teat exposure to vacuum forces, thus increasing the risk of teat damages and then mastitis. The treatment with ketoprofen was efficacious in reducing the effects of mastitis on milk ejection. These results can be explained by the anti-inflammatory activity of the product, but also by its capability to reduce oxytocin inhibition, mediated by a reduction in pain at local level.