RESUMO
In this research communication we address the hypothesis that a single intramammary infusion of casein hydrolyzate (CH) would have a similar effect to three intramammary infusions of CH for drying-off quarters with chronic mastitis (CM) during lactation. Sixty cows with CM were selected and randomly distributed into two treatment groups: (a) three intramammary CH infusions (100 mg, 50 ml per infusion, with 24-h intervals) or (b) single intramammary CH infusion (300 mg, 50 ml). Milk samples from the treated and untreated quarters were collected for microbiological culture and somatic cell count (SCC) before and after CH infusions. Milk yield was recorded and a manual pressure index measurement was used to evaluate cessation of lactation. Of the 60 quarters selected, 43 (71.67%) had positive microbiological culture. The quarters treated with three intramammary CH infusions had higher udder pressure index than those treated with single CH infusion. However, the average milk yield and composite SCC of three functional quarters were not different among treatments. Therefore, a single infusion of CH has the potential to be used as an alternative method for drying-off mammary quarters with CM during lactation.