Resumen

CERON-MUNOZ, Mario F; AGUDELO, Edwin J  y  MALDONADO-ESTRADA, Juan G. Relationship between individual and bull tank somatic cell counts with CMT test in two dairy herds in Antioquia (Colombia). Rev Colom Cienc Pecua [online]. 2007, vol.20, n.4, pp.472-483. ISSN 0120-0690.

In order to establish a mathematical model with which to predict the Bull Tank Somatic Cell Count (BTSCC) of herds with sub clinical mastitis and to search for possible relationships between CMT results and individual somatic cell counts (SCC) or BTSCC, a descriptive study was carried out in two farms located in the dairy region of Antioquia (Colombia), in which lactating dairy cows (n = 95) were sampled during the morning and afternoon milking (once a month/3 months). CMT evaluation was performed at the afternoon milking at each time point of evaluation. In addition, total milk produced by individual cows was recorded and a milk sample was taken to perform SCC. Similarly, three samples of milk were taken from the tank to measure BTSCC. All milk samples were processed by triplicates by using a Fossomatic-90 equipment. Logarithmic transformation of data were done to normalize the SCC and BTSCC results according to the model: logarithmic SCC (SCCL) = Log₂(SCC/100) +3, and analysis of variance were performed. A significant relationship (p<0.05) was found between the percent of positive quarters (at least one cross by CMT) and the BTSCC taken at the afternoon milking. Accordingly, a model was established to define the BTSCC value depending on the percentage of CMT positive quarters. The average SCC of 206.630 and 145.935 cel/ml, were found for afternoon and morning milking, respectively; in as much as the average BTSCC found were 186.830 and 93.145 cel/ml, for afternoon and morning milking, respectively. Furthermore, a significant relationship (p<0.05) was found between the SCC of the afternoon milking and the BTSCC. The BTSCC values were lower than the limit values accepted for the United Sates and European countries, which suggest that under strictly controlled management policies the dairy herds from Antioquia could meet the international standards for milk exportation. Finally, further studies are required in order to precise and define the source of variations found between the SCC and BTSCC for both the morning and afternoon milking.

Palabras clave : bovine; BON x Holstein cows; holstein cows; milk quality; somatic cell counts.

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