[Cellular element study of bulk milk]

Cytologic and microbiological investigations were carried out of pooled milk arriving in two milk plants, coming from various farms in amounts of 300 to 4 000 1. Additional studies were made of milk samples taken in the barn after milking a group of 15--30 cows in amounts of 80--260 1 and samples from tanks with capacity of 6 to 10 tons stored in the milk plants. Cell content was indirectly determined by rapid mastitis tests and directly by Breed's method; cultures were made on TCT medium to establish mastitis Streprococci and most of all of Str. agalactiae. It was found that the cell content of pooled milk arriving in the milk plants is in 80.74 per cent under 400 000 and in 19.26 per cent over 400 000 cells per cc milk. Their determination in pooled milk is a reliable orientation index for evaluation of the farm's mastitis status. A norm is suggested for the cell content of pooled milk--400 000 in cc milk--which corresponds to the present yeild conditions and to those in the near future and to the real possibilities of occurence of secretion disturbances and bovine mastitis. The adoption of the norm will improve mastitis control and will raise milk quality.