Quality of ewe milk as affected by stocking density and litter treatment with bentonite

Three groups of 12 lactating Comisana ewes were housed in separate rooms in the same building. Two rooms were 18 m 2 straw-bedded pens and the third had a total area of 24 m 2 . Three treatments were tested: low stocking density (LD = 2 m 2 /animal); high stocking density (HD = 1.5 m 2 /animal); high stocking density with a fortnightly application of 0,5 kg bentonite per m 2 of litter (HDB). Air concentrations of micro-organisms were determined twice weekly inside each room. Ewe milk yield was recorded daily and individual samples were analysed weekly for milk composition, renneting properties and bacteriological characteristics. Treatment HD resulted in higher air concentrations of total micro-organisms and of yeasts/moulds than treatments HDB and LD and higher amounts of coliform bacteria than treatment LD. Ewes in the HD group produced milk with a lower casein, fat and lactose content compared to LD animals, whereas no differences in milk constituents were found between HD and HDB ewes. Renneting properties were improved and somatic cell and bacterial counts were lower in treatments LD and HDB as compared to treatment HD. These findings indicate that increased stocking density can reduce the cheese making efficiency of ovine milk and suggest that litter treatment with bentonite can partially alleviate adverse effects of reduced space on both renneting ability and the hygienic quality of ewe milk.