Effect of stocking density on ewes' milk yield, udder health and microenvironment

Three groups of 12 lactating Comisana ewes were housed in separate rooms of the same building that contained straw-bedded pens with total areas of 12, 18 and 24 m(2). The ewes were assigned to groups with different stocking d ensities: high (HSD, 1 m(2)/animal), medium (MSD, 1.5 m(2)/animal) or low ( LSD, 2 m(2)/animal). The LSD treatment resulted in lower air concentrations of total microorganisms and coliform bacteria than the other two. Ewes in the LSD group gave greater yields of milk, total protein and fat than those in the other two groups. LSD treatment increased milk casein content and i mproved clotting time and clot firmness. LSD also resulted in ewes giving m ilk with lower somatic cell counts and smaller concentrations of mesophiles , psychrotrophs and faecal coliforms than MSD and HSD. Subclinical mastitis occurred in three ewes of the MSD group and four ewes of the HSD group, wh ile no cases were recorded in the LSD group. These results indicate that st ocking density is a critical factor in dairy sheep housing and suggest that a space allocation <2 m(2)/animal may adversely affect the performance and health of the lactating ewe.