Abstract/Summary

Twenty eight lactating Chios ewes were used in an experiment to determine effects of dietary activated micronized palygorskite (Pal; Sanfed® Ultra, Geohellas SA, Athens, Greece) supplementation on productivity and milk composition. In the experiment, which started on day 43 postpartum, ewes were allocated after equal distribution relative to milk yield and lactation number (i.e., 2 or 3), into 4 treatment groups being Pal0, Pal2.5, Pal5.0 and Pal7.5 of 7 ewes each and accommodated in individual pens. For a period of 60 days (i.e., days 43–102 postpartum), ewes were fed one of four isonitrogenous (crude protein 175 g/kg, dry matter (DM) basis) and isoenergetic (net energy for lactation (NEl) 7.69 MJ/kg DM) concentrates (1.35 kg DM/ewe/day) and alfalfa hay (1.02 kg DM/ewe/day). The concentrate for treatment Pal0 (Control) had no Pal, while that for treatments Pal2.5, Pal5.0 and Pal7.5 contained 2.5, 5.0 and 7.5 g/kg of Pal (as mixed basis), respectively. All ewes remained healthy until the end of the experiment without visually altered behavior. In the 60 day experimental period, milk fat, crude protein and NEl contents were highest with the Pal5.0 treatment (P < 0.01, P = 0.01 and P < 0.01, respectively). In contrast, milk lactose content was lowest (P < 0.01) with the Pal2.5 treatment. With increased Pal feeding, milk fat and NEl yields were highest with the Pal5.0 treatment (P < 0.01 and P = 0.03, respectively), but milk yield and yields of other components, as well as milk somatic cell counts and colony forming units were not affected. Dietary Pal supplementation, at levels up to 5.0 g/kg, in isonitrogenous and iso-NEl diets fed to lactating ewes increased milk fat and NEl yields and improved milk quality, increasing fat, crude protein and NEl contents, while, at higher level (7.5 g/kg), dietary Pal supplementation did not affect milk yield and composition, with optimal Pal feeding levels identified between 3.4 and 4.0 g/kg of concentrate.