Effects of short-term supplementation with selenised yeast on milk production and composition of lactating cows

Abstract

The work described was conducted to provide Se-fortified milk protein for cancer research using animal models by CSIRO Health Sciences and Nutrition. Sixty spring-calving cows grazing perennial pasture at a herbage allowance of 40 kg DM/cow/day were supplemented with crushed barley grain and a formulated concentrate containing selenised yeast. The effects of the selenium supplement (25 mg Se/day) on milk production, selenium concentration in milk and somatic cell counts were determined by comparison with 60 cows consuming a similar diet without the selenised yeast. There were no effects of short-term selenium supplementation on milk production, the concentrations of protein, fat or lactose in milk or on somatic cell counts. The selenium concentration in bulk milk samples increased from 10.3 to 128.3 µg/L from day 0 to day 9 of the treatment period. These results are discussed in relation to practical approaches to producing milk with enhanced selenium concentrations to meet human nutritional requirements or to be used for preventative health purposes.