Performance and milk composition of Holstein cows fed with dried malt bagasse and selenium-enriched Saccharomyces cerevisiae

Abstract

• Addition of selenized Saccharomyces cerevisiae did not improve fiber digestibility. • Use of selenium-enriched yeast increased the milk selenium concentration. • Use of selenium-enriched yeast had no effect oxidative stability of the milk. • Inclusion of malt bagasse reduced energy intake and microbial protein synthesis. • Inclusion of 24% dried malt bagasse reduced energy-corrected milk production. The objective of this study was to evaluate the effect of selenium-enriched Saccharomyces cerevisiae on the performance, composition and quality of milk from cows fed diets containing dried malt bagasse. Eight Holstein cows were distributed in a 4 × 4 double Latin square. The treatments were in a 2 × 2 factorial scheme: with or without the inclusion of malt bagasse x with or without the addition of selenium-enriched Saccharomyces cerevisiae . Dried malt bagasse was included at 24% in the dry matter (DM) of the diet; the amount of yeast supplied was 15 g/day and was composed of strain Saccharomyces cerevisiae CNCM I-1077 containing 1.0 × 10 9 CFU/g and 170 mg selenium/kg. Cows fed diets containing malt bagasse presented lower intakes of DM, crude protein and non-fibrous carbohydrates (NFC) and higher intakes of ethereal extract and neutral detergent fiber (P < 0.05). The digestibility of DM and the NFC of the diets with malt bagasse were lower in relation to the diets without this ingredient (P < 0.01). The addition of yeast did not influence the intake and digestibility of nutrients or any blood parameters. The levels of cholesterol and triglycerides of cows fed malt bagasse were higher than those that did not receive this by-product (P < 0.01). There was an interaction for blood urea, wherein the concentrations of the malt bagasse diet were higher than the diets without bagasse and without bagasse with yeast (P < 0.05). Cows fed diets without malt bagasse and with yeast produced more microbial protein than those fed with malt bagasse and yeast (P < 0.05). The use of selenium-enriched Saccharomyces cerevisiae had no effect on the production, composition and oxidative stability of the milk, but increased the milk selenium concentration (P < 0.05). The inclusion of malt bagasse reduced energy-corrected milk production, fat, protein, casein and total solids content of milk (P < 0.05), and increased milk urea nitrogen and the conjugated diene concentration (P < 0.01). Thus, the use of selenium-enriched Saccharomyces cerevisiae in the diet of lactating cows increased the selenium concentration, but did not improve the production and oxidative stability of the milk, whereas the inclusion of dried malt bagasse reduced energy intake, energy-corrected milk production and the milk fat and protein contents.