Rumen bacteria, archaea and ciliate protozoa data from animal trial with Nordic Red dairy cows

Four multiparous dairy cows fitted with rumen cannula were used in a 4 × 4 Latin square with 2 × 2 factorial arrangement of treatments to examine how starch level and oil mixture impact dry matter (DM) intake and digestibility, milk yield and composition, rumen fermentation, ruminal methane (CH4) emissions, and microbial diversity. Experimental treatments were comprised of high (HS) or low (LS) levels of starch containing 0 or 30 g of a mixture of sunflower and fish oils (2:1 w/w) per kg diet DM (LSO and HSO, respectively). Digestibility was measured by total collection of feces and CH4 was measured using SF6 technique. Rumen microbial community was assessed by 16S/18S rRNA gene amplicon sequencing.