Performance and rumen parameters of crossbred dairy cows fed two sugarcane varieties combined or not with soybean hulls

Abstract

Two sugarcane varieties (IAC86-2480 and IAC91-2195) combined or not with soybean hulls (SH), partially replacing corn in concentrate, were included in the diet of crossbred dairy cows to evaluate the effects on feed intake, milk production, milk composition and rumen parameters of crossbred cows. The sugarcane varieties (IAC86-2480 and IAC91-2195) and concentrate compositions (with and without SH) were analyzed in a 2 × 2 factorial arrangement. Treatments were assigned to blocks by lactation period to evaluate feed intake, milk production and milk composition. A Latin square design was used to analyze rumen parameters. Feed intake, milk production and composition were similar among treatments. Average daily feed intake was 19.93 kg DM in cows fed IAC86-2480 sugarcane and 17.98 kg DM in those fed IAC91-2195, and their average milk production was 19.27 kg and 18.94 kg, respectively. The treatments with IAC86-2480 and IAC91-2195 had different effects on ruminal pH (6.47 and 6.61, respectively) and ammoniacal nitrogen (12.88 and 16.57 mg/dL, respectively). Sugarcane variety and concentrate composition had an interaction effect on volatile fatty acid levels and acetic acid/propionic acid ratio (93.62 mM and 2.54 for IAC86-2480 with SH; 106.70 mM and 2.41 for IAC86-2480 without SH; 115.70 mM and 3.30 for IAC91-2195 with SH; and 93.21 mM and 1.81 for IAC91-2195 without SH, respectively). Sugarcane variety and soybean hull inclusion in feed concentrate do not affect feed intake, milk production or composition in crossbred cows, although these variables change fatty acid production and ruminal pH.