Performance of Holstein x Gyr dairy cows fed hydrolyzed sugarcane-based diets

Abstract

Twelve multiparous 7/8 Holstein x Gyr dairy cows were fed diets based on chopped sugarcane supplied in natura (control) or after being hydrolyzed (fresh matter basis) for 24 h with 0.5%, 1% or 2% calcium oxide (CaO). The voluntary consumption and digestibility of dietary nutrients, milk production and composition, and feeding behavior of cows were evaluated. A switchback design with three periods, four treatments and three blocks was used. The linear and quadratic effects of the treatments were analyzed using orthogonal contrasts, and the effects were considered significant when P ? 0.05. Compared to the that in the control treatment, the Ca concentration increased by 297%, 570% and 1,083% in the diets including sugarcane hydrolyzed with 0.5%, 1% and 2% CaO, respectively, while the respective Ca:P ratios were 6.58:1, 10.70:1 and 19.77:1 (control Ca:P ratio: 1.55:1). The hydrolysis of sugarcane with increasing amounts of CaO promoted a linear reduction (P 0.05), but there were linear reductions (P 0.05) in response to the inclusion of hydrolyzed sugarcane in the diets. There was no effect (P > 0.05) of sugarcane hydrolysis with increasing amounts of CaO on the time the cows spent idle, ruminating and feeding, but there was a linear increase (P < 0.05) in the minutes spent ruminating 1 kg of DM and NDF. Chopped sugarcane hydrolyzed for 24 h with 0.5% to 2.0% CaO should not be used as exclusive roughage in diets for Holstein x Gyr dairy cows with an average milk production of 10 kg day?1.

Keywords

• Alcali
• Bovine
• Calcium oxide
• Digestibility
• Feeding behavior
• Saccharum officinarum.