Influence of Salix babylonica extract on daily milk production and composition as well as in vitro gas production in dairy cows

Abstract

A 3 × 3 Latin square design was used to evaluate the effect of 0, 150, and 300 mL of Salix babylonica extract on daily milk production and composition in dairy cows. Cows (3 cows for each treatment, 390 ± 10 kg) were fed on 5 kg of commercial concentrate (14% CP and 33% NDF- to meet 70% of their daily metabolizable energy) and oat hay ad libitum. Experiment was carried out in 3 experimental periods of 21 d (14 d of adaptation and 7 d for samples collection). Extract doses were mixed daily morning with a small amount of concentrate (approximately 1 kg) and fed to cows. Daily feed intake, water consumption, milk production and composition (solids not fat, fat, protein and lactose) were determined. In vitro gas production of the diet fed to cows (40: 60, concentrate: Oat hay) was recorded after 2, 4, 6, 8, 10, 12, 24, 48, 72 and 96 h of incubation with 0, 06, 1.2 and 1.8 mL extract/g DM. Rumen liquor was collected from 2 Brown Swiss cows (450 kg BW) and ftted with permanent cannulas. Milk production was increased (P < 0.05) with the extract addition at 150 or 300 mL/d while all the milk composition parameters were not affected by the extract addition. Milk energy output (Mcal/d) and milk density were also increased (P < 0.05) with extract addition at the 2 doses. Milk effciency (kg DM/kg of milk) was improved (P < 0.05) with the extract doses versus control (1.59, 1.56 and 1.35, for 150, 300 and 0 mL extract/d, respectively). In vitro gas production of the diet fed to cows was increased (P < 0.05) dramatically with the 2 levels of extract with a short lag time and high rate of gas production per hour versus control (i.e., 0 mL). Addition of Salix babylonica extract improved milk production by 12%, without effect on milk composition in dairy cows probably due to its positive impact of ruminal microorganism’s activities.