Chaya (Cnidoscolus aconitifolius, Mill. Johnston) pellet supplementation improved rumen fermentation, milk yield and milk composition of lactating dairy cows

Chaya (Cnidoscolus aconitifolius, Mill. Johnston) is a fodder shrub that contains flavonoid compounds and uses as feeds, medicine and food, respectively. This study examined the effects of Chaya leaf pellet (CHYP) supplementation on nutrient digestibilities, feed intake, rumen fermentation, milk yield and milk compositions. Four lactating crossbred (75% Holstein-Friesian × 25% Thai native cows) dairy cows with average body weight (440 ± 10), milk production (12 ± 2 kg/h/d) and days- in- milk (126 ± 20) were randomly assigned to a 2 × 2 factorial arrangement in a 4 × 4 Latin square design. Two ratio of concentrate to milk yield, (1:1; CM1 and 1:2; CM2) and two CHYP levels at 0 and 6% of total dry matter intake (TDMI) were imposed. The results revealed that concentrate to milk yield ratio and CHYP supplementation had interactive effect (P < 0.05) on nutrient intake except ADF, fat -corrected milk and total solids. Rumen pH was decreased (P < 0.05) in cows receiving high concentrate, while the pH was in normal range for animals fed with CHYP. Ruminal NH3-N concentration was increased (P < 0.05) by the 6% CHYP supplementation. The level of blood urea nitrogen (BUN) (P < 0.05) was increased with the increase of ruminal NH3-N (P < 0.01), and bacterial population, while the, protozoal counts were slightly reduced by the supplementation of CHYP. The CHYP supplementation significantly increased total VFA and propionate concentration, while decreased acetate to propionate ratio and estimated methane emission. In conclusion, concentrate to milk yield at 1:1 ratio and CHYP supplementation at 6% significantly modulated rumen fermentation end-products and milk composition in lactating dairy cows.