Replacing alfalfa hay with paper mulberry (Broussonetia papyrifera L.) silage in diets do not affect the production performance of the low lactating dairy cows

Abstract

Developing and utilizing more roughage resources is conducive in improving the health status of dairy cows and beneficial in controlling the production costs of raw milk. In the current study, we investigated the impact of replacing alfalfa hay with paper mulberry silage (PMS) on the production performance of low lactating dairy cows. Sixty multiparous Holstein cows were stratified by milk yield, days in milk and parity and randomly assigned to 4 treatments: control diet without PMS (CON) or 33.33 %, 66.67 % and 100 % alfalfa hay replaced by an equal amount of PMS (DM basis, PMS1, PMS2, and PMS3, respectively). The experiment lasted for 14 weeks, with the first 2 weeks for adaptation. Dry matter intake of low lactating dairy cows was not affected by PMS, and though milk yield of PMS3 was 1 kg lower than CON, no statistical differences were observed. Lactose yield and feed conversion efficiency (FCE) tended to be affected by treatment × week interaction (P = 0.07 and P = 0.08, respectively), and the FCE of PMS groups was lower than CON in wk12 (P = 0.08). No treatment effect on oxidative stress-related variables was detected, except malondialdehyde (MDA), which tended to be decreased by PMS (P = 0.06). Cows in PMS3 had lower CP digestibility than CON (P = 0.004), and the apparent digestibility of NDF and ADF were lower for PMS2 compared to CON (P = 0.004 and P = 0.05, respectively) and PMS1 (P = 0.005 and P = 0.006, respectively). In conclusion, replacing alfalfa hay with paper mulberry in the diet of low lactating dairy cows did not affect DMI and milk yield, but improved their antioxidative capacity. However, the amount of paper mulberry should be added to the diet cautiously, due to its potentially adverse effect on digestibility and milk yield in dairy cows.