Abstract #W135

# W135
Effects of replacing alfalfa hay and whole corn silage with paper mulberry (Broussonetia papyrifera L.) silage in high lactating cow diets on dry matter intake, milk yield, and milk composition.
Z. H. Wu1, C. Y. Liang1, R. C. Huang1, J. L. Ouyang1, L. Ma1, L. S. Zhao1, D. P. Bu*1, 1Institute of Animal Science, State Key Laboratory of Animal Nutrition, Chinese Academy of Agricultural Sciences, Beijing, Beijing, China.

The lack of high-quality roughage resources has gradually limited the development of China dairy industry. The objective of this study was to evaluate the possible application of paper mulberry (Broussonetia papyrifera L.) silage (PMS) in high lactating cow diets. Sixty multiparous Holstein dairy cows were enrolled into this study based on days in milk, milk yield, and parity. The cows were then randomly assigned to 4 treatments of no PMS added in the diet (CON), 15.7% of alfalfa hay and whole corn silage replaced by 7% PMS (PMS1), 31.4% of alfalfa hay and whole corn silage replaced by 14% PMS (PMS2), and 47.1% of alfalfa hay and whole corn silage replaced by 21% PMS (PMS3). The pre-feeding period for the trial was 14 d, while the trial period was 84 d. Dry matter intake (DMI) was measured for 3 consecutive days every week and condensed into weekly means. Milk yield was recorded daily, and milk composition was analyzed every other week. A mixed-effects model with repeated measures and generalized linear model that included the effect of treatment at each sampling point was used for the data analysis. The results showed that DMI was affected by treatment (P < 0.05) and decreased linearly with the increase in PMS feeding (P < 0.05). Milk yield of CON was numerically higher than PMS3, and lower than PMS1 and PMS2, but no treatment effects or treatment × time interaction was detected. The effects of feeding PMS on milk components and somatic cell count were also not observed in the current study. In conclusion, paper mulberry silage can be used in high lactating cow diets, while high feeding ratio should be used with caution, as it may decrease the DMI and milk yield.

Key Words: diet, high lactating cow, paper mulberry silage