Ruminal environment and forage ruminal digestion in milking cows under grazing and zero-grazing

摘要

Cows grazing high quality temperate pasture had a rumen environment characterized by low pH, high NH_3 concentration and a low C_2:C_3 ratio. A trial was run to study the effect of zero grazing on rumen environment and protein and fiber digestion. SixHolstein dairy cows with rumen cannula were used under grazing or zero-grazing of a mixed pasture of ryegrass, cocksfoot, phalaris, red clover and white clover during spring time. Pasture offered had 13 % crude protein (CP), 55 % neutral detergent fiber(NDF) and 65 % in-vitro digestibility. Treatments were : TO, strip-grazing (estimated forage utilization 30-50 %) and T1, fresh chopped herbage supplied twice a day (estimated forage utilization 80 %). A cross over design with two treatments and two ten-day periods was used.