Characteristics of Rumen Development of calves

At birth, the rumen of calves is very small and underdeveloped, and the rumen volume accounts for 70% of the rumen volume. After 3 weeks of age, the rumen gradually develops. After 6 months of age, the total volume of the first 3 stomachs accounts for 70% of the stomach volume, while the true stomach accounts for only 30%. By the age of 12 months, the stomach is close to the level of adult cattle. A week later, as a result of eating forage, the microbes propagated through the mouth into the rumen and began to show digestion. The ciliate fauna appeared from 3 to 4 months old. After eating forage, calves regurgitate and saliva is secreted by parotid gland, so early feeding of forage can accelerate rumen development and promote microbial reproduction, so they can successfully pass the weaning barrier.