Effect of processed cereal grains as a supplement on grass intake, rumen pool sizes, ruminal kinetics and the performance of grazing lactating dairy cows
2003
Tothi, R. (Kaposvdr University (Hungary). Dept. of Animal Nutrition) | Zhang, R.H. (Inner Mongolia Agricultural University, Huhhot (China)) | Chilibroste, P. (Facultad de Agronomia, EEMAC, Paysandu (Uruguay)) | Boer, H. | Tamminga, S. (Wageningen Institute of Animal Science (Netherlands). Animal Nutrition Group)
Two multiparous lactating Holstein-Friesian dairy cows fitted with rumen cannula were allowed to graze perennial ryegrass swards. Next to a control treatment of grazing only, pelleted barley (PB), pellted maize (PM), toasted and subsequently pelleted barley (TPB), and toasted and subsequently pelleted maize (TPM) were fed as a supplement in two equal portions. Before and after 3 h of grazing the rumen content was evaluated, weighed, sampled and returned to the animals. Then the cows were kept inside the barn and starved for 6 h, after which rumen evacuations were repeated. The estimated clearance rates of starch showed significant differences between grain types and compared tu unsupplemented animals the apparent ruminal clearance of nitrogen was significantly reduced. Supplementation with processed grains significantly increase the milk production and significantly decreased milk fat percentage. It is concluded that supplementing grass with high-energy low protein feeds, such as grains, substantially improves the N utilization and reduces the urea output in milk
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