Apparent digestibility of nitrogen in rumen and whole tract of Friesian cattle fed direct-cut and wilted grass silages.
Spring grass consisting of Lolium perene L. (81%), Poa pratensis L. (9%), and annual weeds (5%) was stored as direct-cut or as wilted silage and used in feeding trials to determine the effects of wilting on N utilization. Six mature Friesian cattle, fitted with rumen and simple duodenal cannulae, were fed the silages for ad libitum intake in a crossover design consisting of two 49-d periods. Wilting increased intake of organic matter and decreased ruminal apparent digestibility or organic matter and whole tract apparent digestibilities of organic matter, NDF, and total N. Rumen degradability of silage N was increased by wilting (.7 vs. .67). Direct-cut silage, in comparison with wilted silage, provide (g/d) less N intake (232 vs. 286) and lower duodenal flows of total N (215 vs. 293), non-NH3 N (202 vs. 280), microbial N (111 vs. 177), and total amino acids (1056.8 vs. 1342.7). Duodenal flows of NH3 N and undegraded N were not different between silages. Efficiency of bacterial N synthesis in rumen was higher for wilted than for direct-cut silage (32.3 vs. 21.4 g N/kg organic matter apparently digested in rumen). It was concluded that wilting increase silage intake, rumen bacterial synthetic efficiency, and duodenal flow of non-NH3 N in cattle.
Narasimhalu
P
P
Catholic University of Louvain, Department of Nutritional Biochemistry, Louvain-la-Neuve, Belgium.
Teller
E
E
Vanbelle
M
M
Foulon
M
M
Dasnoy
F
F
D000818:Animals; D002417:Cattle / Q000378:metabolism*; D004063:Digestion; D004064:Digestive System / Q000378:metabolism; D005260:Female; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D006109:Poaceae / Q000032:analysis / Q000378:metabolism*; D012417:Rumen / Q000378:metabolism* / Q000382:microbiology; D012820:Silage / Q000032:analysis
D009584:Nitrogen