Using in situ technique to estimate nutrient availability of six barley varieties for ruminants
Barley grains are as a main source of feed for ruminants in Canada. Although barley varieties have similar chemical composition, they exhibit different rumen degradation characteristics and nutrient availability. The objective of this study was to estimate nutrient availability of the six barley varieties using nylon bags incubated for 0, 2, 4, 8, 12, 24 and 48 h in the rumen of dairy cow and determine the rumen degradation parameters of DM, CP and starch according to the first order degradation kinetics equation. The results indicated that the barley varieties showed different degradation rate (Kd) of DM, CP and starch during incubation period. CDC Trey was the highest (P<0.05) in effective degradability of DM (498.04g/kg) while AC Metcalfe showed the highest (P<0.05) effective degradability of CP (63.06g/kg) and starch (344.82g/kg) compared with other barley varieties. CDC Helgason had the largest size of rumen undegradable fraction of DM (640.21g/kg), CP (83.85g/kg, NRC 2001 model) and starch (321.85g/kg). Feeds degradation features from this study involved nutrients utilization in ruminant digestive systems. Further study to investigate and compare the structural/chemical make-up characteristics between barley varieties may provide more information as to why barley varieties exhibit different biodegradation behaviors.
rumen degradation characteristics
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