Comparative evaluation of nutritional values in different forage sources using in vitro and in vivo rumen fermentation in Hanwoo cattle

Hu Seong Lee1   Sung Dae Lee2   Seul Lee2   Sangsoo Sun1   Minseok Kim1   Hyuck Choi3   Yookyung Lee2   Youl-Chang Baek2,*   

1Department of Animal Science, Chonnam National University, Gwangju 61186, Korea
2Animal Nutrition and Physiology Team, National Institute of Animal Science, Wanju 55365, Korea
3Department of Pet Science, Seojeong College, Yangju 11429, Korea


This study evaluated the nutritional value of Italian ryegrass (IRG) as a forage source for Hanwoo. The nutritional value of IRG was assessed and compared to that of rice straw, oat hay, and timothy hay using two different methods: 1) in vitro ruminal fermentation 2) in vivo total tract digestibility. in vitro DM digestibility was lower in rice straw compared to the other three forage sources after both 24 and 48 h of incubation (p < 0.01). Among the four forage sources, IRG had a higher NH3-N concentration after both 24 and 48 h of incubation (p < 0.01). In the in vivo digestibility trials, four different substrates were used: 1) 80% concentrate with 20% rice straw, 2) 80% concentrate with 20% oat hay, 3) 80% concentrate with 20% IRG, and 4) 80% concentrate with 20% timothy hay. The dry matter, crude protein, non-fiber carbohydrate, and detergent fiber digestibility were the greatest in the C80-IRG20 among the four forage groups. In summary, IRG had a similar level of energy efficiency compared to oat hay and timothy hay. Furthermore, the result of the chemical composition analysis showing a higher ammonia concentration in the in vitro fermentation experiment and the high protein digestibility in the in vivo experiment indicate that IRG is a good source of protein compared to oat hay and timothy hay.

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