Chemical composition and ruminal degradability of lucerne (Medicago sativa) products
2001
Mustafa, A.F. | Christensen, D.A. | McKinnon, J.J.
A study was conducted to determine the chemical composition and in situ nutrient ruminal degradability of three lucerne products. These were dehydrated pellets, sun-cured pellets and cubes. Results of the chemical analysis showed that sun-cured pellets had the highest (P<0.05) neutral and acid detergent fibre as well as total carbohydrate levels, followed by cubes and dehydrated pellets respectively. Crude protein (CP) content was highest (P<0.05) for dehydrated pellets (204.3 g kg(-1)), intermediate for sun-cured pellets (160.0 g kg(-1)) and lowest for cubes (153.2 g kg(-1)). Intermediately degradable CP (buffer-insoluble CP minus neutral detergent-insoluble CP) was the main protein fraction in the three products and was higher (P<0.05) in cubes than in dehydrated and sun-cured pellets. Estimated net energy of lactation was highest (P<0.05) for dehydrated pellets (5.9 MJ kg(-1)), intermediate for cubes (5.23 MJ kg(-1)) and lowest (P<0.05) for sun-cured pellets (5.15 MJ kg(-1)). Results of the in situ experiment indicated that dehydrated pellets had higher (P<0.05) ruminal protein degradability than sun-cured pellets and cubes. The estimated ruminal escape protein values for dehydrated pellets, sun-cured pellets and cubes were 361, 420 and 498 g kg(-1) CP respectively. It was concluded that differences in chemical composition and ruminal degradability among the three lucerne products were mainly due to differences in stage of maturity. It was also concluded that the dehydration process failed to increase the ruminal escape protein value of dehydrated pellets relative to sun-cured pellets and cubes.
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