Authors : S. Arias , O.N. Di Marco , M.S. Aello , A.J. Freddi and A.M. Piazza
Abstract: The objective of this study, was to evaluate 3 different sorghum hybrids for whole plant silage on crop production, morphological composition and silages in situ degradability. Two Double Purpose (DP) hybrids (AG 200 and Nutritop) and one for grain production (G, Vdh 303) were sown in Azul, Argentina. Yield, plant fractions and chemical composition of plant fractions and silages were determined. Silage samples were incubated in situ for 0, 4, 15, 24 and 48 h and the effective dry matter degradation (ED) was calculated assuming a fractional passage rate of 2, 4 and 8%/h. Data were adjusted to the exponential equation of: p = a + b (1-e�ct) and analyzed as a complete randomized block design considering field plots as experimental unit. The G hybrid yielded more (55%) than the other two DP hybrids, although the head content in the plant was not different between hybrids, being in average 42%. Heads presented higher CP and lower FDN content than leaf and stalks and also presented higher in vitro organic matter degradability (OMD, 729 g kg-1 DM) than leaves (605 g kg-1 DM). Silage in vitro OMD (average 558 g kg-1 DM) and chemical composition did not differ among hybrids. Soluble fraction (a) was higher in the DP silages, but degradable fraction (b) was higher in the G sorghum Vdh 302 than in AG 200 but not differed from the Nutritop. Potential degradability (a + b) was no different among hybrids (72% in average), neither rate of DM degradability. Silage EDs were not different at a kp of 2% h 1 (54.5% in average), but differed at higher rumen outflow rates.
S. Arias , O.N. Di Marco , M.S. Aello , A.J. Freddi and A.M. Piazza , 2008. Crop Production, Plant Fractions and In situ Degradability of Silages from Different Sorghum Hybrids. Journal of Animal and Veterinary Advances, 7: 1387-1393.