Feedlot Performance of Steers Fed with Silages of Different Sorghum Hybrids (Sorghum bicolor, L. Moench)

[摘要] - The experiment was conducted to evaluate the parameters of dry matter intake, weight gain, feed conversion and energy efficiency of feedlot steers, fed with four diets that included silage of hybrids of sorghum with different agricultural behavior: AGX-213 and AG-2002 (forage), AGX-217 and AG-2005E (double purpose). Forty-eight steers with an average age of 19 months and average live weight of 316 kg, were used. The roughage:concentrate ratio was 63:37, for all the diets tested. No significant interaction was observed between roughage source and feedlot evaluation period. The sorghum silage of hybrid AG-2005E caused higher dry matter intake, digestible energy intake, daily weight gain and better feed conversion and energy efficiency than the other genotypes. The contrast analysis showed that the silage of the forage hybrids (AGX-213 and AG-2002) caused a significant reduction of the daily voluntary dry matter intake (8.84%) and digestible energy intake (12.11%) in comparison to the silage of the double purpose hybrids (AGX-217 and AG-2005E). Steers fed with silage of the double purpose hybrids showed higher daily weight gain (1.163 vs .943 kg) and were more efficient (P<.05) in converting dry matter intake and digestible energy intake into weight gain (7.65 vs 8.73 kg of DM/kg LW and 19.76 vs 21.84 Mcal/kg LW).

[学科分类] 兽医学

[关键词] daily weight gain;dry matter intake;energy efficiency;feed conversion     IntroduçãoA produção de silagem de alta qualidade é um aspecto que vem sendo trabalhado no setor pecuário;com o objetivo de diminuir os custos de produção