Protein Sources for Growing Beef Steers Fed with a Diet Based on Corn Silage

This study was conducted to determine the effect of different protein sources in growing beef cattle (25 Aberdeen Angus steers) fed with a corn silage based diet on daily live weight gain (DLWG), dry matter intake (DMI) and feed conversion (FC). Five treatments with different supplies of crude, degradable and metabolizable protein (MP) were used. The treatments were formulated with different protein sources to provide different rate and extents of protein degradation, as follow: a negative control (T0) without protein supplements and below animal requirements, urea (T1), soybean meal (T2), whole cotton seed (T3) and a positive control (T4), which include a mixture of protein sources in excess of animal requirements. The treatments were planned to be isoenergetics (2.63 Mcal ME kg -1 DM) and also T1, T2 and T3 were isoprotein. The data were analyzed statistically by ANOVA. The DGWG were significant different 730, 869, 1006, 946 and 979 g.day-1 for T0, T1, T2, T3, and T4 respectively. The main differences in DMI were obtained in the isoprotein treatments. Exceeding the animal requirements of metabolizable protein to achieve a suitable nitrogenous supply to rumen did not produce any improvement in the animal performance. The supply of nitrogenous in diets based on corn silage improves the DLWG and FC. This effect was higher with the use of true protein

Evaluation of Forage Sorghum Silages with the Addition of Sorghum Grain

The aim of this experiment was to evaluate the effect of additional sorghum grain and stage of maturity of forage sorghum silage on the animal performance. Two feeding trials were conducted with forage sorghum silage made at different stage of plant maturity. In trial 1, early silage was made with the crop harvested in early bloom stage. Four diets based on different ratios of silage: sorghum grain were evaluated: 100% silage (ES); 80% silage: 20% dry grain (ES20D); 60% silage: 40% dry grain (ES40D) and 60% silage: 40% wet grain silage (ES40W). In trial 2, late silage was made with the forage sorghum crop in dough maturity stage. Four diets combining different proportions of silage and sorghum grain (wet grain silage) were evaluated: 100% silage (LS); 90% silage: 10% grain (LS10W); 80% silage: 20% grain (LS20W); 70% silage: 30% grain (LS30W). In all components and diets, chemical composition was analyzed and animal performance was determined. In all cases the addition of sorghum grain to the forage sorghum silage improved the diet chemical composition. With early silage there was a high response in the daily live weigh gain (DLWG) (g/day) to the addition of sorghum grain (ES: 232; ES20D: 477, ES40D: 788; ES40W: 687), but there was no difference in dry matter intake between treatments with an average of 92 g DM/ kg 0.75 BW. With late silage, the DLWG only was higher than LS when grain was added in 30% of the diet (LS: 505; LS10W: 529; LS20W: 583, LS30W: 688). There was difference in the DLWG and in feed intake between the two maturity stages of the silages (ES vs LS)

Desaparición de la materia seca in situ de algunas especies forrajeras tropicales en la fase de rebrote

El objetivo del trabajo fue comparar la desaparición de la materia seca in situ (DMS in situ) en algunas especies forrajeras tropicales en la fase de rebrote. Las especies analizadas fueron: Setaria anceps cv. Kazungula, Antephora pubescens,Cenchrus ciliaris cv. Molopo, Panicum coloratum var. Makarikariense, Chlorisgayana Ecotipo Norte de Córdoba, Panicum maximum cv. Gatton y Eragrostiscurvula cv. Tanganyka. Se analizaron muestras de planta entera y de 2 alturas de corte, la primera de 5 a 20 cm de altura desde el suelo y la segunda de 21 a 40cm. La desaparición de la materia seca fue medida por el método de digestión in situ, utilizando 2 animales con fístula de rumen e incubando las muestras durante 96 horas. Se concluyó que las especies forrajeras tropicales evaluadas en el estado fenológico de rebrote presentaron diferencias marcadas de calidad.Las especies de mayor DMS in situ fueron Panicum maximum y Setaria anceps,siendo la de menor DMS in situ Eragrostis curvula. La calidad de las especies expresada en DMS in situ no varió con las diferentes alturas de corte, a excepción de Cenchrus ciliaris