Rumen pH and NH3-N concentration of sheep fed temperate pastures supplemented with sorghum grain

Abstract

The aim of this study was to evaluate the effect of sorghum grain supplementation on ruminal pH and NH 3 -N concentration of wethers consuming a fresh temperate pasture (Lotus corniculatus) in metabolism cages. Sixteen Corriedale x Milchschaf wethers were fed temperate pastures ad libitum and were nonsupplemented or supplemented with ground sorghum grain at 5, 10 or 15 g/kg of their body weight (BW). Rumen fluid samples were collected at 0, 1, 2, 3, 4, 5 and 6 h after supplementation through permanent tubes inserted in the rumen. Ruminal pH was measured immediately and NH 3 -N concentration was determined by direct distillation. Mean daily pH values for non-supplemented wethers and supplemented with 5, 10 and 15 g/kg of their BW were 6.45, 6.14, 6.09 and 5.43, respectively. Significant differences in pH were found between the 15 g/kg supplemented group and non-supplemented, 5 and 10 g/kg supplemented groups, while a trend was found between non-supplemented and 10 g/kg supplemented group. After 0 h, all mean pH values for the non-supplemented group were above 6.15, while values for the 10 and 15 g/kg supplemented groups were below 6.2 and 6.0, respectively. No differences in NH 3 -N concentration among groups (mean = 37.15 mg/100 mL), between time or interaction between time and treatment were found. There was a correlation between pH and NH 3 -N when all measurements were considered. Ground sorghum grain supplementation significantly reduced rumen pH when 15 g/kg of BW was provided to wethers fed temperate pastures, but it did not affect NH 3 -N concentration. _______________________________________________________________________________________

Air-Dried Brown Seaweed, Ascophyllum nodosum , Alters the Rumen Microbiome in a Manner That Changes Rumen Fermentation Profiles and Lowers the Prevalence of Foodborne Pathogens

“…The reduced bacterial population size ( Table 3 ) and greater protozoal population size ( Table 3 ) in Tasco-fed rams suggest that protozoal predation of bacteria may have been heightened in the rumens of rams fed Tasco, a possibility that is supported by the higher NH 3 -N concentration in Tasco-fed rams than in Con-fed rams ( Table 2 ). However, although the bacterial population in Con-fed rams was more than 10 times that in Tasco-fed rams, the ruminal NH 3 -N concentration of the Tasco-fed rams was only 30 to 90% greater than that of controls yet within the normal range observed in ovine studies ( 19 – 21 ). Therefore, the higher ruminal NH 3 -N concentration observed in Tasco-fed rams was not considered to have significant adverse environmental or economic effects.…”

¿Cómo integramos las pasturas templadas a los nuevos sistemas intensivos de producción de leche y carne?

“…Algunos resultados n a c i o n a l e s n a c i o n a l e s n a c i o n a l e s n a c i o n a l e s n a c i o n a l e s Teóricamente, la captura del exceso de N-NH 3 ruminal, proveniente de forrajes con cantidades importantes de N de rápida degradación, podría ser mejorada utilizando como complemento carbohidratos de rápida degradación. Ello llevaría a mejorar la eficiencia de síntesis de proteína microbiana y a disminuir la excreción de N. Sin embargo, trabajos recientes en los que se agregaron almidones u otros carbohidratos no fibrosos en animales consumiendo pasturas de buena calidad, indican que esta práctica no mejora la captación de amonio en el rumen (Tebot, 2008, Aguerre et al, 2009b, Aguerre, 2010, ni tampoco aumenta la producción de proteína microbiana ni su eficiencia de síntesis (García et al, 2000;Azevedo, 2008;Tebot, 2008;Aguerre et al, 2009c). En general, los resultados positivos de la suplementación, cuando observados, han sido atribuidos a un aumento global de la MS o de la MO consumida (Azevedo, 2008;Aguerre, 2010).…”