Effect of Genus and Growth Stage on the Chemical and Mineral Composition of Tropical Grasses Used to Feed Dairy Cows

Abstract

In tropical production systems, dairy cows are rarely supplemented with minerals, which often lead to mineral imbalances. Grasses grown together in the same soil type and sampled at the same growth stage can vary widely in chemical and mineral composition; therefore, the objective of this study was to characterize the chemical and mineral composition of Urochloa spp., Megathyrsus spp., and Andropogon spp. at three different stages of growth in the same soil type. The content of dry matter (DM; g 100 g -1 ) was higher (P≤0.05) in Urochloa spp. than in Andropogon spp. and Megathyrsus spp. Hemicellulose, non-fiber carbohydrates and slowly degraded true protein contents were higher (P≤0.05) in Andropogon spp. than in Urochloa spp. and Megathyrsus spp. Ether extract, crude protein, rapidly degraded true protein and unavailable protein contents were not affected by genus, whereas ether extract, ash, neutral detergent fiber, non-fiber carbohydrates, rapidly degraded true protein and unavailable protein contents were not affected by growth stage. Compared with Urochloa spp. and Andropogon spp., Megathyrsus spp. had higher (P≤0.05) contents of Na and Mg, intermediate (P≤0.05) contents of Mn and lower (P≤0.05) contents of Zn. P, Na, and K contents were affected by growth stage. Compared with Megathyrsus spp. and Andropogon spp., Urochloa spp. was higher (P≤0.05) in P and Na contents. Results from this study may be useful in predicting the nutrient and mineral supply from forages in dairy production systems in tropical areas.

In vitro ruminal degradation of carbohydrate fractions in tropical grasses fertilized with nitrogen

“…Across these studies high amounts of ash in Megathyrsus, low lignin in Urochloa and low amounts of crude protein in Cynodon were consistently observed. The chemical constituent findings are consistent with other reports for Cynodon (34) , Megathyrsus (35) , Urochloa (36) and Andropogon (29) , suggesting potential inherent growth differences in their plant tissues (33) . Fertilization with N modified the amount and distribution pattern of the nutrients in these plants (Table 1).…”

“…Megathyrsus, however, was distinguished for its high content of ash and acid insoluble ashes (AIA), and its low content (7.2 %) of CP. These values mirrored those found in the same similar-age species with climate Aw0 in Guerrero, Mexico (29) . Cynodon had high NDF and low NSC contents.…”

Ensilados de Megathyrsus maximus: Efecto del horario de corte y de la inoculación microbiana

“…(17). El contenido de materia orgánica (MO) se calculó a partir de la diferencia entre 100 y el porcentaje de cenizas, el de hemicelulosa mediante la diferencia entre los valores de FDN y FDA, y el de carbohidratos no fibrosos (CNF) con la fórmula CNF = 100 -(PB + CENIZAS + FDN + EE) (18). Para estimar la concentración de nutrientes digestibles totales (NDT) se utilizó como variable la concentración de FDN (19).…”

Ruminant Trace Minerals Deficiency and the Potential Link Between the Source and Rumen Interaction. A Review

“…The assessment of TM status of ruminants is often quite challenging, especially when clinical signs of deficiency are lacking [15]. Furthermore, the TM content of pasture herbage and forages are highly variable and influenced by factors such as region, season, harvest, or farming and feeding practices [30][31][32][33][34][35]; and have a strong effect on the TM status of ruminants [36][37][38][39]. The low level of TM in forages coupled with rumen antagonisms [17,40] can result in an epidemiology of TM deficiencies in ruminants [41].…”