Kinetics of digestion of low-quality forage grazed by beef cattle fed supplements containing increasing levels of rumen undegradable protein

Abstract

-This experiment was conducted to evaluate the degradation kinetics and microbial efficiency of beef cattle grazing on low-quality forage and receiving supplements with different levels of rumen undegradable protein (RUP). The animals grazed on palisade grass pasture solely or this pasture and supplement containing 40 or 60 g of RUP per 100 g of crude protein (CP). The degradation profiles of neutral detergent fiber, fiber carbohydrates, and neutral detergent insoluble protein were interpreted kinetically by using a decreasing logistic model. Treatments (no supplement, or RUP at 40 or 60 g −1 100 g CP) did not affect rumen fill; however, the increase in the indigestible fiber carbohydrate fraction that occurred at the expense of the digestible fiber carbohydrate fraction resulted in a greater rumen fill effect. The palisade grass showed a significant proportion of its nitrogen in the form of slowly degradable protein as neutral detergent insoluble protein, which amounted to 26 g per 100 g CP. Supplementation with 40 g of RUP per 100 g CP decresead the indigestible fraction of the low-quality forage. However, the absence of a rumen-fill effect demonstrates that the additional supply of nutrients contributes greatly to increasing growth efficiency and use of the available energy from the forage by the ruminal microorganisms.

Pasture characteristics and productive performance of dairy cows under two grazing management strategies

“…The higher CP content observed in those pastures may be attributed to the greater participation of green and tender leaf blades in the forage canopy, due to the younger age of the plants (22.8 days) when compared with that of the plants managed at 30 days of defoliation. It is notable that diets with CP levels lower than 70 g/kg can cause an imbalance in rumen degradation and microbial synthesis (Van Soest, 1994;Gomes et al, 2016). In our study, as can be observed, CP values ranged between 141.27 (TZ95) and 119.91 (TZ30) g/kg DM (Table 1).…”

“…It should be stressed that pastures managed with 95% interception of the PAR will also provide larger quantities of fermentable carbohydrates, potentiating microbial synthesis (Andrade-Montemayor, Gasca, & Kawas, 2009). This results in a shorter retention time of the herbage in the rumen (Gomes et al, 2016), ultimately maximizing intake (Table 2) and animal performance (Table 3).…”

Evaluation of sugarcane rind on the nutritional value of ruminant feeding

“…Sugarcane is grown extensively in America, Africa, Asia, and Oceania on account of its ease of cultivation and outstanding production of green mass, which facilitate its use in ruminant feeding during the dry season (characterized by low rainfall and high temperatures), which results in a shortage of forage (Bento et al, 2018). Thus, sugarcane is an excellent option for farmers as it has advantages such as great nutritional value and forage production per area, concurring with the period of forage shortage compared to tropical forages (Gomes et al, 2016). However, sugarcane production in Brazil focuses on the sugar-energy industry rather than on animal nutrition, making selecting varieties with better nutritional value for animal feeding necessary (Carvalho et al, 2022).…”

“…Sugarcane deserves some attention due to its nutritional limitations, such as low protein and mineral levels and low-quality fibrous fractions. Among the nutritional limitations, the fibrous fractions significantly impact feed digestion, and protein and minerals can be corrected by supplements (Gomes et al, 2016). Sugarcane constituents with high lignification are in the strongly recalcitrant rind (Maziero et al, 2013).…”

Biometric evaluation and nutrients of the corn, pearl millet, and sorghum crops

“…Brazil is the second largest meat producer in the world, producing about 10.32 million tons in 2020 and exporting 2.7 million with revenues of US$ 7.7 billion (Abiec, 2021). About 90% of this meat comes from cattle finished on pasture, which can significantly impact animal production in countries with a tropical climate, such as Brazil, where the dry season, from May to September, affects the growth capacity and vigor of grasses, i.e., the nutritive value of the pasture (Gomes et al, 2016). For this reason, supplementary practices, such as silage use, are adopted to keep the herd fed, healthy, and productive, regardless of drought duration and intensity (Henriksson et al, 2014).…”