Ruminal degradation of Panicum grasses in three post-regrowth ages

Abstract

The objective was to evaluate the chemical composition and in situ degradation of Maasai, Mombasa and Tanzania grasses belonging to the genus Panicum, at 22, 34 and 46 days after regrowth. The contents of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were determined. For the evaluation of ruminal degradation, 4 g sample were placed in nylon bags and incubated in the rumen of a fistulated animal, for 6, 24 and 72 h. The experiment had a completely randomized design for chemical composition analysis and a split-split plot completely randomized design for in situ degradation, with means compared by Tukey test at 5%. There was an increase in the contents of DM (+ 1.69%) and NDF (+ 5.06%) (P <0.05) of the grasses at the highest cutting ages with reduction in the CP fraction. The potential degradation (PD) of DM, NDF and CP decreased with advancing age of grasses, with an increase in colonization time (0.69 h) and NDF degradation rate (1.14%/h). The increase in the post-regrowth age of the Massai, Mombasa, and Tanzania grasses increases the acid detergent fiber content and reduces the crude protein content, with a negative effect on the degradation of DM, PB and NDF. The management of these cultivars is indicated at 22 and 34 days post-regrowth to obtain forage with better nutritional value.

How Are Warm-Season Pastures’ Nutritive Value and Fermentation Characteristics Affected by Open Pasture, Silvopasture, and Sward Herbage Maturity?

“…In the same way, the lignification of structural tissue hinders the performance of digestive enzymes produced by ruminal microorganisms, reducing degradability [27,33]. Similar results were observed in Guinea Massai grass [31], Marandu palisade grass (Urochloa brizantha) [37], and different Cynodon cultivars [28], in which there was a reduction in degradability as the forage age progressed.…”

“…The advance of SD is responsible for the thickening and lignification of the cell wall, increasing the proportion of fiber constituents [31]. Young plant cells have only one outer layer, called the primary wall.…”

Ruminal degradation and fermentation kinetics of the Mulato II grass (Convert HD364) under different sources of nitrogen fertilization

“…This contributes to improved forage digestibility during the period of maximum vegetative growth, resulting in increased ruminal emptying and a greater nutrient availability for ruminants. Consequently, better animal performance can be achieved during this period (33,34) .…”

NIRS Estimation of the Nutritive Value of Megathyrsus maximus (Syn. Panicum sp.) Forages

“…The decrease in CP in forage becomes the primary limiting factor for intake, as a result of reduced rumen microbial activity due to low availability of nitrogenous substrate, causing negative effects on digestibility [3]. Therefore, it is recommended that harvesting or grazing be done up to 57 days (Massai), 64 days (Tamani), 69 days (Mombasa), 73 days (Tanzania), 76 days (Kenya and Paredao), 78 days (Zuri), 79 days (Aries), and 90 days (Atlas).…”

“…Reductions in harvesting intervals lead to a lower amount of forage mass but increase the leaf/stem ratio, providing higher nutritional value. As the plants age, there is increased lignification of the cell walls, making it more difficult for rumen microorganisms to act, resulting in reduced degradability of the fibrous fraction [3].…”