Ensiling Total Mixed Ration for Ruminants: A Review

Abstract

The interest of ensiling total mixed rations (TMR) for ruminants reemerged in the last decades. In many situations, ensiling TMR has been a sustainable alternative to efficiently handle wet byproducts in ruminant diets. An ensiled TMR typically has a markedly higher aerobic stability than its respective fresh TMR. Ensiling a TMR increases ruminal protein degradability due to proteolysis during storage. An increase of feed efficiency by ruminants fed ensiled rations have been reported, due to the improved starch digestibility in TMR silages containing cereal grains. This manuscript brings an overview of the main nutrient transformations during the ensiling of TMR and their feeding value for ruminants.

Chemical composition and fatty acid profile of BRS Capiaçu ensiled at different regrowth ages

“…The main changes in the FA profile during ensiling are related to the action of plant lipases, which are activated after injury of forage tissue during harvesting operations, especially the leaves, which are less resistant than the stems because they are less lignified and therefore more sensitive to the action of tools (Baumont et al, 2011). Lipase and lipoxygenase activities are elevated soon after harvesting or in poorly preserved silages (Bueno, Lazzari, Jobim, & Daniel, 2020), and the microbial lipases in silos do not contribute to a large extent to the lipolysis of forage membrane lipids (Ding et al, 2013;Gadeyne et al, 2016).…”

“…Plant lipases remain functional, and their activity is higher during the first two days of ensiling, declining with a reduction in silage pH, and residual oxygen is consumed with the progress of ensiling (Han & Zhou, 2013). Thus, considering that the rapid acidification of the silage might preclude FA cleavage (Bueno et al, 2020), the low DM contents of forages with 50 and 70 days of regrowth probably promoted a slow, prolonged and inefficient fermentation process in the silo (as indicated by the pH>5.0; Table 1), leading to higher lipolysis in silage lipids (Van Ranst et al, 2009a), resulting in free FA accumulation in the silo (Van Ranst, Fievez, Vandewalle, De Riek, & Van Bockstaele, 2009b). Considering that the most common substrates for plant lipoxygenases are α-linolenic and linoleic acids, these FAs can be further oxidized by the actions of these enzymes to form hydroperoxides and are finally decomposed into aldehydes and ketones (Han & Zhou, 2013) as well as be biohydrogenated into stearic acid by microbes in the silo (Liu et al, 2019).…”

“…The greatest increases in the contents (g 100 g -1 FA) of palmitic and stearic acids in the silages in relation to those in chopped grass observed at 50 and 70 days of regrowth (Table 3) can be considered indicative that, at these regrowth ages, there was an intense activity of lipases, releasing palmitic, α-linolenic and linoleic acids; the last two of these were further oxidized by lipoxygenases and biohydrogenated to stearic acid by microbes in the silo (Liu et al, 2019), as demonstrated by the significant reductions in their silage contents (Table 3). On the other hand, it is possible that the higher DM contents in forages with 90 and 110 days of regrowth promote a more rapid acidification of silage, precluding the oxidation of FAs (Bueno et al, 2020). This can be shown, at least in part, by the similar total FA, linoleic acid and α-linolenic acid contents (g kg -1 DM) in the silages compared to the chopped grass at 110 days of regrowth (Table 2).…”

Pelleting of a Total Mixed Ration Affects Growth Performance of Fattening Lambs

“…Since being introduced to ruminant production systems over a half century ago, total mixed rations (TMR) have nowadays become common practice ( 1 – 3 ). Although there are many advantages of TMR, this feeding system also has some limitations ( 2 ), particularly feed sorting, which need to be addressed ( 4 ).…”

Agro-economic efficiency dynamics in vegetable cowpea and radish cultivar combinations in strip-intercropping systems

“…This can be explained by the lower fat content of tropical forages (Table 1) than of sorghum. According to Bueno, Lazzari, Jobim and Daniel (2020), lipids are not typical fuels for fermentation; thus, well-preserved silages have levels of ether extract that are similar to those in fresh material. This finding is in line with the results of the present study.…”