Influence of stage of maturity on bromatological quality of corn forage

Abstract

-The objective of this study was to evaluate the effects of stalk/leaf ratio and the stage of maturity on the digestibility of the corn plant. Hybrids AG1051, AG4051, AG5011, DOW2B710, DOW2C577, DOW2A525, NB7315 and P30F90 were used, harvested at the one-half milk line (½ ML), three-quarters milk line (¾ ML) and black layer (BL) stages.A randomized block design was used in an 8 (hybrids) × 3 (stages of maturity) factorial design, with three replications. The means generated were used for grouping into high and low stalk/leaf ratio and a new analysis of variance was generated in a 2 × 3 (two groups and three stages of maturity) factorial design. The whole plant and its stalk, leaf, husk, cob and grain components were incubated in situ in the rumen of three cows for determination of degradability of dry matter and degradable neutral detergent fiber. Stalk/leaf ratio did not influence neutral detergent fiber content or the degradability of dry matter and neutral detergent fiber of any of the components, except for the cob, in which the high ratio group had greater degradable neutral detergent fiber contents. There was a reduction in the degradability of all the parts, except for the stalk and cob, and an increase in the neutral detergent fiber contents of the vegetative parts, except for the stalk. Unlike the vegetative components, the neutral detergent fiber contents of the whole plant decreased throughout the stages evaluated. For degradable neutral detergent fiber, there was a reduction in the whole plant and in its components. The advance of maturity reduces the quality of the vegetative components; however, this loss in the entire plant is moderated by grain filling. Forage quality depends more on the quality of the components than on their proportions in the dry matter.

Effects of Hybrid and Grain Maturity Stage on the Ruminal Degradation and the Nutritive Value of Maize Forage for Silage

“…Vials containing only inoculum were used for blank correction. Once filled, the vials were sealed with rubber stoppers and aluminum caps, shaken and placed in an incubator (Shel Lab, Sheldon Manufacturing, Inc., Cornelius, OR, USA) at 39 ± 0.5 • C. The gas pressure in the headspace was measured manually by inserting a sterile needle connected to the pressure transducer at 3,6,9,12,15,18,21,24,30,36,48,60,72,96, and 144 h after inoculation. The volume of gas produced was estimated from the pressure values as proposed by López et al [13].…”

“…Usually, the dry matter yield and the amount of grain present in the plant were considered the main indicators for the selection of hybrids. However, recent studies have linked several other attributes to the nutritional quality of silage, with emphasis on the use of the vegetative fraction of the plant [2,3]. Di Marco et al [4] underlined that under unfavorable weather conditions, silage digestibility may be better correlated with cell wall digestibility than with starch content.…”

Corn Silage, Meta-Analysis of The Quality and Yield of Different Regions in the World

“…Some varieties of corn with a higher lysine content, allow a softer endosperm, generating a higher DMD and starch content [3]. Marchesini et al [41] mentioned that a lower NDF content occurs at advanced stages of maturity, resulting in higher grain content and low fiber content; this grain increases the energy value [34], providing a higher amount of starch [45], and this presents a dilution effect of the NDF [46], being the grain, the most digestible part of the plant, resulting in a higher DMD in vitro [25]. Higher NDF levels are associated with increased starch content in late harvest; this concentration is a consequence of the transport of sugars from the remains to the cob to be converted into starch [44].…”

“…In CL5 "NDF", a lower DM content was observed, which is attributed to a forage harvested before it has reached maturity, resulting in lower DM yields, starch and energy concentrations [29,44,50]. NDF values decrease with advancing maturity [46]. It can be attributed to late or tropical hybrids that tend to produce higher NDF content and low NDF [43] and their slower grain-filling period is related to high temperatures, which increase the DM to more lignified tissues, causing an increase in DM and lignin content and generating a rapid filling of the cob, in a low concentration of starch, by the affectation of the starch-synthase enzyme that controls starch synthesis [19].…”

“…Higher yield of DM, with a large plant population, leads to higher milk production, due to increased DMI [61]. As for the correlation between DM and NDFD and starch, it is affected by the plant's maturity stage, modifying the starch and NDFD content [29]; NDF and NDFD concentrations of the whole plant were influenced by the maturity stages; NDF content of the whole plant decreased with the maturity stage [46], showing that the DM content (> 35 g/100 g DM) mainly causes a decrease in the NDD, while at a very early stage of DM harvest (<25 g/100 g DM) there is a relationship between starch and NDFD [3]. The NDF correlations, indicated that a higher NDF content commonly occurs with silage at a very early maturity (<25 g/100 g DM), resulting in a lower starch content [3] and by silageing the material with more moisture, it will generate a low concentration of NFC resulting from filtration in by increased fluid production in the silo and will cause a decrease in the NDFD [25]; including silage will have a low concentration of TND, Mcal/kg/DM and lower DMI, resulting in lower milk yields [3].…”