**1. Introduction**

The preparation of conventional silage considers crops for this specific purpose; these crops include corn, sorghum or other forages. Nonconventional silages use by-products, co-products and other materials different from conventional crops; they include by-products of sugarcane, juice extraction of citrus, pineapple, cassava, pumpkin and others. These products are available

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

in high amounts during a short period of time, the harvest season. Their preservation is required so they can be maintained for longer periods of time and used then as feed for animals. Silage represents an appropriate technique for this purpose. Also these materials may have adequate characteristics for ensiling, i.e., adequate moisture content and high fermentable carbohydrates. These byproducts may have low crude protein (CP) and mineral concentration and some additives may help increase the nutritive value of these silages.

stability are acetic, propionic and caproic acids; also ammonia and some inoculants may contribute to silage stability [2]. To reduce the spoilage of ensiled material in phase 4, it is

Potential Use of Nonconventional Silages in Ruminant Feeding for Tropical and Subtropical Areas

http://dx.doi.org/10.5772/64382

87

In tropical areas, high amounts of vegetal biomass are produced due to the dynamic ecosystem, which is favored by the climatic conditions, i.e., humidity and temperature that propitiate accelerated growth of plants. An example of these plants is sugarcane (*Saccharum officinarum*); it can be fed to animals as an entire plant [3]. During the harvest of sugarcane for sugar extraction in the field an abundant biomass of sugarcane tops is wasted or burned; they constitute about 15% dry matter of total plant [4] and have greater protein content than the stalks [5], representing an alternative forage for ruminants in subtropical areas, where the climatic conditions complicate forage preservation; for this, sugarcane tops silage represents an alternative. The replacement of stalks by fresh tops of sugarcane in feedlot cattle diets has increased dry matter intake and body weight gain, **Table 1** [6]. The supplementation with urea of slow ruminal degradation to fresh sugarcane tops improved weight gain in lambs, **Table 2** [7]. Ruminal fermentation of fresh sugarcane tops is improved when supplemented with nitrogen and nonstructural carbohydrates [8], also similar results are observed in **Table 3** [9].

**0:100 20:80 40:60 60:40 80:20 100:00**

recommended that the silage be used as fast as possible once the silo is opened [1].

**3. Nutritive value of silages**

**3.1. Nutritive value of sugarcane tops silage**

**Top:stalk fresh basis**

Adapted with permission from Ferreiro and Preston [6].

Adapted with permission from Galina et al. [7].

degrading urea and corn plant.

ADG, g/d 70 135 218 DMI, g/d 474 797 917

SCT = sugarcane tops; ADG = average daily gain; DMI = dry matter intake.

ADG, kg/d 0.605 0.614 0.699 0.760 0.788 0.839 DMI, kg/d 4.52 4.66 6.49 6.40 6.76 7.50 Feed/gain 7.47 7.59 9.28 8.35 8.57 8.94

**Table 1.** Summary of growth performance of feedlot cattle fed with different proportions of tops:stalks of sugarcane.

**Table 2.** Summary of growth performance of feedlot lambs fed with sugarcane tops supplemented with slow

**SCT SCT plus slow degrading urea SCT plus slow degrading urea plus corn plant**

ADG = average daily gain; DMI = dry matter intake; feed conversion = feed intake/weight gain.

The improvement in nutritional quality of silages with nonconventional products may contribute to better animal feeding and production in tropical and subtropical areas. In addition, the use of alternative silages for animal feeding also may contribute by reducing environmental pollution. If by-products are not used in a short time (during the harvest season) they will be wasted in fields and in other cases they are burned. The objective of this chapter is to review the potential use of nonconventional silages (sugarcane tops [SCT], citrus byproducts, pumpkin and cassava) for ruminant feeding in tropical and subtropical areas.

## **2. Ensiling process**

Silage is the preservation of feeds by anaerobic fermentation, usually by epiphytic bacteria that convert soluble carbohydrates mainly to lactic acid, and minor amounts of other volatile fatty acids. This reduces pH, which inactivates or inhibits microbial growth and results in the preservation of ensiled material. The ensiling process has four stages. In phase 1, aerobic microorganisms are active during the aerobic phase and occur under aerobic conditions during the few hours after ensiling. The ensiled material and facultative microorganisms (yeasts and enterobacteria) continue respiration, reducing the oxygen present. The enzymes of the ensiled material are active and pH is close to 6. In phase 2, anaerobic fermentation starts and continues for several days depending on substrate availability and ensiling conditions. Lactic bacteria become the main strain, and lactic acid reduces pH to 3.8–5.0. In phase 3, the process is stable, because changes can occur even in anaerobic conditions; most microorganisms reduce their numbers. During this phase, while the silage maintains anaerobic conditions, the process is practically unchanged. Phase 4 starts with the opening of the silage, or air exposure. The spoilage of silage in this phase is due to two processes: one is the degradation of acids that preserve the silage and the second is the spoilage by some microorganisms [1].

To produce good quality silage the following principles of fermentation during the phases of ensiling should be considered. For phase 1, adequate particle size of ensiled material with efficient filling (adequate packing density) will reduce aerobic respiration that allows faster growth of anaerobic microorganisms that produce lactic acid. Phases 2 and 3 can be enhanced and/or stabilized using some additives to silage during its preparation. For fast time of pH reduction and decrease dry matter (DM) losses, additives containing water soluble carbohydrates are used. To improve the fermentation process, some microbial inoculants, organic acids and enzymes can also be used. It is pointed out [2] that additives in silage stimulate lactic acid bacteria growth, responsible of silage stability, decreasing nutrient loss during fermentation and resulting in silage of higher nutrient concentration. Additives that contribute to silage stability are acetic, propionic and caproic acids; also ammonia and some inoculants may contribute to silage stability [2]. To reduce the spoilage of ensiled material in phase 4, it is recommended that the silage be used as fast as possible once the silo is opened [1].
