**3.7. Ensiling on nutrient composition and utilization**

digestible nutrient intakes by replacing with oaten hay. In addition to feed shortage, water scarcity compromises livestock performances in dry areas. Because of its succulence, cactus could overcome this constraint as ruminants do not need to drink water when receiving cactus cladodes (35 g DM/kgW0.75) [50]. It is reported that ensiled mixture of spineless cactus, olive cake and wheat bran could be used to replace totally or partially oaten hay without affecting lamb performances and meat quality [49]. It is thus advocated to go for mixed silage with cactus and protein-rich dry forages (e.g. Ardu leaves, gram straw, pea crop residues), so as to balance the minimum moisture content (i.e. 35–40%) in making of good quality silage [31]. A reasonable intake of 3–4 kg cactus silage in adult sheep was recorded that meet 900–1200 g DM

Utilization of fruit and vegetable co-products, such as grape, tomato, olive or citrus pomace that are voluminously produced and have an important impact on the environment, in the animal feed holds promise in expanding the forage biomass, thereby meeting the increasing demands of feeds and fodder. Besides the fact that fruit and vegetable co-products are good sources of phenolic constituents [12, 51] that act as natural antioxidants, and research emphasis has now been directed at use of these co-products in improving products' quality [14]. They evaluated pomegranate byproduct silage supplementation to growing lambs and found improved nutritional and functional qualities as indicated by the increase in essential

National Institute of Animal Nutrition and Physiology (NIANP), Bengaluru (India), has developed a silage technology to preserve pineapple fruit residue (PFR) and use it as fodder for livestock [52]. More than 70% of pineapple fruit is wasted during processing in industry, and there is potential availability of PFR to the tune of 1.35 million tonnes per year in India. PFR is high in moisture and sugars and thus can suitably preserved in the form of silage, which otherwise become a waste in processing industries. Nutritionally, PFR silage is demonstrated as a valuable fodder resource comparable to maize green fodder and increases milk yield and quality.

Cassava (*Manihot esculenta*) is known as a highly productive tropical crop that is traditionally cultivated to produce roots for human consumption or for starch production. The yield of cassava leaves is recorded as much as 4.6 thousand tonnes of DM/ha when taken as a by-product at root harvesting. Cassava leaf silage was successfully introduced to small holder farmers in Indonesia [38]. The chemical and microbiological composition, silage preparation and the effects of LAB inoculants on silage fermentation of cassava residues including cassava leaves, peel and pulp were studied to effectively use in livestock diets [53, 54]. They found improved fermentation quality with lower pH, butyric acid and higher lactic acid when the residues

and enough nutrients to support minimum production during scarcity.

FA, intramuscular fat, total phenolic content and antioxidant activity.

**3.6. Silage from by-products**

*3.6.2. Pineapple fruit residue silage*

were ensiled with LAB inoculants.

*3.6.3. Cassava silage*

*3.6.1. Silage from fruit and vegetable co-products*

24 Ruminants - The Husbandry, Economic and Health Aspects

Differences in WSC and protein (particularly, the A and B fractions) contents and fermentative characteristics between plant parts and plant species contribute to the differences in ensiling process, be it lactic acid production, pH reduction and modification/reduction in the phytochemical constituents. The use of molasses has been in practice for stepping up the initial fermentation process during ensiling. It is suggested that a critical WSC concentration in herbage for successful preservation as silage without additives is 30 g/kg DM. Sugars, such as fructosans, starch, pectins and soluble fiber content, greatly decline during the fermentation process [55]. A part of the OM gets lost in the initial phase owing to respiration of plants and during fermentation to CO<sup>2</sup> and other fermentation products and storage of silage by microbial activity. Total DM losses for optimal lactic acid fermentation are relatively low and should range between 2 and 6%. The proteolytic activities are restricted when the pH of the silage is ≤4.3 [56], and in good silage, the process will stop earlier and limit the loss of protein. Tannin might limit the proteolytic activities and reduce the loss of silage CP (soluble NPN) [19]. Different ratios of grass to red clover silage in TMR demonstrated improved performance when they were offered as a mixture than when fed alone [57]. Red clover contains PPO, which binds protein and it tended to reduce whole body N balance at higher inclusion levels due to increased partitioning of N into urine and feces. Legumes that contain CT also have the potential to reduce the degradation of plant protein to NH3 -N in the rumen, thereby releasing proteins in the abomasum, leading to improvements in feed efficiency and reduction of N excretion. Research emphasis should therefore be needed to explore the interactions of CT-containing legume feeds with other dietary components, fiber digestion and the consequential N partitioning effects, thereby reducing N excretion and improving efficiency and environmental quality.

#### **3.8. Ensiling effect on phytochemicals/anti-nutritive factors**

Phytochemical determination showed that ensiling reduces the presence of some anti-nutritional factors such as tannins, phytic acid and trypsin inhibitors [58]. A low pH, which is critical to make good silages from wet crops, also dissociates tannin-protein complexes and may compromise formation of rumen escape protein that can improve protein utilization. Invariably, ensiling of tannin-rich, legume, cereal or mixed forages shows a pH decline not beyond 4.0, and hence, any possibility of dissociation of tannin-protein binding complex does not arise, which requires pH of 2–3 [59]. Increase in ensiling duration also reduces tannin concentration. At pH range 3.5–5.5, insoluble tannin and plant leaf protein complex was established [60]. A reduction of 25 and 42% in the tannin content of fresh cassava and Gliricidia tops, respectively, was found after ensiling [34]. This phenomenon can be correlated to hydrolysis of hydrolysable tannins. Moreover, diets containing 2–4% of CT reduce proteolysis during ensiling and rumen fermentation by up to 50% [61]. Similarly, a continuous decline in HCN to the tune of 68 and 43 % was found in ensiled cassava and Gliricidia tops, respectively after 2 months of ensiling [60]. Handling and ensiling process and the initial environment of the aerobic phase created favorable environment for reducing the HCN. A rapid reduction in pH restricts the enzyme activities that reduce the speed of HCN elimination during storage. Pyrrolizidine alkaloids remain unaltered in silage and are not toxic [62]. The PPO activity, associated predominately with the detrimental effect of browning fruit and vegetables, showed potential to inhibit proteolysis that draws interest to improve animal forage quality through greater N utilization [63]. The mechanism for PPO protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation, and these complexed proteins reduce protein digestibility in the rumen and subsequently increase undegraded dietary protein flow to the intestine. It catalyzes the conversion of phenols to quinones, which are extremely reactive and bind with cellular nucleophiles such as proteins to form protein-bound phenols. Red clover and cocks foot (*Dactylis glomerata*) showed high PPO activity compared to other forages [64]. There are several reports on the positive effect of PPO on preserving polyunsaturated FA (PUFA) within rumen simulation models [17] and limiting post-harvest proteolysis [64, 65]. The effect of PPO on inhibition of ruminal proteolysis and biohydrogenation is reported at 25 and 11%, respectively [66]. Thus, the benefit of red clover silage is attributed to a reduction in lipolysis in silo and an increase in beneficial C18 PUFA in animal products. A number of factors, e.g. cultivar, growing season, stage of maturity, sward management including forage conservation method and cell damage, play a role in the extent of enzyme activity.

trough. Speed of harvest needs to be coordinated with packing to achieve a minimum

**iii. Type of additives**: Use of additives is advisable when there is risk of meeting these

**iv. Silo sealing**: Post-exposure sealing of silage pit/bags/drums helps prevent aerobic expo-

The epiphytic microbial populations are the starter culture and the survival and activity of these populations are also among the factors influenced by the characteristics of the crop at the time of ensiling and often contribute to spoilage and could be a potential health risk. Therefore, the types of LAB rather than the total numbers of bacteria present in the epiphytic populations may be more important in determining the efficiency of the fermentation process. Manuring onto forage prior to ensiling increases numbers of epiphytic enterobacteria (e.g. *Bacillus* and *Clostridium* spp.) and contact of the forage with soil can also increase yeast and mold counts in the silage [69]. Although these microorganisms are usually inactivated during ensiling, they can become active and contribute to accelerated spoilage when the silage is exposed to air upon feeding. Well-preserved silages are dependent on appropriate fermentation after storage, which results in low pH and production of sufficient acid to inhibit the growth of undesirable microorganisms. Lactate-oxidizing yeasts are generally responsible for the initiation of aerobic spoilage, and the secondary aerobic spoilage flora consists of molds, bacilli, listeria and enterobacteria [70]. The activity of harmful microorganisms not only reduces the silage quality (e.g. formation of butyric acid) but also increases the losses of energy and DM [71]. Hexoses are fermented to carbon dioxide and hydrogen, and subsequent decarboxylation and deamination of amino acids by these bacteria contribute to a decrease in the quality and quantity of forage. Yeasts also ferment sugars to ethanol and carbon dioxide with higher fermentation losses. Spoilage after opening the silage pit or bags seems to be concurrent problems faced by many farmers because LAB typically reduces the concentration of acetate, which is strongly antifungal, and increases concentration of lactate, which is a growth substrate for spoilage yeasts [6]. When silage is exposed to air during storage or at feeding, aerobic spoilage leads to increase in pH and losses of DM and nutrients [72] due to lactic acid degradation by mainly the lactic acid-utilizing yeasts (e.g. *Pichia*, *Candida*) [73]. Difference in anaerobic degradation of cereal and legume forages during silage making leaves more residual WSC than do legume silages, which is a readily available source of energy for the animal. But, upon exposure to air, these WSC are readily utilized by spoilage microorganisms

by the time of feed out and a rate of silage removal to

Silage for Climate Resilient Small Ruminant Production http://dx.doi.org/10.5772/intechopen.74667 27

silage density of 210 kg DM/m3

**3.11. Spoilage and fungal contamination**

objectives.

match or exceed the depth of air penetration into the silo.

sure and infestation of bacteria, molds and yeast/fungal growth.

and often become more prone to aerobic deterioration than legume silage.

Growth of spoilage fungi in baled silage is not of random occurrence but is facilitated where in-bale environments allow the fungi to survive, colonize and reproduce. Visible fungal growth was observed on baled grass silage during the winter feeding season [74]. The factors analyzed are the concentrations of ethanol and lactic acid, DM content, bale tying, month of bale feed-out, age of bales, polythene film damage, ryegrass dominance, bale storage location
