Silage! A Vital Solution of Fodder Scarcity in the Country
Nasir Ali Tauqir and Dr. Muhammad Sarwar,
Institute of Animal Nutrition and Feed Technology,
University of Agriculture, Faisalabad
The critical constraint for profitable livestock production in developing countries is the inadequacy of quality forage. Because of ever growing human need for food, only limited cultivated land can be allocated to fodder production. Due to low per acre yield and minimum area under fodder production, the available fodder supply is much less than actually needed. This shortage in fodder supply is further being aggravated by increased urbanization and enhanced shifting trend of agriculture towards cash crops which further reduced the area under fodder crops by 2% after each decade. Moreover in our region, low per acre fodder yield coupled with two important fodder scarcity periods (one during summer and other during winter months), which, further aggravated the fodder availability situations.
Manipulating surplus fodder can go a long way to bridge this wider gap between fodder supply and demand during scarcity periods. Improvement in quality and quantity of feeds could result in the improvement of livestock production up to 50% from existing genetic potential of animals. So there is an immediate need to explore the available feed resources for sustainable livestock production and to suggest remedies to minimize the gap between nutrients availability and requirements of animals. One of the important feasible alternatives is to overcome the fodder shortage during severe weather conditions or a prolonged drought is the silage making of fodder when it is abundantly available. Preservation of surplus fodder by silage making can help reduce this irregular fodder supply pattern round the year.
Non-leguminous crops like corn, oat, barley, mott grass and jambo grass have relatively low buffering capacity and low concentrations of fermentable carbohydrates. Leguminous crops, on the other hand, have high moisture content, high buffering capacity (due to high protein and mineral content) and relatively low concentrations of fermentable carbohydrates therefore, pH drop in leguminous crops is also slow. Leguminous crops are extensively wilted prior to ensiling to lower the moisture content either by field wilting or by the addition of some absorbent. Dry roughages high in dry matter, low in N content like wheat and rice straws can be added successfully before ensilation. The information regarding the nutritive value of Mott grass, Jambo grass, Berseem and Lucerne plus wheat straw silage and its impact on lactation performance of Nili-Ravi buffaloes is not available in the literature.
The objective of the present project was to examine the influence of various additives, moisture levels and fermentation periods on nutritive value of leguminous (Berseem and Lucerne) and non- leguminous (Jambo and Mott grass) fodders and their silages and their influence on feed intake, digestion kinetics, nutrient digestibility, milk yield and its composition in lactating Nili-Ravi buffaloes. The hypothesis was that silages of various fodders (Jambo, Mott, Berseem and Lucerne) could successfully replace the conventional fodders in buffalo diets without adversely affecting their lactation performance.
The trials were conducted in three phases i.e. laboratory, in situ and lactation performance phases. Samples of Jambo and Mott grass fodders harvested at 50 days of maturity were analyzed for dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), hemicellulose, cellulose and ash contents. Jambo and mott grasses were ensiled in laboratory silos using two silage additives, molasses and crushed corn grains at 2, 4 and 6% of forage DM. The material in these silos was allowed 30, 35 and 40 days fermentation periods. While, berseem and lucerne fodders harvested at one tenth bloom were ensiled in laboratory silos at 20, 30, 40% DM and fodder as such (without wheat straw) each with three levels of molasses as additive i.e. 2, 4 and 6% of forage DM. Wheat straw was added in different proportions to increase DM of leguminous fodders. After opening these silos, the pH and lactic acid concentration were measured and thereafter these
silages were subjected to complete chemical analysis. Jambo grass ensiled with 2% molasses for 30 days proved to be the best as evidenced by low pH value and high lactic acid concentration. The pH of all treatments ranged from 3.50 to 3.90 while, the lactic acid concentration ranged from 3.86 to 4.10% but the results were non- significant statistically. These results showed that fermentation was predominantly of lactic acid an indication of well-preserved and good quality silage. Dry matter, TP, NDF and hemicellulose values were significantly affected by additive type being better with molasses at 2% level. There was non-significant change in CP, ADF, ADL, cellulose and ash contents during ensiling of jambo grass. At all inclusion levels of corn and molasses, fermentation periods did not affect the results. However, results indicated that preservation of jambo grass was comparatively better with a little loss of nutrients when it was ensiled with 2% molasses for 30 days.
The pH and lactic acid of mott grass ensiled with molasses and corn at all inclusion levels and fermentation periods were non-significant across all treatment means. Similarly, DM, CP, TP, ash and cell wall fractions (NDF, ADF, ADL, hemicellulose and cellulose) of mott grass silage remained unaffected by additives, their levels and fermentation periods. These results revealed that hydrolysis of fermentable carbohydrates from both the additives were similar during ensilation of mott grass. Therefore, being economical mott grass ensiled with 2% molasses for 30 days was selected for subsequent investigations.
Lactic acid and pH values of berseem ensiled at various DM contents with all inclusion levels of molasses were non-significant across all treatment means. Dry matter, CP, ash and cell wall fractions (NDF, ADF, hemicellulose, cellulose and ADL) were significantly affected by DM content at ensiling. However, the effect of additive levels and the interaction between additive levels and DM content were non-significant statistically. Regardless of additive levels, results were significantly better for berseem ensiled at 30% DM. Non-significant results of pH and lactic acid of lucerne silage revealed that all the silages were preserved well in small-scale laboratory silos. Dry matter, CP, NDF, ADF, hemicellulose, cellulose, ADL and ash contents of lucerne silage were significantly affected by DM content at ensiling while, the affect of additive levels and DM at ensiling were non-significant. However, the results of chemical composition were comparatively better when lucerne was ensiled at 30% DM with 2% molasses.
For in situ digestion kinetics studies, a male buffalo bull fitted with ruminal cannula was used of each study. Nylon bags measuring 10 23 cm with an average pore size of 50µm were used for determination of digestion kinetics. These bags separately contained 10g samples of Jambo and Mott grass harvested at 50 days of maturity, Berseem and Lucerne fodders harvested at one tenth bloom and their best screened silages from laboratory studies. For each time point, there were three bags for each sample. Two bags were used to determine DM and NDF degradabilities while third was kept as a blank. These bags were exposed to ruminal fermentation for 1, 2, 4, 6, 10, 16, 24, 36, 48 and 96 hours. After removal from the rumen, residues in the bags were analyzed for DM and NDF.
Dry matter and NDF degradabilities (at 48 hours of incubation) of jambo and mott grasses were significantly higher (p<0.05) than that of their respective silages. Dry matter and NDF degradabilities of berseem and its silage were non-significant different. However, DM degradabilities of lucerne and its silage were non-significant but NDF degradability of lucerne was significantly higher than that of its silage. Dry matter and NDF lag time, rate and extent digestion of jambo grass, mott grass, berseem and lucerne were non-significant across their respective silages. The results showed that all the silages were preserved well with minimum loss of soluble carbohydrates and ensilation rather improve their digestibility.
For lactation trials each non-leguminous fodder (jambo and mott grasses) was ensiled with 2% molasses for 30 days on large scale in bunker silos. While, each leguminous fodder (berseem and lucerne) was ensiled at 30% DM with 2% molasses. Wheat straw was added to reduce moisture content of leguminous fodders. Fifteen, early lactating Nili-Ravi buffaloes, five animals in each group, were employed in a Completely Randomized Design for each leguminous and non-leguminous study. Three experimental iso-nitrogenous and iso-caloric diets were formulated that contained 75% of jambo grass (control), jambo grass silage or mott grass silage and 25% concentrate for non-leguminous fodders. While in case of leguminous fodders, diets contained 75% of berseem fodder (control), berseem or lucerne silage and 25% concentrate. The buffaloes were fed for 60 days at ad libitum intakes. First 10 days were allowed for dietary adaptation and 50 days were for sample collection. Milk samples (a.m. & p.m.) were collected daily during the last 7 days of feeding trial and were analyzed for CP, fat, solid not fat and total solids. During last week of the study, a digestibility trial was conducted. The acid insoluble ash was used as digestibility marker.
Intake of DM was the highest (13.3 kg/d) in animals fed jambo grass (control) diet followed by those fed jambo grass silage (12.5 kg/d) and mott grass silage (12.03) diets. The difference in DMI was significant across fodder and silage based diets but the difference was non-significant across both silage-based diets. The depression in DMI may be attributed to the presence of fermentation products in the silage. However, DMI as a percent of body weight was non-significant across all treatments. Crude protein intake showed a similar trend across all treatments as was observed in DMI. Intake of NDF (NDFI) was significantly higher (8.35 kg/d) in buffaloes fed jambo grass diet followed by those fed mott grass silage (7.99 kg/d) and jambo grass silage (7.32 kg/d) diets. Similar trend was also noted for NDF intake as percent of body weight and digestible NDF intake across all diets. The apparent digestibilies of DM, CP and NDF did not show any treatment effect.
Dry matter intakes by lactating buffaloes differed significantly across berseem fodder (control), lucerne silage and berseem silage diets. Intake of DM was higher (13.8 kg/d) in animals fed berseem fodder (control) diet followed by those fed lucerne silage (12.5 kg/d) and berseem silage (11.9 kg/day) diets. However, DMI as a percent body weight was higher (3.24) in animals fed berseem fodder diet followed those fed lucerne silage (2.89) and berseem silage (2.63) diets. The difference in DMI percent body weight was significant across fodder and silage based diets while these results were non-significant across both silage-based diets. Digestible DMI also followed the similar trend as was observed in DMI which was higher (8.95 kg/day) in animals fed berseem fodder diet followed by those fed lucerne silage (7.94 kg/day) and berseem silage (7.39 kg/day) diets. Similarly, CP intake and digestible CP intake also showed a similar trend as was observed in DMI and digestible DMI across all treatments. Intake of NDF was the highest (5.68 kg/d) in buffaloes fed berseem fodder diet followed by those fed lucerne silage (5.50 kg/d) and berseem silage (5.00 kg/d) diets. The difference was significant across fodder and silage based diets but NDFI was non-significant across both silage-based diets. Similar trend was also noted for NDF intake as percent body weight and digestible NDF intake across all diets. The apparent DMD was the highest (64.8%) in animals fed berseem fodder diet followed by those fed lucerne silage (63.4%) and berseem silage (62.0%) diets. The apparent DMD was statistically significant across fodder and silage based diets but DMD was non-significant across both silage-based diets. However, apparent CP and NDF digestibilities remained unaltered across all treatments.
Milk yield (4% FCM) was non-significant in animals fed leguminous and non-leguminous fodders and their silages. Milk fat, total solids, solid not fat, milk CP, TP and NPN values also remained unaltered in animals fed non-leguminous fodder or silage diets. These results may be attributed to insignificant variation in DMI percent body weight and nutrient digestibility in animals fed all experimental diets. However, milk fat and total solids were significantly higher in animals fed berseem silage and lucerne silage diets as compared to those fed berseem fodder (control) diet. It was attributed to increased intake of structural carbohydrates, which were degraded by cellulolytic microbes for the production of acetate and milk fat. However, milk CP, TP, NPN and solid not fat values did not show any treatment effect.
Grasses and legumes were ensiled with different additives at various moisture levels for various fermentation periods, 2% molasses proved to be best additive at 30% DM for 30 days. When these silages were subjected to lactation performance study it was revealed that despite low feed intake of silage there was not any depression in milk yield and its composition. So replacing fodder with silage no adverse effect was noted on the performance of lactating buffaloes. Thus silage making of surplus fodders during their abundant growth period will not only help overcome the irregular fodder supply pattern, one of the major culprit for lower ruminant productivity, but it will also enhance fodder yield of multicut fodder crops by increasing their number of cuts.
Source: This article has previously been published in THE VETERINARY NEWS & VIEWS [WEEKLY] and on World Veterinary Association web site (March 25, 2004 at 02:09 PM).