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Effects of feeding ensiled mixtures of elephant grass (Pennisetum purpureum) with three grain legume plants on digestibility and nitrogen balance of West African Dwarf goats
Livestock Science 142 (2011) 80–84
Contents lists available at ScienceDirect
Livestock Science j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / l i v s c i
Effects of feeding ensiled mixtures of elephant grass (Pennisetum purpureum) with three grain legume plants on digestibility and nitrogen balance of West African Dwarf goats F.T. Ajayi ⁎ Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria
a r t i c l e
i n f o
Article history: Received 14 August 2010 Received in revised form 27 June 2011 Accepted 28 June 2011 Keywords: Digestibility Elephant grass Intake Grain legume plants WAD goats
a b s t r a c t This study was designed to assess the nutrient digestibility and nitrogen balance of goats fed silage made from mixtures of elephant grass and each of lima bean, pigeon pea and African yam bean plants. Sixteen West African Dwarf goats comprising of four goats per treatment were used for feeding trials which lasted for 82 days in a completely randomized design. Proximate composition of silage made from grass/legume mixtures ranged from 30.8%–31.5% crude protein; 5.9%–6.5% ash; 37.8%–40.2% neutral detergent fiber; metabolizable energy ranged from 11.9 to 13.1 MJ/kg DM; digestible energy was between 14.9 and 16.4 MJ/kg DM while sole grass silage was only high in the fiber fractions. Crude protein digestibility of the goats ranged from 94.6% in African yam bean/grass silage to 96.4% in lima bean/grass silage. The digestibility of the fiber fractions were highest in lima bean/grass silage and was followed by that of pigeon pea/grass silage, the least percent digestibility was observed in goats fed elephant grass silage. Nitrogen absorbed (69.7%) and nitrogen retention (54.8%) were highest in goats fed lima bean/grass silage and were significantly (P b 0.05) different from other treatments. The least nitrogen absorbed and retention percents were lowest in elephant grass silage. It can be concluded that silage made from grass and legume plants enhanced nutrient digestibility, nitrogen absorption and retention. It can be used to mitigate weight loss of animals during the dry season, ensiling of lima bean plant and elephant grass is the best among three legume/grass silages. Sole grass silage should not be fed solely to ruminant livestock as it would lead to poor performance if not supplemented with protein source. © 2011 Elsevier B.V. All rights reserved.
1. Introduction The productivity of livestock is low in Nigeria due to the inadequate intake of poor quality pasture. Coleman et al. (1999) stated that the ultimate criteria for assessing the quality of forages are their potential to support animal maintenance and production. Forage and fodder can be produced and fed as basal diet or as supplement to meet dietary requirements of livestock instead of dependence of natural pastures. These can be grazed or conserved as silage for use in deficit periods. Silage making is a feeding strategy to circumvent forage scarcity and weight ⁎ Tel.: + 2348059397580; fax: + 234 2 2312567. E-mail address: [email protected]. 1871-1413/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2011.06.020
losses in ruminant livestock. Igbekoyi (2008) described that silage production in the tropics is a sustainable means of supplementing poor quality feed for ruminants in the dry season. Ensiling is a potent general method for forage preservation and a form of treatment to occasionally salvage the impoverished pastures for acceptability and degradation by livestock (Igbekoyi, 2008). Silage is material produced by controlled fermentation of a crop of high moisture content. The materials to be ensiled are filled into a silo, compacted and properly sealed to exclude air. The process of respiration and proteolysis are important and influences nutritional value of the silage (Oduguwa et al., 2007). Elephant grass (Pennisetum purpureum Schum) cv S9 is tropical forage that favors the hot and humid conditions. The
F.T. Ajayi / Livestock Science 142 (2011) 80–84
leaf is about 30–120 cm long and 1.5 cm wide, leaf-sheaths has stiff hairs and usually yellow–brown in color. It produces about three million fertile spikelets or seed per kilogram and grows best in deep, well-drained friable loams with pH of 4.5–8.2 and temperatures of 25–40 °C. The dry matter yield of 10–30 t/ha/y is achievable under good management and up to 85 t/ha/y if fertilized; soil may require 150–300 kg/ha/y of nitrogen ('t Mannetje, 1992). It should not be allowed to grow above 1.5 m before cutting in order to have high proportion of leaf to stem. The grass has been utilized in feeding ruminants solely or with supplements (Mpairwe et al., 1998). African yam bean (Sphenostylis stenocarpa, Hochst, ex A. Rich) produces both edible seeds and tubers yet is one of the underutilized legumes in Nigeria. Areas of cultivation include West Africa (Guinea, Cote d'Ivore, Nigeria and Togoland) and also parts of equatorial Africa (Adeparusi, 2001). The foliage contains 23.9% crude protein (Ajayi et al., 2009). There are many cultivars of lima bean (Phaseolus lunatus) in Nigeria (Ologhobo and Fetuga, 1983a,b); usage is so prevalent in Nigeria that virtually every village or clan has a distinct vernacular for it. It is used in weaning diets in Nigeria and other African countries (Nwokolo, 1987). Ologhobo and Fetuga (1983b) reported the nutrient composition of seeds of lima bean cultivars on dry matter basis as follows: crude protein content about 22%, fat content (1.5%) and moderate ash and fiber content. Ajayi et al. (2009) reported 19.4% and 1.5% for the crude protein and fat content, respectively, for the foliage. Pigeon pea (Cajanus cajan) is widely distributed throughout the tropics as pulse crop mainly for grain and also as a cover crop or green manure crop. It is drought tolerant and has great adaptation to poor soil condition than most tropical legumes. The foliage contains crude protein and fat contents of 20.2% and 1.7%, respectively (Ajayi et al., 2009). These legumes are classified as minor grain legumes because they are under-utilized as human food in Nigeria due to the long hours of cooking them before consumption. However, utilization could be expanded because they are sources of dietary protein. They are indigenous and usually cultivated in association with arable crops like yam and cassava (Adeparusi, 2001). Large biomass of these legume foliages are produced annually (Ajayi et al., 2009). The objective of this study was to assess the performance of West African dwarf goats fed silage made from mixtures of elephant grass with under-utilized grain legume plants such as lima bean, pigeon pea and African yam bean. 2. Materials and methods The experiment was carried out at the sheep and goat section of the Institute of Agricultural Research and Training, Moor Plantation, Ibadan, Nigeria (latitude 7 0 15 1 to 7 0301N and longitude 30451 to 4001E). The area has a tropical humid climate with mean annual rainfall of 1415 mm and the average daily temperature is between 28 and 35 °C. The experimental house and individual pens for the goats were cleaned with disinfectant before arrival of the goats. Individual pens were covered with wood shavings up to 5 cm in depth. A number of 16 West African Dwarf (WAD) breed of goat was used, age between 3 and 4 months and average live weight of 6.54 ± 0.23 kg. They were purchased from villages about
81
45 km from the study area. Goats were given prophylactic treatments on arrival at the farm; long acting antibiotics and levamisole were administered at a dose of 1 ml/10 kg each. Goats were also dipped in Diazintol at a dose of 2 ml to 6 l of water against ectoparasite. Adaptation period lasted 14 days after which the goats were introduced to the silage diets for 82 days. 2.1. Forage grass and legumes Elephant grass (P. purpureum Schum) cv S9 was planted in the paddock of the livestock farm of the Institute in 2008 in a sandy–loamy soil at a spacing of 1 m apart. The plot was weeded manually throughout the season. An average dry matter yield of 22 t/ha/y was obtained for the grass in the first and second year period. The grass was cutback to 15 cm above ground level prior to feeding trial during which harvesting was done at 6 weekly intervals. African yam bean, lima bean and pigeon pea plants were harvested from the cropping field prior to flowering. 2.2. Silage preparation A 100 kg capacity plastic Silo was lined with 20 mm thick nylon and used for the ensiling of elephant grass with each of the lima bean, pigeon pea and African yam bean. The grass was chopped into 5–7 cm sizes and allowed to wilt; all the legumes were harvested after 3 months of planting and also chopped into about 7 cm sizes and wilted. Mixture of grass and each of the legumes and pineapple pulp was packed into the Silo already lined with the nylon at a ratio 60:30:10 while the control had grass and pineapple pulp at a ratio of 90:10 proportions. Ensiling was done in layers. Each layer was compacted with 20 kg load to remove air and ensure even compaction until the silo became filled up. Fifty grams of sodium chloride salt was added to the materials in layers in the silo as sterilant. The nylon sheet was sealed and a heavy stone of about 20 kg was placed on it. The Silo was closed with the lid and placed with 20 kg load of metal until the expiration of fermentation that lasted 42 days. 2.3. Feeding trial Goats were subjected to dietary treatments of silage mixtures as follows: Treatment 1: Treatment 2: Treatment 3: Treatment 4:
P. P. P. P.
purpureum + C. cajan + Pineapple pulp purpureum + P. lunatus + Pineapple pulp purpureum + S. stenocarpa + Pineapple pulp purpureum + Pineapple pulp
There were four goats per treatment; each goat serving as a replicate was housed in a separate pen with provision for feeding and water troughs. Goats were introduced to the diets in a completely randomized design at 3% of their body weight. Silages were offered at 08:00 h and 16:00 h. Provision was made for daily feed allowance of 10% above previous week's consumption. Fresh water was made available always. Daily voluntary intake was calculated by subtracting feed remnants from feed offered in previous day. Goats were weighed every week before feeding in the morning. The change in weight is the observed difference in weight per goat within a week.
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2.4. Digestibility and nitrogen balance Goats were adapted to metabolism cages for 14 days; each goat was kept in the cage designed for separate collection of urine and feces. The study was carried out for a 21 day period during which the quantity of feed offered, feed residues, feces and volume of urine from each goat were determined. Loss of nitrogen was prevented by adding 10 ml of 10% H2SO4 into each container for collection of urine (Chen and Gomex, 1992). Daily collections of feces and urine were bulked and 10% sub sample of each was taken. Urine samples were freezed for nitrogen determination while the fecal samples were oven dried at 105 °C, ground and analyzed for nitrogen. 2.5. Chemical analysis Dried samples of feeds and feces were milled using 2 mm sieve of Thompson hammer mill. Samples were analyzed for nitrogen by the Micro-kjeldahi method. DM, EE, ash were determined according to the Official Methods of Analysis (AOAC, 1990) while NDF, ADF and ADL were determined according to Van Soest and Robertson (1985) method. Metabolizable energy of ensiled materials was determined from Pauzenga equation: 37 × % crude protein + 81.8 × % fat + 35.5 × NFE (Pauzenga, 1985). NFE=100− {% (CP −EE− ash− CF)}. 2.6. Statistical analysis Data obtained were analyzed with the general linear model of SAS (1998) and the Duncan option of SAS (1998) and multiple range tests were used to detect significant differences among means. 3. Results and discussion The proximate composition (%) of pigeon pea, lima bean, AYB plants and elephant grass is presented in Table 1. There were no significant (P N 0.05) differences in the EE and ADL values of the lima bean, AYB and pigeon pea. The highest CP (25.3%) and DM (40.5%) were observed in AYB. Crude protein, ash content, NDF, ADF and ADL values obtained in this study correspond with values reported for pigeon pea, lima bean and AYB foliages (Ajayi et al., 2009). Elephant grass had the highest mean value in DM (58.4%), NDF (44.0%), ADF (27.4%), ADL (9.5%) and NFE (54.8%). Table 2 shows the proximate composition of ensiled mixtures of elephant grass with lima bean, pigeon pea and African yam bean fed to West African Dwarf goats. There were no significant differences (P N 0.05) in the DM of T1 and T4 as well as T2 and T3 silages. Among the ensiled mixtures, CP
ranged from 30.8% in T1 to 31.5% in T2. Ether extract was between 4.8% in T1 and 6.1% in T2. The lowest value of EE was obtained in T1. However, T3 was highest in NDF (40.2%) and in ADF (21.0%). The highest values of ADL (8.3%) and NFE (41.2%) were obtained for mixtures of T2 and values differed (P b 0.05) significantly from other treatments. The DM, CP, ash and EE values were higher than values reported by Nkosi et al. (2010) probably due to combination of legume with grass. This corroborates the findings of Baraza et al. (2009) that different silage types result in different nutritional characteristics. The high NDF, ADF and ADL values obtained for elephant grass correspond with reported values for guinea grass (Babayemi, 2009; Oduguwa et al., 2007). Crude protein obtained for the mixtures of legume/grass silages and sole grass in this study was higher than 7.0 g/100 g recommended for small ruminants (NRC, 1981) and 10–12 g/100 g recommended by ARC (1980). Apparent digestibility of goats fed ensiled mixtures of the grain legume plants and elephant grass is shown on Table 3. High digestibility values were observed in all treatments. Dry matter digestibility of mixtures did not differ (P N 0.05) significantly, it ranged from 90.49% in T4 silage to 92.16% in T2 silage. Highest CP digestibility was observed in goats on T2 but variations in values among other treatments were not significantly (P N 0.05) different. The NDF and ADF digestibility of goats on T2 were highest (86.09% and 63.65%, respectively). ADF digestibility values among the goats showed no significant (P N 0.05) differences in all treatments. The ADL digestibility value was highest (47.06%) in goats on T2, followed by that of T1 (45.22%), the least ADL digestibility was in goats on T3. The EE digestibility of the goats in all treatments was not significantly (P N 0.05) different, however, highest value was observed in goats on T2. Digestible energy (DE) and metabolizable energy (ME) values differed (P b 0.05) significantly in the treatments. Goats on T2 had the highest values of DE (16.42 MJ/kg DM) and ME (13.13 MJ/kg DM). The variations observed in the values for T1, T3 and T4 were not significantly (P N 0.05) different. Nitrogen utilization of West African Dwarf goats fed ensiled mixtures of grain legume plants with elephant grass is shown on Table 4, nitrogen intake value were not significantly (P N 0.05) different, however, intake was in the order of T2N T1N T4N T3. Fecal loss of nitrogen was observed to be highest in T4 (1.16 g/day) and was least in T1 (1.02 g/day). Urinary nitrogen loss was highest in goats on T1 (0.81 g/day) whereas goats on T3 had the least value. The highest total nitrogen excreted was observed in goats on T1 and T4 which were 1.83 g/day and 1.84 g/day, respectively. Goats on T2 had the highest percent of nitrogen absorbed (69.66%) and nitrogen retained (54.78%) when compared to other treatments. The low
Table 1 Proximate composition (%) of elephant grass, pigeon pea, lima bean and African yam bean plants on dry matter basis. Forage Pigeon pea Lima bean African yam bean Elephant grass SEM
Dry matter c
36.8 37.5c 40.5b 58.4a 2.30
Crude protein b
22.0 18.7c 25.3a 8.05d 1.80
Ether extract b
1.5 1.6b 1.6b 0.8c 0.30
ASH b
5.8 6.2a 5.7b 1.4c 0.68
NDF
ADF a
43.4 40.2b 42.8ab 44.0a 0.96
ADL b
20.1 17.5c 20.5b 27.4a 2.30
b
8.5 8.7b 8.2b 9.5a 0.45
NFE 45.7b 48.3b 39.2c 54.8a 3.11
abc = means in the same column with similar superscript are not significantly different (P N 0.05). NDF = neutral detergent fiber, ADF = acid detergent fiber, ADL = acid detergent lignin, NFE = nitrogen free extract, SEM = standard error of the mean.
F.T. Ajayi / Livestock Science 142 (2011) 80–84
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Table 2 Proximate composition of ensiled mixture of elephant grass and lima bean, pigeon pea and African yam bean plants on dry matter basis. Silage mixture
Dry matter
Crude protein
Ether extract
Ash
NDF
ADF
ADL
NFE
Pigeon pea + elephant grass Lima bean + elephant grass African yam bean + elephant grass Elephant grass only SEM
36.2b 38.4a 38.6a 36.6b 0.21
30.8a 31.5a 31.2a 12.4b 4.21
4.8ab 6.1a 5.4a 2.8b 1.22
6.5a 6.4a 5.9a 2.5b 1.50
39.4a 37.8b 40.2a 41.4a 1.31
20.2b 17.4c 21.0b 25.2a 1.27
7.7b 8.3ab 7.9b 8.6a 0.28
36.5c 41.2b 35.0c 56.6a 3.44
abc = means in the same column with similar superscript are not significantly different (P N 0.05). NDF = neutral detergent fiber, ADF = acid detergent fiber, ADL = acid detergent lignin, NFE = nitrogen free extract, SEM = standard error of the mean.
Table 3 Apparent digestibility (%) of West African Dwarf goats fed ensiled mixture of elephant grass and lima bean, pigeon pea and African yam bean plants. Parameters
Pigeon pea + elephant grass (T1)
Lima bean + elephant grass (T2)
African yam bean + elephant grass (T3)
Elephant grass (T4)
SEM
Dry matter Crude protein NDF ADF ADL Ether extract
92.1a 96.0 85.5a 62.4 45.2b 76.2ab
92.2a 96.4 86.1a 63.7 47.1a 77.2a
92.1a 94.6 85.4a 61.9 42.3c 77.0a
90.5b 95.8 84.3b 62.8 44.5b 76.5a
1.20 1.31 1.04 1.12 1.30 0.85
Energy (MJ/kg DM) Digestible energy Metabolizable energy
15.3b 12.2b
16.4a 13.1a
14.9b 11.9b
14.2b 11.3b
0.77 0.68
abc = means in the same row with similar superscript are not significantly (P N 0.05) different. NDF = neutral detergent fiber, ADF = acid detergent fiber, ADL = acid detergent lignin, SEM = standard error of the mean. Table 4 Nitrogen balance of West African Dwarf goats fed ensiled mixture of elephant grass and lima bean, pigeon pea and African yam bean plants. Parameters Nitrogen intake (g/day) Nitrogen excretion (g/day) Fecal Urinary Total N-retention N-absorbed N-absorbed (%) N-retention (%)
Pigeon pea + elephant grass (T1)
Lima bean + elephant grass (T2)
African yam bean + elephant grass (T3)
Elephant grass (T4)
SEM
3.34
3.56
3.22
3.26
1.08
1.0b 0.8a 1.8a 1.5b 2.3b 69.5a 45.2bc
1.1a 0.5a 1.6b 2.0a 2.5a 69.7a 54.8a
1.1a 0.4a 1.5b 1.7b 2.1b 65.2b 52.2b
1.2a 0.7a 1.8a 1.4b 2.1b 64.4b 43.6c
0.65 0.47 0.08 0.26 0.12 1.04 2.32
abc = means in the same row with similar superscript are not significantly (P N 0.05) different. NDF = neutral detergent fiber, ADF = acid detergent fiber, ADL = acid detergent lignin, SEM = standard error of the mean.
fiber fractions, coupled with high CP of the grass/legume silage were responsible for the high DM and nutrient digestibility observed in the goats. Silages made from grass and legume mixtures had higher intake of nitrogen and percent nitrogen retention compared to sole grass silage. 4. Conclusion This study revealed that African yam bean, lima bean and pigeon pea plants which are referred to as under-utilized grain legume plants could be ensiled with elephant grass to increase livestock production. After harvesting the seeds of these legumes, the remaining plants could be ensiled with grass and used in feeding ruminants. Since harvesting of the seeds is usually towards the dry season, ensiling of the plants with grass could solve the problem of feeding ruminant livestock during the dry season. The high nutrient profile after
ensiling enhanced dry matter intake of goats, digestibility and nutrient retention which was translated to increased weight gain over the sole grass silage. In order to have quality silage that would promote increase in livestock enterprise, silage should be composed of energy and protein sources. Among the silages made, lima bean with elephant grass mixture had the highest nutrient profile and goats that were fed with it had the highest DM intake, nutrient digestibility, nitrogen retention and weight gain. References Adeparusi, E.O., 2001. Effect of processing on same minerals, anti-nutrient and nutritional composition of African yam bean. Journal of Sustainable Agriculture and Environment 3 (1), 101–108. Ajayi, F., Akande, S.R., Adegbite, A.A., Idowu, B., 2009. Assessment of seven under-utilized gain legume foliagec as feed resources for ruminants. Livestock Research for Rural Development 21 (9) www.lrrd.org/lrrd21/ 9/ajay21149.htm retrieved on 6th June, 2011.
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AOAC, 1990. Official method of analysis, 15th edn. Association of Analytical Chemist, Washington D.C., pp. 69–88. ARC, 1980. The nutrient requirements of farm livestock no. 2. Ruminants, Agricultural Research Council, London. Babayemi, O.J., 2009. Silage quality, dry matter intake and disputability by West African dwarf sheep of guinea grass (Panicum maximum cv Ntchisi) harvested at 4 and 12 week regrowths. African Journal of Biotechnology 8 (16), 3983–3988. Baraza, E., Angeles, S., Garcia, A., Valiente-Banuet, A., 2009. Adoption of silage as a methodology to improve domestic goat productivity for marginal farmers of the Tehuacan valley in Mexico. Livestock Research for Rural Development 21 (9) www.lrrd.org/lrrd21/9/ajay21149.htm retrieved on 6th June, 2011. Chen, X.B., Gomex, M.J., 1992. Estimation of microbial protein supply to sheep and cattle based on urinary excretion of prime derivative, an overview of the technical details. International Feed Res. Unit, Ronett Res. Inst. Occasional Public. Aberdeen, pp. 2–20. Coleman, S.W., Lippke, H., Gill, M., 1999. Estimating the nutritive potential of forages. The 5th International symposium on the nutrition of Herbivores. Nutritional Ecology of Herbivores and Integration. San Antonio, Texas. April 11 – 16. Igbekoyi, A.J. 2008: Intake growth and digestibility of ensiled Albizia saman pods with guinea grass (Panicum maximum cv Ntchisi) by West African dwarf rams. M. Sc dissertation, University of Ibadan, Nigeria. Mpairwe, D.R., Sabiiti, E.N., Mugerwa, J.S., 1998. Effects of dried Gliricidia sepium leaf supplement on feed intake, digestibility and nitrogen retention in sheep fed KW4 elephant grass (Pennisetum purpureum) ad libitum. Agroforestry Systems 41 (2), 139–150.
NRC, 1981. Nutrient requirement of goats. Angara: dairy and meat goats in temperate and tropical countries. National Academy of Sciences, Washington D.C. Nkosi, B.D., Meeske, R., Groenewald, I.B., 2010. Effects of ensiling potato hash with either whey or sugarcane molasses on silage quality and nutrient digestibility in sheep. Livestock Research for Rural Development 22 www.lrrd.org/lrrd22/1/nkos22001.htm retrieved on 6th June, 2011. Nwokolo, E., 1987. A nutritional assessment of African yam bean (Sphenostylis stenocarpa ex Rich) Harms, and Bambara groundnut (Voandzeia subtenanean L). Journal of Food Science and Agriculture 41, 123–129. Oduguwa, B.O., Jolaosho, A.O., Ayankoso, M.T., 2007. Effects of ensiling on the physical properties, chemical composition and mineral contents of guinea grass and cassava top silage. Nigerian Journal of Animal Production 34, 100–106. Ologhobo, D.A., Fetuga, B.L., 1983a. Trypsin inhibitor activity in sesame lima bean (Phaseolus lunatus) varieties. Food Chemistry 27, 41–47. Ologhobo, D.A., Fetuga, B.L., 1983b. Compositional differences in some lima bean (Phaseolus lunatus) varieties. Food Chemistry 10, 297–307. Pauzenga, U., 1985. Feeding parent stock. Zootecnica International, pp. 22–24. SAS, 1998. Statistical Analytical Systems. SAS/STAT User's Guide Statistical Analysis Institute Inc. Version 6, 3rd edn. Cary, North Carolina, U.S.A. , p. 943. 't Mannetje, L., 1992. Pennisetum purpureum Schumach. In: 't Mannetje, L., Jones, R.M. (Eds.), Plant Resources of South–East Asia Number 4 Forages. Pudoc Scientific Publishers, Wageningen, the Netherlands, pp. 191–192. Van Soest, P.J., Robertson, J.B., 1985. Analysis of forage and fibrous foods As 613 mammal. Department of Animal Science Cornell University, Ithaca, pp. 105–106.
Contents lists available at ScienceDirect
Livestock Science j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / l i v s c i
Effects of feeding ensiled mixtures of elephant grass (Pennisetum purpureum) with three grain legume plants on digestibility and nitrogen balance of West African Dwarf goats F.T. Ajayi ⁎ Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria
a r t i c l e
i n f o
Article history: Received 14 August 2010 Received in revised form 27 June 2011 Accepted 28 June 2011 Keywords: Digestibility Elephant grass Intake Grain legume plants WAD goats
a b s t r a c t This study was designed to assess the nutrient digestibility and nitrogen balance of goats fed silage made from mixtures of elephant grass and each of lima bean, pigeon pea and African yam bean plants. Sixteen West African Dwarf goats comprising of four goats per treatment were used for feeding trials which lasted for 82 days in a completely randomized design. Proximate composition of silage made from grass/legume mixtures ranged from 30.8%–31.5% crude protein; 5.9%–6.5% ash; 37.8%–40.2% neutral detergent fiber; metabolizable energy ranged from 11.9 to 13.1 MJ/kg DM; digestible energy was between 14.9 and 16.4 MJ/kg DM while sole grass silage was only high in the fiber fractions. Crude protein digestibility of the goats ranged from 94.6% in African yam bean/grass silage to 96.4% in lima bean/grass silage. The digestibility of the fiber fractions were highest in lima bean/grass silage and was followed by that of pigeon pea/grass silage, the least percent digestibility was observed in goats fed elephant grass silage. Nitrogen absorbed (69.7%) and nitrogen retention (54.8%) were highest in goats fed lima bean/grass silage and were significantly (P b 0.05) different from other treatments. The least nitrogen absorbed and retention percents were lowest in elephant grass silage. It can be concluded that silage made from grass and legume plants enhanced nutrient digestibility, nitrogen absorption and retention. It can be used to mitigate weight loss of animals during the dry season, ensiling of lima bean plant and elephant grass is the best among three legume/grass silages. Sole grass silage should not be fed solely to ruminant livestock as it would lead to poor performance if not supplemented with protein source. © 2011 Elsevier B.V. All rights reserved.
1. Introduction The productivity of livestock is low in Nigeria due to the inadequate intake of poor quality pasture. Coleman et al. (1999) stated that the ultimate criteria for assessing the quality of forages are their potential to support animal maintenance and production. Forage and fodder can be produced and fed as basal diet or as supplement to meet dietary requirements of livestock instead of dependence of natural pastures. These can be grazed or conserved as silage for use in deficit periods. Silage making is a feeding strategy to circumvent forage scarcity and weight ⁎ Tel.: + 2348059397580; fax: + 234 2 2312567. E-mail address: [email protected]. 1871-1413/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2011.06.020
losses in ruminant livestock. Igbekoyi (2008) described that silage production in the tropics is a sustainable means of supplementing poor quality feed for ruminants in the dry season. Ensiling is a potent general method for forage preservation and a form of treatment to occasionally salvage the impoverished pastures for acceptability and degradation by livestock (Igbekoyi, 2008). Silage is material produced by controlled fermentation of a crop of high moisture content. The materials to be ensiled are filled into a silo, compacted and properly sealed to exclude air. The process of respiration and proteolysis are important and influences nutritional value of the silage (Oduguwa et al., 2007). Elephant grass (Pennisetum purpureum Schum) cv S9 is tropical forage that favors the hot and humid conditions. The
F.T. Ajayi / Livestock Science 142 (2011) 80–84
leaf is about 30–120 cm long and 1.5 cm wide, leaf-sheaths has stiff hairs and usually yellow–brown in color. It produces about three million fertile spikelets or seed per kilogram and grows best in deep, well-drained friable loams with pH of 4.5–8.2 and temperatures of 25–40 °C. The dry matter yield of 10–30 t/ha/y is achievable under good management and up to 85 t/ha/y if fertilized; soil may require 150–300 kg/ha/y of nitrogen ('t Mannetje, 1992). It should not be allowed to grow above 1.5 m before cutting in order to have high proportion of leaf to stem. The grass has been utilized in feeding ruminants solely or with supplements (Mpairwe et al., 1998). African yam bean (Sphenostylis stenocarpa, Hochst, ex A. Rich) produces both edible seeds and tubers yet is one of the underutilized legumes in Nigeria. Areas of cultivation include West Africa (Guinea, Cote d'Ivore, Nigeria and Togoland) and also parts of equatorial Africa (Adeparusi, 2001). The foliage contains 23.9% crude protein (Ajayi et al., 2009). There are many cultivars of lima bean (Phaseolus lunatus) in Nigeria (Ologhobo and Fetuga, 1983a,b); usage is so prevalent in Nigeria that virtually every village or clan has a distinct vernacular for it. It is used in weaning diets in Nigeria and other African countries (Nwokolo, 1987). Ologhobo and Fetuga (1983b) reported the nutrient composition of seeds of lima bean cultivars on dry matter basis as follows: crude protein content about 22%, fat content (1.5%) and moderate ash and fiber content. Ajayi et al. (2009) reported 19.4% and 1.5% for the crude protein and fat content, respectively, for the foliage. Pigeon pea (Cajanus cajan) is widely distributed throughout the tropics as pulse crop mainly for grain and also as a cover crop or green manure crop. It is drought tolerant and has great adaptation to poor soil condition than most tropical legumes. The foliage contains crude protein and fat contents of 20.2% and 1.7%, respectively (Ajayi et al., 2009). These legumes are classified as minor grain legumes because they are under-utilized as human food in Nigeria due to the long hours of cooking them before consumption. However, utilization could be expanded because they are sources of dietary protein. They are indigenous and usually cultivated in association with arable crops like yam and cassava (Adeparusi, 2001). Large biomass of these legume foliages are produced annually (Ajayi et al., 2009). The objective of this study was to assess the performance of West African dwarf goats fed silage made from mixtures of elephant grass with under-utilized grain legume plants such as lima bean, pigeon pea and African yam bean. 2. Materials and methods The experiment was carried out at the sheep and goat section of the Institute of Agricultural Research and Training, Moor Plantation, Ibadan, Nigeria (latitude 7 0 15 1 to 7 0301N and longitude 30451 to 4001E). The area has a tropical humid climate with mean annual rainfall of 1415 mm and the average daily temperature is between 28 and 35 °C. The experimental house and individual pens for the goats were cleaned with disinfectant before arrival of the goats. Individual pens were covered with wood shavings up to 5 cm in depth. A number of 16 West African Dwarf (WAD) breed of goat was used, age between 3 and 4 months and average live weight of 6.54 ± 0.23 kg. They were purchased from villages about
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45 km from the study area. Goats were given prophylactic treatments on arrival at the farm; long acting antibiotics and levamisole were administered at a dose of 1 ml/10 kg each. Goats were also dipped in Diazintol at a dose of 2 ml to 6 l of water against ectoparasite. Adaptation period lasted 14 days after which the goats were introduced to the silage diets for 82 days. 2.1. Forage grass and legumes Elephant grass (P. purpureum Schum) cv S9 was planted in the paddock of the livestock farm of the Institute in 2008 in a sandy–loamy soil at a spacing of 1 m apart. The plot was weeded manually throughout the season. An average dry matter yield of 22 t/ha/y was obtained for the grass in the first and second year period. The grass was cutback to 15 cm above ground level prior to feeding trial during which harvesting was done at 6 weekly intervals. African yam bean, lima bean and pigeon pea plants were harvested from the cropping field prior to flowering. 2.2. Silage preparation A 100 kg capacity plastic Silo was lined with 20 mm thick nylon and used for the ensiling of elephant grass with each of the lima bean, pigeon pea and African yam bean. The grass was chopped into 5–7 cm sizes and allowed to wilt; all the legumes were harvested after 3 months of planting and also chopped into about 7 cm sizes and wilted. Mixture of grass and each of the legumes and pineapple pulp was packed into the Silo already lined with the nylon at a ratio 60:30:10 while the control had grass and pineapple pulp at a ratio of 90:10 proportions. Ensiling was done in layers. Each layer was compacted with 20 kg load to remove air and ensure even compaction until the silo became filled up. Fifty grams of sodium chloride salt was added to the materials in layers in the silo as sterilant. The nylon sheet was sealed and a heavy stone of about 20 kg was placed on it. The Silo was closed with the lid and placed with 20 kg load of metal until the expiration of fermentation that lasted 42 days. 2.3. Feeding trial Goats were subjected to dietary treatments of silage mixtures as follows: Treatment 1: Treatment 2: Treatment 3: Treatment 4:
P. P. P. P.
purpureum + C. cajan + Pineapple pulp purpureum + P. lunatus + Pineapple pulp purpureum + S. stenocarpa + Pineapple pulp purpureum + Pineapple pulp
There were four goats per treatment; each goat serving as a replicate was housed in a separate pen with provision for feeding and water troughs. Goats were introduced to the diets in a completely randomized design at 3% of their body weight. Silages were offered at 08:00 h and 16:00 h. Provision was made for daily feed allowance of 10% above previous week's consumption. Fresh water was made available always. Daily voluntary intake was calculated by subtracting feed remnants from feed offered in previous day. Goats were weighed every week before feeding in the morning. The change in weight is the observed difference in weight per goat within a week.
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2.4. Digestibility and nitrogen balance Goats were adapted to metabolism cages for 14 days; each goat was kept in the cage designed for separate collection of urine and feces. The study was carried out for a 21 day period during which the quantity of feed offered, feed residues, feces and volume of urine from each goat were determined. Loss of nitrogen was prevented by adding 10 ml of 10% H2SO4 into each container for collection of urine (Chen and Gomex, 1992). Daily collections of feces and urine were bulked and 10% sub sample of each was taken. Urine samples were freezed for nitrogen determination while the fecal samples were oven dried at 105 °C, ground and analyzed for nitrogen. 2.5. Chemical analysis Dried samples of feeds and feces were milled using 2 mm sieve of Thompson hammer mill. Samples were analyzed for nitrogen by the Micro-kjeldahi method. DM, EE, ash were determined according to the Official Methods of Analysis (AOAC, 1990) while NDF, ADF and ADL were determined according to Van Soest and Robertson (1985) method. Metabolizable energy of ensiled materials was determined from Pauzenga equation: 37 × % crude protein + 81.8 × % fat + 35.5 × NFE (Pauzenga, 1985). NFE=100− {% (CP −EE− ash− CF)}. 2.6. Statistical analysis Data obtained were analyzed with the general linear model of SAS (1998) and the Duncan option of SAS (1998) and multiple range tests were used to detect significant differences among means. 3. Results and discussion The proximate composition (%) of pigeon pea, lima bean, AYB plants and elephant grass is presented in Table 1. There were no significant (P N 0.05) differences in the EE and ADL values of the lima bean, AYB and pigeon pea. The highest CP (25.3%) and DM (40.5%) were observed in AYB. Crude protein, ash content, NDF, ADF and ADL values obtained in this study correspond with values reported for pigeon pea, lima bean and AYB foliages (Ajayi et al., 2009). Elephant grass had the highest mean value in DM (58.4%), NDF (44.0%), ADF (27.4%), ADL (9.5%) and NFE (54.8%). Table 2 shows the proximate composition of ensiled mixtures of elephant grass with lima bean, pigeon pea and African yam bean fed to West African Dwarf goats. There were no significant differences (P N 0.05) in the DM of T1 and T4 as well as T2 and T3 silages. Among the ensiled mixtures, CP
ranged from 30.8% in T1 to 31.5% in T2. Ether extract was between 4.8% in T1 and 6.1% in T2. The lowest value of EE was obtained in T1. However, T3 was highest in NDF (40.2%) and in ADF (21.0%). The highest values of ADL (8.3%) and NFE (41.2%) were obtained for mixtures of T2 and values differed (P b 0.05) significantly from other treatments. The DM, CP, ash and EE values were higher than values reported by Nkosi et al. (2010) probably due to combination of legume with grass. This corroborates the findings of Baraza et al. (2009) that different silage types result in different nutritional characteristics. The high NDF, ADF and ADL values obtained for elephant grass correspond with reported values for guinea grass (Babayemi, 2009; Oduguwa et al., 2007). Crude protein obtained for the mixtures of legume/grass silages and sole grass in this study was higher than 7.0 g/100 g recommended for small ruminants (NRC, 1981) and 10–12 g/100 g recommended by ARC (1980). Apparent digestibility of goats fed ensiled mixtures of the grain legume plants and elephant grass is shown on Table 3. High digestibility values were observed in all treatments. Dry matter digestibility of mixtures did not differ (P N 0.05) significantly, it ranged from 90.49% in T4 silage to 92.16% in T2 silage. Highest CP digestibility was observed in goats on T2 but variations in values among other treatments were not significantly (P N 0.05) different. The NDF and ADF digestibility of goats on T2 were highest (86.09% and 63.65%, respectively). ADF digestibility values among the goats showed no significant (P N 0.05) differences in all treatments. The ADL digestibility value was highest (47.06%) in goats on T2, followed by that of T1 (45.22%), the least ADL digestibility was in goats on T3. The EE digestibility of the goats in all treatments was not significantly (P N 0.05) different, however, highest value was observed in goats on T2. Digestible energy (DE) and metabolizable energy (ME) values differed (P b 0.05) significantly in the treatments. Goats on T2 had the highest values of DE (16.42 MJ/kg DM) and ME (13.13 MJ/kg DM). The variations observed in the values for T1, T3 and T4 were not significantly (P N 0.05) different. Nitrogen utilization of West African Dwarf goats fed ensiled mixtures of grain legume plants with elephant grass is shown on Table 4, nitrogen intake value were not significantly (P N 0.05) different, however, intake was in the order of T2N T1N T4N T3. Fecal loss of nitrogen was observed to be highest in T4 (1.16 g/day) and was least in T1 (1.02 g/day). Urinary nitrogen loss was highest in goats on T1 (0.81 g/day) whereas goats on T3 had the least value. The highest total nitrogen excreted was observed in goats on T1 and T4 which were 1.83 g/day and 1.84 g/day, respectively. Goats on T2 had the highest percent of nitrogen absorbed (69.66%) and nitrogen retained (54.78%) when compared to other treatments. The low
Table 1 Proximate composition (%) of elephant grass, pigeon pea, lima bean and African yam bean plants on dry matter basis. Forage Pigeon pea Lima bean African yam bean Elephant grass SEM
Dry matter c
36.8 37.5c 40.5b 58.4a 2.30
Crude protein b
22.0 18.7c 25.3a 8.05d 1.80
Ether extract b
1.5 1.6b 1.6b 0.8c 0.30
ASH b
5.8 6.2a 5.7b 1.4c 0.68
NDF
ADF a
43.4 40.2b 42.8ab 44.0a 0.96
ADL b
20.1 17.5c 20.5b 27.4a 2.30
b
8.5 8.7b 8.2b 9.5a 0.45
NFE 45.7b 48.3b 39.2c 54.8a 3.11
abc = means in the same column with similar superscript are not significantly different (P N 0.05). NDF = neutral detergent fiber, ADF = acid detergent fiber, ADL = acid detergent lignin, NFE = nitrogen free extract, SEM = standard error of the mean.
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Table 2 Proximate composition of ensiled mixture of elephant grass and lima bean, pigeon pea and African yam bean plants on dry matter basis. Silage mixture
Dry matter
Crude protein
Ether extract
Ash
NDF
ADF
ADL
NFE
Pigeon pea + elephant grass Lima bean + elephant grass African yam bean + elephant grass Elephant grass only SEM
36.2b 38.4a 38.6a 36.6b 0.21
30.8a 31.5a 31.2a 12.4b 4.21
4.8ab 6.1a 5.4a 2.8b 1.22
6.5a 6.4a 5.9a 2.5b 1.50
39.4a 37.8b 40.2a 41.4a 1.31
20.2b 17.4c 21.0b 25.2a 1.27
7.7b 8.3ab 7.9b 8.6a 0.28
36.5c 41.2b 35.0c 56.6a 3.44
abc = means in the same column with similar superscript are not significantly different (P N 0.05). NDF = neutral detergent fiber, ADF = acid detergent fiber, ADL = acid detergent lignin, NFE = nitrogen free extract, SEM = standard error of the mean.
Table 3 Apparent digestibility (%) of West African Dwarf goats fed ensiled mixture of elephant grass and lima bean, pigeon pea and African yam bean plants. Parameters
Pigeon pea + elephant grass (T1)
Lima bean + elephant grass (T2)
African yam bean + elephant grass (T3)
Elephant grass (T4)
SEM
Dry matter Crude protein NDF ADF ADL Ether extract
92.1a 96.0 85.5a 62.4 45.2b 76.2ab
92.2a 96.4 86.1a 63.7 47.1a 77.2a
92.1a 94.6 85.4a 61.9 42.3c 77.0a
90.5b 95.8 84.3b 62.8 44.5b 76.5a
1.20 1.31 1.04 1.12 1.30 0.85
Energy (MJ/kg DM) Digestible energy Metabolizable energy
15.3b 12.2b
16.4a 13.1a
14.9b 11.9b
14.2b 11.3b
0.77 0.68
abc = means in the same row with similar superscript are not significantly (P N 0.05) different. NDF = neutral detergent fiber, ADF = acid detergent fiber, ADL = acid detergent lignin, SEM = standard error of the mean. Table 4 Nitrogen balance of West African Dwarf goats fed ensiled mixture of elephant grass and lima bean, pigeon pea and African yam bean plants. Parameters Nitrogen intake (g/day) Nitrogen excretion (g/day) Fecal Urinary Total N-retention N-absorbed N-absorbed (%) N-retention (%)
Pigeon pea + elephant grass (T1)
Lima bean + elephant grass (T2)
African yam bean + elephant grass (T3)
Elephant grass (T4)
SEM
3.34
3.56
3.22
3.26
1.08
1.0b 0.8a 1.8a 1.5b 2.3b 69.5a 45.2bc
1.1a 0.5a 1.6b 2.0a 2.5a 69.7a 54.8a
1.1a 0.4a 1.5b 1.7b 2.1b 65.2b 52.2b
1.2a 0.7a 1.8a 1.4b 2.1b 64.4b 43.6c
0.65 0.47 0.08 0.26 0.12 1.04 2.32
abc = means in the same row with similar superscript are not significantly (P N 0.05) different. NDF = neutral detergent fiber, ADF = acid detergent fiber, ADL = acid detergent lignin, SEM = standard error of the mean.
fiber fractions, coupled with high CP of the grass/legume silage were responsible for the high DM and nutrient digestibility observed in the goats. Silages made from grass and legume mixtures had higher intake of nitrogen and percent nitrogen retention compared to sole grass silage. 4. Conclusion This study revealed that African yam bean, lima bean and pigeon pea plants which are referred to as under-utilized grain legume plants could be ensiled with elephant grass to increase livestock production. After harvesting the seeds of these legumes, the remaining plants could be ensiled with grass and used in feeding ruminants. Since harvesting of the seeds is usually towards the dry season, ensiling of the plants with grass could solve the problem of feeding ruminant livestock during the dry season. The high nutrient profile after
ensiling enhanced dry matter intake of goats, digestibility and nutrient retention which was translated to increased weight gain over the sole grass silage. In order to have quality silage that would promote increase in livestock enterprise, silage should be composed of energy and protein sources. Among the silages made, lima bean with elephant grass mixture had the highest nutrient profile and goats that were fed with it had the highest DM intake, nutrient digestibility, nitrogen retention and weight gain. References Adeparusi, E.O., 2001. Effect of processing on same minerals, anti-nutrient and nutritional composition of African yam bean. Journal of Sustainable Agriculture and Environment 3 (1), 101–108. Ajayi, F., Akande, S.R., Adegbite, A.A., Idowu, B., 2009. Assessment of seven under-utilized gain legume foliagec as feed resources for ruminants. Livestock Research for Rural Development 21 (9) www.lrrd.org/lrrd21/ 9/ajay21149.htm retrieved on 6th June, 2011.
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AOAC, 1990. Official method of analysis, 15th edn. Association of Analytical Chemist, Washington D.C., pp. 69–88. ARC, 1980. The nutrient requirements of farm livestock no. 2. Ruminants, Agricultural Research Council, London. Babayemi, O.J., 2009. Silage quality, dry matter intake and disputability by West African dwarf sheep of guinea grass (Panicum maximum cv Ntchisi) harvested at 4 and 12 week regrowths. African Journal of Biotechnology 8 (16), 3983–3988. Baraza, E., Angeles, S., Garcia, A., Valiente-Banuet, A., 2009. Adoption of silage as a methodology to improve domestic goat productivity for marginal farmers of the Tehuacan valley in Mexico. Livestock Research for Rural Development 21 (9) www.lrrd.org/lrrd21/9/ajay21149.htm retrieved on 6th June, 2011. Chen, X.B., Gomex, M.J., 1992. Estimation of microbial protein supply to sheep and cattle based on urinary excretion of prime derivative, an overview of the technical details. International Feed Res. Unit, Ronett Res. Inst. Occasional Public. Aberdeen, pp. 2–20. Coleman, S.W., Lippke, H., Gill, M., 1999. Estimating the nutritive potential of forages. The 5th International symposium on the nutrition of Herbivores. Nutritional Ecology of Herbivores and Integration. San Antonio, Texas. April 11 – 16. Igbekoyi, A.J. 2008: Intake growth and digestibility of ensiled Albizia saman pods with guinea grass (Panicum maximum cv Ntchisi) by West African dwarf rams. M. Sc dissertation, University of Ibadan, Nigeria. Mpairwe, D.R., Sabiiti, E.N., Mugerwa, J.S., 1998. Effects of dried Gliricidia sepium leaf supplement on feed intake, digestibility and nitrogen retention in sheep fed KW4 elephant grass (Pennisetum purpureum) ad libitum. Agroforestry Systems 41 (2), 139–150.
NRC, 1981. Nutrient requirement of goats. Angara: dairy and meat goats in temperate and tropical countries. National Academy of Sciences, Washington D.C. Nkosi, B.D., Meeske, R., Groenewald, I.B., 2010. Effects of ensiling potato hash with either whey or sugarcane molasses on silage quality and nutrient digestibility in sheep. Livestock Research for Rural Development 22 www.lrrd.org/lrrd22/1/nkos22001.htm retrieved on 6th June, 2011. Nwokolo, E., 1987. A nutritional assessment of African yam bean (Sphenostylis stenocarpa ex Rich) Harms, and Bambara groundnut (Voandzeia subtenanean L). Journal of Food Science and Agriculture 41, 123–129. Oduguwa, B.O., Jolaosho, A.O., Ayankoso, M.T., 2007. Effects of ensiling on the physical properties, chemical composition and mineral contents of guinea grass and cassava top silage. Nigerian Journal of Animal Production 34, 100–106. Ologhobo, D.A., Fetuga, B.L., 1983a. Trypsin inhibitor activity in sesame lima bean (Phaseolus lunatus) varieties. Food Chemistry 27, 41–47. Ologhobo, D.A., Fetuga, B.L., 1983b. Compositional differences in some lima bean (Phaseolus lunatus) varieties. Food Chemistry 10, 297–307. Pauzenga, U., 1985. Feeding parent stock. Zootecnica International, pp. 22–24. SAS, 1998. Statistical Analytical Systems. SAS/STAT User's Guide Statistical Analysis Institute Inc. Version 6, 3rd edn. Cary, North Carolina, U.S.A. , p. 943. 't Mannetje, L., 1992. Pennisetum purpureum Schumach. In: 't Mannetje, L., Jones, R.M. (Eds.), Plant Resources of South–East Asia Number 4 Forages. Pudoc Scientific Publishers, Wageningen, the Netherlands, pp. 191–192. Van Soest, P.J., Robertson, J.B., 1985. Analysis of forage and fibrous foods As 613 mammal. Department of Animal Science Cornell University, Ithaca, pp. 105–106.