Supplementing Rhodes grass Chloris gayana hay with Maerua angolensis improves weight gain of growing small East African goats

J O Ondiek, S A Abdulrazak and E N Njoka¹

Egerton University, Department of Animal Science, P O Box 536-20115 Egerton, Kenya
ondiekjo2002@yahoo.com
¹ Chuka University, P O Box 109-60400 Chuka, Kenya

Abstract

To study the performance of Small East African goats fed Rhodes grass(Chloris gayana) hay supplemented with 5 levels of Maerua angolensis (0, 15, 20, 25, 30g DM W^0.75) 20 goats were divided into five groups and randomly assigned five treatments in a randomized complete block design based on initial body weight (10.3±1.3kg). The treatment diets were offered twice daily at 08.00 and 14.00 hours with C. gayana and clean water were available ad libitum. Feed intake increased with increasing level ofM. angolensis, whereas, average daily gain, digestibility of DM, CP, NDF and rumen NH₃N were the highest on 20g supplementation level. It is concluded that M. angolensis is a potential protein source and can be supplemented at 124 gd^-1 (or 20% of metabolic weight, i.e. 20gDM/kgW^0.75) for growing Small East African goats.

Key words: average daily gain, digestibility, growing goats, nitrogen balance, tree forage, voluntary feed intake

Introduction

Tropical grasses are mostly inadequate in quantity, nutritive value and feed intake, resulting in poor animal performance Leng (1990).Unlike grasses, multipurpose tree and shrubs (MPTS) support more leaf biomass longer for browsing animals. MPTS forages are rich in crude protein (CP) and minerals [3] therefore, supplementing poor roughage-basal diets containing <7% CP with legume forages improves both feed intake and animal production performance (Abdulrazak et al 1997, Ondiek et al 1999, Ondiek et al 2000), hence there is need to exploit this abundant MPTS forage resource.

Maerua angolensisis a small shrub commonly found in Northern Kenya from deciduous bushland to semi-arid desert at altitudes between 100 to 1200 m above sea level. A large number of legume shrubs and tree species have been documented as useful livestock fodders (Topps 1992, World Agroforestry Centre 2005) and their nutritive value varies widely (Aganga and Tshwenyane2003). Many species contain antinutritive compounds (Woodward and Reed 1997) which may affect the nutritive value of the fodders variously (Swain 1979;Ash 990; Hangerman et al 1992; Reed 1995). The browse from M.angolensis is abundantly available in Kenya and other parts of the world, whose potential as protein source does not appear to have been exploited. Thus the objective of this study was to assess the potential value of M. angolensis as a protein supplement for growing Small East African Goats.

Materials and methods

Twenty Small East African goats aged 6 months and weighing 10.3±1.3kg were confined in individual, well-ventilated raised cages within a common house and were reared following standard managerial practices. All goats were healthy before and during the experiment and were treated against internal and external parasites.Rhodes grass hay was hammer milled through a 4 mm mesh to minimize preferential selection and wastage. M. angolensis forage was harvested by partially hand stripping the leaves from 200 bushes in Marigat, Baringo District. The forage was dried for 7 days in a shed to avoid bleaching and was turned twice daily to effect uniform drying and later milled to pass a 4 mm screen.

Goats were randomly divided in 5 equal groups that were blocked on weight so that the mean weight of each group were not significantly different (RCBD) and offered hay twice daily at 0830 and 1400 hr ad libitum and consumption recorded. M. angolensis was offered at 0800 hr to goats of group 2 to 5 at the rate of 15, 20, 25 and 30g/kg^-1 W ^0.75. The feeds offered were adjusted weekly based on the live weight and sampled every two weeks, bulked and later analyzed for chemical composition. Total daily faecal and urine output of all goats was collected during the last 7 days, sampled and stored for analysis for N balance and nutrient digestibility.

During the last three days of the trial, 10 ml of rumen liquor was collected using a stomach tube before supplement was offered and thereafter at 2, 4, 6 and 8 hr after supplement was offered. The pH of the sample was determined immediately using a pH meter, then the sample was strained through two layers of clean cotton cloth and the liquid fraction acidified with 2-3 drops of H₂SO₄ acid and stored at-20 ^oC for later analysis of NH₃-N. The DM, CP and OM in feed and faeces and N were determined using standard methods of AOAC (1990). Neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) were determined according toVan Soest et al (1991). Total extractable tannins (TET) and total extractable polyphenols (TEPH) were assayed as described by Abdulrazak and Fujihara (1999). Data were analysed for ANOVA using the General Linear Model of SAS computer package (Statistical analysis System (SAS) 2000). Initial live weight was a covariate in the analysis of DMI and live weight changes.

Results and discussions

Maerua angolensis , being a legume, was rich in protein content (Table 1). Feed DM intake from hay did not decrease in supplemented group (Table 2). This and consumption of all supplement by goats indicated that the legume was palatable. As expected, DMI increased with increasing amount of supplement. It has been reported that supplementation of low quality diets can either improve intake of the basal diet (Pathirana et al 1992; Abdulrazak et al 1997) or reduce intake (Getachew et al 1998). Egan (1986) indicated that legume supplements are usually most effective when offered with roughage containing less than 20 gN/kg digestible organic matter, because they increase the rumen fermentable N., which is required by rumen microbes to carry out digestion of the basal roughage diet.

Live weight gains of the control animals were low and animals lost weight during the adjustment period and during the initial two weeks (Table 2). Highest ADG in 20g supplement coincided with the highest rumen ammonia nitrogen level. It is possible that the supplemented diets created more suitable rumen environment by supplying a ready source of energy for the micro flora, which in turn led to a higher microbial activity and NH ₃-N turnover. Since all the animals had equal access to the hay, NH₃-N appears to have been the main limiting factor restricting intake rather than energy. Improved live weights in goats when legumes supplemented roughage based diets low in N, have also been reported.

The digestibility of DM, CP and NDF and percent N retained were highest in 20g supplement group (Table 3). Apparent digestibility of DM, CP, OM, and fibre was significantly increased with supplementation. Treatment MA20 showed better digestible constituents (P<0.05) with the control group being lowest in all values. The improvement in digestibility could have resulted from reduced levels of ADF and lignin. That M. Angolensis had an ADL of 969gkg^-1, then it follows that its proportional increase from 0, 15, 20, 25 and 30 levels should have increased the lignin contribution to the diet rather than decrease. So the argument for ADF may be true but not for lignin.

Figure 1. Total dry matter intake of various levels of M. angolensis

Figure 2. Average daily gain by various levels of M. angolensis

Conclusion

• It is concluded that M. angolensis is a good protein supplement and growing Small East African goats can be supplemented at the rate of 20gkg^-1 W^0.75.

Acknowledgement

The authors are grateful to the African Academy of Sciences for financial support and Egerton University and Tatton Demonstration Unit for availing facilities.

References

Abdulrazak S A, Muinga R W, Thorpe W and Ørskov E R 1997 The effect of incremental supplementation with Gliricidia sepium and Leucaena leucocephala on voluntary food intake, rumen fermentation, microbial N supply and live-weight changes ofBostaurus x Bosindicus steers offered Zea mays Hay ad libitum. Livestock Production Science 49:43-52.

Abdulrazak S A and Fujihara T 1999 Animal Nutrition: A Laboratory Manual . KASHIWAGI Printing Co. (Matsue-shi, JAPAN). Shimane University, Japan. pp 44.

Abdulrazak S A Fujihara T, Ondiek J O and Ørskov E R 2000 Nutritive evaluation of some Acacia tree leaves from Kenya. Animal Feed Science and Technology 85:89-98.

Aganga A A and Tshwenyane S O 2003 Feeding values and antinutritive factors of forage tree legumes. Pakistan Journal of Nutrition 2:170-177.

Ash AJ 990 The effect of supplementation with leaves from leguminous treesSesbania grandiflora, Albizia chinensis and Gliricidia sepium on the intake and digestibility of Guinea grass hay by goats. Animal Feed Science and Technology 28:225-231.

AOAC 1990 Association of Official Analytical Chemists. Official methods of analysis. Washington, D.C.

Egan A R 1986 Principles of supplementation of poor quality roughage with nitrogen. In: R.M. Dixon (Ed), Ruminant Feeding Systems Utilizing Fibrous Agricultural Residues-1985. International development Programme of Australian universities and Colleges limited (IDP), Canberra, A.C.T., Australia, pp 49-57.

Getachew G, Blümmel M, Makkar H PS and Becker K 1998 In vitro gas measuring techniques for assessment of nutritional quality of feeds: a review. Animal Feed Science and Technology 72:261-281.

Hangerman A E, Robins C T, Weerasuriya Y, Wilson T C and McArthur C 1992 Tannin chemistry in relation to digestion. Journal of Range Management 45:57.

Leng R A 1990 Factors affecting the utilization of ‘poor quality’ forages by ruminants particularly under tropical condition.Nutritional Research Reviews 3: 277-303.

Ondiek J O, Abdulrazak S A, Tuitoek J K and Bareeba F B 1999 The effects of Gliricidia sepium and maize bran as supplementary feed to Rhodes grass hay on intake, digestion and live-weight of dairy goats. Livestock Production Science 61:27-38.

Ondiek J O, Tuitoek J K, Abdulrazak S A, Bareeba F B and Fujihara T 2000 Use of Leucaena leucocephala and Gliricidia sepium as nitrogen sources in supplementary concentrates for dairy goats offered Rhodes grass hay. Asian-Australasian Journal of Animal Science 13:1249-1254.

Pathirana K K, Mandalita U L P and Gunaratne S S N 1992 Straw based supplementation of low output system for zebu heifers. In: Int. Atomic Energy Agency, TEC Document 691 IAEA Vienna, Austria.

Reed J D 1995 Nutritional toxicology of tannins and related polyphenols in forage legumes. Journal of Animal Science 73:1516.

Statistical analysis System (SAS) 2000 Guide for personal Computer version 6 ed. SAS institute Inc. North Carolina, USA.

Swain T 1979 Tannins and lignins. In: Herbivores, their interaction with secondary plant metabolites. G. Rosenthal and D.H. Jansen (Eds.). Academic Press, New York. p657.

Topps J H 1992 Potential, composition and use of legume shrubs and trees as fodder for livestock in the tropics (a review). Journal of Agricultural Science 118: 1-8.

Van Soest P J, Robertson J D and Lewis B A 1991 Methods of dietary, neutral detergent and non-starch polysaccharides in relation to animal nutrition. Journal of Dairy Science 74:3583-3597.

World Agroforestry Centre 2005 Useful trees and shrubs for Kenya. World Agroforestry Centre –Eastern and Central Africa Regional Programme (World Agroforestry Centre, 2005-ECA). Technical Handbook No. 35. Eds. Patrick Maundu and Bo Tengnas. Nairobi, Kenya. 484pp.

Woodward A and Reed J D 1997 Nitrogen metabolism of sheep and goats consuming Acacia brevispica and Sesbania sesban. Journal of Animal Science 75:1130-1139.

Received 5 June 2017; Accepted 10 November 2017; Published 1 March 2018

Go to top