Livestock Research for Rural Development 18 (9) 2006 Guidelines to authors LRRD News

Citation of this paper

Evaluation of dried cassava leaf meal and maize offal as supplements for goats fed rice straw in dry season

J Ngi, J A Ayoade and O I A Oluremi*

Department of Animal Production, *Department of Animal Nutrition,
College of Animal Science, University of Agriculture, P.M.B. 2373 Makurdi. Benue State. Nigeria



Nine Maradi x West African Dwarf cross bred goats of mixed sexes between 8-10 months old and with an average body weight of 10 kg were used to evaluate mixtures of dried cassava leaf meal and maize offal as dietary supplements to rice straw ad libitum. The animals were randomly allotted to three dietary groups of three animals each and each animal put in a metabolic cage. The diets were: diet CL30 (70% maize offal: 30% dried cassava leaf meal, diet CLM50 (50% maize offal:50% dried cassava leaf meal) and diet CLM70  (30% maize offal:70% dried cassava leaf meal).

Daily rice straw intake was significantly lower for goats on diet CLM30 than for goats on diets CLM50 and CLM70. There were no statistical differences in average daily gains and feed conversion ratio (p>0.05). Goats on diet CLM50 had a daily weight gain of 20.8g which is relatively higher than 13.1g and 18.6g for dietary groups CLM30 and CLM70, respectively. Goats on diet CLM30 had a significantly higher (p<0.05) apparent dry matter digestibility of 64.49% than those on diets CLM50 (57.27%) and CLM70 (54.01%). Digestibility of dry matter, crude protein, crude fibre and nitrogen free extract decreased as dietary inclusion of dried cassava leaf meal increased.

The optimum level of inclusion of CLM in a basal diet of rice straw and maize offal appears to be of the order of 20% of the DM intake, which is equivalent to about 1 g crude protein (from the CLM) per 1 kg live weight.

Keywords: cassava leaf, goats, maize offal, rice straw


Goats play a significant role in providing animal protein for the human population, and they are found generally in every region of the world (Akinsoyinu 1985). A major problem facing stockowners in the tropical and sub-tropical regions of the world is the provision of adequate nutrition for ruminants during the long dry season (De Leeuw and Brinckmann 1973). The crude protein contents of principal forages such as gamba (Andropogon spp ) and guinea grass (Panicum maximum) fall to as low as 2% for most part of the dry season, thus affecting intake and digestibility of dry matter (Obioha and Ndukwu 1976; Pond et al 1995). There is thus the need to search for, and utilize other alternative low cost feeds for ruminants at such critical periods.

Rice straw is an abundant by-product of paddy rice threshing in Nigeria; it is relatively more digestible than other straws and stovers and can be used in feeding ruminants (Adegbola 2002). Cassava leaf is a fibrous feedstuff and this characteristic helps it to provide dietary energy. It is a good source of protein, minerals and vitamins (Ravindran 1995). Cassava contains cyanogenic glucosides which in the animal can give rise to hydrogen cyanide an anti-nutritional factor, which however can be reduced to safe limits through processing (Adegbola and Okonkwo 2002). Maize offal a by product of maize grains obtained after dehulling the maize is yet another feedstuff rich in crude protein and energy (McDonald et al 1988) and abundantly available in all the geo-political zones in Nigeria.

The objective of this study was to evaluate dried cassava leaf meal and maize offal mixtures at graded levels when fed as supplements for goats placed on rice straw as basal diet.

Material and methods

The study was conducted in the University of Agriculture Makurdi, Teaching and Research farm located in latitude 7o 44'N and longitude 8o 21'E of the guinea savanna zone of West Africa.

Rice Straw (RS) was obtained from rice farms within the University. It was chopped into smaller pieces of 10-20cm and kept in a cool dry store. Similarly cassava leaves were obtained from farms within the University. The leaves were dried for a period of 5-7 days on concrete floors and intermittently turned to prevent scorching and fermentation as recommended by Ravindran (1995). Thereafter, the leaves were crushed into a meal (CLM) using a mortar and a pestle. Maize offal (MO) was purchased and sun-dried for a day before storage in synthetic bags. The CLM and MO were mixed fortnightly in different proportions of 70% MO: 30% CLM (diet CLM30), 50% MO: 50% CLM (diet CLM50) and 30% MO: 70% CLM (diet CLM70) and fed at the rate of 140g per animal per day while rice straw, salt lick and water were served to each goat ad libitum.

A total of nine (9) Maradi x West African dwarf cross bred goats of mixed sexes between 8-10 months with an average weight of 10kg were used. Each goat was singly put in a metabolism cage of .90m x .80m x .45m. Removable feed troughs and water containers were used to serve the feed supplement and water while rice straw was put in wooden in-built trough. The animals were allowed an adjustment period of 14 days to the new environment at the end of which their live weights were taken and the feeding trial commenced. They were weighed weekly thereafter for 10 weeks the experiment lasted. Feed intake per goat was recorded while feed conversion ratio (FCR) was obtained from the ratio of feed intake to body weight gain (BWG). A digestibility trial was conducted during the last 7 days of the trail. Faeces from each animal were collected daily, oven-dried, bulked, milled and a homogenous sample taken to the Institute of Agricultural Research and Training (IAR&T), Ibadan for proximate analysis using the standard methods (AOAC 1990). Data collected were subjected to analysis of variance using the complete randomized design (CRD) model; means of parameters which differed significantly (p<0.05) were separated using the procedure outlined by Snedecor and Cochran (1980).

Results and discussion

The chemical composition of the feed ingredients and experimental diets is shown in Table 1.

Table 1.  Proximate composition of feedstuffs and formulated diets

Nutrient, %




Diet CLM30

Diet CLM50

Diet CLM70




Dry matter







Crude Protein







Crude Fibre







Ether Extract














Nitrogen free extracts







Gross energy, kcal/g







RS= Rice Straw, MO=Maize Offal, CLM=Dried Cassava Leaf Meal

It was observed that the dry matter (DM) contents of diets CLM30, CLM50 and CLM70 slightly decreased from 89.30% to 88.70% as the quantity of CLM increased, probably as a result of the low dry matter in cassava leaves as also observed by Adegbola and Okonkwo (2002). The crude protein [CP) and crude fibre [CF] contents of the diets on the other hand increased from 15.33% to 17.38% and 15.06% to 19.40%, respectively as the level of CLM increased. This may be as a result of the high CP of 20.29% and CF of 22.65% present in CLM. Nitrogen free extracts [NFE] and gross energy values decreased with increasing dietary inclusion of CLM. Rice straw had a DM of 88.89%, which is comparable with 90.00% reported by Promma et al (1985). Its CP of 5.66% is higher than 4.85% reported by Aduku (1993) and 4.00% according to NRC (1981). These variations may have been as a result of varietal differences and processing techniques. However, the CF content of rice straw in this study (42.07%], was similar to 42.30% reported by Promma et al (1985) and 42.28% by Aduku (1993).

Table 2.  Mean values of performance parameters of goats fed the experimental diets


Diet CLM30

Diet CLM50

Diet CLM70





Initial weight, kg





Mean daily rice straw intake, g DM





Mean daily supplement intake, g DM





Mean total daily feed intake, g DM





Final mean weight, kg





Mean daily weight gain, g





Feed conversion ratio, kg feed/kg gain





* (p<0.05), NS Not Significant (p>0.05), SEM=Standard error of mean

a,b,cMeans followed by the same superscript in a row are not significantly different (p>0.05)

Diet CLM50 tended to encourage rice straw intake more than diets CLM30 and CLM70 (Table 2). Increase in rice straw intake by sheep when supplemented with concentrate mixtures of cassava leaf  has earlier been reported (Winugroho 1985). Feed intake pattern in the present trial has a corresponding beneficial effect on weight gain. Dietary group CLM50 with the highest mean daily feed intake had the highest mean daily gain. This is similar to the findings of Arigbede et al (2004) when WAD goats were fed graded levels of Panicum maximum supplemented with Stylosanthes hamata. Supplementation of roughage feeds with legume foliages and/or concentrate thus increase feed intake causing higher body weight gains. However, in the three dietary groups daily feed intake was between 2.21% and 2.65% of the live weight of the experimental animals, which is lower than the optimum value of 4 to 5% recommended by Devendra and Burns [1983) for meat type goats. The improvement in the live weight gains of the animals may have been due to the ability of the supplement to provide sufficient fermentable nitrogen to ensure optimal microbial growth in the rumen.  This, together with possible by-pass protein from the supplement will enhance the production of body tissues as reported by Leng (1990). There were no significant differences (p>0.05) in the feed conversion ratio among the treatment groups.

Table 3.  Apparent nutrient digestibility for goats on experimental diets


Diet CLM30

Diet CLM50

Diet CLM70





Dry matter





Crude protein





Crude Fibre





Ether extract





Nitrogen free extract





*(p<0.05), NSNot Significant (p>0.05), SEM= Standard error of mean

a,b,cMeans followed by the same superscripts in horizontal rows are not significantly different (p>0.05)

Apparent digestibility coefficients for DM and all the other nutrients had a similar trend (Table 3), each decreased with increasing level of CLM inclusion except EE that did not follow a particular trend.

The optimum level of inclusion of CLM in the diet appeared to be of the order of 20% of the DM intake. This is equivalent to about 1 g crude protein (from the CLM) per 1 kg live weight which is close to the optimum amount or a protein source rich in bypass characteristics as recommended by Preston and Leng (1987)


The optimum level of inclusion of CLM in a basal diet of rice straw and maize offal appears to be of the order of 20% of the DM intake, which is equivalent to about 1 g crude protein (from the CLM) per 1 kg live weight.


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Received 21 May 2006; Accepted 21 July 2006; Published 12 September 2006

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