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
juliangi@yahoo.com

Abstract

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

Introduction

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 7^o 44'N and longitude 8^o 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, %	CLM	RS	MO	Diet CLM30	Diet CLM50	Diet CLM70
Nutrient, %	CLM	RS	MO	70%MO:30%CLM	50%MO:50%CLM	30%MO:70%CLM
Dry matter	88.09	88.89	88.95	89.30	88.82	88.72
Crude Protein	20.29	5.66	13.21	15.33	16.75	17.38
Crude Fibre	22.65	42.07	11.81	15.06	17.23	19.40
Ether Extract	5.94	1.78	7.89	4.43	4.48	5.52
Ash	13.84	13.46	3.37	9.37	11.04	11.70
Nitrogen free extracts	37.28	37.05	63.75	55.80	50.51	46.00
Gross energy, kcal/g	3.01	1.83	4.13	2.92	2.86	2.23
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
Parameters	Diet CLM30	Diet CLM50	Diet CLM70	SEM
Parameters	70%MO+30%CLM	50%MO+50%CLM	30%MO+70%CLM	SEM
Initial weight, kg	10.38	10.25	10.23	1.06^NS
Mean daily rice straw intake, g DM	123.87^C	183.78^a	155.15^b	8.03^*
Mean daily supplement intake, g DM	126.93	126.23	126.10	1.22^NS
Mean total daily feed intake, g DM	250.80^c	310.01	281.23^b	8.03*
Final mean weight, kg	11.30	11.72	11.53	1.96^NS
Mean daily weight gain, g	13.10	20.75	18.57	2.22^NS
Feed conversion ratio, kg feed/kg gain	19.15	14.94	15.14	3.61^NS
* (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
Nutrients	Diet CLM30	Diet CLM50	Diet CLM70	SEM
Nutrients	70%MO:30%CLM	50%MO:50CLM	30%MO:70%CLM	SEM
Dry matter	68.49^a	57.27^b	54.01^b	2.03^x
Crude protein	38.22	27.02	22.21	4.43^NS
Crude Fibre	54.27	45.89	37.80	4.60^NS
Ether extract	73.20^a	56.96^c	64.44^b	1.86^*
Nitrogen free extract	75.41^a	69.24^ab	64.84^b	1.36^*
(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)

Conclusions

References

AdegbolaA A 2002 Nutrient intake digestibility and rumen metabolites in bulls fed rice straw with or without supplements. Nigerian Journal of Animal Production 29:40-45.

AdegbolaT A and Okonkwo J C 2002 Nutrient intake, digestibility and growth of rabbits fed varying level of cassava leaf meal. Nigerian Journal of Animal Production 29 1:21-26.

AdukuA O 1993 Tropical Feedstuffs Analysis Table. Department of Animal Science, Faculty of Agriculture, Ahmadu Bello University, Samaru, Nigeria. Pp 1-4.

AkinsoyinuA O 1985 Nutrient requirements of sheep and goats in Nigeria In: Small Ruminant Production in Nigeria. Proceedings of the National Conference on Small Ruminant Production, Zaria, Nigeria, October 6-10 1985.

AOAC 1990 Association of Official Analytical Chemists. 15^th edition. Washington D.C.

Arigbede O M Olanite J A and Oni A O 2004 Voluntary intake, digestibility and performance of WAD goats fed graded levels of Panicum maximum and Stylosanthes hamata. Proceedings of the Nigerian Society of Animal Production 29:355-359.

De Leeuw P N and BrinckmannW C 1973 Pasture and rangeland improvement in Northern and Sudan zones of Nigeria. In: Animal Production in the Tropics. Edited by Loosli J K, Oyenuga V A and Babatunde G M, Pp 167-176.

DevendraC and Burns M 1983 Goat production in the Tropics. Commonwealth Agricultural Bureaux Fanham Hons. UK. Pp 90-114.

Leng R A 1990 Factors affecting the utilization of poor quality forages by ruminants particularly under tropical conditions. Nutrition Reviews 3: 277-303.

McDonald P, Edwards R A and Greenhalgh J F D 1988 Animal Nutrition. 4^th edition. Longman Hons. Burntmill, Harlow, Essex, England. Pp 216-297.

NRC 1981 Nutrient requirements of goats. National Academy of Science, Washington D.C. Pp 1-10.

ObiohaF C and Ndukwe N 1976. Change in yield and chemical composition of outstanding and conserved forages during the dry season in East Central Nigeria. Nigerian Journal of Animal Production 6:133-151.

Pond W G, Church D C and Pond K K 1995 Basic Animal Nutrition and Feeding. 4^th edition. John Wiley and Sons Publishers, New York, USA. Pp 415-450.

Preston T R and Leng R A 1987 Matching ruminant production systems with available resources in the tropics and sub-tropics. Penambul books Ltd. Armidale, New South Wales, Australia. 245pp.

Promma S, Tuikumpee S, Ratnavaniji A and Vidhyakorn N 1985 Effect of Urea treated rice straw on growth and milk production of cross bred Holstein Friesian dairy cattle. Proceedings of the 4^th Annual workshop of Australian-Asian Fibrous Agricultural Residue Research Network in Khon Kaen Thailand. Pp 88-94.

RavindranV 1995 Use of cassava and sweet potatoes in animal feeding. Food and Agriculture Organisation. Rome, Pp 24-36. http://www.fao.org/ag/AGA/AGAP/FRG/FRG1.htm

SnedecorG W and Cochran W G 1980 Statistical methods, 7^th edition. The Iowa State University Press. Ames, Iowa. USA. Pp 593.

Winugroho M 1985 Intake and digestibility of the upper and lower fractions of rice straw by sheep and goats. Proceedings of the 4th Annual workshop of Australian-Asian Fibrous Agricultural Residue Research Network in Khon Kaen Thailand, Pp 123-126.

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

Go to top