Cattle fattening on basal diets of maize stoves and groundnut tops in Malawi

J T Munthali
Chitedze Agricultural Research Station, Lilongwe, Malawi

Abstract
Introduction
Research on the utilization of crop residues
Conclusion
References

Abstract

Maize stover is the most abundant crop residue in Malawi followed by groundnut tops. Both of these crop residues are widely used for grazing and stallfeeding cattle. Maize bran is the main supplement fed to stallfed cattle whilst cottonseed cake and leucaena (L. leucocephala) are sometimes fed with maize bran. A review of the utilization of crop residues for stallfed cattle revealed that composite maize have about 2.5% crude protein (CP) higher than that of hybrid maize and groundnut tops contain almost twice the CP content of maize stover. Adequate liveweight gains by cattle can be achieved by supplementing a maize stover and restricted (3.6 kg) maize bran diet with either groundnut tops, cottonseed cake or leucaena. Large gross margins can be obtained by fattening cattle on crop residues and the stall-feeding of cattle is likely to increase as land pressure continues to increase.

Introduction

Maize (Zea mays) and groundnut tops (Arachis hypogaea) are major food crops in Malawi. Approximately 59 and 24% of the total area cropped by smallholder farmers is devoted to maize and groundnut production respectively (Manda et al., 1985). The corresponding production of crop residues from these crops in 1985 was 2.71 and 0.7 million tonnes for maize and groundnuts, respectively (Munthali and Dzowela 1985). The majority of these crop residues are grazed in situ while variable quantities are either burnt, ploughed into the soil or stallfed to cattle. Hence crop residues constitute a major feed resource for cattle during the dry seasons.

This paper gives the scope for the utilization of crop residues in Malawi and a review of the research findings aimed at improving animal performance from feeding crop residues, mainly maize stover and groundnut tops.

Scope for utilization of maize stover and groundnut tops

Utilization of crop residues in Malawi is optimal on smallholder farms where both crops and cattle are raised. Small-scale zero grazing commercial livestock production, based on one to four dairy cows or steers, is being practiced. Increased land pressure (Table 1) is likely to result in increased intensive livestock production. Zero grazing is already popular in Malawi not only because of immediate cash benefits from the sale of milk or fattened cattle, but also because of the large quantities of organic manure produced in the feeding pens. The manure is widely used in the production of cash crops such as tobacco and maize.

The production of milk and high quality beef from fattened steers makes a tremendous saving on imports of animal products by the country.

Table 1. Per capita land availability by smallholder farmers in Malawi

Year	Population	Land availability
	(x 100)	(ha)
1966	4031	1.65
1970	4441	1.50
1974	4916	1.35
1978	5723	1.16
1982	6410	1.04
1986	7017	.95

The traditional stallfeeding diets are maize stover and/or groundnut tops supplemented with maize bran. Animal production from these diets is very variable. Research on the utilization of maize stover and groundnut tops as basal diets for stallfed cattle has been conducted since the early 1970's (Anonymous, 1972-1979). The main objective of such studies were to determine the production levels that could be achieved by feeding various quantities of these roughages with various supplements.

Research on the utilization of crop residues

Yield and chemical composition of common crop residues

Up until now, crop residues are being fed to cattle without any regard to varietal differences in their quality. For example, there are several varieties of maize grown in Malawi which can broadly be categorized into hybrids and composites, whose residues might have different nutritive value. Thus a survey of common crop residues was carried out at Chitedze Research Station to find out if large varietal differences in quality exist and to estimate their yields. Samples were collected from maize agronomy, groundnut breeding and sweet potato (Ipomea batatas) breeding trials. The maize crop was given 105 kg N/ha while groundnuts were sprayed with Daconil 2787 W 75 at the rate of 3.6 kg/ha. Sweet potatoes did not receive any fertilizer. Crop residue samples were collected from the fields soon after harvesting. The results of their nutritive value and dry matter production are given in Table 2. The composites (local and UCA) tended to have more crude protein than hybrid maize (NSCM 41 and MH 12). The acid detergent fibre (ADF) was high in all maize stovers which is consistent with other studies (Holloway et al. 1977; Berger et al. 1979; Oji and Mowat 1979; Butterworth and Mosi 1986).

Dry matter yields of maize stover were also higher for the composites than for the hybrids used. In a mixed farming system (crops and livestock) commonly seen on smallholder farms composites could be more attractive than hybrids for cattle feeding; based the chemical analysis and dry matter production.

Table 2. Nutritive value and dry matter production of some common crop residues in Malawi

Crop residue		%DM	%CP	%ADF	Dry matter Production (kg/ha)
Maize stover
	Local	93.1	8.9	49.7	5864
	UCA	92.8	8.6	45.5	6260
	NSCM 41	92.08	6.5	48.4	4748
	MH 12	93.0	6.0	41.4	4945
Groundnut tops
	Chalimbana (untreated)	91.8	14.0	40.7	2528
	Chalimbana (treated) 1	93.7	16.3	37.3	3062
	Mawanga (untreated)	90.9	14.0	36.7	3030
	Mawanga (treated) 1	92.5	14.0	29.9	3607
	Mani Pintar (untreated)	94.5	12.4	39.5	1897
	Mani Pintar (treated) 1	94.5	12.0	33.4	2871
	Chitembana (untreated)	93.9	13.0	39.6	1777
	Chitembana (treated) 1	92.7	13.4	37.1	2619
	RGI (unseated)	92.9	6.5	37.6	-
	RGI (treated) 1	91.4	10.0	36.4	-
Sweet potato vines
	Kenya	90.7	5.0	38.6	7532
	Yoyela	91.6	7.1	36.2	5554
	LRS 407	90.1	4.2	38.6	7156
	Kamchiputu	89.4	4.2	33.7	872

1 = Treated with Daconil.

Differences in CP content amongst groundnut tops were also observed (Table 2). RG1, a rosette resistant variety, was the poorest in CP content whilst Chalimbana (the most susceptible variety to rosette) had the highest level of CP. The differences in CP between the sprayed and unsprayed groundnut tops was negligible except for RG1 in which the sprayed crop had a high CP. The ADF content was similar amongst the groundnut tops although the sprayed crop tended to have lower ADF content. The application of Daconil increased dry matter production which could be beneficial to livestock feeding. Potato vines had similar CP and ADF contents except vines from Yoyela which had a high level of CP.

Groundnut tops had the highest content of CP whilst potato vines had the lowest. Maize stover had the highest levels of ADF, characteristic of most crop residues from cereals. Groundnut tops might be used to supplement maize stover to raise its CP content and its composite maize is likely to produce better animal production if fed with groundnut tops.

Stallfeeding experiments

The most abundant crop residue is maize stover and it is commonly stallfed to cattle in combination with maize bran. Experiments have been conducted to determine the level of feeding of these ingredients and the expected animal performances. Table 3 summarizes results of such trials. Feeding ad libitum quantities of maize stover with restricted amounts of maize bran produced lower daily liveweight gain than ad libitum maize bran; indicating that most of the liveweight gain was due to maize bran. The consumption of maize bran increased by 44 and 78% when it was fed ad libitum with ad libitum or restricted maize stover respectively. Daily liveweight gain was increased by corresponding 70 and 84%. As maize bran becomes more expensive (than the present MKO.02* per kg) ad libitum maize stover and maize bran would become more popular than just ad libitum maize bran.

* 1 US$ = 2.23 Malawi Kwacha

Table 3. Effect of supplementing maize stover with maize bran to beef cattle

Method of feeding
Maize stover	Maize bran	Maize bran consumed (kg/d)	Liveweight gain (kg/d)
Ad libitum	Restricted	3.6	0.37
Ad libitum	Ad libitum	5.2	0.63
Restricted	Ad libitum	6.4	0.68

In cognizance of the limitations of a maize stover/maize bran diet for fattening cattle, trials were carried out to find out if nitrogen supplementation would improve daily liveweight gains beyond the maximum of 0.68 kg/day (Table 3). Table 4 gives the results of feeding maize stover and maize bran with different sources of nitrogen.

Table 4. Effect of supplementing maize stover and maize bran with different sources of nitrogen to steers

Crop residue			Supplement
Type	Feeding	Type	Consumption (kg/d)	Daily gain (kg/d)
MS 1	Ad lib. 3	Maize bran	3.6	0.37
MS + GNT 2	Ad lib.	Maize bran	3.6	0.68
MS	Ad lib.	Maize bran + CSC 4	3.5	0.75
MS	Ad lib.	Maize bran + Leucaena (4:1)	4.2	0.77

¹ = maize stover
² = groundnut tops
³ = ad libitum
⁴ = cotton seed cake.

The supplements were fed to give similar levels (18.5% CP in supplement) of CP intake. When groundnut tops were fed with restricted (3.6 kg) amount of maize bran, daily gain by steers almost doubled (Table 4), and that was similar to daily liveweight gains obtained by feeding ad libitum (5-6 kg) amounts of maize bran (Table 3). Feeding cottonseed cake or leucaena (Leucaena leucocephala) with maize bran produced similar average daily liveweight gains but slightly higher than those obtained with feeding groundnut tops. This indicated that CP was indeed a limiting nutrient in promoting liveweight gains of steers fed a maize stover/maize bran diet.

Another experiment was conducted to determine the effect of feeding groundnut tops as a sole roughage with either plain maize bran or maize bran with leucaena. Leucaena was fed to ascertain if additional CP would be required when groundnut tops are fed with maize bran. Two breeds of steers, Malawi Zebu (MZ) and Friesian (F) x MZ, were used. They were divided into two groups and fed either ration A (maize bran + salt) at the rate of 5 and 6.5 kg/head/day for the MZ and F x MZ, respectively, or ration B (maize bran + leucaena (4:1) + salt) at similar rates to those fed in ration A. Groundnut tops and-water were given ad libitum. The results are given in Table 5. There were no differences (P<0.5) in both total and daily liveweight gain between the rations for both breeds. The F x MZ steers gained more liveweight and consumed more DM than MZ steers (P<.01). There were no differences within breeds in feed conversion between rations, but feed conversion efficiency was higher in F x MZ than in MZ steers. The results indicate that feeding groundnut tops to appetite would provide enough nutrients to offset any deficiencies found in maize bran. Similar results were obtained by Addy and Thomas (1976) who also reported breed differences between MZ and F x MZ in rate of gain and feed consumption.

Table 5. Effect of feeding groundnut tops with maize bran or maize bran leucaena (4:1) to steers

Item	Ration A		Ration B
	MZ 1	(FxMZ) 2	MZ 1	(FxMZ) 2
Initial liveweight, kg	301.0a	382.7b	307.8a	404.3b
Final liveweight, kg	368.8a	483.4b	377.5a	504.4b
Days on test	80	80	80	80
Total gain, kg	67.8a	100.7b	69.7a	100.1b
Daily gain, kg	0.9a	1.3b	0.9b	1.3b
Conc. DM 3 intake/day, kg	4.5	5.9	4.5	5.9
Roughage DM intake/day, kg	3.0a	3.7b	3.2a	4.5b
Total DM intake/day, kg	7.5a	9.5b	7.7a	10.4b
kg DM intake/kg gain	8.9a	7.6b	8.9a	8.3b

¹ Malawi zebu
² Friesian x MZ
³ Dry matter
a, b figures with the same subscript are not sufficantly different.

Although groundnut tops have consistently been found to be better than maize stover in promoting liveweight gain of steers, the quantities available in Malawi are far lower than maize stover (Munthali and Dzowela 1975). Hence farmers frequently feed it in unknown combinations with maize stover. A trial was conducted to determine the best combination of maize stover and groundnut tops in stallfed animals. Unchopped maize stover and groundnut tops were fed ad libitum in five combinations as shown in Table 6. Maize bran was fed at the rate of 4 kg/steer daily on as is basis. Results of the experiment are given in Table 6. Daily liveweight gains and cold dressed weights increased (P<0.05) with increased groundnut tops ratios in the diet. Total dry matter intakes were similar for all diets even though steers tended to consume more groundnut tops than maize stover. Butter-worth and Mosi (1986) reported improvements in DM intake when 0 to 50% trifolium (T. tembense) was fed with maize stover. Lack of improvements in DM intake in the present study was due to the poorer quality of groundnut tops than trifolium; 9.2 and 20.1% CP for groundnut tops and T. tembense respectively. The best combination of maize stover and groundnut tops in promoting liveweight gain of steers was as 50: 50 ratio (Table 6). This study confirmed that ad libitum maize stover and restricted maize bran is not adequate to finish steers, but that groundnut tops could be useful in improving daily gains.

Table 6. Performance of steers fed different combinations of maize stover and groundnut tops

Component	Maize stover to groundnut tops ratio
	100:0	75:50	50:50	25:75	0:100
Initial liveweight, kg	202.0	201.5	198.5	214.5	202.6
Final liveweight, kg	234.2	248.5	266.3	260.6
Days on test	90	90	90	90	90
Total gain, kg	32.2	46.9	64.0	51.8	58.0
Daily gain, kg	0.36c	0.52d	0.58de	0.66de
Cold dressed weight, kg	118.0c	129.7d	141.3e	141.3e	140.5e
Dressing percentage	50.4	52.2	53.8	53.2	53.9
Roughage DM intake, kg/day	4.6c	4.8c	5.2c	5.0c	4.7c
Maize bran DM intake, kg/day	3.7	3.8	3.8	3.8	3.8
Total DM intake, kg/day	8.3c	8.6c	9.0c	8.8c	8.5c
DM intake/kg gain	23.1	16.5	12.7	15.3	12.9

c, d, e - Figures within the same row but having different subscripts are statistically different (P<0.05).

Prospects for Future Utilization of Crop Residues

The picture of land availability presented in Table 1 indicates that little cultivable land will be available for arable crop production, let alone the production of forages for animal production. Improvements in plant breeding and husbandry might increase both crop and by-products yields per unit area generating feed for livestock. A farmer's choice to raise cattle will depend upon their importance in the overall farming system (manure and draft) and the demand for milk and meat.

Economic analyses of feeding crop residues were conducted by I. H. Proverbs (unpublished) and A.P. Mtukuso, R.C. Graaf and D.W. Pervis (unpublished), and both reports showed favourable gross margins. An economic analysis based on data in Table 5 is given in Table 7. The cost of feed is strikingly low under smallholder conditions where crop residues are used at very low cost and maize bran is obtained by batter with salt. The cost of maize bran was estimated at MK 0.02/kg while the price of a steer was MK 0.46/kg liveweight and the carcass (first grade) was valued at MK 1.35/kg. The gross margins are higher for producer feeders than for those steers issued on loan, mainly because of the cost of servicing the loan. Stall feeding is likely to remain profitable in Malawi so long as family labour is not costed and as long as the cost of crop residues and by-products remains low.

Table 7. The potential profitability of stallfeeding of steers using groundnut tops as the sole roughage

Item	Ration A		Ration B
	MZ 1	(F x MZ) 2	MZ 1	(F x MZ) 2
Grade at start	Feeder A	Feeder A	Feeder A	Feeder A
Grade at finish	Choice	Choice	Choice	Choice
Liveweight at start, kg	301.0	382.7	307.8	404.3
Liveweight at finish, kg	368.8	483.4	377.5	504.4
Carcass weight, kg	230.0	283.0	232.0	276.0
Carcass value at Variable Costs:	310.5	382.1	313.2	372.6
Producer stallfeeder Steer at MK 0.46/kg Liveweight	138.5	176.0	141.6	186.0
Concentrate consumed, kg	410.0	533.0	410.0	533.0
Cost of concentrate MK 3	6.2	8.0	10.7	14.0
Transport to abbatoir MK	5.2	5.2	5.2	5.2
Insurance at 1.25% cdw 4, MK	3.2	3.9	3.2	3.8
Total variable costs, MK	153.1	193.1	160.7	209.0
Gross margin, MK	15.4	189.0	152.5	163.6
Feeder issued on credit Steer at MK 0.46/kg liveweight	138.5	176.0	177.7	232.0
20% interest, insurance and transport, MK	27.7	35.2	35.5	46.4
Concentrate cost, MK	6.2	8.0	10.7	14.0
Total variable costs, MK	172.4	219.2	223.9	292.4
Gross margin, MK	138.1	162.9	89.3	80.2

¹ Malawi Zebu
(F x MZ) ² = Friesian x MZ
³ Malawi Kwacha (1 US$ = 2.23 MK)
⁴ Cold dressed weight

Conclusion

Adequate animal gains can be achieved by feeding either maize stover with ad libitum amounts of maize bran, or maize stover and restricted amounts of maize bran supplemented with nitrogen. The source of nitrogen can either be groundnut tops, leucaena or cottonseed cake. It is still profitable to fatten steers on crop residue in Malawi and stallfeeding is likely to increase in future due to an increase in land pressure.

References

Addy B.L. and Thomas D. 1976. Utilization of Crop Residues, Madeya and Leucaena for Winter Feeding in Lilongwe District. Research Bulletin No. 2/76. Ministry of Agriculture, Malawi.

Anonymous. 1972-79. Chitedze Research Station Annual Reports. Lilongwe, Malawi.

Berger L.L., Patterson J.A., Klopfenstein T.J. and Britton R.A. 1979. Effect of harvest date and chemical treatment on the feeding value of corn stalkage. Journal of Animal Science. 49: 1312-1316.

Butterworth M.H. and Mosi A.K. 1986. The voluntary intake and digestibility of combinations of cereal crop residues and legume hay for sheep. ILCA Buttetin No. 24: 14-17.

Holloway J.W., Damron W.S., Barth K.M. and Freeland R.D. 1977. Corn crop residue as feed for wintering mature, dry pregnant beef cows. Tennessee Farm and Home Science, pp 38-40.

Manda D.R.B., Dzowela B.H. and Johnson W.J. 1985. Agricultural Research Resource Assessment in the SADCC Countries. Vol. II Country Report: Malawi.

Munthali J.T. and Dzowela B.H. 1985. Inventory of livestock feeds in Malawi - to be published in Pasture Improvement Research in Eastern and Southern Africa.

Oji U.I. and Mowat D.N. 1979. Nutritive value of thermoammoniated and steam-treated maize stover. I. Intake, digestibility and nitrogen retention. Animal Feed Science and Technology. 4: 177-186.