optimising the quality and biomass production of maize stover tops for stall-fed dual purpose dairy...

Livestock Production Science 77 (2002) 207–215www.elsevier.com/ locate/ livprodsci

O ptimising the quality and biomass production of maize stovertops for stall-fed dual purpose dairy cows in semiarid central

Tanzaniaa,b a ,*J.M. Bwire , H. Wiktorsson

aDepartment of Animal Nutrition and Management, Swedish University of Agricultural Sciences, P.O. Box 7024, S-75007 Uppsala,Sweden

bLivestock Production Research Institute, P.O. Box 202, Mpwapwa, Tanzania

Received 13 August 2001; accepted 26 February 2002

Abstract

Maize was grown to investigate maize stover tops production, conservation methods and feeding value, when harvested atdifferent intervals after grain maturity. It was either planted as a pure stand or intercropped with lab lab plants. Maize topswere harvested after grain maturity (stage1) and at 3, 6, 9 and 12 weeks thereafter (stages 2, 3, 4 and 5). The tops werestacked in the field (A), laid down in the field (B), or stored in a shed (C). A feeding trial with 12 cows was carried out toinvestigate DM intake, milk yield and composition. The cows were fed grass hay mixture (T1), green maize tops (T2), andmaize stovers after grain harvest (T3) supplemented with lab lab forage and maize bran. Harvesting stages 1 and 2 yieldedmore tops (1.5 and 1.4 tonne/ha, respectively), higher crude protein, digestibility and metabolizable energy, lower acid andneutral detergent fibre than 3 to 5. The potential nutritive values were higher in maize tops stored in C than B and A. Totalintake and milk yield were higher on T1 and T2 than on T3 (8.06 and 7.98 vs. 6.25 kg DM/day) and (5.05 and 5.02 vs. 4.4kg/day), respectively. Milk components were similar. Harvesting stages 1 and 2 provided larger amounts of tops of highpotential nutritive value than stages 3 to 5. Storing in a shed conserved nutritive value of green maize fodder better thanlaying and stacking methods. It compared well with grass hay mixture for milk production when supplemented with lab labforage. 2002 Elsevier Science B.V. All rights reserved.

Keywords: Maize tops; Conservation method; Dual-purpose cattle; Milk yield; Lab lab forage

1 . Introduction central Tanzania. The pastures and forages availablemature early and become scarce and of low nutritive

Dry season feed is one of the major constraints to value at this particular time of the year. During thisincreased animal productivity in semi-arid areas of period, crop residues play an important role as feed

resources for ruminant livestock. Over 75% of thisfeed resource consists of crop residues: sorghum,*Corresponding author. Tel.:1 46-18-672-102; fax:1 46-18-millet and maize (Kitalyi and Masaoa, 1991).672-995.

E-mail address: [email protected](H. Wiktorsson). Maize dominates the world’s total production of

0301-6226/02/$ – see front matter 2002 Elsevier Science B.V. All rights reserved.PI I : S0301-6226( 02 )00060-X

mailto:[email protected]

208 J.M. Bwire, H. Wiktorsson / Livestock Production Science 77 (2002) 207–215

crop residues, while wheat, rice paddy and pulse located in the central part of Tanzania. The annualresidues each yield only about half the amount of rainfall is 660 mm on average, falling mainly frommaize (Chenost and Sansoucy, 1991). However, the December to April, with a dry spell in February. Thelow voluntary intake, low digestibility and low dry season extends from May to November. Meannitrogen, mineral and vitamin content makes it temperature ranges between 24 and 298C and theinadequate even to meet the daily maintenance elevation is 1100 m above sea level.requirement of dairy cows. Using maize stover as adry season feed resource and other crop residues has2 .2. Land preparation and planting proceduregenerated considerable research work into chemicaland physical treatment methods. Unfortunately, there About 2.8 ha of land was ploughed and dividedhas been less applied work in the tropical countries. into three plots (1, 2 and 3) with an area of 1.2, 0.8,Research advances in feeding strategies include the and 0.8 ha, respectively. Planting was done on theuse of green maize stover tops as fodder (Roy and last week of December 1999. Maize was planted inBiswas, 1992; Shirima and Wiktorsson, 1994; Bwire plot 1, maize/ lab lab intercrop in plot 2 and lab labet al., 1998) sometimes supplemented with grain alone in plot 3. Each plot was further divided intolegume crops (Kitalyi and Masaoa, 1991). three subplots. The spacing (inter-row3 intra-row)

Time of harvesting maize stover tops has been was 90360 cm for maize alone, 90 cm (with maizereported to influence yield and potential nutritive and lab lab planted on every other row)3 60 cm forvalue, due to rapidly declining quality occurring maize/ lab lab intercrop and 1003 60 cm for lab labwhen plant matter remains on the field (Shirima and alone. A sowing practice of one seed per hole wasWiktorsson, 1994). Quality analysis on whole stover employed in all plots. No fertiliser was applied andmay also have limited use. When given the oppor- hand weeding was done twice for all plots totunity, animals select the most nutritious plant com- maintain the crops free from weeds.ponents.

Grain legume crops such asLablab purpureus can 2 .3. Harvesting of feeding materials and samplingbe integrated into the agricultural systems and used procedurein several ways. The leaves and shoots form hay orhaulm, which are important feed resources for lives- Maize tops (including leaves and tassels) weretock feeding. They can therefore replace the conven- harvested after grain maturity when the plants com-tional supplements, which are expensive and in most pleted silking and pollen shedding (stage1) and at 3,cases are not readily available to smallholder dairy 6, 9 and 12 weeks thereafter (stages 2, 3, 4 and 5,farmers. respectively) by cutting the maize plant parts above

The objective of the study was three-fold: to the cobs. Harvesting stages 1 and 2 took place whenassess the yield and quality of maize stover tops and the maize stover tops were still green, while thethe components harvested at different intervals after remaining stages the tops were changing towardsgrain maturity; to assess different conservation meth- yellowish and later brownish in colour. All the stagesods of maize stover tops following topping for dry took place prior to normal harvesting time of theseason feeding; lastly, to compare maize stover tops maize cobs. The harvested material of whole topsand grass hay for feeding stall-fed dairy cows from each sub-plot in plot 1 was separated into stemsupplemented with grain legumeLablab purpureus and leaf (sheath and blades) fractions. One repre-forage (Red seeded lab lab). sentative sample of the leaf, stem and whole top

from stages 1–5 was later subjected to laboratorychemical analysis in duplicate. The harvested maize

2 . Materials and methods stover tops from an area of 103 10 m for each oneof the five harvesting stages were then divided

2 .1. Location equally into three parts for conservation methodsassessment, where part 1 was stacked in the field (A),

The experiment was conducted at the Livestock part 2 was laid down in the field (B), and part 3Production Research Institute (LPRI), Mpwapwa, stored in a shed (C). Samples of maize stover tops

J.M. Bwire, H. Wiktorsson / Livestock Production Science 77 (2002) 207–215 209

from conservation methods A–C were taken for during the experiment. The cows exercised weeklylaboratory chemical analysis when all the harvesting on their way to the dipping site, and daily whenstages were completed. Samples from stages 1, 2, walking to the milking parlour. The cows wereand 3 were stored longer than 4 and 5. Additional penned and individually fed the grass hay mixturetops from stages 1 and 2 were harvested and stored (T1), green maize stover tops from stage 1 and 2in a well-ventilated feed barn with a raised wire (T2), and normal maize stovers after grain harvestmesh floor. Later, following proper drying, these (T3). Lab lab forage and maize bran supplementstops were baled before used in the feeding experi- were planned to account for about 30% of thement with lactating dual-purpose dairy cows. One of expected daily voluntary dry matter intake. The dailythe treatments in the feeding experiment included amount of lab lab and maize bran offered were 2 andgrass hay for comparison with the maize stover tops. 1 kg DM, respectively. The dry lab lab forage wasThe grass mixture, grown on a field nearby the maize fed first followed by the basal diets (T1 to T3) whichand lab lab plots, comprised ofCenchrus ciliaris, was given on ad libitum basis at a total amount ofChloris gayana, Panicum maximum, Cynadon plec- 30% above the expected voluntary dry matter intake.tostachyus, Heteropogon contortus, and Rottiboeria Basal diets were fed three times a day at 08:30,exeltata in different proportions. It was cut with a 12:00, and 16:30 h. Each cow had a mineral block toreciprocating mower. The cutting was done at ap- lick in an individual feeding trough. Water wasproximately 5 cm above the ground level, after about available at all times. Each cow received 1 kg DM of6 weeks of re-growth. After drying in the field, the maize bran as an energy source daily during milking,hay was baled prior to the feeding experiment. The equally divided at 08:00 and at 16:00 h. Calves werelegume lab lab plants at the flowering stage were allowed to suckle their dams for 30 s before milkingsampled for estimation of dry matter yield, by to stimulate milk letdown as an element in the

2cutting the plants from an area of 1 m , weighing restricted suckling calf management system. Afterthem and later taking samples for laboratory chemi- hand milking of the three teats, calves were allowedcal analysis. After weighing, the whole plot 3 was to socialise with their dams and suckle milk in theharvested and wilted in the field for 2 days. Drying rear right hand quarter that was left unmilked and thewas completed indoors on a cemented floor in a residual milk in the other three teats. The calveswell-ventilated feed barn. Turning of the cut lab lab were weaned at 45 days post-partum.forage was done three times a week to allow a Feeds were weighed prior to feeding. Refusalsthorough drying and to avoid rotting due to moisture were collected and weighed the morning after. Theemanating from the lab lab forage. Following proper difference between feeds offered and refusals indi-drying the lab lab forage was then hand chopped to cated the voluntary dry matter intake of the basalabout 5–10 cm lengths, stored in gunny bags and diets. Ten percent of the refusals collected werelater used as a protein supplement in the feeding bulked for a period of 4 weeks and later sub sampledexperiment. for laboratory chemical analysis. No refusals were

registered for lab lab and the maize bran supple-2 .4. Cow management and feeding ments. Total voluntary dry matter intake was the sum

of intake of the basal diets and supplements. MilkTwelve lactating dual purpose Mpwapwa dairy yield was recorded every day, at the morning and

cows in their third and fourth lactation, weighing evening milking sessions. Milk samples for butterfat225–378 kg (S.D.5 43.5), were used in the experi- (BF), ASH, crude protein (CP) and total solids (TS)ment. The cows were selected for the experiment were collected during the last week of the ex-when they were in the second week of lactation and, perimental period.milk for the first week was considered colostrum.The trial lasted 12 weeks, with a 3-week preliminary 2 .5. Laboratory chemical analysis of the feeds andperiod and a 9-week collection period. energy estimation

The animals were de-wormed to control endo-parasites before commencement of the trial and were Dry matter (DM), ASH, CP, crude fibre (CF),dipped once a week to control external parasites ether extract (EE) and nitrogen free extract (NFE) of


the basal diets (T1 to T3) and supplements, as well 3 . Resultsas BF, ASH, CP and TS of milk samples weredetermined according to the procedures of AOAC 3 .1. Dry matter yield(1985). Neutral detergent fibre (NDF) and aciddetergent fibre (ADF) were determined according to Dry matter production of maize stover tops asthe procedures of Goering and Van Soest (1970). influenced by harvesting stages 1–5 is shown inEnergy estimation of maize bran, lab lab forage and Table 1. There was a significant difference betweenmaize stover tops was done according to the pro- harvesting stages on dry matter yield. Stage1 and 2cedures of MAFF (1975), while an in vitro di- yielded more tops than 3–5 (P ,0.05). Dry mattergestibility procedure of the basal feeds and lab lab production for stages 1 and 2 was around 1 tonne/was performed according to Goering and Van Soest ha. For stages 3–5, it was less than half of that yield.

´(1970), modified slightly by Mbwile and Uden Dry matter yield of lab lab forage, not shown in the(1991). table, averaged 3.5 tonne/ha for the pure stand and

1.9 tonne/ha for the maize/ lab lab intercrop. Thiswas partly due to the differences in spacing, with

2 .6. Experimental design and statistical analysis100 cm (inter-row)360 cm (intra-row) for purestand and 180 cm (inter-row, i.e. between maize

A randomised complete block-design was used forrows)3 60 cm (intra-row, i.e. for lab lab and maize

the fieldwork. There were three blocks, with blockrows) for intercropping.

one comprised of maize alone, the second, a maize/lab lab intercrop and the third, lab lab as a pure

3 .2. Chemical composition and energy contentstand. The variations in maize stover tops yield andnutritive value occurred during harvesting stages 1,

The chemical composition and energy content of2, 3, 4, and 5. The methods of conservation, such as

maize stover tops from the different harvestingstacking in the field (A), laying down in the field (B)

stages 1–5 is shown in Table1. Harvesting stageand storing in a shed (C) were considered sources of

influenced the potential nutritive value of maizevariation to potential nutritive value disappearance.

stover tops. Harvesting stages 1 and 2 had higher CP,Assignment of experimental animals to the treat-

ME and IVOMD and lower ADF and NDF thanments and placing of the animals in individual

stages 3–5. There was a general trend for CP,feeding stalls was done by the use of random

IVOMD and ME to decline with advancing stage ofnumbers (Snedecor and Cochran, 1980). A total of

harvesting, while ADF and NDF increased. Also the12 Mpwapwa breed cows was used and each treat-

leaf component had higher CP, IVOMD and ME thanment included four lactating dairy cows. A complete

whole top and stem component (Table 1). Therandomised block-design was used with the follow-

leaf:stem ratio decreased with advancing maize planting treatments:

maturity. The nutritive values of maize stover topsfor the three conservation methods are shown in

• T1—Grass hay mixture Table 2. Conservation methods influenced nutritive• T2—Green maize stover tops value with CP and IVOMD found to be higher in• T3—Normal maize stovers after grain harvest maize stover tops stored in a shed when compared to

maize tops stored by laying and stacking. Theopposite was seen for NDF content. Topping wasThe general linear model (GLM) in the Minitabdone towards the end of April 2000. This is the end(1998) Statistical Software Version 12.0 was em-of the rainy season and thus the stacked or lying topsployed in all cases. The Tukey pairwise procedure inwere not threatened or damaged by the rains. Chemi-the Minitab (1998) Statistical Software was usedcal composition, IVOMD, and ME of the basal feedswhen the difference between treatment means wasof grass hay, dry green maize tops and maize stoverssignificant. The initial weight of the lactating dairyafter normal grain harvest (T1–T3), maize bran andcows was used as a covariate for voluntary DMlab lab forage are shown in Table 3. Green maizeintake.


Table 1Chemical composition (% of DM), metabolisable energy (ME MJ/kg DM), in vitro organic matter digestibility (IVOMD %) of whole plant(W), leaf component (L) and stem component (S), leaf:stem ratio (L:S) and dry matter yield (DMY) (kg/ha) of maize stover tops harvestedat grain maturity (stage 1) and at 3, 6, 9, 12 weeks thereafter (stages 2–5) (mean6S.E.)

Stage Part Composition IVOMD ME L:S DMY

CP ASH ADF NDFb b a a a a1 W 5.9 60.54 6.660.33 41.160.43 67.960.34 65.063.71 9.060.55a a b b a a aL 6.1 60.26 7.160.18 31.461.50 56.060.80 69.063.25 9.660.48 1.8:1 1520651c c a a b bS 4.160.16 4.760.08 43.061.19 69.260.87 54.063.16 7.460.47b a a a b b2 W 5.6 60.53 7.460.32 41.360.44 69.260.33 62.463.70 8.660.56a a b b a a aL 6.0 60.27 7.660.20 33.260.50 57.060.81 68.063.30 9.560.50 1.5:1 1427647c b a a c cS 3.960.15 4.860.10 44.360.20 70.460.87 52.063.20 7.160.47b a b b b b3 W 4.9 60.53 7.460.30 42.860.42 69.360.34 51.863.66 7.160.55a a c c a a bL 5.2 60.25 7.560.19 36.360.51 58.760.82 62.063.25 8.660.49 1.3:1 657654c b a a c cS 3.460.15 4.460.08 47.060.20 72.360.90 47.963.16 6.560.46b a b b b b4 W 3.7 60.53 8.560.32 42.860.44 69.860.34 47.363.67 6.460.60a b c c a a bL 4.9 60.27 6.760.18 38.960.50 60.060.77 54.063.30 7.460.49 1:1 647665c c a a c cS 3.360.20 4.560.10 48.760.20 73.060.90 39.1620 5.160.50b a b b b b5 W 3.1 60.52 8.060.33 43.260.40 69.760.33 47.863.71 6.560.56

b c c a a cL 4.9a60.26 6.760.19 38.860.50 60.060.76 54.063.24 7.260.48 1:1 483647b c a a c cS 3.360.16 4.460.10 49.060.19 74.060.86 39.063.20 5.160.47

CP, crude protein; ADF, acid detergent fibre; NDF, neutral detergent fibre.abc Means with different superscripts within a column differ significantly (P , 0.05).

Table 2Chemical composition (% DM), in vitro organic matter digestibility (IVOMD %) and metabolizable energy (ME MJ/kg DM) of the maizestover tops from harvesting stages 1–5 under the different conservation methods, stacking in the field (A), laying down in the field (B), andstoring in a shed (C) for the period from grain maturity until normal harvesting of the grains at 12 weeks (mean6S.E.)

Stage Method Composition IVOMD ME

CP ASH ADF NDFb c a a b b1 A 3.7 60.15 7.660.25 44.760.97 70.760.90 54.860.29 7.360.18b a a a c cB 3.5 60.21 9.560.32 42.760.96 73.860.94 49.460.44 6.560.07a b b b a aC 5.760.41 8.060.18 39.260.94 66.460.29 58.660.72 7.860.23b b b b b b2 A 3.0 60.20 6.560.25 37.660.98 68.960.92 48.760.30 6.460.19b a a a b bB 2.8 60.19 7.860.33 41.660.96 72.360.94 47.860.44 6.360.07a a b a a aC 5.660.40 7.160.17 38.760.94 70.560.30 52.160.73 6.960.24b a b b b a3 A 2.9 60.16 7.960.24 43.660.96 73.660.98 48.360.29 6.460.17b a a a b aB 2.3 60.22 7.760.34 48.660.98 80.360.93 47.060.45 6.260.08a a b b a aC 4.060.42 7.460.18 43.760.93 74.560.94 51.260.73 6.860.23b a b b a a4 A 2.9 60.16 7.860.25 48.660.98 73.260.97 48.460.28 6.460.17b a a a a aB 2.5 60.20 8.360.33 50.760.96 81.360.95 47.360.43 6.260.08a b c b a aC 4.060.41 7.160.19 42.060.91 71.060.94 49.560.71 6.660.24b a b b a a5 A 2.9 60.15 7.760.26 48.060.97 73.060.90 48.060.29 6.360.18b a a a a aB 2.5 60.20 8.060.35 50.060.95 81.060.94 47.060.44 6.260.08a b c b a aC 3.960.41 7.060.18 42.060.94 71.060.91 49.060.73 6.560.23

CP, crude protein; ADF, acid detergent fibre; NDF, neutral detergent fibre.abc Means with different superscripts in a column differ (P ,0.05).

stover tops (T2) had the highest IVOMD and CP and NDF compared to T2. Average chemical com-concentration compared to the grass hay mixture position of the lab lab fodder was 16.7 and 63.7% for(T1) and normal maize stovers after the grain harvest CP and IVOMD, respectively. Lab lab leaves con-(T3). Conversely, T1 and T3 had the highest ADF tained more CP than stems (18.0 vs. 8.0%) but had


Table 3 ordinary maize stovers after grain harvest (5.05 andChemical composition (%), in vitro organic matter digestibility 5.02 vs. 4.4 kg/day). The daily milk yield excluded(IVOMD %), and metabolizable energy (ME MJ/kg DM) of grass

the milk suckled by the calves that was estimated tohay mixture (T1), green maize stover tops from harvesting stagesbe about 2.8 kg/day. Calves were weighed before1–2 (T2), normal maize stovers after grain harvest (T3), maize

bran and lab lab forage used for feeding the lactating dairy cows and after suckling according to Bwire and Wiktor-sson (2001). Milk components, BF, CP, ASH and TSParameter Composition IVOMD MEwere fairly similar among the treatments.

CP ASH ADF NDF

T1 5.1 8.2 48.3 76.1 57.2 7.7T2 5.7 8.0 39.2 66.4 64.6 8.7 4 . DiscussionT3 3.7 9.5 44.7 70.4 48.2 6.4Maize bran 11.6 4.6 11.8 34.0 – 13.8

This study has shown that harvesting maize stoverLab lab 16.7 7.0 37.3 58.2 63.69 8.6tops at grain maturity (stage 1) and 3 weeks laterCP, crude protein; ADF, acid detergent fibre; NDF, neutral(stage 2) resulted in higher dry matter yield com-detergent fibre.pared to later stages (Table1). A possible explanationcould be that harvesting maize stover tops when the

lower ADF and NDF compared to stems (34.8 and leaves are yellow or brownish (stages 3–5) is also54.2% vs. 46.9 and 61.6%, respectively). accompanied by falling to the ground probably due

to wind shattering, and are therefore unavailable,3 .3. Feed intake which is verified by the lower leaf: stem ratio. Also

when the foliage falls down, it is easily damaged byVoluntary DM intake of basal diets differed (P , insects such as termites or trampled, soiled and

0.05) among treatments (Table 4). Cows consumed therefore not available as a feed resource. The drymore grass hay and green maize stover tops than matter yield of green maize stover tops averaged 1.5maize stover after grain harvest (5.20 and 5.13 vs. and 1.4 tonne/ha for harvesting stages1 and 2, which3.27 kg/day). Dry matter intake of grass hay and was lower than yields reported by Shirima andgreen maize stover tops was thus fairly similar. Total Wiktorsson (1994), where they averaged 1.8 tonne/dry matter intake including basal diets, lab lab and ha. The possible reason could be due to differencesmaize bran also differed among treatments (P , in management and planting technique. The dry0.05), with cows on T1 and T2 consuming more dry matter yield obtained in the current study is slightlymatter than cows on T3 (8.06, 7.98 vs. 6.25 kg/day). higher than reported previously by Bwire et al.

(1998), which averaged 1.3 and 1.2 tonne/ha for3 .4. Milk yield and milk composition stages 1 and 2, respectively. All these findings

indicate that the dry matter yield of green maizeDaily milk yield differed among treatments (Table stover tops in the semi-arid areas of Tanzania ranges

4) with cows on grass hay and green maize stover between 1.2 and 1.8 tonne/ha. The stover parts lefttops producing more milk (P , 0.05) than cows on in the field after topping can also be used for

Table 4Dry matter intake of basal diets (BDMI) of grass hay mixture (T1), green maize stover tops (T2) and normal maize stovers after grainharvest (T3) (kg DM/day) and total dry matter intake (TDMI) (T1 to T31 lab lab forage and maize bran), milk yield (kg/day) excludingmilk suckled by the calves, and milk composition (%) (means6S.E.)

Factor BDMI TDMI Milk yield Milk composition

BF CP ASH TSa a a a a a aT1 5.2060.09 7.9860.09 5.0560.04 4.460.12 2.860.04 0.660.01 12.460.24a a a a a a aT2 5.1360.09 8.0660.09 5.0260.03 4.360.13 2.460.04 0.660.02 12.360.22b b b a a a aT3 3.2760.03 6.2560.03 4.4060.05 4.560.12 2.560.05 0.660.03 12.260.15

ab Means within a column with different superscripts differ significantly (P ,0.05).


feeding. According to Shirima and Wiktorsson tops stored in a shed had higher IVOMD, ME and(1994), the cumulative dry matter yield (tops and CP in all the harvesting stages. This occurs becauseresidual parts) was found to be higher than the of the loss of nutrients when the tops are stacked ornormal stovers after grain harvest (5.4 vs. 4.2 tonne/ laid in the fields where they are exposed to highha), respectively. This is comparatively higher than temperatures and other factors, such as termite attackthe dry matter yield of most of the tropical grasses or grazing animals can easily invade the field andfound in the grasslands of semi-arid central Tanzania trample the stacked or laid down tops.(Mwilawa et al., 1998, Bwire and Wiktorsson, Dry matter yield of lab lab forage averaged 3.52001). In addition, stages 1 and 2 were found to have and 1.9 tonne/ha for pure stand and intercroppedmaize stover tops higher in CP, IVOMD, ME and with maize, respectively. This is higher than theleaf: stem ratio compared to stages 3 to 5. Delaying yield reported by Kitalyi (1989), who reported atime of harvesting of maize stover tops, as for most range of 0.6–2.3 tonne/ha for pure stand for the fiveof the tropical pastures, results in a decline of seed types of local lab lab tested. There are manynutritive value (Shirima and Wiktorsson, 1994, Mero possible reasons for the observed wide range in yield

´and Uden, 1997). The in vitro dry matter digestibility but most important is the delayed harvesting timeof stages1 and 2 compares well with findings of that results in leaf abscission.Shirima and Wiktorsson (1994). The energy content Dry matter intake of maize stover tops fromis much higher than in most of the tropical grasses harvesting stages 1 and 2 (T2) was similar to that offound in the grasslands of semi-arid areas of Tan- the grass hay mixture (T1) but significantly higherzania (Mwilawa et al., 1998; Bwire and Wiktorsson, than that of the normal maize stovers after grain2001). The IVOMD and CP also was found to vary harvest (T3), (Table 4). The actual cause for thebetween the maize stover tops parts within the higher dry matter intake in T 1 and T 2 cannot beharvesting stages, with the leaf parts having higher given. The higher DM digestibility, CP and MEIVOMD and CP followed by whole plant and stem content of the basal diets are obvious factors, whileparts, respectively. This is due to differences in fibre the influence of the lab lab and maize bran supple-contents (NDF) where in many cases the leaves ments cannot be specified. Protein supplementationnormally have lower NDF as compared to whole has been found to increase dry matter intake of lowplant and stem components. When comparing the quality roughage (Church and Santos, 1981; Guthriemaize tops, parts left after topping and the normal and Wagner, 1988), resulting in a mere additivemaize stovers after grain harvest, Shirima and Wik- effect (sum of basal diets and supplements), astorsson (1994) found CP content of 6.8, 3 and 3.3%, reported by Bwire and Wiktorsson (1996) and Shayorespectively. This, again, indicates the superiority of et al. (1997). The reason could be that lab lab andthe maize tops to stovers which was also observed in maize bran supplements have a low ‘rumen load’ andthis study with CP content of 5.7 and 3.7% for would leave the rumen quickly and therefore haveconserved green maize tops and maize stover after little effect on rumen distension and intake of thegrain harvest, respectively. Harvesting of maize tops basal feeds (Preston and Leng, 1987). Milk yieldafter silking and pollen shedding apart from giving was also similar among cows fed on grass hay andvaluable green feed materials, has also been found to green maize stover tops and was significantly higherhave no adverse effect on grain production (Roy and than that from cows that were on a normal maizeBiswas, 1992; Shirima and Wiktorsson, 1994). How- stovers diet after grain harvest (5.05 and 5.02 vs.ever, the grain production was not measured in the 4.40 kg/day), thus reflecting the similar dry matterpresent study. intake among cows given maize stover tops and the

In addition to time of harvesting, storage is grass hay mixture, which was higher than those onanother factor that can influence the nutritive value normal maize stovers after grain harvest. The ob-of the maize stover tops. In this study, storing the served daily milk excludes milk suckled by themaize stover tops in a shed was found to optimise calves because it covers the 45-day suckling periodthe potential nutritive value compared to stacking and the remaining 84 days of the experiment. Milkand laying the tops in the field. The maize stover components were fairly similar among the treatments


Bwire, J.M.N., Wiktorsson, H., 1996. Pre-weaning nutritionaland this is an indication that the basal diets had amanagement and dry season nutritional supplementation onsimilar influence on milk composition. Milk fat,intake, growth and onset of puberty of improved zebu heifers.

which is known to be the most variable component Livest. Prod. Sci. 46, 229–238.of milk, was found to be stable between the treat- ´Bwire, J.M., Uden, P., Masaoa, A.P., 1998. Optimising the quality

and biomass production of maize stover tops for dairy cowsments.through strategic harvesting. In: Proceedings of the BSAS/KARI Conference on Food, Land and Livelihood: SettingResearch Agenda for Animal Science, 27–30 January 1998,Nairobi, Kenya, pp. 131–132.5 . Conclusion

Chenost, M., Sansoucy, R., 1991. Nutritional characteristics oftropical feed resources: natural and improved grasslands, crop

Harvesting green maize stover tops at grain ma- residues and agro-industrial by-products. FAO Anim. Prod.turity was found to optimise the potential nutritive Health Paper 86, 66–78.

Church, D.C., Santos, A., 1981. Effect of graded levels of soybeanvalue and dry matter yield compared to later harvest,meal and of a non-protein nitrogen-molasses supplement onwhen the tops had changed towards yellowish orconsumption and digestibility of wheat straw. J. Anim. Sci. 53brownish in colour and particularly the maize stover(6), 1609–1615.

after grain harvest. The leaves had higher potential Goering, H.K., Van Soest, P.J., 1970. Forage fibre analysis. USDAnutritive value compared to stems components of the Agric. Handbook 379, 1–20.

Guthrie, M.J., Wagner, D.G., 1988. Influence of protein or gradedmaize tops in all the harvesting stages. Storing maizegrain supplement and increasing levels of soybean meal onstover tops in a shed conserved nutritive value muchintake, utilisation and passage rate of prairie hay in beef steersbetter than laying and stacking methods that acceler-and heifers. J. Anim. Sci. 66, 1529–1537.

ate loss of nutritive value and expose the maize Kitalyi, A.J., 1989. Production and nutritional characteristics ofstover tops to vermin and termite attack. Green local lab lab bean (Lablab purpureus) in semi-arid areas of

Tanzania. In: Kabatange, M.A. et al. (Ed.), Proceedings of themaize stover tops therefore provide green fodder thatTALIRO/SAREC Conference on Development and Utilisationcan be used during the dry season in tropicalof Forages for Livestock Feeding in Tanzania, 14–15 Marchcountries and compare well with grass hay mixture1989, pp. 32–40.

for improved milk production and voluntary dry Kitalyi, A.J., Masaoa, A.P., 1991. Use of dual purpose legumematter intake when supplemented with lab lab for- crops in the agro-pastoral systems of the semi-arid areas: A

review. In: Masaoa, A.P. et al. (Ed.), Proceedings of a Seminarage.on Milk Production from Smallholder Systems with Emphasison Feeding Strategies in Semi-arid Areas, 22–24 January 1991,Morogoro, Tanzania, pp. 26–34.

A cknowledgements MAFF, 1975. Energy allowances and feeding systems for rumin-ants. Tech. Bull 32, 243–251.

´Mbwile, R.P., Uden, P., 1991. Comparison of laboratory methodsThe authors wish to acknowledge the financialon precision and accuracy of predicting forage organic mattersupport from the IDA through the World Bank to the and digestibility. Anim. Feed. Sci. Technol. 32, 243–251.

Tanzania Agricultural Research Project (TARP II). ´Mero, R.N., Uden, P., 1997. Promising tropical grasses andAnderson Seif and Albert Lubeleje are thanked for legumes as feed resources in central Tanzania. I. Effect of

different cutting patterns on production and nutritive value offeeding and management of the experimental ani-six grasses and six legumes. In: Improved Grasses andmals, and Joseph Malale and Neema Urasa for theLegumes as feed resources for central Tanzania. PhD thesis.laboratory chemical analysis of the feeds and milk Department of Animal Nutrition and Management, Swedish

samples. University of Agricultural Sciences, Uppsala.Minitab, 1998. Reference Manual PC Version 12.0. Minitab Inc,

Staten Island, NY.Mwilawa, A.J., Musimba, N.K.R., Kidunda, R.S., 1998. Tradition-

R eferences al range resource utilisation, experience gained among thepastoralists of Tanzania. J. Soc. Sci. 2 (1), 53–57.

Preston, R.T., Leng, R.A., 1987. Matching Ruminant ProductionAOAC, 1985. Official Methods of Analysis, 12th Edition. As-Systems With Available Resources in the Tropics and Sub-sociation of Official Analytical Chemists, Washington, DC.tropics. Penumb Books, Armidale, NSW, Australia, pp. 93–Bwire, J.M.N., Wiktorsson, H., 2001. A Feeding System of200.Combining Tropical Grass Species For Stall-fed Dairy Cows.

Roy, S.K., Biswas, P.K., 1992. Effect of plant density andLPRI, Mpwapwa, unpublished manuscript.


detopping following silking on cob growth, fodder and grain and tops prior to harvesting as fodder for livestock. In: Qualityyield of maize (Zea mays). J. Agric. Sci. 119, 297–301. and Quantity of Maize and Sorghum Vegetative Parts Har-

´Shayo, C.M., Ogle, B., Uden, P., 1997. Comparison of water vested at Different Stages of Plant Growth as Fodder Formelon (Citrullus vulgaris) seed meal,Acacia tortilis pods and Livestock. MSc thesis. Department of Animal Nutrition andsunflower seed cake supplements in Tanzania. 2. Effect on Management, Swedish University of Agricultural Sciences,intake and milk yield and composition. Trop. Grasslands 31, Uppsala.13–14. Snedecor, G.W., Cochran, W.G., 1980. Statistical Methods, 7th

Shirima, E.J.M., Wiktorsson, H., 1994. Utilisation of maize leaves Edition. Iowa State University Press, Ames, IA, pp. 463.

optimising the quality and biomass production of maize stover tops for stall-fed dual purpose dairy...

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