1. WHAT IS SUGARCANE TOP (SCT)?
It is generally known to be a major byproduct of the sugarcane industry which is left in the field after cane harvest. It is, however, rarely realized that the ‘top’ has been removed from the cane at a very ‘arbitrary’ point. This results in important variations in the composition - especially for neutral detergent solubles or nitrogen-free extractives. Sugarcane millers have widely different opinions as to the optimum topping point, but the consensus is that it should be the highest fully formed node. SCT, therefore, consists of 3 distinct parts - the green leaves (blades), the bundle leaf sheath and variable amounts of immature cane.
2. Sugarcane top production
SCT production varies considerably with variety, age at harvest, growing conditions and management practices. Data available for Natal are shown in Table 1. The relative yield of SCT in Natal is much lower than values reported for Mauritius and Hawaii (Table 2) where SCT represents 16 – 18 percent of the aerial biomass respectively. Based on a conservative figure of 5 tonnes of dry matter (DM) per hectare, Mauritius produces around 390 000 tonnes of DM from SCT annually (equivalent to 1.5 million tonnes of fresh SCT at 26 percent DM). Assuming SCT loss by burning at 5 percent and unavailability due to flowering at 10 percent, 1.3 million tonnes of SCT are therefore produced annually.
The SCT produced per hectare (21 tonnes) is theoretically enough to provide forage for 1 livestock unit (LU) over a year (1 LU = 500 kg). The present ruminant population in Mauritius represents only 15 000 LU while the SCT produced is sufficient for 78 000 LU. The dependence of Mauritius on sugar for currency earnings and the guaranteed prices obtained do not justify the feeding of whole cane to ruminants at this stage.
3. LIVESTOCK PRODUCTION SYSTEMS IN MAURITIUS AND UTILIZATION OF SCT2 FOR RUMINANTS
In Mauritius, livestock depend heavily on SCT, especially in winter when the productivity of most other species is at its lowest. The most difficult months for fodder availability are November, December, January, May and June. Figure 2 illustrates the availability-deficit picture.
Three distinct groups of livestock producers can be identified in Mauritius: (i) Small cowkeepers owning 1 – 4 head per family; (ii) Medium-scale entrepreneurs having 10 to 100 head of cattle, mostly self-owned; (iii) Large-scale breeders - having over 100 head, generally private companies or subsidiaries of sugar estates and Government farms.
The small cowkeepers utilize SCT massively in winter but have so far thought very little about preserving it. In the intercrop season they cover relatively long distances to collect fodder from crown lands, forest reserves, river sides and mountain slopes. They own the majority of the cattle in the country (70 percent), 100 percent of the goats and produce most of the local fresh milk. This group should, therefore, be a major target for new SCT utilization technology although the response may be relatively less being a traditionally low input - low output system.
The medium-scale entrepreneurs are a new generation who find self-employment in livestock rearing and are keen to adopt new technologies. SCT is used massively in winter but, during periods of fodder shortage, they purchase either poor quality fodder from the humid uplands or use dried grass cut from mountain sides - some grazing is practised for beef stock while dairy animals are zero-grazed. Molasses/urea and protein supplements are major inputs in the system.
The large-scale breeders on the other hand have little choice. They improve marginal lands for grazing part of the stock in summer but rely heavily on sugarcane tops both in the harvest and the intercrop season. The larger the farms, the more they depend on SCT for year-round feeding. The system is heavily mechanized and molasses/urea forms an important constituent of the year-round ration.
Land for fodder cultivation is not available in Mauritius (and many Caribbean countries). Figure 1 clearly shows that SCT is, therefore, not only essential for the livestock industry in Mauritius, but forms the basis of feeding for any major expansion and development of the livestock sector.
4. CONSTRAINTS LIMITING THE USE OF SCT
4.1 The seasonal availability:
Various methods of preservation for SCT have been tried ranging from small plastic bag silos, below ground trench silos, above ground low cost silos (1 – 4 tonnes), small concrete silos (2 – 6 tonnes), and large concrete silos (100 – 4 000 tonnes).
Large concrete silos have been successfully used in Mauritius for the past 10 years but small concrete silos for the medium and small livestock breeders are more recent achievements. Loss of ensiled materials is very low (5 percent) and the quality of the preserved materials is very good. The quality of the silage made with SCT and molasses from 1 to 5 percent of cane tops (fresh) and 1 percent ammonium sulphate compares very well with norms set for temperate crops silage (Deville et al., 1979). The recent technology of preserving cane tops with NH3 produced in situ from urea has also been successfully applied in small concrete silos (1 – 4 tonnes) at small cowkeepers' sites. The resulting preserved materials have been well received by both the livestock and the farmers. The rate of urea application has been 4 – 5 percent of SCT dry matter. An aggressive demonstration programme funded by the UNDP is in progress to make 50 silos (5 – 6 tonnes) to disseminate the technology and another 100 will be built this year with grants from USAID. The results from low cost above ground silos (chipped material was heaped on the ground, trodden upon with addition of urea and covered with pieces of plastic and soil) have given variable recoveries and were susceptible to rapid spoilage especially during periods of heavy rainfall.
4.2 The relatively low nutritive value of the SCT on its own: or rather the lack of knowledge on the best ways to use SCT. This is extensively covered in another section.
4.3 The labour intensive collection of the cane tops in the field:
Collection of cane tops for small cowkeepers is easily achieved because of the abundant family labour available but for larger units, this is a costly and labour intensive item (1 tonne of SCT may be collected by 1 female worker daily = Rs 50/t). Baling of SCT has been tried in South Africa and Australia and this year a round baler is working in Mauritius. This partially solves the problem of collection and presents the material in a compacted form for easy storage.
4.4 The restricted access to cane fields:
Although SCT is considered free (at present), large scale collection on private lands requires the permission of the land owners. Some planters practise trash conservation and view the excessive removal of SCT from the fields as a loss of soil nutrients and impose some sort of quotas. The issue of leaving livestock breeders a more liberal access to private cane fields needs to be resolved by mutual cooperation by the people concerned - an exchange of SCT with manure being just an example. In the long term as demand increases, a price will probably have to be paid.
4.5 Transport of SCT over long distances:
This involves additional costs and is accentuated by the bulkiness of the collected material (half the weight of cane a lorry normally carries) and competition with the priority of carrying cane for sugar production.
4.6 The increasing use of burning:
Burning is practised to ease harvest, especially with cane having trashing problems. In Mauritius it is estimated that only 5 to 10 percent of the cane fields are burnt prior to harvest. Although some losses of dry matter occur, the burnt cane tops are still a valuable feed for feeding livestock directly and processed (Pate and Coleman, 1975) or for silage making. The severity of losses to SCT due to burning depend on the initial ‘greenness’ of the leaves, the amount of dry trash and strippings, their humidity and the prevalence of winds. Generally the bundle leaf sheath is recovered with variable proportions of partially burnt leaf blades.
4.7 The construction of silos for preserving SCT
This involves capital costs which the small farmer does not readily possess. The need for credit facilities and ‘package’ approach is discussed in the last section.
4.8 Other factors
Flowered tassels of sugarcane are not normally utilized for feeding livestock by small breeders. Some varieties, e.g. S17, flower precociously and profusely, hence limiting SCT availability for small cowkeepers. However, under large scale collection, a large part of it is collected with the SCT and is chipped. The specific nutritive value of flowered tassels is not known.
The use of chemical cane ripeners (e.g. polaris) on a large scale to increase cane sucrose content is practised by the MSIRI in Mauritius and many cane producing countries. Their effect on the nutritive value of SCT has not yet been determined.
5. COMPOSITION AND NUTRITIVE VALUE OF SCT
Classical analytical techniques have been extensively used to estimate the nutritive value of SCT based on chemical composition. Table 3 presents data from a wide geographical area. The mean values presented do not include cases which exert an artificial difference in the normal composition of SCT.
Table 3 also summarizes data for digestibility coefficients of the components of SCT. Dry matter digestibility (DMD) is low (54 percent) while crude protein digestibility is much lower (39 percent). Thus only 23 g of digestible crude protein are available per kg of SCT dry matter. The total digestible nutrients calculated from the mean values is 510 g/kg of SCT (DM).
The composition of organic structural components of SCT is shown in Table 4. The neutral detergent solubles (NDS) are almost completely digested (98 percent) while the in vitro coefficient of digestibility of the fibre has been found to be 50.2 percent (Kevelenge et al., 1983a). Using a correction of 12.9 percent for endogenous and bacterial matter as a percentage of intake (Kevelenge et al., 1983a) the apparent dry matter digestibility is calculated to be 54.0 percent. This figure is similar to the in vivo DM digestibility presented in Table 3.
Large variations exist in the literature for the nylon bag degradability of SCT. Some are real differences while part is due to the basal rations used. It appears, however, that most of the difference is due to the use of non-standard procedures - especially fineness of grinding. Hughes-Jones and Peralta (1981) found that only 18.2 percent of SCT dry matter disappeared from nylon bags after 48 hours in bulls fed a basal diet of sugarcane and molasses ad lib while removal of the molasses increased it to 31.8 percent. In this case the SCT was passed twice through a hammer mill without a screen to simulate animal mastication. In Mauritius the degradation of SCT in nylon bags in the rumen of cattle fed a basal diet of poor quality fodder was found to be 43 percent after 48 hours. The SCT was oven dried at 100°C and ground through a 2.5 mm screen (Naseeven, unpublished data). San Martin et al (1983a,b) have demonstrated the rapid drop in the degradability of SCT in the presence of high levels of starch. Similar results were obtained by Ma Poon (1981) with increasing levels of molasses in the basal diets. These illustrate the need for a judicious choice of supplements (and levels) on SCT diets.
The gross energy of SCT is 15.9 MJ per kg DM and the coefficient of digestibility with sheep being 52.4, the digestible energy (DE) is calculated as 8.3, and ME = 6.9 MJ/kg DM (Kevelenge et al., 1983b). This value is much lower than values of 10 MJ/kg ME normally obtained for good quality fodder.
The average mineral composition of SCT (percent on DM basis) is as follows: Ash:9.6; Ca:0.43; P:0.15; Na:0.05; K:2.31.
Sheep fed only sugarcane tops were found to be in positive balance for major minerals with the exception of phosphorus (Kevelenge et al., 1983c).
The nutritive value of SCT fed alone
There are few reports where sugarcane tops have been fed alone to ruminants. Information available shows that SCT is a highly palatable forage with good voluntary consumption indices (Table 5). However, animals either lose condition or just maintain themselves or at best have very low levels of production.
Similar results are reported from the Philippines (Roxas, 1985) and Pakistan (Amanat Ali and Amanullah Cheema, undated). Kevelenge et al. (1983b) calculated the ME intake of sheep (42.6kg) fed only SCT to be 6.0 MJ/d and compared it to ARC (1965) data which requires 5.48 – 6.65 MJ/d for maintenance of sheep between 30 – 40 kg liveweight. In Mauritius it is known that ruminants are fed exclusively on cane tops for most of the harvest season. Based on island-wide analyses, it has been estimated that SCT can provide for maintenance and 2 – 4 litres of milk (Sansoucy, 1972).
The reasons why ruminants fed only SCT in Mauritius are able to achieve low-moderate levels of production are two-fold: firstly a high selection is exerted by the small cowkeepers who peel the cane tops keeping the succulent central portion only. Secondly, the animals in turn select the succulent bundle leaf sheath and eat very little green leaf - a luxury they can afford because of the amount fed (up to 90 kg/head/d). It is known that the bundle leaf sheath and the young cane inside have a higher amount of sugars and it was found that the rate of degradability of the bundle leaf sheath was relatively higher although the potential degradability was similar to green leaves (Boodoo, unpublished).
Similar results were obtained (Naseeven, unpublished data) when the components of different varieties were studied using the nylon bag. The degradability of the bundle leaf sheath was 50 percent higher than that of the green leaf blade after 48 hours of incubation in the rumen of cattle (Table 6). If the rate of digestion proceeds faster, it would be expected that animals would be able to consume more feed and nutrients. This probably explains the Mauritian performances.
A study carried out by FAO in Mauritius in 1971 showed that village cows prduced 1 500 kg milk without supplementation of traditional concentrates. However, although the fodder was predominantly cane tops during the harvest season, other highly nutritive fodder species were utilized in summer.
6. IMPROVING THE VALUE OF SUGARCANE TOPS FOR RUMINANT FEEDING
There are basically three approaches:
The first one, already discussed, is a selection of the succulent bundle leaf sheath - obviously not practical for large units and overall SCT utilization;
The second one, and the most complex, is the optimum combination of products and byproducts for supplementation at the best economic levels to achieve the maximum of returns;
The third is treatment action directly on the SCT to increase its DMD by physical, chemical, as well as biological means.
6.1 Supplementation of sugarcane top-based diets
With the low amount of digestible crude protein obtainable from SCT (23 g/kg DM), it is logical that the first supplement should be a nitrogen source. Pate et al. (1971) obtained average daily liveweight gains (ADG) of 0.52 kg by supplementing SCT with 1 kg cotton seed meal/hd/day while animals just maintained weight without the supplement. Ferreiro and Preston (1976) obtained ADG of 0.84 kg when zebu bulls were fed 1 kg rice polishings with SCT. In Mauritius, feeding of SCT silage together with 1 kg copra cake, 0.2 kg fish meal, 0.5 kg rice bran and molasses/urea 3 percent fed at 3 percent of liveweight gave ADG of 0.57 – 0.67 kg (Deville et al. 1978). Tuazon (1974) obtained lower ADG of 0.41 kg by feeding SCT silage (60 percent of DM), molasses (20 percent of DM) and copra meal (20 percent of DM).
However, these growth rates are well below the genetic potential of these animals which indicates that nutrients are still limiting. Luz Meyreles and Preston (1982) and Luz Meyreles et al. (1982) have fed growing bulls ad libitum SCT and ad libitum molasses but with different sources of nitrogen: urea, poultry litter and wheat bran (see Figure 1). Leaving aside the 1.01 peak (the experiment was of short duration and with a small number of animals), it is safe to conclude that the addition of molasses worsens a situation where N was already limiting and the supply from 1 kg bran is not sufficient for high production. Further addition of nitrogen is seen to result in corresponding increases in performance. The effects of nitrogen/SCT are confounded by the presence of ad libitum molasses in the system. Referring to the high liveweight gain, the authors say ‘better performance due to combining the supplements was obtained with a slightly reduced intake of molasses, but a higher intake of forage’. It is very unfortunate that this question was not followed closely.
Recent findings in Mauritius on a commercial farm show that SCT silage at 15 kg + molasses/urea 4 percent at 1.5 percent LW (7 kg) and brewer's grain 14 kg + CSC 1 kg in rations for finishing beef cattle give ADG of over 1.4 kg. This represents a total DM intake of 13.7 kg or 3 percent of LW for a 450 kg animal. These data which are actual production figures from the largest livestock fattening enterprise in Mauritius indicate that the 1.01 kg ADG reported by Meyreles and Preston (1982) was possibly not a chance occurrence. The common factor is the lower level of molasses. According to the manager, the level of urea in the molasses was brought down from 6 to 4 percent without any adverse effects on performance. This is plausible in view of the large amount of N entering the system (1 030 g DCP/hd/d). In view of the generally poor performance obtained on diets based on both molasses and canetops Brewer's grains appear to have a very positive effect.
Following the work of Ma Poon (1981) it would appear that molasses levels up to 1.5 percent of LW could be used advantageously without affecting the energy contributed by the SCT, but it has been current practice to limit molasses to 1.0 percent of LW to be safe.
6.2 Supplementing for milk production
A UNDP-funded pilot project to demonstrate the use of Cotton Seed Cake for milking cows fed predominantly on SCT in the harvest season has given the following preliminary results (Boodoo, unpublished data):
|Cows on fodder + cowfeed||(29 cows)||12.6||kg milk/day|
|Cows on fodder + 250 kg CSC||(34 ")||12.5||"|
|Cows in FAO - No concentrates||(980 ")||5.0||"|
|Cows in FAO - Concentrates||(- ")||8.0||"|
It is therefore clearly demonstrated that cowkeepers can increase their milk production from 5 litres average daily yields (FAO, 1971) to 13 litres with the supplementation of protein supplements.
Concentrates being relatively expensive to provide all the nitrogen requirement, current research is looking into the use of molasses blocks with high urea levels to supplement part of the nitrogen. This is expected to bring further reduction in the cost of production.
6.3 SCT treatment
Apart from the judicious use of appropriate supplements with SCT rations, attempts have been made to treat SCT for improving its nutritive value especially with alkali. The data in Table 7 show that ammonia/urea treatment did not improve DM digestibility as previously believed and as exhaustively reported for cereal straws. There is no explanation to this difference in behaviour of SCT and this is probably the only report on the subject. However, the advantage of the urea treatment is an increase in the crude protein content to levels optimal for microbial degradation.
6.4 Physical factors
Ferreiro and Preston (1977) found that fine chopping of SCT decreased the voluntary intake while coarse chopping 5 – 15 cm significantly increased it. This aspect has not been investigated further. It could be important in the design for better chipping equipment and improvement of feed intake.
7. Improving the overall use of SCT from field to animal silage
The high seasonal peak availability (Figure 2) pattern of SCT poses a problem for its year-round utilization. As far as large sugar estate farms are concerned, it is now an established practice to fill the silos of 100 to 4 000 tonnes during periods of availability. The material is chipped and sprayed with molasses partially diluted with water at the rate of 1 to 5 percent of fresh SCT followed by trampling. The silos are subsequently sealed by PVC or butyl sheeting.
An attempt to make a communal trench silo for village cowkeepers in 1968 failed completely. It was surprising that although faced with a major crisis of fodder shortage during the off-harvest period, the small cowkeepers were not interested in communal silos. The main reason was the availability of scrub lands, river sides, crown reserves and forest land from where it was possible to get a daily fodder requirement with the family labour - although it meant walking long distances. The other factor was the psychological aspect - farmers are very sentimental about their cows and are reluctant to feed them with feeds they judge ‘unfit’ for the cows.
However, times have changed - with the increasing number of livestock, an increasing awareness of silage technology and increasing pressure on the scrub lands, today many small farmers are very keen in preserving cane tops. Since the small cowkeepers are the owners of most of the ruminant livestock in Mauritius, any plan to increase SCT utilization through silage making must make them the main target.
Extension services play an important role in the education process and sensibilize farmers to the new technology. Afterwards elite farmers keenly interested and in great need of silage are selected for pilot silos to be used as a demonstration for other cowkeepers in the village. Apart from technical advice, a national silage programme requires credit facilities for the initial silo construction, basic equipment for chipping, additives (molasses and urea) for improving preservation and feed supplements to ensure improved animal performance on the silage. It is only through an integrated approach that chances for success exist. The medium to large farms could be encouraged to increase their storage capacity with soft loans and subsidies on silage making equipment and materials used in the construction of silos.
A longer term approach should, however, involve a higher degree of integration with the cane milling industry. As sugarcane is considered a precious crop, the SCT could also be harvested and carried to the factory where an additional chain + knives would do the chipping and offer the chipped material for sale on a weight basis. Any excess could be ensiled for sale during the intercrop season. Alternatively the Government could encourage entrepreneurs to offer chipping services directly in the field or at the farms. Contractors could even propose the complete filling of the silo on a weight basis.
It has been estimated that for a small cowkeeper owning 2 head of cattle and requiring about 5 tonnes of silage for feeding them for 3 months the cost of ensiling would be about 185 Rs/tonne. It would only be 155 Rs/t for a 2 000 t silo (1 US$ = 12.9 Rs). In both cases, these values are lower than the cost of producing planted fodder.
SCT is abundantly available and by tackling the major constraints limiting its use priority-wise, more fodder will be made available during the off-harvest ‘difficult’ months. The first priority is preservation.
The problem of relatively low nutritive value of SCT is rather a lack of knowledge of judicious supplementing to exploit the most out of the ration. Research is desperately needed to find other forms of cheap ‘ideal supplements’.
SCT does not behave like cereal straws. It has good voluntary intakes and does not appear to respond to ammonia treatment. This deserves the attention of research workers for elucidation.
In countries like Mauritius, instead of planting graminaceous species, the limited land should rather be exploited with high yielding legumes while SCT and molasses are exploited for energy. An integrated approach to encourage farmers and parallel services to move to SCT preservation is a major step towards the increase in livestock numbers and production.
ARC-Agricultural Research Council. 1965 The nutrient requirements for farm livestock No. 2 ruminants. Agric. Res. Council, London.
Amanat Ali and Amanullah Cheema, Animal Sciences Institute, NARC, Islamabad.
Barnes, A.C. 1974 The sugarcane. 2nd edition. Leonard Hill Books, London.
Deville, J.P., 1979 Wong You Cheong, Y., Leclezio, P. and Duvivier, P. Producción de ensilaje de cogollo de caña y su uso para el ganado bovino. Producción Animal Tropical, 4 (2):134–137.
FAO. 1971 Meat and Milk Project (Mauritius). Working Report, FAO Rome.
Ferreiro, H.M. and Preston, T.R. 1976 Fattening cattle with sugarcane: the effect of different proportions of stalk and tops. Trop. Anim. Prod., 1:178–185.
Ferreiro, H.M. and Preston, T.R. 1977 Digestibility and voluntary intake of derinded sugarcane stalk with and without addition of cane tops. Trop. Anim. Prod., 2:90–99.
Godoy, R. and Elliott, R. 1981 Effect of tropical forages on rumen function and flow of nutrients to the proximal duodenum in cattle fed a molasses/urea diet. Trop. Anim. Prod., 6:159–166.
Hughes-Jones, 1981 M. and Peralta, G. Observations on the degradabilities of feedstuffs in situ in cattle on diets with or without molasses. Trop. Anim. Prod., 6:174–177.
Kevelenge, J.E.E., Said, A.N. and Kiflewahid, B. 1983a,b,c The nutritive value
of four arable farm byproducts commonly fed to dairy cattle
by small scale farmers in Kenya.
(a) I. Organic structural components and in vitro digestibility. Trop. Anim. Prod., 8:162–170.
(b) II. The utilization of nutrients by wether sheep. Trop. Anim. Prod., 8:171–179.
(c) III. Nitrogen and mineral retentions by wether sheep. Trop. Anim. Prod., 8:180–186.
Luz Meyreles, Pound, B. and Preston, T.R. 1982 The use of leucaena leucocephala or sugarcane tops as sources of forage in cattle diets based on molasses/urea, supplemented with chicken litter and/or wheat bran. Trop. Anim. Prod., 7:92–97.
Luz Meyreles and Preston, T.R. 1982 The role of poultry litter in molasses/urea diets for the fattening of cattle. Trop. Anim. Prod., 7:138–141.
Ma Poon, L.K. Ann. Rep. Min. of Agric. 1981 Fisheries and N.R. Mauritius.
Pate, F.M., Beardsley, D.W. and Jayes, B.W. 1971 Chopped sugarcane tops as a feedstuff for cattle and horses. Everglades Station Mimeo Report EES 71 – 5.
Pate, F.M. and Coleman, S.W. 1975 Sugarcane tops for cattle feed. Proc. Am. Soc. Sugarcane Technologist, 4:131–136.
Roxas, B.D. 1985 Sugarcane and its byproducts for animal feed. Animal Production Technology, (Philippines) 1:18–21.
Sanchez Nunez, E., Gonzalez, A. and Boza, J. 1974 Use of sugarcane tops silage in feeding beef cattle. Proc. IV Int. Congress Food Sci. and Technol., 4:302–305.
San Martin, F., Pezo D., Ruiz, M.E., 1983a Vohnout, K. and Li Pun, H.H. Supplementation of cattle with green banana. I. Effect on the digestion parameters of the fibre in sugarcane tops. Trop. Anim. Prod., 8:215–222.
San Martin, F., Pezo, D., Ruiz, M.E., Vohnout, K. and Li Pun, H.H. 1983b Green banana supplementation for cattle. II. Effect on the intake of sugarcane tops. Trop. Anim. Prod., 8:223–229.
Sansoucy, R. 1972 Valeur nutritive des têtes de canne. Ministry of Agriculture and N.R., Animal Production Division Report. Expt. 26 May 1972.
Figure 1 : Performance of bulls fed ad lib sugarcane tops
Figure 2 : Theoretical availability/deficit of fodder and their seasonality
|Green wt. (tonne/ha||DM%||Dry Wt. (Tonne/ha|
Source: Barnes, 1974.
|Millage cane (DM)||62.4||56.2||59.3|
|Sugarcane tops (DM)||12.6||18.1||16.3|
|(Dry matter basis)||20.2||32.2||27.5|
|means, %||SD ±||Sheep||Cattle|
|Sources||Calculated from various sources||Kevelenge et al.,|
|Sanchez Nunes et al. 1974|
|% in DM|
Source: Kevelenge et al.,1983b
Godoy and Elliott, 1981
|Species||Live wt.||VCI1 kg||ADG (L)||Source|
|Steers||330 kg||1.78||0.000||Pate et al., (1971)|
|Sheep||42.6 kg||2.02||-0.010||Kevelenge et al.|
1 Voluntary intake: kg DM/100 kg LW
|Varieties||M 2173||M 13/56|
|Bundle Leaf sheath||51.6||52.4||52.0|
|Green Leaf blade||35.4||35.4||35.4|
|SCT + urea||24.2||21.9||8.6||48.4||1.7|
|SCT + molasses||26.3||25.4||4||60.1||2.4||6.6|
|SCT + molasses +|
Source: Naseeven, 1986 - unpublished data
Se producen actualmente por hectárea alrededor de 15 – 18 toneladas de cogollos de caña fresca (5 – 6 toneladas de materia seca), lo cual representa suficiente forraje para una cabeza de ganado (500 kilos de peso en vivo) durante un año.
La producción mundial de cogollos de caña se calcula en 60 millones de toneladas. En Mauricio se producen 1 – 3 millones de toneladas, de las cuale sólo el 15 por ciento se utilizan en sistemas de alimentación animal. Es pos ble cuadruplicar el número de rumiantes que se alimente con cogollos, melaza suplementos nitrogenados, y la utilización de la caña integral no se justific mientras no se utilice la cantidad máxima de subproductos posible. Una de la principales limitaciones a un mayor uso de las puntas de caña es su disponibi lidad estacional lo cual entraña costos adicionales de almacenamiento y conse vación durante casi seis meses. También son consideraciones importantes el acceso a tierras privadas para la recolección en gran escala, los aspectos logísticos o los elevados costos de transporte, especialmente de material voluminoso. Aunque la quema reduce la cantidad de cogollos frescos disponibi el material quemado puede utilizarse directamente o ensilarse. En Mauricio, ganado depende mucho de los cogollos de caña fresca, los cuales representan mayor parte del pienso utilizado en el invierno, cuando la productividad de mayor parte de las especies tropicales es baja. Sin embargo, su valor nutrit vo es bastante reducido lo cual entraña una producción baja, si bien su cons es bien aceptado. Se examinan los resultados de investigaciones sobre el va nutritivo de los cogollos frescos, los tratamientos y las combinaciones óptir y se indican los sectores en los que es posible mejorar de manera fundamenta nuestros conocimientos relativos a la utilización del mencionado producto. miras a mejorar la producción pecuaria potenciando al máximo la utilización cogollos de caña, se propone un enfoque integrado que entraña actividades de investigación y extensión, crédito, y otros servicios (transporte, picado, ve ta de la melaza, urea y telones de plástico), y se examinan brevemente los aspectos económicos.