1.INTRODUCTION
This case study on sugarcane as feed is based on a drought relief exercise carried out during the 1983/84 drought situtation in Zimbabwe. The southern part of the country which, traditionally, carries the bulk of the beef herd, was the worst effected. It should be noted here that the drought came at the same time as the introduction of veterinary controls which meant that the cattle could not be moved to the north where there was some grazing. The only alternative was to feed the cattle where they were. Soon after the ministerial approval of the drought relief national herd rescue programme, a total of 120 000 head of cattle were purchased by the Cold Storage Commission (CSC) from various drought stricken commercial producers as well as from communal farmers.
Due to the lack of grazing, it was evident that any survival of the cattle which had been purchased was only possible through pen feeding. However, the aim here was not to finish the cattle for slaughter but only to enable them to survive until the next rains then eight months away. Two basic feed formulae were arrived at to solve the situation:
Generally, maize is the traditional energy source in all our feed formulae in Zimbabwe. However, because of the drought, all available maize had to be reserved for human consumption and as a result an alternative had to be found.
2. THE FEEDING OF CATTLE ON BAGASSE AND MOLASSES
Triangle Sugar Estates comprises 13 000 ha of irrigated cane fields. The factory operates two sugar mills which crush a total of 2 million tonnes per year, producing 220 000 tonnes of sugar. The main byproducts obtainable from the mill are bagasse and molasses.
Included in the factory complex is the ethanol plant which produces petrol blend, utilizing 90 percent of the molasses. Bagasse is also used as fuel for the boilers and approximately 60 percent is committed for this purpose. These parameters of quantity had to be considered carefully in determining the numbers of cattle to be survival fed and the composition of the feed formula.
The analysis of the two sugarcane byproducts used is as follows:
| Prot. | TDN | Cal. | Phos. | Fibre | Fat | Ash | |
|---|---|---|---|---|---|---|---|
| Molasses | 3.50 | 70 | - | 0.40 | - | 0.1 | 9.0 |
| Bagasse | 1.00 | 43 | 0.07 | 0.03 | 35 | 0.4 | 4.0 |
Based on the nutritive value of these byproducts two feed formulae were established:
| a) Survival feed composition | ||
| Wet bagasse | 50% | |
| Molasses | 16% | |
| Maize | 34% | |
| Analysis | ||
| Dry matter | 67% | |
| Crude protein | 6.25% | |
| TDN | 46% | |
| The recommended daily distribution was as follows: | ||
| 3 kg/hd/day for | +/- 300 kg livemass | |
| 5 kg/hd/day for | +/- 450 kg livemass | |
| 7 kg/hd/day for | Mature cows in calf | |
| b)Maintenance feed formulation | ||
| Bagasse | 20% | |
| Molasses | 45% | |
| Soya oil cake | 5.5% | |
| MCP | 0.5% | |
| Maize offal | 25% | |
| Urea | 2% | |
| Limestone | 1% | |
The TDN on this formula was calculated at 60 percent. However, to provide a maintenance function only, this feed was given to animals of weights described above to a maximum of 5 kg/head/day. After the animals had finished the feed, some additional semi-wet bagasse was added into the troughs to provide a filler.
3. THE USE OF CANE TOPS
Due to difficulty in handling as well as the non-availability of effective mechanization in collecting the cane tops on the veld, it was virtually impossible to utilize them on a large scale. The use of cane tops was eventually left to small scale survival feeders who had to collect them manually off the veld. Here again, a number of variations had to be applied in feed mixing:
80 percent cane tops, 1 percent urea, 15 percent molasses, 4 percent maintenance feed formulation (see paragraph 2 b)
75 percent cane tops, 2 percent urea, 18 percent molasses, 5 percent chicken litter
70 percent cane tops, 20 percent molasses, 10 percent protein cake
80 percent cane tops, 20 percent molasses
In most cases, the cane tops had to be chopped to about 12–15 cm pieces using a threader and in some cases, this was done manually.
4. OBSERVATIONS AND CONCLUSIONS
Molasses, especially in our case (Zimbabwe), where maize is required for human consumption, is a very valuable stock feed.
Under drought conditions, molasses can be used to induce animals to consume coarse fibres which would assist them to survive.
Bagasse, as a sugarcane byproduct, requires minimal blending with some appropriate supplement to be converted into a valuable feed under drought conditions.
Use of cane tops on a large scale is restricted by low levels of mechanization.
In cases where transportation of feed with high molasses content is involved, substantial losses are incurred due to compaction especially where the molasses exceeds 15 percent.
Wherever possible, the use of jute bags must be avoided. To minimize loss only poly-propylene bags should be used in conjunction with molasses, as they can easily be recycled.
Where no feed troughs are available, bagasse and molasses based feeds can be fed on the ground without substantial loss as, on drying, it quickly forms a hard surface.
La parte sur de Zimbabwe, que es la zona productora de carne de vacuno más importante del país, fue gravemente afectada por una sequía en 1982/84. Durante ese período, el transporte de animales desde el sur hasta las zonas septentrionales menos afectadas de Zimbabwe no fue posible por razones veterinarias.
La Comisión de almacenamiento en frigorífico elaboró un plan nacional de salvación de la cabaña que afectó a 120 000 cabezas de diversas razas pertenecientes diferentes granjeros comunales comerciales.
Los únicos piensos disponibles eran los subproductos de la industria zucarera. Se preparó un pienso de supervivencia compuesto de bagazo, maía y nerales, y otro pienso de mantenimiento compuesto de bagazo, melaza, torta de ja, residuos, urea y minerales.
Se ensayó la utilización de cogollos de caña, pero debido a dificultades recolección se dejaron para los pequeños agricultores.
