Previous Page Table of Contents Next Page


The primary value of livestock in agriculture is to convert plant material which is unsuitable for human food into meat, hides, wool, dairy and other products. The dung and urine from the animals and the waste products from their carcases can be used as fertilizer for crops and forage. Because the majority of aquatic plants have little, if any, value as human food, a practical form of utilization of this resource is as fodder for livestock. If aquatic plants are considered in this way then it is appropriate to treat them as a forage crop and consider whether they can best be used fresh, dried as hay, or preserved as silage, and also for which kinds of livestock they may be the most appropriate and profitable to use.

A disadvantage of an aquatic crop as fodder for livestock is that it can rarely be fed in situ because of the depth of the water, hazards from mud and pathogenic organisms, or the contamination of the water by the animals. Thus, although the crop takes up no useful land and costs nothing to grow, the expense of harvesting (as discussed in Chapter IV) has to be met. Fish or aquatic animals can be used to graze the crop without harvesting, and are dealt with in Chapter VIII).

There is an extensive literature on the use of aquatic plants as fodder. The subject has been reviewed by the Indian Council for Scientific and Industrial Research (1952) and Boyd (1974). Boyd, by his extensive work on the analysis of aquatic plants (see Chapter III), has contributed significantly to information on the potential uses of aquatic plants for animal nutrition. Villadolid and Bunag (1953) have given a short but useful review of the uses of water hyacinth for animal, fish and human food. Sharma (1971) has also discussed the uses of water hyacinth for livestock food.

Gaevskaya (1966, in Russian) gives a general review of the utilization of aquatic plants by animals. This book has been reviewed by Davis (1970) who writes: “The author has done a great service by reviewing the world's literature. She finds that the higher plants are consumed by a wide variety of animals including insects, birds and mammals. Plants considered, in addition to all those truly aquatic, are various sedges and other plants growing in and near to water. There is a total of 550 references of which 200 are from non-Soviet journals.”

The National Academy of Sciences, National Research Council, U.S.A. (1976) has a chapter (No.5) on ducks, geese and swans in its book “Making aquatic weeds useful”. The advantages and disadvantages of farming these birds to help control aquatic vegetation in Central Europe, Greece, Hawaii, New Guinea and South Africa are discussed. Chapter 6 deals with the potential for farming water buffalo, pigs and the domesticated rodents capybara and nutria. The dangers of introducing these rodents to new areas are emphasized. Reference is made to the harvesting of water hyacinth in Bangladesh, India, Indonesia and the Sudan to feed livestock.

The National Council for Research, Sudan, and National Academy of Sciences, U.S.A. (1975) have included in their book a chapter (No.5) on feeding animals with aquatic plants which grow in the Sudan. The literature on this subject is reviewed (13 references). The advantages and limitations are discussed. The authors conclude that during the dry season water hyacinth could usefully be fed to cattle, buffalo, sheep, goats and poultry. Other forage such as Typha spp. shoots exist in abundance along the banks of the White Nile and could be fed to ruminants, and also Lemna spp. which could be fed to poultry. A call is made for more and detailed research into all aspects of livestock utilization of aquatic plants.

The University of Florida, Gainesville, U.S.A., has carried out a great deal of work on the utilization of aquatic weeds for stock foods. Papers from various authors involved are referred to in the following pages.

In a review specifically about Azolla spp. Moore (1969) notes that in Indochina Azolla (with or without other aquatic plants, e.g. Lemna, Eichhornia, Pistia, Salvinia, etc.) is collected from ponds and ditches and fed to pigs and ducks. It is claimed that Azolla developed the body fat of these animals. In Vietnam it is reported as food for cattle, poultry and fish. In Singapore Azolla is common in tanks used by Chinese to grow Pistia for pig food. In Formosa its use for pigs is normal. The author comments that, judged by its analysis (see Chapter III), Azolla should provide good quality forage.

For convenience, this chapter has been divided into uses of aquatic plants as food for cattle and sheep (1), pigs (2) and poultry (3), and as preparation for silage (4).

1. Cattle and Sheep

*Alford, L.W., 1952 Alligator weed- a good cattle food. Chemurg.Dig., 2(9):10–2

The author discusses the spread of alligator weed (Alternanthera philoxeroides) in South Carolina, U.S.A. He describes how in the 1890s the plant occupied areas formerly cultivated with rice. By 1925 the plant was being widely used for all– round cattle feed, but mainly in the winter. In 1941 systematic farming of areas of South Carolina infested with alligator weed was carried out. (For analyses see Chapter III.) The land was periodically flooded, as for rice cultivation, as a means of promoting the weed growth. The resultant feed was adequate for a stocking rate of 7.5 cows/ha for about 300 days in the year. Under flooded conditions the plant is protected under water against frosts and provides good winter feed. It grows to 30–45 cm above the water and sometimes roots into the soil, but much of it floats with stems 120–440 cm long intertwined in a dense mass about 45 cm below the surface.

The cattle wade, sometimes almost swimming, into the fields to graze. They readily eat the dead part on top, then pull the green stems from below the surface.

The weed can also be harvested for stall fodder. The author reports on the success of farmers planting alligator weed on new land by scattering chopped up portions of the stems onto muddy soil. He says that alligator weed seems to make its best growth in the fresh–water areas of the tidelands where the streams run both ways. If the stream is shallow, it will root into the soil but it does equally as well or better where it floats on the surface. When floating, the underwater stems are four to ten times the length of the top portion. There are just a few short, fine roots at each joint. These float back and forth with the current and are constantly bathed in the dark water laden with plant food and minerals. Further up stream where the current is constant in its direction, the plant thrives in shallow water where it can root into the soil and not be washed away. The growth is very poor in still water, but it may respond to fertilizer.

Bagnall, L.O., 1971 Processed aquatic plants for animal nutrition. Annu.Res.Rep.Inst.Food Agric.Sci.Univ.Fla., 1971:49 (Abstr.)

Progress in cattle and pig feeding trials with water hyacinth and Hydrilla is reported. The rates of drying and pressing were measured at different temperatures and pressures, and also the tension, compression and shear strength of hyacinth. Dry matter is lost in the fluid expressed from the plants. Some can be recovered by filtration or centrifuging. The need for additives to the water plant fodder was also explored.

Bates, R.P. and J.F. Hentges, 1976 Aquatic weeds – eradicate or cultivate? Econ.Bot., 30(1): 39–50

In this review of the utilization of aquatic plants the authors state that diets for cattle containing aquatic plants are accepted and consumed like diets containing land forages with no signs of toxicity. The seasonal variations in nutritive value of aquatic plants must be considered in preparing such forages. Care must be taken to exclude herbicide or pesticide residues, environmentally produced plant toxins or pathogenic organisms.

In general Hydrilla spp. appear to be as well tolerated by cattle and sheep as water hyacinth but neither is adequate as the sole component of the ration, being most effective at less than 33% of the organic matter in pelleted diets. Ensilage tests show that water hyacinth wet–press residue makes excellent silage when combined with additives which provide fermentable carbohydrates and absorb moisture, thereby preventing run–off of nutrients. The more nutritious press juice and its components have not yet been studied in livestock metabolism trials.

Boyd, C.E., Evaluation of some common aquatic weeds as possible feedstuffs. Hyacinth 1968a Control J., 7:26–7

In a review of the analyses of many aquatic plants (see Chapter III) the author states that on a dry weight basis many aquatic plants contain as much or more crude protein, crude fat and mineral matter as many conventional forage crops. Fibre values were usually lower than for forages. High quantities of tannin may decrease the digestibility of protein. Using aquatic plants as fodder would help to pay for harvesting, which is the best way to remove nutrients from lakes suffering from artificial enrichment. This is the only practical method. Harvesting should be done when protein content of the plants is highest for their maximum usefulness as feedstuffs.

Chalmers, M.I., 1968 Report to World food Programme on a visit to Sudan. In Animal production WFP. Mission report on animal nutrition in Sudan. Study on the use of water hyacinths in ruminant animal feeding and also as a means of weed control. Rome, FAO, Acc. No. 02787–68–WS

Reporting on the potential of water hyacinth as a feed for ruminants the author states that because the protein and fibre are mainly in the lamina, and the carbohydrate mainly in the petiole (see Chapter III), the best results from ruminant feeding could be expected from feeding them together. Animals eating fresh water hyacinth as sole ingredient of the diet could not ingest sufficient dry matter, quite apart from the imbalance of the nutrients. On a dry matter basis water hyacinth is better than straw but a little low in protein to compare with hay. The physical structure of the plant is not suitable for hay or silage making and the product would not have much nutritional value. It could be considered as roughage feed if processed to remove the moisture and compacted for easy transport. The nutritional value could be increased by mixing with molasses, at present a waste product in Sudan. If the molassed water hyacinth feed proved acceptable to livestock it could be introduced as the roughage component of feed used regularly to feed and finish animals held in quarantine for export, vaccination, or any large congregation of stock in and around Khartoum. It could also be used in a ration balanced with dura and oil seed cakes and could make a valuable contribution to beef fattening units. The hyacinth is rich in minerals, but it would be simple to incorporate any necessary food additives in the processing.

*Chatterjee, I. and M.A. Hye, 1938 Can water hyacinth be used as a cattle feed? Agric.Live– stock India, 8:547–53

The authors refer to the common habit of cattle and buffaloes browsing on water hyacinth in shallow water (which is still being done), a habit encouraged by the annual flooding of large areas of the country. It is also common for villagers to collect water hyacinth and sell it as cattle fodder in Bengal. In order to measure the feeding value of hyacinth the authors carried out long–term (up to one year) feeding trials in which hyacinth was fed as a mixture with rice straw, with and without the addition of linseed cake (0.45 kg/day). As the trial animals were not accustomed to water hyacinth the authors describe the methods adopted to introduce them to the plant. Straw was given at one feeding in restricted amounts. Then at the second feeding of the day hyacinth only was offered. When no added linseed cake was offered the animals took to the hyacinth more quickly, but there were considerable variations between animals in their acceptance of the hyacinth. There was also variation in preference between the leaves and stems of the plants. The results of the trial showed that animals fed on hyacinth and straw only lost weight, but with the addition of the cake they were able to maintain weight or achieve a slight gain. The authors conclude that the results might have been better if the test animals had been chosen from cattle known to be adapted to water hyacinth browsing. They add:

“It will be noted that the digestible nutrients in hyacinth compare quite favourably with green fodders like Guinea grass or Napier grass and show an apparent superiority over rice straw (Aus or Aman). This superiority would have been real if the palatability of hyacinth had not come in the way. It is just possible that this lack of palatability is associated with a heavy percentage of potash and chlorine. The presence of such a heavy quantity of potash probably reacts on the general mineral metabolism also. The tests on the mineral side were limited but the few done show that the feeding involved an ingestion per 500 lbs of about 96–106 g of k2O, 18–20 g of chlorine, 48–65 g of CaO. The potash and chlorine balances were clearly negative and though lime ingestion was high, the balance figures were 50% negative.

“It will thus be seen that hyacinth can hardly occupy a high place as a fodder. If its value had been high, popular usages would have already forestalled it on an established footing. But here we are faced with its existence more as a necessary evil; and the problem is not so much as to establish it as a fodder but to explore the avenues of its possible utilization. The experiment shows that under the singular circumstances in which the country is placed, the moderate use of hyacinth as a fodder can be permissible, but in order that full benefit is derived from it, it should always be fed in combination with cake or concentrate and still better in a combination of a number of feeds.”

Combs, G.E., J.F. Hentages and R.L. Shirley, 1973 Processed aquatic plants for animal nutrition. Annu.Res.Rep.Inst.Food Agric.Sci.Univ.Fla., 1973:81 (Abstr.)

Voluntary intake of water hyacinth by sheep and cattle was highest with treatments containing 4 kg dried citrus pulp and 1 kg sugar cane molasses per 100 kg of hyacinth press residue.

*Davies, H.R.J., 1959 Effects of the water hyacinth (Eichhornia crassipes) in the Nile Valley. Nature, Lond., 184(4692):1085–6

The following is an extract from the paper:

“In most areas the effect on animal dry–season grazing appears negligible. In some areas where this grazing, exposed by the falling rivers, usually called ‘toich’ in the Nilotic regions of the Sudan, is limited it is possible that the powerful Eichhornia may restrict the growth of other more valuable forage grasses, whilst also it makes it more difficult for cattle to drink in safety from crocodile–infested rivers. An interesting situation is to be found in the lower Sobat. Here the river is incised, with the result that the grazing exposed by the falling river is of very narrow extent. The cattle grazed near the river bank during the rainy season are taken towards better pastures along the White Nile during the dry season after that river has begun to fall. The most difficult time for animals along the lower Sobat is during the early dry season after the grass brought by the rains has dried up and before the Nile pastures are ready. At this period of the year Eichhornia, in spite of its low grazing value, provides a welcome source of green matter for the cattle”

*Dirven, J.G.P., 1965 The protein content of Surinam roughages. Qual.Plant.Mater.Veg., 12:172–84

Cattle feed on water hyacinth only in the dry season. It only has a low protein content, but that of Ipomoea reptans is more favourable.

Easley, J.F. and R.L. Shirley, 1974 Nutrient elements for livestock in aquatic plants. Hyacinth Control J., 12:82–5

The authors points out that public concern in the U.S.A. that aquatic plants should be removed mechanically from water rather than killed by herbicides may cause them to be available in quantity as livestock feeds. The study described in this paper was made to determine the range of concentrations of nutrient minerals in six aquatic plants throughout one year of monthly or bimonthly sampling. The plants were: Hydrilla verticillata, Eichhornia crassipes (water hyacinth), Ceratophyllum demersum (hornwort), Potamogeton pectinatus (pondweed), Vallisneria americana (eelgrass), and Najas guadalupensis (naiad). Tables are given of the maximum, minimum and average mineral concentrations found in these plants. Also shown are the daily requirements of a 300–kg steer in respect of these elements. The conclusions from these data are given in terms of the percentage of the animal's daily requirements present in 1 kg of dry matter of each plant. The figures are tabulated below:

Nutrient Elements
 % concentration of animal requirements in 1 kg dry weight
H. verticillata300–60010–2650100–160100–20070–1406333100–200
E. crassipes8510–2682100–160100–20070–1405–2133100–200
C. demersum300–60010–2650100–160100–20070–1405–219–18600–200
P. pectinatus300–60010–2650100–160100–20070–1405–219–18600–200
V. americana300–60010–262550–80100–200685–219–18100–200
N. guadalupensis300–60010–265050–80100–20070–1405–219–18100–200

*Fish, G.R. and G.M. Will, 1966 Fluctuations in the chemical composition of two lakeweeds from New Zealand. Weed Res., 6(4):346–9

Describing lake weeds growing in the North Island of New Zealand, the authors state that in the summer cattle grazing on paddocks adjoining shallow weedy shores of Lake Rotorua will wade into the water and graze onLagarosiphon in preference to the grassland pastures. “The dry–weight composition of these lake weeds is comparable with the normal dry–weight composition of leaves of rye grass (Lolium perenne). But although the lake weeds may provide a fodder that is both palatable and of good quality, their high water content (92% compared with 82% for Lolium perenne diminishes their value as food for stock.”

Gangstad, E.O., D.E. Seaman and M.L. Nelson, 1972 Potential growth of aquatic plants of the Lower Mekong River Basin, Laos–Thailand. Hyacinth Control J., 10:4–9

The paper discusses uses for aquatic weeds in Thailand. Because it is usually at hand, water hyacinth is used to feed water buffalo, cattle and pigs, and these uses have been mentioned as a means of control. But the plant has a limited food value (protein content 8–12% of dry weight). Its water content is too high for direct consumption and the cost of drying and transporting to dryers or feed-lots precludes its use for animal feed in quantities sufficient to control its growth and spread. The same would be true of the other noxious aquatic plants such as water lettuce and water fern.

Gortner, R.A., 1934 Lake vegetation as a possible source of forage. Science Wash., 80:531–3

The author comments on the analyses of a variety of lake weed (given in Chapter III). He states that the literature on the feeding value of aquatic plants (in 1934) was meagre. However there were European reports that Elodea canadensis was an excellent food for cattle and pigs. He added that there was no obvious reason why many types of lake vegetation should not be suitable feeding stuffs. The analyses indicate that they may be superior to much of the forage which is used on farms in the Great Plains area of the U.S.A. He adds that the uniformly high crude protein content of lake vegetation suggests the possibility of growing suitable non–leguminous plants in shallow lakes, and preparing from them concentrates for animal feeding. He predicts that a high protein, high lime, low fibre meal may be of commercial value. He observes that in thickly populated areas of Asia “a hectare of water may produce more than a hectare of land.” Thus aquaculture, in suitable areas, may become part of changing agriculture.

Hentges, J.F., R.L. Shirley and G.E. Combs, 1971 Processed plants for animal nutrition. Annu.Res.Rep.Inst.Food Agric.Sci.Univ.Fla., 1971:67 (Abstr.)

Intake and digestion trials with steers were carried out comparing pelleted cattle diets made up with 33% of water hyacinth, or Hydrilla, or the grass Cynodon dactylon. On all diets the animals remained healthy and in positive nitrogen balance. Intake of the grass and the hyacinth mixtures was about equal, and each was higher than for Hydrilla mixture. The following table summarizes results:

 Digestion coefficients %Estimated digestible energy in diets
PlantOMCPCelluloseMcal/kg DMMoal/kg OM
C. dactylon72.465.
Hydrilla sp.70.547.954.12.73.2
E. crassipes     

The authors comment that in the aquatic plants nutritive value exists in the energy-yielding components but apparently not in the nitrogenous components, as processed for these studies.

Hentages, J.F., R.L. Shirley and J.F. Easley, 1973 Toxic substances and chemical composition of hyacinths and other water plants. Annu.Res.Rep.Inst.Food Agric.Sci.Univ. Fla., 1973:79 (Abstr.)

Hydrilla verticillata, Eichhornia crassipes, Ceratophyllum demersum, Potamogeton pectinatus, Vallisneria americana and Najas guadalupensis were analysed. Their mineral content was found to be within the range of land forages in the U.S.A. Sodium was 10–100 times higher and iron exceeded the range by 4–19 times. Phosphorus concentration was generally lower and calcium higher, except for E. crassipes which had about 2% Ca, the Ca/P ratio being suitable for cattle. H. verticillata in a lake contained 14 mg As/kg dry matter compared with 1 mg/kg in the river. E. crassipes from a lake contained 9 mg As/kg. (From Weed Abstracts)

*Hossain, W., 1959 Investigation of water hyacinth as fodder. Agric.Pak., 10(4):513–8

The following is the author's summary of a feeding trial carried out:

“To study how far water hyacinth could be fed to animals a feeding trial was conducted over a prolonged period of more than two years. The investigation was conducted under different dietetic conditions:

  1. To start with the animals were given 10 lbs of fresh water hyacinth, 8 lbs of paddy straw, 2 lbs of gram and 1 lb of mustard cake. The animals were found to relish water hyacinth.

  2. Water hyacinth portion of the ration was increased gradually after reducing the other items.

  3. The animals were fed exclusively on water hyacinth for some time.

  4. Water hyacinth after being partially dried in the sun for about seven hours was fed, with 3 lbs of paddy straw and 1 1/2 lbs of mustard cake.

Maximum consumption of fresh water hyacinth was 33 lbs together with 3 1/2 lbs of paddy straw and 1 1/2 lbs of mustard cake. This showed that water hyacinth was palatable if properly supplemented and when animals were accustomed to such feed. Previous workers postulated that lack of palatability of water hyacinth was probably associated with the presence of high percentage of potash and chlorine in water hyacinth. But in this experiment no such evidence could be noticed. Water hyacinth when fed as sole feed caused diarrhoea and this might be due to the presence of high percentage of alkali. It might be recommended that besides supplementing water hyacinth with mustard cake for protein and phosphorus it is also expedient to have 50 percent of the dry matter requirement from straw or hay to prevent undesirable laxity of bowels. Intake of water hyacinth fell during dry season and increased during monsoon when water hyacinth grew luxuriantly.

Consumption of water hyacinth did not improve when fed in partially dried condition, but the animals gained considerably in their live weights when water hyacinth, as one of the ingredients of the ration, was fed in partially dried condition. This might be the result of better assimilation of nutrients from the ration when water hyacinth was given in partially dried condition. From the general trend of the experiment and from the considerable gain in live weights in particular, it might be inferred that a ration composed of 40 lbs of fresh water hyacinth dried in sun to 23 lbs together with 3 1/2 lbs of paddy straw and 1 1/2 lbs of mustard cake might be allowed to animals weighing on an average 400 lbs for moderate production.”

Ingvason, P.A., 1969 The golden of Iceland. World Crops, 21(3):218–20

Carex lyngbei, ‘gulstör’ or golden sedge, has been cultivated for hundreds of years for forage by seasonal inundations in a way similar to rice culture. It is also found in coastal Labrador and in the littorals of the eastern Pacific end of Siberia, where it is found in abundance and has a high rating as forage. In Iceland it has been shown that well cured hay made from gülstor is equal to upland meadow hay (Tada sp.) for feeding cattle and sheep. It keeps the animals healthy and vigorous.

The forage makes good silage without the addition of molasses or chemical preservatives. An average yield of silage per hectare is 8–12 tons. Records from one meadow in the western littoral show a yield of hay as high as 5 t/ha. In this case the soil was limy and manure may have been applied. In curing sedge hay it is best to let the stacks heat up a little and settle down well. This makes the hay palatable to the animals. C. lyngbei has been collected as seed from Iceland for sowing around lakes in Finland.

C. rostrata, blue sedge, is a large aquatic species forming fringe growth around lakes and ponds. It is excellent forage for cattle, which will wade deep into the water to reach it. It is widespread in Siberia and rated highly as a forage.

Knipling, E.B., S.H. West and W.T. Haller, Growth characteristics, yield potential and 1971 nutritive content of water hyacinths. Proc.Soil Crop Sci.Soc.Fla., 30:51–63

Citing the analysis of water hyacinth (given in Chapter III) the authors state that this favours the use of the plant as livestock food supplement.

Koegel, R.G., 1973a et al., Utilization of Eurasian water milfoil. Abstr.Meet.Weed Sci.Soc. Am., 1973

The relative abundance of Myriophyllum spicatum (Eurasian water milfoil) and the reports of its relatively high protein and xanthophyll content have led to interest in its utilization. The problem of high water content can be overcome by mechanical dewatering with minimal nutrient losses. In utilizing the weed its high mineral content and low fibre content relative to terrestrial forage plants is of importance. Blending of milfoil with conventional forage plants may be desirable to increase its acceptence as a livestock feed. Partial incineration also tends to increase its acceptance. (From Weed Abstracts)

Lancaster, R.J., M.R. Coup and J.W. Hughes, Toxicity of arsenic present in lakeweed. 1971 N.Z.Vet.J., 19(7):141–5

Lagarosiphon major is a lake weed of importance in the North Island of New Zealand. It was investigated for usefulness as animal fodder using sheep as test animals. A difficulty is the high arsenic content of the weed (288 ppm), so the experiments measured the effect of this mineral on the animals and the amount of uptake. A lamb was force-fed with sufficient L. major to contain a toxic dose of arsenic. On slaughter the lamb was found to be healthy and unaffected by arsenic.

L. major and other important weeds, Elodea and Ceratophyllum, when fed to sheep were found to be unpalatable but were accepted when mixed with pasture (1:5 dry matter basis). The following is the authors' summary of the results:

“Four samples of lake weed were found to contain large amounts of fibre but small amounts of soluble carbohydrate. Levels of minerals and nitrogen were similar to those in high quality pasture herbage, but some high levels of arsenic were also demonstrated. To assess the toxicity of lake weed a ration of grass and 200 g of dried lake weed containing approximately 300 ppm of arsenic was fed daily to sheep for 21 days to give a mean daily uptake of 1.4 mg As/kg of body weight. All animals in the test remained healthy and examination of organs and tissues removed from the animals slaughtered at weekly intervals did not reveal any gross lesions or macroscopic changes. Small amounts of arsenic were retained in organs (maximum 3.8 ppm in kidney) but this had virtually disappeared four weeks after the cessation of lake-weed feeding (maximum 0.3 ppm in kidney).”

Little, E.C.S., 1970 From water weeds to milk. (Letter) PANS, 16(1):198–9

The author describes an emergent weed problem on a farmer's lake in Kenya which was solved by cutting the weeds by hand and, after chopping them, stall feeding them to dairy cows as a supplement to their ration. The plant was Cyperus digitatus, a sedge about 2 m high. It took the cows a few days to become accustomed to this new fodder. When they did it was possible to increase the proportion of the sedge in the ration to 60% without any diminution in normal milk production. Thus the weed became a useful supplemental source of fodder when grass was not available in the dry season.

Mara, M.J., 1976 Estimated values for selected water hyacinth by-products. Econ.Bot., 30(4): 383–7

The author has made a detailed economic assessment of the use of water hyacinth as livestock food. He considers the least cost diets for feeding cows and calves and steers (based on 1973/74 prices for feed). He calculates that if all the cattle in Florida (estimated at 2 1/2 million in 1974) were fed at the rate of about 164 kg/year then about 450 000 t/year of hyacinth would be needed. This could be provided from only about 1 000 ha of water surface assuming about 450 kg/ha of water hyacinth. This area is estimated to be only about 2.25% of the total area estimated to be infested. Thus livestock feeding is not a significant way of disposing of the amount of hyacinth available. In these calculations it was assumed that hyacinths were to be used at the point of harvest. If processing and transport costs were to be added for places distant from the hyacinth source then not even the low fraction of the ration mentioned could be considered. If feed costs rise then the use of hyacinth could become correspondingly more economically attractive.

Mishin, G.M. and I.F. Gribovskaya, 1969 (Ecology of Elodea canadensis in the reservoirs of central Urals). Biol.Nauki, 11(8):72–8 (in Russian)

The biological characteristics, distribution and yields of Elodea canadensis are considered from the viewpoint of using the weed as a potential supply of food for livestock. (From Weed Abstracts)

Mrsic, V., 1936 Lake vegetation as a possible source of forage. Science, Wash., 83(2156): 391–2

Commenting on the paper by Gortner (1934) the author states that in Yugoslavia it is a general custom for the peasants to use water plants as forage in districts subject to drought in summer and where there is abundant vegetation on the waters. Such vegetation commonly includes Myriophyllum, Potamogeton, Ranunculus and Callitriche. Nasturtium grows near springs and Sphagnum in lakes. The peasants cut these plants with scythes or pull them out with rakes, and feed them to cattle fresh. The cattle like the fodder and digest it easily. Vegetation growing in marshes, or in ponds used for carp breeding, or at margins of ponds, is not so palatable and is less productive of milk.

Nelson, W.J. and L.S. Palmer, 1938 Nutritive value and chemical composition of certain freshwater plants of Minnesota. Tech.Bull.Min.Agric.Exp.Stn., (136):1–34

Working with Elodea, Myriophyllum and Vallisneria, which they analysed in detail (see Chapter III), the authors comment: “Of interest from the viewpoint of using these aquatic plants as a forage crop is the fact that they appear to contain all the vitamins in at least as high an amount as alfalfa. Of more interest is the fact that the biological value of the protein in Elodea is about 70% that of alfalfa and the digestibility is apparently better. Cystine seems to be the limiting amino acid in Elodea as well as in alfalfa. The low biological value and digestibility of the proteins in Myriophyllum and Vallisneria practically eliminates them as animal food. This might be one explanation for their unpalatability because if the right supplements of protein, fat and vitamins are made these plants seem to be eaten readily and give good gains. Under such conditions there is no evidence of any toxicity. This suggests the possibility that other plants might be found suitable for aquaculture. Elodea from lakes might be as satisfactory as from streams.”

“All the plants were sufficiently rich in minerals so that at a 20% level in rations (dry basis) they would furnish all the materials needed in nutrition with the possible exceptions of P, Na and Cl.”

Osman, H.E., G.A. El Hag, and M.M. Osman, 1975 The nutritive value of water hyacinth. In Aquatic weeds in the Sudan, edited by M. Obeid, Khartoum, Sudan, National Council for Research, pp.104–27

Detailed results are given of studies to determine the nutritive value of water hyacinth and its possibilities for use alone or with other foods in feeding ruminants during the dry season. It was evident that hyacinth alone or mixed with local grasses was poor quality roughage and would be unsuitable unless supplemented with high protein concentrates. Alternatively, palatability could be increased by adding molasses. (From Weed Abstracts)

*Oyakawa, N., W. Orlandi and E.O.L. Valente, 1965 The use of Eichhornia crassipes in the production of yeast, feeds, and forages. Proc.Int.Grasslands Congr., 9(2): 1707–10

The authors describe a method of growing yeast on water hyacinth as a substrate in Brazil and suggest that it may be used as a source of protein for animal feed (for details see Chapter V).

Pirie, N.W., Weeds are not all bad. (Water hyacinths and other pests can also be good 1970 animal fodder). Ceres, 3(4):31–4

The author states: “In principle ruminants are better adapted than single-stomached animals for eating water weeds. Buffaloes and cattle will eat hyacinth voluntarily. It is claimed that cattle do not like hyacinth because the crystals in it prick their tongue, and eat it only when there is no other fodder. I doubt this having seen animals eating hyacinth although there was grass on the edges of the pool. However if most buffaloes and cows do not in fact like hyacinth the dislike may be overcome by ensiling, wilting, crushing or some other form of pre-treatment.

“To establish the value of water weeds to ruminants we should experiment with the performance of a group of animals given diets in which the proportion of hyacinth is gradually increased compared with the performance of others on a conventional diet. It is important that the change should be gradual, that is, it should be 5% of the diet at first and be raised to 10% after two weeks, to 15% two weeks later and so on to give time for the rumen flora to adapt to the change in diet.”

Pirie points out that Pistia floats and has potential as fodder. Salvinia he says is less useful because many forms are poisonous. He considers Justicia americana as promising and points out that Alternanthera philoxeroides is eaten by stock. Both these plants need testing critically.

*Ramarokoto, M.R., 1965 Water hyacinth in Madagascar. Working paper presented to the FAO Conference on Quelea and water hyacinth control. Douala, Africa. Rome, FAO, Working Pap. (WH/4)

“Water hyacinth has one advantage and one only. During the austral winter when all other grasses have dried out and have sometimes disappeared completely, the water hyacinth provides a considerable amount of feed which is relished by cattle. Sometimes it is sold commercially in the high plateau areas.”

Shirley, R.L., J.F. Easley and J.F. Hentges, 1971 Toxic substances and chemical composition of hyacinths and other water plants. Annu.Res.Rep.Inst.Food Agric.Sci.Univ. Fla., 1971:65 (Abstr.)

Water hyacinth and Hydrilla verticillata were compared with Bermuda grass, Cynodon dactylon, as 33% components of pelleted diets for steers. Measurements were made of uptake of a range of minerals, oxalates, tannins and nitrates.

Analyses were made of Hydrilla, Ceratophyllum, Potamogeton, Chara and Vallisneria taken from lakes, rivers and ditches. From these data the authors concluded “that these aquatic plants were all liberally supplied with many nutrients required by livestock. It is apparent that the time of year and water from which the plants are obtained are factors affecting variation in composition.”

Wolverton, B.C. and R.C. 1976 McDonald, Don't waste waterweeds. New Sci., 71(1013):318–20

The authors state that the National Space Technology Laboratories (U.S.A.) have made a water hyacinth meal by drying whole green plants to moisture contents of less than 15%. This can provide a 10–20% supplement to the diet of beef cattle. Beyond this amount animals can suffer from a mineral imbalance due to the high levels of K, Fe and Mg normally found in water hyacinth. Other aspects of this work (reported in U.S. National Aeronautics and Space Administration, 1976) is the harvesting of water hyacinth from sewage ponds and drying and grinding this into a meal rich in minerals and proteins. This was fed to beef cattle mixed with corn silage. At the end of four months the weight gains were satisfactory, being comparable to a diet of cotton seed and soya bean meal. As the cost of fuel for drying the hyacinth meal is an impediment to its use, a prototype solar drier has been made. With this it is expected that 18 tons of we material can be dried every 36 hours.

*Anon., 1951 Water hyacinth - a new use. Madras Agric.J., 38(1):27–8

“Water hyacinth is an aquatic plant which has been looked upon as an unwanted and obnoxious material condemned as much by agriculturists as by irrigation authorities. Its prolific growth and spreading habit makes it all the more unpopular, for in watercourses it obstructs the flow of water and blocks the sluices thus impairing the efficiency of irrigation. Recently however, a new use has been found for this plant. Head loads of the plant weighing 50 lb are taken out daily for feeding buffaloes in the neighbouring area. It has been found that feeding the buffaloes with 15 lb of water hyacinth per day increases their milk by 10–15%, but the milk is rather watery and the butter extracted does not possess the proper consistency and flavour. Possibly a suitable combination of this feed with concentrates to be worked out by feeding trials might remove this defect. The nutritive value of the material is higher than that in grass. It is phosphoric acid alone that needs to be supplemented. The average yield per acre of water surface has been estimated at 60 tons per annum. Since the removal of this plant will be a great boon to the authorities, cuttings can be taken free of charge, and hence the buffalo feed is within the reach of every buffalo owner.”

2. Pigs

*Hora, S.L., 1951 The water hyacinth problem and pig farming. Sci.Cult., 17(6):231–2

The author briefly reviews uses for water hyacinth, in particular as fodder for pigs. He cites reports that in China the plant presents no serious problem because it is kept in check by feeding to pigs. He also refers to the pig–fish–water hyacinth culture in Malaya (see Chapter VIII). He comments: “This Chinese economy of food production impressed us very much because the possibility of adopting similar practices seemed to be very great in India. It was learned that it was a very lucrative business. Though there is demand for pig flesh in all big cities, little attention seems to have been paid to pig farming in this country. Perhaps when we seriously take up piggery as an item on the “Grow More Food” programme, instead of eradication of water hyacinth we may begin to cultivate this weed as fodder for pigs.”

*Le Mare, D.W., 1952 Pig rearing, fish farming and vegetable growing. Malay.Agric.J., 35(3): 156–66

The paper describes the use of Ipomoea reptans (‘kangkong’) as a means of extracting nutrients from fish ponds fed with effluent from pigsties. The plant was then returned to the pigs as fodder. From eight ponds, 1 m deep, with a total area of just over 1 ha, a harvest of about 112 kg/ha of kangkong was obtained, which rose to about 450 kg/day. (Details of the fish used in this system are given in Chapter VIII.)

*Ling, S.W., 1960 control of aquatic vegetation. In Lectures presented at the Third Inter-national Inland Fisheries Training Centre, Bogor, Indonesia, 31 October-10 December 1955, conducted by the Government of Indonesia and FAO with the cooperation of IPFC. Vol.1. Rome, FAO, (3.23):12 p.

The tender parts of water hyacinth are suitable as fodder for pigs.

*Little, E.C.S. (Ed). 1968 Handbook of utilization of aquatic plants. Rome, FAO, Plant Production and Protection Division, PL:CP/20:123 p.

In an article, “Lake weed could make a useful crop” (reprinted in the first edition of the Handbook on p. 117), the author discusses the possibilities of utilizing lake weeds as feed for livestock. He suggests that pigs are obvious candidates because they are omnivorous, can deal with watery food, can tolerate crowded conditions under close control, and produce a diversity of meat which is all of high value and in constant demand. The turnover of pigs is rapid so that their population could readily be adapted to the amount of weed available.

Mahendranathan, T., 1971 Water hyacinth has value as pig feed. Pig Farmer, Malaysia (January issue):599–607

The author describes the system of pig farming using water hyacinth grown in ponds fertilized with human and animal waste. Pig feeding with hyacinth is well established in Malaysia. The hyacinth can be fed fresh after removal of the roots. Some people boil the plant. Pigs readily eat the hyacinth and thrive on it. Some farmers have machines for slicing the plants into small pieces. The high vitamin content (A, B and C) and easy availability of the plant are important advantages. But the high moisture content and the possibility of the material being contaminated with pathogens seem to deter the extensive practice of fresh plant feeding.

Consequently most farmers (70–80%) prefer to cook the sliced hyacinth with other feed ingredients for 5 to 6 hours and feed the boiled material as a slop. It is usually boiled with tapioca chips, ground maize, rice bran, wheat bran, sago, groundnut cake and fish waste. Of the mixture the hyacinth forms 60–65% of the bulk. The boiling is believed to increase the digestibility of the fibre content of the hyacinth. It is also believed that the hyacinth acts as a laxative and is especially beneficial to pregnant sows and any animals that are off feed.

Silage is also fed to the pigs. It is made by chopping the hyacinth and wilting it in the sun for 2 to 3 days; it is then mixed with ground maize and molasses and stored for 1 1/2 to 2 months in pits about 1 m wide and 2 m deep. The silage is used as 15–25% of the total feed. Farmers believe that pigs fed on this silage sleep longer, eat more, and show greater increase in weight. The author cites Choy and Deveraj (1958) who conducted a feed trial with pigs using rations containing water hyacinth. Each pig received daily a slop containing 1.54 kg of boiled water hyacinth and 2.4 kg of concentrate. The controls received dry mash ad lib. The pigs on hyacinth gained 1.54 kg/week while those on the mash gained 2 kg/week. Also cited are Fischer and Devendra (1963) who found that crossbred pigs fed on a slop feed containing water hyacinth showed a live weight gain of 0.48 kg/day at a feed conversion ratio of 3.38.

*Mahmud, E.A.B., 1968 The use of water hyacinth in animal feeding (pigs). A review - 1967. In Handbook of utilization of aquatic plants, edited by E.C.S. Little. Rome, FAO, Plant Production and Protection Division, PL:CP/20:49

The author reviews various results of using water hyacinth for pig farming in Malaysia. He says that “water hyacinth found mainly in ponds and slow-flowing streams of the rural areas of this country is used by Chinese pig rearers in feeding pigs. The weed is chopped into reasonably small pieces and together with other vegetable tops, like banana stalks, is then boiled. To this fluid is added rice bran, copra cake, groundnut cake, sometimes maize and salt. The proportions of water hyacinth in the mixture varies from farm to farm and, according to information gathered from the farmers themselves, it constitutes about 5–10% of the total ingredients.”

Pigs from approximately 25 lb live weight are given this liquid feed. Pigs normally take longer to reach market weight of 133 lb on such feed than those fed with dry mashes. The causes of the delay could be due to the margin of nutrients above maintenance requirements being insufficient, and foods of high fibre content are indigestible for young pigs. In most cases pigs take about 7 to 10 months to reach the slaughter weight. Of course, this is not altogether a disadvantage because the manure is available to the farmer for his vegetables. In a trial with rations containing water hyacinth each pig received a slop consisting of 3.5 lb of boiled water hyacinth and 5.3 lb of concentrate given three times daily. Another group of pigs was fed with dry mash ad lib., and the weekly weight gains were compared. Pigs fed with wet mash containing water hyacinth gained from 2.5 to 4.6 lb per week, while those on dry mash gained from 2.6 to 6.5 lb per week.

Pirie, N.W., 1970 Weeds are not all bad. (Water hyacinths and other pests can also be good animal fodder). Ceres, 3(4):31–4

In this paper the author gives figures (cited in Chapter III) for the high N content of aquatic weeds which at certain stages of growth makes them equivalent to the best forage plants. These aquatic weeds are used as fodder in many parts of the world. In regard to fodder for pigs he states: “In Singapore water hyacinth is not a weed but a crop deliberately cultivated in well fertilized fish ponds for use as pig food. In the Philippines it is boiled and given to pigs … In India also it is collected for pigs and I have seen pigs eat it there of their own accord when they have access to the edge of a tank. In Canton, Pistia and other important weeds play an important part in pig feeding. It is unlikely that weeds would continue to be used so extensively if they were of no value as pig food. Nevertheless there is a point that should be properly established; it cannot be assumed that traditional techniques are invariably sound. If it could be established that a weed such as hyacinth, at a certain stage of growth, and pretreated in a specified way, could usefully replace part of a conventional pig diet the fact would deserve publicity so that the technique could be more widely adopted. If on the other hand it should prove to be of so little value that it does not repay the labour of collection, people should be advised not to waste their time.”

Siriwardene, J.A. de, S.S.E. Ranawana and G.A. Piyasena, 1970 Study of the feeding value of Salvinia auriculata for growing pigs. Trop.Agric., Colombo, 126(1):31–4

Trials were carried out with crossbred pigs to measure weight gains when fed on a diet of Salvinia auriculata, compared with a grass, Brachiaria brizantha, each as a supplement to a basic ration of rice bran, maize and coconut meal. The pigs ate less of the Salvinia (0.76 kg daily) than the grass (1.5 kg). This was attributed both to the bulkiness of the fresh Salvinia and to its unpalatability. Dried Salvinia was offered to the pigs but they would not eat it at all. Thus the pigs made much less weight gain on Salvinia than on the grass. The authors concluded, therefore, that Salvinia is of no practical value in the feeding of pigs.

* Villadolid, D.V. and D.M. Bunag, 1953 New uses for water hyacinths. Philipp.Fish.Yearb., 1953:80–1, 241–2

The authors give details of a mixture, which includes water hyacinth, used by Malay farmers for pig food and which they say is also good for ducks and pond fish:

(i)Rice middlings (‘binlid’)100 kg
(ii)Rice bran (‘darak’)50 kg
(iii)Salted fish of any cheap kind or fish meal25 kg
(iv)Water hyacinth chopped into small pieces400 kg
(v)Copra meal or coconut scrapings after oil has been extracted (‘sapal’)50 kg
 Total:625 kg

The greatest bulk of this feed formula is provided by the water hyacinth. The ingredients, with the exception of (v), are boiled in an iron vat or ‘kawa’ over an earthen oven and stirred over a slow fire until they are well mixed. After four hours of slow cooking they become a paste which is then mixed with 50 kg of coconut scrapings or copra meal previously soaked in water. The resulting broth is ready to be fed to the pigs when cooled. This mixture is good only for three days after which it will turn sour. Cooking brings out the appetising flavour from the ingredients and makes them more digestible for the pigs. It also removes the bitter and raw taste in the water hyacinth. Frequency of cooking depends on the amount consumed by the pigs. For example, when they are six to eight months old they are given up to 10 kg of the broth at one time. It is best to prepare the broth once in two days.

This combination is economical and nourishing as well as filling and the pigs thrive best on it. From the list of components we find carbohydrates in (i), (ii) and (v), vitamin B in (ii), protein in (iii), (iv) and (v). The required minerals for rapid growth are amply supplied by water hyacinth. It will be observed that out of the 625 kg of foodstuffs 400 kg are represented by the hyacinth which can be had free. When cooked in a rice hull-fired oven, the fuel used can also be obtained free from rice mills.

3. Poultry

*Bailey, T.A., 1965 Commercial possibilities of dehydrated aquatic plants. Proc.Annu.Meet. South.Weed Sci.Soc., 18:543–51

Bailey reports on the possibilities of extracting xanthophyll from Ceratophyllum sp. Elodea densa and Myriophyllum exalbescens. (The analyses of these plants are given in Chapter III.) He states:

“The feed ingredient industry is constantly alert for new ingredients or new additives which can improve the efficiency of the finished feed or can effect savings without detracting from the quality of the feed. In the above instance, we were impressed by the xanthophyll content of these dehydrated aquatic plants. Xanthophylls are oil-soluble carotenoid pigments found in some plants. There are many different xanthophylls. Some are effective in imparting a yellow colour to the skin of chickens and in darkening the yolk colour of eggs used mainly for the egg-breaking industry. Other xanthophylls are ineffective in this respect. Dr. J.B. Couch and associates of Texas A & M recently reported that xanthophyll in these aquatic plants gave good colouration to egg yolks, and rated xanthophyll in aquatic plants about equal to that in alfalfa meal in this respect. The most common feed ingredients supplying xanthophyll are yellow corn, dehydrated alfalfa meal and corn gluten meal.

“Although there is not much xanthophyll shortage here in the United States, many countries do not have much dehydrated alfalfa or other xanthophyll source ingredients available, and yet have a high demand for highly pigmented broilers and dark egg yolks. Thus there apparently exists a sizeable worldwide shortage of xanthophyll.”

Bruhn, H.D., R.G. Koegel and D.F. Livermore, 1975 Utilization of aquatic vegetation. Paper presented to the Annual Meeting of the Northern Atlantic Region of the American Society of Agricultural Engineers, New York, 13 p.

Referring to the utilization of Myriophyllum spicatum and filamentous algae, the authors contend that research promises a considerable return from the recovery of protein and xanthophyll (used for egg yolk and poultry skin pigmentation). (From Weed Abstracts)

Creger, C.R., 1963 et al., The pigmenting value of aquatic flowering plants. Poultry Sci., 42:1262–3 (Abstr.)

A dehydrated blend of three species of flowering aquatic plants was analysed and found to contain 17.9% protein, 11% crude fibre, and 440 mg of xanthophyll per kg. Levels of 5, 10, 15, 20 and 25% of this blend produced NEPA numbers of 3, 4.5, 5.5, 6.3 and 6.8, respectively, when incorporated into milo-soybean oil meal basal diet and fed to laying hens. Levels of 10 and 20% of dehydrated alfalfa meal, which analysed 20% protein and 500 mg xanthophyll per kg, produced NEPA numbers of 4.75 and 6.1 under similar conditions. From these data it can be concluded that the naturally occurring xanthophylls found in a dehydrated blend of three species of flowering aquatic plants were biologically available and produced egg yolks of NEPA numbers similar to those which resulted from the feeding of approximately equivalent levels of xanthophyll from dehydrated alfalfa meal.

*Lange, S.R., 1965 The control of aquatic plants by commercial harvesting, processing and marketing. Proc.Annu.Meet.South.Weed Sci.Soc., 18:536–42

The author reports the harvesting of Myriophyllum, Elodea and Ceratophyllum in north eastern Texas. The weeds were processed through a conventional alfalfa (lucerne) dehydration mill to produce 40 t of dried meal. This was sent to Texas A & M University for a stock feeding programme which involved poultry, pigs and cattle. The results gave strong indication that the potential for commercial production and marketing lay in the direction of a poultry feed supplement for egg yolk and broiler pigmentation. This was based on xanthophyll values in excess of 660 mg/kg, protein in the 20% range, and a low fibre of 10–15%.

*Ling, S.W., 1960 Control of aquatic vegetation. In Lectures presented at the Third International Inland Fisheries Training Centre, Bogor, Indonesia, 31 October - 10 December 1955, conducted by the Government of Indonesia and FAO with the cooperation of IPFC. Vol.1. Rome, FAO, (3.23):12 p.

Small and tender plants such as Lemna and Wolffia are excellent as feed for ducks.

Little, E.C.S., The floating islands of Rawa Pening. PANS, 15(2):147–53 1969

The author refers to duck farming on the Rawa Pening lake in Central Java in Indonesia. The emergent grass Echinochloa stagnina, common in the shallow water of the lake, was readily grazed by flocks of ducks which pulled down the stalks to eat the seed heads.

Maciejewska-potapczykowa, W., L. Konopska and E. Narzymska, 1970 Proteins in duckweed (Lemna minor). Acta Soc.Bot.Pol., 39(2):251–5

The authors state that water plants belonging to Lemnaceae such as Lemna, Spirodela and Wolffia are willingly eaten by poultry, particularly ducks.

Muzaffarov, A.M., T. Taubaev and M. Abdiev, 1968 (The utilization of duckweed for poultry feed). Uzb.Biol.Zh., 12(3):44–6 (in Russian)

In the summary of their paper the authors say that Lemna minor is rich in nutrients and vitamins. It contains 30–32% albumins and 30–35% starch. It is readily eaten by poultry with gain in weight. In the livers and egg yolks of poultry fed on L. minor the content of vitamin A and carotene was 2 to 2.3 times greater than that of the control birds.

Ross, E., Biological control of pond weeds with white Chinese geese. Hawaii Farm Sci., 1971 20(2):11–2

On a fish pond heavily infested with Brachiaria mutica an attempt at control was made by releasing 5-week-old goslings. However the weed provided insufficient protein and carbohydrate with the result that the geese lost weight. Feeding daily with a food supplement prevented further losses. The geese thrived and made steady inroads into the B. mutica, and within 2 1/2 years the pond was almost clear. (From Weed Abstracts)

*Smetana, P., 1968 Water hyacinth compared with elephant grass. Extract from report to the Government of Burma, by P. Smetana, FAO Poultry Expert, Burma. In Handbook of utilization of aquatic plants, edited by E.C.S. Little. Rome, FAO, Plant Production and Protection Division, PL:CP/20:51

The author briefly refers to the use of water hyacinth and elephant grass as green feed for poultry in Burma. Commenting on this, Mr. W.V. Thomann, poultry expert at FAO, Rome, in 1967, pointed out that water hyacinth, being high in carotene, intermediate in fibre, and low in protein, could be used as a valuable feed instead of being looked upon as pest.

*Villadolid, D.V. and D.M. Bunag, 1953 New uses for water hyacinths. Philipp.Fish.Yearb., 1953:80–1

Around Laguna de Bay, Philippines, but especially in Pasig and Pateros, the water hyacinth is directly fed to ducks for their roughage requirement. The ducks readily consume the live plant leaving only the hard stems. (See also p. 94 for details of a food ration made with water hyacinth which the authors state is good for ducks.)

4. Silage

*Agrupis, F.M., 1953 The value of water hyacinth as silage. Philipp.Agric., 37(1–2):50–6

The author compared the value of silage made from water hyacinth with that from para grass (Panicum purpurascens). Two silos were filled with either of the test plants and a third with an equal mixture. Before packing carefully in the silos, bundles of the plants were dipped in a mixture of one part of molasses and four and a half parts of water. The tops of the silos were well covered to exclude air and then allowed to stand undisturbed for two months. The experiment was repeated. Red Sindhi cows were used to test the palatability of the different kinds of silage. Analyses of the three kinds of silage are given in the following table:

Nutrient and mineral contentPara grass %Mixture of para grass and water hyacinth %Water hyacinth %
Crude protein (N x 6.25)1.571.020.85
Carbohydrates (N.F.E.)9.167.483.93
Crude fats (ether extract)1.221.560.39
Calorific value for every 100 g54.0048.0023.00

Agrupis reported: “In this experiment, the animals were reluctant to take the water hyacinth silage even after salt had been added. The feeding of water hyacinth was therefore discontinued and the silo containing it was closed. The mixture of para grass and water hyacinth was next fed to the cows. It was surprising to see the animals eat this kind of silage which also contained water hyacinth. After the animals had been fed this silage for six days, water hyacinth silage was tried again. This time the animals relished the feed. The water hyacinth in the mixture was probably the cause for the animals eating the pure water hyacinth silage later. The average consumption of para grass silage range from 9.52 to 13.52 kg, or an average of 11.52 kg; of the mixture of para grass and water hyacinth silage, 10.01 to 14.53 kg or an average of 12.27 kg; and of water hyacinth silage, 12.79 to 17.97 kg or an average of 15.38 kg.”

“The colours of the different kinds of silage varied. Water hyacinth silage had the best colour; it was yellow or amber. Para grass silage was dull brown-yellow. The mixture of para grass and water hyacinth silage had a colour that was intermediate between the two.”

Bagnall, L.O., J.A. Baldwin and J.F. Hentges, 1974 Processing and storage of water hyacinth silage. Hyacinth Control J., 12:73–9

Water hyacinth was harvested and chopped into 10–25 mm lengths. It was then dewatered by screw-pressing using either a 30–cm Vincent screw press or a portable 23–cm press. Operating pressures were 90–152 KN/m2 at 15–50 rpm. Pressing was repeated two to three times as needed for the trials. Additives at various rates were either dried citrus pulp, standard cane molasses, yellow dent corn or dried water hyacinth. Various sized silos were used, up to a 3.7 x 12.2 m concrete tower. Run-off from the silos was collected and measured. The silage was tested and then fed to sheep and cattle. Tables are given showing the percentage of water expression with different pressures (45–74%), the contributions of dry matter from different additives, and the density shrinkage and losses to the silage from different treatments. The test animals rejected the plain chopped hyacinth silage but accepted the pressed material.

It was concluded that acceptable silage can be produced from water hyacinth by removing 50% or more of the water and adding free carbohydrates. Dried citrus pulp or cracked yellow dent corn at 2–4% are satisfactory additives. Standard cane molasses at 1% or less is not satisfactory as it did not affect the quality of the silage.

Baldwin, J.A., J.F. Hentges and L.O. Bagnall, 1974 Preservation and cattle acceptability of water hyacinth silage. Hyacinth Control J., 12:79–81

The water hyacinth silage most acceptable to cattle contained supplements of 4 kg dried citrus pulp, and 1 kg standard cane molasses as preservatives per 100 kg of chopped and pressed plant material. The silage with the lowest ash content (14.7%) was the most favoured. Yellow dent corn was also compared with dried citrus pulp, and at 4 kg/100 kg plant material was equally acceptable.

Baldwin, J.A., et al., 1975 Comparison of pangola grass and water hyacinth silages as diet for sheep. J.Anim.Sci., 40(5):968–71

Water hyacinth was compared with pangola grass (Digitaria decumbens) when made into silage as fodder for sheep. The pangola grass was harvested without wilting, chopped (1.6 cm pieces), and packed in tower silos 1.23 m x 2.46 m. The hyacinth silage was chopped (1.6 cm), pressed in a Vincent press (1.27 kg/cm2, 49 rpm) to remove moisture, and similarly ensiled. Four kg of dried citrus pulp and 0.5 kg of sugar cane molasses were added per 100 kg of pressed plant material. Analyses of the two silages were tabulated (% dry matter):

ComponentPangola grass choppedWater hyacinth
Organic matter93.977.082.7
Crude protein6.211.310.6
Dry matter %   
wet weight22.43.810.0

A further table of chemical composition of the two silages showed similar analyses except that the water hyacinth figures were again higher for crude protein and ash.

The wethers used for the tests ate more of the pangola grass silage. The digestibility of the dry matter, organic matter and crude protein of the pangola grass was higher than the hyacinth. The authors comment that more research is needed into water hyacinth silage and the mineral imbalances, especially the CA:P ratio, and the high K would need to be corrected.

Byron, H.T., 1975 et al., Organic acid preservation of water hyacinth silage. Hyacinth Control J., 13:64–6

Acetic acid, formic acid and a commercial product containing 80% propionic and 20% acetic acid by weight, were individually evaluated at high (0.5%) and low (0.25%) levels to determine their effect on ensilability of chopped, pressed water hyacinth, and voluntary intake by cattle of acid-treated water hyacinth silage. Preservation of ensiled water hyacinth as evaluated by silage acidity, temperature profile and degree of spoilage was acceptable for all acid treatments. Voluntary intake of silage treatments improved as lactic acid concentration increased and pH decreased. Treatment with high and low levels of a commercial product (containing 80% propionic acid and 20% acetic acid), and high formic acid were more acceptable to cattle than low formic acid, control, high acetic acid, and low acetic acid silage.

Chibbar, S.S. and G.D. Singh, 1971 Paddy straw and water hyacinth silage. Indian Farming, 20(11):24–6

Paddy straw and water hyacinth can be mixed to form a valuable silage. Experiments are described in this paper.

After washing, the hyacinth was drained and then cut by chaff-cutter into 2.5–4 cm pieces. The paddy straw was similarly chopped, and mixed into the hyacinth at the rate of 1:4. Molasses diluted with water was added at the rate of 70 kg per tonne and evenly mixed in. The material was compacted into silos and covered with weighted polythene sheet. After four months the silage was analysed:

SilageDry matterCrude proteinEther extractCrude fibreNitrogen free extractAshCarbohydrates
Average digestible crude protein (DCP) = 2.4%
Average total digestible nutrients (TDN) = 41.8%

Feeding trials with cows showed that the nutritive value of the silage was adequate for maintenance. But to meet full DCP and TDN requirements the authors recommend a supplement like groundnut cake or 1–2 kg of lucerne or berseem hay. They conclude that the straw and hyacinth silage could help to meet the unsatisfied demand in India for nutritious cattle fodder, and at the same time help to keep paddy fields and water channels clean of hitherto unwanted plant material. More milk, which is badly needed for poor people, would be produced.

Combs, G.E., J.F. Hentges and R.L. Shirley, 1973 Processed aquatic plants for animal nutrition. Annu.Res.Rep.Inst.Food Agric.Sci.Univ.Fla., 1973:81 (Abstr.)

Voluntary intake of water hyacinth by sheep and cattle was highest with treatments containing 4 kg dried citrus pulp and 1 kg sugar cane molasses per 100 kg hyacinth press residue; these treatments had the highest acidity, lowest ash and least surface spoilage. Both in vivo (sheep) and in vitro o.m. digestibilities of a land forage, pangola grass (Digitaria decumbens) were higher than for the best treatments of hyacinth silage. Preservation of hyacinth silage was satisfactory with formic, propionic and acetic acids and their mixtures as measured by acidity, temperature and spoilage. Acceptability of these treatments by cattle was highest with high lactic acid and low pH. These results indicate a potential value as ensiled ruminant animal feed for mechanically harvested and processed water hyacinths. (From Weed Abstracts)

Kiflewahid, B., 1975 Nutrient composition and digestibility of water hyacinth - by cattle. Diss.Abstr.Int., 36(12):5878–9

In trials using steers, silage containing 20% Eichhornia crassipes showed generally similar digestibility coefficients to that containing 20% cotton seed, and appeared to be suitable in cattle diets when supplemented. Structural organic components and in vitro digestibility of organic matter and dry matter of fresh and processed E. crassipes parts were examined in detail. (From Weed Abstracts)

Linn, J.G., 1975 et al., Nutritive value of dried or ensiled aquatic plants. 1. Chemical composition. J.Anim.Sci., 41(1):601–9

In this paper detailed analyses of 21 aquatic plants are given (see Chapter III). The authors concluded that such plants could be useful forages for ruminants, especially because many were high in protein and low in crude fibre thus indicating a high nutritive value. Also, estimates of hemicellulose, cellulose and lignin contents suggested that many of the plants should be highly digestible.

A fermentation study was carried out with a mixture of aquatic plants : 50% Myriophyllum exalbescens, 30% Ceratophyllum, 10% Potamogeton pectinatus and 5% Vallisneria (the remaining 5% was not identified). This was ensiled, on a laboratory scale, with different organic acids and additives of corn grain and chopped alfalfa. The silages were analysed and the detailed results tabulated. Conclusions were:

  1. Dry matter of aquatic plant silage and alfalfa silages were 33.3 and 32.3%, respectively.

  2. All acid-treated silages were higher in protein than untreated, indicating less loss of proteins during ensilage.

  3. Ash contents of all aquatic silages were high (average 47.5%), indicating soil contamination.

  4. No large chemical differences, including organic content, were noted when 5% corn grain or 75% alfalfa was added to the aquatic plant silages.

  5. Formic acid was the most effective in reducing butyric acid formation.

  6. Addition of alfalfa to sterilized aquatic plants produces more acceptable silage than when added to unsterilized aquatic plants.

Linn, J.G., 1975a et al., Nutritive value of dried or ensiled aquatic plants. 2. Digestibility by sheep. J.Anim.Sci., 41(1):610–5

The authors report on the digestibility to sheep of the same aquatic plants as tested in the paper referred to above, when dried or ensiled. It was found that dried Myriophyllum exalbescens and Potamogeton pectinatus were unpalatable (less than 600 g dry matter consumed daily) to lambs. Mixing an equal proportion of dehydrated alfalfa to either of these two species resulted in dry matter and crude protein digestibilities, as determined by difference, of 43.8 and 46.0% for M. exalbescens and 43.4 and 44.1% for P. pectinatus. Energy digestibility was higher for M. exalbescens (53.7%) than P. pectinatus (47.4%). Lambs fed on diets of ensiled aquaticplants, aquatic plants plus corn, or aquatic plants plus alfalfa silage, had dry matter digestibilities of 61.9 and 66.2%, respectively. Nitrogen and energy digestibilities of 61.9 and 66.2% were lower for lambs fed rations that contained aquatic plants than for lambs fed alfalfa silage or silage plus corn. Rumen fluid pH was higher, and molar percentages of acetic acid were lower, for lambs fed rations that contained aquatic plants than those fed alfalfa silage. Propionic acid was highest in rumen propionic ratio was observed these lambs.

The results of this study suggest that palatability of aquatic plants may be a limiting factor in their use as a forage for ruminants. Drying or ensiling did not appear to be satisfactory procedures for improving palatability.

*Loosli, J.K., 1954 et al., The digestibility of water hyacinth (Eichhornia crassipes) silage by sheep. Philipp.Agric., 38(2–3):146–8

The authors prepared water hyacinth silage in a manner similar to that carried out by Agrupis (1953). This was fed ad lib. to sheep. They state: “On a dry basis the silage appears fairly nutritious. The sheep were unable to eat enough to maintain their weights unless a concentrate was also fed.” They give three analyses of their water hyacinth silage as follows:


A detailed table of digestion coefficients of the silage with and without added concentrate is also given.

They conclude: “On account of the low feeding value of water hyacinth silage, preparing it does not seem worthwhile, unless other feeds are scarce or very expensive. Of course, water hyacinth silage can be greatly improved in value by adding to it during ensiling nutritive feeds such as undiluted molasses, copra meal, and rice bran, but fermentation losses may be too great to make this procedure economically advisable. Perhaps a mixture of rice straw and water hyacinth would make a silage suitable for maintaining cattle or carabaos during periods of feed shortage.”

Fresh water hyacinth used as cattle fodder in the Sudan

Duck farming on Rawa Pening lake, Central Java, Indonesia

Ducks controlling water hyacinth in borrow pit, Bangkok, Thailand

Previous Page Top of Page Next Page