Vegetation waters have the appearance of a brown watery residue liquid. The liquid has a pleasant odour but a bitter taste. This effluent, which has relatively high organic matter content, constitutes a source of pollution which creates a serious problem for the olive industry.
Vegetation waters have the following composition:
| water | 83.5% (1) | 83.0% (2) | 88% (3) |
| organic matter | 14.7% | 15% | 10.5% |
| ash | 1.8% | 2% | 1.5% |
| crude protein | 2–8% | 2.4% | 1.25% |
| ether extract | 0.03–0.8% | 1.0% | 0.1% |
| polyphenols | - | 1.5% | 1.0% |
Source: (1) Codounis, 1973;
(2) Cucurachi, 1973;
(3) Fiestas Ros de Ursions, 1981.
Their relatively high polyphenol content is a drawback for animal feeding (antitrypsic action).
Chemical composition varies according to many factors, particularly the oil extraction method.
The documentation on this subject is too scarce. However, Martilotti (1983) has described a method which could prove useful in certain conditions and which has now been developed in Italy (Dalmolive method, Figure 7).
The method combines approximately:
50 kg vegetation waters
20 kg partly destoned exhausted olive cake
12.6 kg of several agricultural residues and by-products
which can produce 29 kg of feed in pellets whose chemical composition is as follows:
Figure 7: Dalmolive method
| Italy (1) | Greece (2) | |
|---|---|---|
| Dry matter : | 85.3% | 93.6% |
| Crude protein : | 21.6% | 21.8% |
| Ether extract : | 4.0% | 3.3% |
| Crude fibre : | 13.1% | 4.7% |
| Ash : | 8.9% | 9.5% |
| Nitrogen-free extract : | 52.5% | 60.7% |
| Digestible crude proteins : | 17.2% | - |
Source: (1) Agricultural chemistry laboratory of Milan
(2) From Zoiopoulos et al (1983)
Bufano et al (1982) conducted a feeding trial using 18 month old ewes receiving hay and a mixture containing 0–20–40 or 60 percent vegetation water paste (moisture content varying from 35 to 57 percent), straw or crushed olive branches, and a 20 percent protein supplement. The results obtained were very unsatisfactory (Table 26). Average daily liveweight gains were low for all the lots during the entire experimental period and did not seem to vary with different rations. However they showed that vegetation water paste was accepted willingly and that rations containing up to 34 percent of the total (60 percent of the mixture) with low nutritive value fodders such as straw or olive branches, hay, and a protein supplement (about 11 percent of the total ration) would at least ensure maintenance of the sheep and even a slight liveweight increase.
Several tests have been undertaken for production of single cell protein from vegetation waters (cited by Zoiopoulos, 1983a). However this method does not seem to be feasible in present production and economic conditions.
Lastly, the direct use of vegetation waters as drinking water for livestock was tested at the Food Oils and Fats Experimental Station in Milan. These waters were suggested to replace drinking water for hens and turkeys (Fedeli and Camurati, 1981). In the case of turkeys it was estimated that the cost of a kilo of meat produced was lower if vegetation waters were used, and a marked decrease of mortality rates was also observed. However the authors do not provide statistical data.
Studies on the nutritive value of vegetation waters and possibilities for their use in animal rations are too few to be able to draw accurate conclusions at present. It would certainly be worth undertaking new experiments on vegetation water paste obtained from the Dalmolive method. The use of vegetation water in other ways, for example as drinking water for turkeys, and probably ducks, could also be the subject of new investigation, but would have only a small impact on the quantity of vegetation waters used.
| Mixture with straw | Mixture with olive branches | |||||||
|---|---|---|---|---|---|---|---|---|
| Vegetation water paste in the mixture % | 0 | 20 | 40 | 60 | 0 | 20 | 40 | 60 |
| Initial weight, kg | 29.2 | 32.4 | 32.5 | 30.9 | 31.3 | 31.6 | 32.9 | 33.1 |
| Final weight, kg | 32.4 | 33.3 | 35.5 | 34.9 | 32.3 | 34.6 | 35.3 | 36.3 |
| Duration, days | 90 | 90 | 90 | 90 | 90 | 90 | 90 | 90 |
| Average daily gain g/d* | 35.8 | 10.4 | 34.5 | 45.5 | 11.0 | 33.3 | 26.6 | 34.7 |
| Consumption | ||||||||
| - mixture g/d | 792 | 992 | 1099 | 922 | 896 | 951 | 948 | 908 |
| - hay g/d | 641 | 602 | 687 | 700 | 610 | 664 | 629 | 676 |
* The average daily gains obtained show very high variation coefficients within thedifferent lots.
