Chapter 2 FEEDING ANIMAL WASTES (Contd.)

2.2 FEEDING POULTRY WASTE TO SHEEP

Sheep, being the most suitable ruminants for in vivo experiments, have been used in most studies volving the feeding of poultry waste. Like cattle, sheep are excellent converters not only of roughages but also of NPN sources. Poultry waste is utilized by sheep in the same manner as by cattle, and because of their lower plane of nutrition and rather longer period of winter feeding, sheep can also utilize poultry waste of poorer quality and with a higher portion of bedding, normally unsuitable for cattle under intensive feeding management.

First pioneering trials with feeding poultry litter to gestating-lactating sheep were reported by Noland et al. (1955). Broiler litter was used as a substitute for conventional sources of protein: soybean meal and ammoniated molasses. Average daily gains of lambs were 200 g on both rations, using either broiler litter or soybean meal as the main protein source.

In the trials of Jordan et al. (1968), a ration containing 22% poultry litter was fed to gestating ewes. The ewes fed this ration gained 130g/day, while control ewes fed a soybean-meal-based ration gained 110g/day. Other performance parameters were similar for both groups, but there was some indication that ewes fed dried poultry litter had a slightly lower lambing percentage.

Mclnnes et al. (1968), in experiments with 6-month-old lambs, reported that lambs fed with a mixture of 235 g of poultry litter and 190 g of wheat meal performed as well as those fed 365 g of wheat meal per day.

Brugman et al. (1969) found that lambs fed on a ration comprising 50% broiler litter and 50% barley, gave better results than those of lambs fed barley and 20% sawdust.

De Gálmez et al. (1970) reported that lambs fed rations containing 38, 58 and 68% poultry litter, based on rice hulls, gave results comparable with those fed on an all-lucerne hay ration.

Feeding a high level of broiler litter (63%) to pregnant ewes was investigated by de Galmez et al. (1970 and 1971). The results are summarized in Table 52. Although there was some evidence in favour of the broiler-litter-based ration, the differences were not statistically significant.

Table 52
RESULTS OF EWES FED ON 63% POULTRY LITTER

The economic aspects of feeding poultry litter to wethers at high levels (50 to 70%) in the form of meal or cubes were also studied by Bishope et al. (1971) in South Africa. Their results, summarized in Table 53, show that feeding poultry litter to wethers more than doubled the profit derived from savings on feed cost.

Table 53
PERFORMANCE OF WETHERS FED POULTRY LITTER

Source: Bishop et al. (1971).

Fattening rations containing 68, 58, 48 and 38% broiler litter were investigated by de Gálmez et al. (1970 and 1971). There were no significant differences among the broiler litter treatments for average daily gain, but the difference between broiler litter and lucerne was significant.

The setup of the experiment and its result were as follows:

The results show tremendous difference in favour of all broiler litter-based rations.

Fontenot et al. (1973) fed broiler litter at the 25 and 50% levels to ewes over long periods to investigate the effect of the waste on performance of ewes and their offspring. The setup of this experiment and its results are summarized in Table 54. For the entire period of the experiment there were no significant differences in any of the observed parameters. Copper toxicity occurred when litter from broilers fed on a high-copper ration was accidentally fed to the ewes. Sheep are more sensitive to increases in the copper content in their diet than cattle and monogastric species.

Jacobs (1975) carried out several experiments with wethers fed broiler litter and barley (1:1 DM), either unprocessed, or ensiled for 3 or 6 weeks. Ensiling increased the feed intake of wethers; when poultry litter was ensiled alone, and barley wes added to the ensiled litter at the time of feeding, the results were different although the chemical composition of both mixtures was the same. This appears to be partly attributable to the increased digestibility of DM and nitrogen in ensiled mixture, and partly to the more favourable ratio of volatile fatty acids in the mixture than in the litter ensiled alone, apparently resulting in better palatibility, as measured by feed intake.

Table 54
EFFECTS OF FEEDING BROILER LITTER TO EWES

a) Code: 13 = average choice; 14 = high choice; 15 = low prime; etc.
Source: Fontenot et al., 1973.

These findings are supported by Harmon et al. (1972, 1975), who found that the DM intake by sheep of maize forage ensiled with 15 or 30% poultry litter (DM basis) was higher than that of maize forage ensiled alone or with 0.5% urea.

In a Zambian study (Gihad, 1976) the value of DPE as a source of protein for sheep was compared with that of soybean concentrate and a urea-molasses mixture in a high-roughage ration. It was concluded that both DPE and the urea-molasses mixture were, in terms of digestibility, excellent sources of protein comparable to soybean concentrate.

Two complete waste-based diets involving broiler litter with apple pulp and feedlot manure with almond hulls were fed to 120 ewe lambs by Torell (1975) with the following results:

The control diet comprising lucerne and almond hulls gave best results, while the diet with feedlot waste, being apparently very low in energy, resulted in very poor performance.

Smith and Lindahl (1977), in several experiments with lambs, substituted lucerne meal by dehydrated layer manure at two levels giving 8 or 12% dietary crude protein in each isocaloric diet (65% TDN). In the 8% CP diet, layer manure contributed 36–40% of the total CP: in the diet containing 12% crude protein the contribution of layer manure was 60–65%. The experiment proved that lambs utilized nitrogen and other nutrients in poultry waste equally well as those from conventional feed sources. In addition, lambs fed on the 12% CP diet consumed 22% more feed, and their feed efficiency was 39% better than those on the 8% diet. It was observed that lambs fed diets containing layer manure tended to consumer more feed and to convert the organic matter of the ration for growth 32% more efficiently than lambs fed diets fed supplemented with alfalfa. The layer-manure-based ration (12% CP) reduced feed costs by 17%.

Comprehensive studies carried out by Goering and Smith (1977) demonstrated that poultry manure and a liquid squeezed by screw-press from cattle manure (LECM) were greatly superior as sources of protein to soybean and urea. In these experiments urea, soybean meal, dry poultry manure and LECM were ensiled with maize forage (whole plant) at levels that would approximate to 12% CP in diets. The results are summarized in Table 55. The silage analyses showed that the actual protein level was slightly different from the calculated value, and DM losses were higher in the manure-based silage. The highest lactic acid level was observed from the LECM. Growth of lambs, measured by daily gain, dramatically increased in all diets without urea. The highest daily gain was recorded with lambs fed on manure-based silage. The results indicated a remarkable trend of lambs to better utilize faecal protein than that from urea or soybean.

Arvat et al. (1978) report a growth trial to compare the nutritional value of two types of poultry wastes. Fresh poultry waste from layers consuming a maize/soybean-meal diet (A) and a grain by-product diet (B) was collected and ensiled for seven weeks. Silage diets were prepared using 22.7% manure of each origin mixed with 15.9% ground maize, 15.9% ground hay, 0.1% salt and 45.4% water. An average pH of 4.0–4.3 demonstrated that fermentation was satisfactory. In the control group maize silage was supplemented with soybean meal, TM salt, and minerals.

Table 55
PERFORMANCE OF LAMBS FED DIFFERENT PROTEIN SOURCES

Note: BW = Body weight;
W^•75_kg = gain per unit of metabolic weight.

Source: Goering and Smith, 1977.

All sheep were fed ad libitum twice daily for 54 days. They consumed all diets readily, but feed consumption for silage A was lower than that for the control. No differences were observed in feed conversion. Daily weight gairt from the control diet (160 g) was greater than those from silage A (100 g) and silage B (120 g). The carcass grade for the wethers in individual groups was as follows:

The following conclusions can be drawn:

1. Feeding poultry waste to sheep has a great economic potential, especially during the wintering period. Even poorer qualities, when fortified with molasses and balanced with minerals, offer an almost total substitute for forage and feed.
2. Incorporation of poultry litter into the ration of growing lambs can be as high as 70%, and for fattening stock up to 50%. Much however depends upon the litter quality and counterpart forage and feed ingredients.
3. Poultry waste fed at levels above 35% usually covers almost the total protein requirement of sheep, and contributes substantially to the energy of the total ration.
4. About 70–74% organic matter and 80% crude protein contained in poultry waste are digestible.
5. Ensiling of poultry waste with forages and other roughages is the most practical processing method for poultry waste. Ensiling increases palatability and reduces health risks.
6. The only problem encountered in feeding processed poultry waste to sheep is the toxicity derived from the high copper level in poultry diets. It is therefore necessary to verify the copper content in the waste, and to include litter in the ration only to such an extent that copper will not exceed the tolerance level.

2.3 FEEDING POULTRY WASTE TO PIGS

The nutritive value of poultry waste for pigs varies considerably: a distinction must be made between waste derived from young birds or layers and waste containing litter. Lower levels (4–7%) of fresh poultry waste without bedding are not only tolerated well in pig rations but apparently stimulate growth and appetite. Fresh manure consumed immediately after excretion apparently has a higher level of protein-bound protein, and very low level of ammoniacal protein, which rapidly increases within hours. This would explain the better utilization of fresh manure than decomposed manure. In reality, decomposition takes place within hours (if not minutes) after excretion because of the extremely high proteolytic activity of the faecal microflora.

An integrated approach hen/pig/fish has been adopted by some farmers in Southeast Asia. They construct cages for laying hens 1.5 m above the pig pen, thus saving the cost of a poultry house. Excreta from laying hens fall down into the pen, where it is consumed by pigs virtually within seconds. One pig is usually “serviced” by 3–7 birds, and the pigs receive 6.3%–14.6% of layer manure (DM) in their ration.

The disadvantage of this system is that smaller pigs consume more manure than larger pigs, while the reverse should the true. On one Thai farm, 50,000 layers are integrated with 10,000 pigs (Kamchai, 1978), and the actual saving derived from the consumption of layer manure represents about US$ 10.20 per pig/year. Dry matter intake of layer manure by pigs is about 10% of the total feed. In this system it is imperative to formulate pig ratons carefully in order to avoid imbalances in calcium and phosphorus. To date, after several years of application at different farm scales, no negative effects on the production or health of pigs have been observed. Table 56 analyses the contribution of layer manure to the feed cost of pigs. The data indicate that three layers should generate an annual profit of US$6.12 per pig (50 kg live weight) while seven laying hens should theortically more than double this profit. In reality, however, four or five laying hens are considered as the optimum average. This system, when complemented with fish, represents a completely closed zero-pollution cycle.

Table 56
LAYER MANURE CONTRIBUTION TO FEED COST AND PROFIT OF GROWING PIGS¹

¹ From 15 kg - 105 kg.
² 32.9 g per layer.
³ Total manure DM intake per pig for the period from 15 to 105 kg = 288 kg (feed efficiency 3.2)
⁴ On actual consumption of grower + finisher, at US$ 170/tonne.

Coffey et al. (1978) studied the effect of poultry manure in growing and finishing diets on performance and carcass traits of pigs. Fresh manure was scraped daily from concrete floors under caged layer hens and mixed with a maize/soybean-meal premix as a source of protein, calcium and phosphorus. Average daily gains for pigs fed 0, 5 and 10% manure were 0.75, 0.68 and 0.63 kg, respectively. Feed: gain ratios were 3.29, 3.66 and 4.2, respectively. The 10% level significantly decreased average daily gain and the feed: gain ratio; pigs fed manure had significantly lower marbling scores and the colour of lean meat was scored significantly lighter. Females had significantly larger loin eye areas, loin weight and percent lean, while males had a significant increase in belly weight. These results conflict with those from Asia; the difference could be attributable to the time between excretion and consumption of layer excreta, plane of pig nutrition and other factors.

In Italy feeding poultry litter to growing pigs was reported by Geri (1968). From the results of three experiements it was concluded that pigs above 30 kg live weight consuming poultry litter at the 10% level gave satisfactory growth for the entire growing period, providing the diet was properly balanced.

In a UNDP/FAO project in Singapore (Müller, 1974), broiler litter was fed to young sows to test the acceptability of rations based on different kinds of litter. Seven different kinds of broiler litter (as described below) were incorporated at 35% in the ration for young breeding. The individuals diets were balanced with other feed ingredients to obtain a similar nutritive value in all diets. They were compared with a commercial sow gestation ration of similar nutritive make-up. The results are given in Table 57.

With the exception of the lucerne-meal litter diets, all diets were readily accepted and produced results similar to or better than the commercial ration. Litter incorporation reduced feed costs substantially.

Table 57
PERFORMANCE OF YOUNG SOWS ON RATIONS CONTAINING
LITTER OF DIFFERENT BEDDING ORIGINS

¹ Fed commercial sow gestation ration.

Source: Müller, 1974.

The possibility of replacing a significant part of pig rations by poultry waste is of great economic importance to mixed farms (pig and poultry). An integrated layer/pig/fish cycle appears to be the most advanced and economically sound recycling system with zero pollution discharge. Research data are not available, but the system is successfully applied by farmers on small and large scales.

2.4 FEEDING POULTRY WASTE TO POULTRY

2.4.1 Refeeding layer manure to layers

Michigan scientists Flegal and collaborators (1969, 1971a, 1971b, 1972) fed laying hens rations containing 10, 20, 30 and 40% dried layer manure (DLM) and balanced in protein, calcium and phosphorus. Egg production (with the exception of layers fed 10% DLM), feed efficiency, and weight gain fell as the proportion of DLM in the ration increased. Feed costs declined with increased proportions of DLM.

Nesheim (1972) compared four least-cost rations, two of them using 22.5% DLM; their composition and results are given in Table 58. No significant differences in egg production and egg weight were observed. Some variations in feed consumption were apparently attributable to a lower energy content in the wheat-bran and DLM diets. The amount of faecal dry matter excreted per hen per day was considerably greater for birds fed DLM than for those of the control group. Apparently only a small portion of DLM was utilized by the hen.

In a completely closed, continuous-recycling experiment on a large number of laying hens, pullets 20 weeks old were fed either 0, 12.5 or 25% dehydrated layer manure (DLM) for 412 consecutive days. Manure was thus returned to the same birds 31 times. The results are given in Table 59. The incorporation of 12.5 or 25% DLM affected neither the production parameters, nor the quality, flavour or taste of eggs or of meat produced by hens fed on any of the tested diets. The chemical composition of DPW monitored from DLM-fed groups for 31 cycles showed no substantial changes (see Table 60). However, some accumulation of mineral matter and fibre took place during later cycles.

Table 58
PERFORMANCE OF LAYERS ON VARIOUS RATIONS

Source: Nesheim, 1972.

Table 59
RECYCLED DLM: INFLUENCE ON EGG PRODUCTION,
FEED EFFICIENCY AND TOTAL MORTALITY

Source: Flegal et al., 1972.

The following conclusions on refeeding layer manure to layers can be drawn:

1. Refeeding of layer manure to layers is technically feasible but offers very few practical benefits.
2. The only benefit appears to be from calcium and phosphorus, because only a small portion of protein in poultry manure is effectively utilized by the laying hen.
3. The accumulation of undigestibles is one of the basic problems, and in countries with a warm climate it may lead to an additional reduction of feed intake.
4. Profitability remains an open question, and much would depend on the cost of the drying process.

Table 60
PROXIMATE ANALYSES OF MANURE FROM HENS FED THEIR OWN MANURE
(on DM)

Source: Flegal et al., 1972.

2.4.2 Feeding poultry waste to other classes of poultry

Feeding poultry litter to other classes of poultry has been reported by only a few researchers. Wehunt et al., (1960) suggested that hydrolyzed broiler litter can be used in chick rations deficient in protein.

Quisenberry and Bradley (1969) found that the overall performance of laying hens on diets containing 10 and 20% of untreated litter and manure was generally better than that of the controls when the diets were properly balanced in protein and energy.

A research programme in feeding DPM to growing chicks and broilers was undertaken by Flegal and Zindel (1970). The results of their experiments, summarized in Table 61, indicated that starting chicks of the laying strain tolerated the incorporation of DPM in their diets up to the 15% level, but the feed efficiency decreased linearly, apparently due to lower energy in the diets containing higher DPM levels. Broiler chicks appeared to be more sensitive, and DPM above 5% level in their diets led to a significant growth reduction due to energy decline in diets with 10 and 15% DPM. This was possible to offset by the addition of fat, as indicated by the response of broilers fed diet with 20% DPM fortified by fat. Feeding DPM to laying strains at a higher level supplied most of the calcium and phosphorus requirements (85% Ca and 78% P at 20% DPM level).

Table 61
UTILIZATION OF DPM TO FEED GROWING CHICKS AND BROILERS

Source: Flegal and Zindel (1970).

It can be concluded that feeding poultry waste to other classes of poultry is technically feasible. The drying cost appears to be the main limiting economic factor. The main contributory nutrients being calcium and phosphorus, the system could become practical where these mineral sources are either not available, or too expensive (developing countries). On the other hand, in warm climates, where feed intake is the main limiting factor, the incorporation of poultry waste into poultry ration may become impossible. It could however be more realistic in rations for developing birds (8–22 weeks), where it can substitute for milling by-products.

2.4.3 Feeding poultry manure to turkey breeders

A Michigan researcher (Wolford, 1975) fed layer manure to caged turkey breeder hens at the 10% level during the entire reproductive period. The results are given in Table 62. There were no significant differences in production and reproduction parameters. A tendency to higher egg production, number of eggs set and fertile egg hatchability was observed in turkey hens receiving DLM.

Table 62
PERFORMANCE OF TURKEY BREEDER HENS FED DLM

Source: Wolford, 1975.

As a follow-up to this experiment, studying the effect of feeding DLM to turkey hens on their reproductive performance and progeny, Wolford et al., (1975) found no adverse effects on production, reproduction and progeny.

In a third experiment on the same research group, Fadika et al. (1975) studied the effect of feeding DLM to growing turkeys at 5, 10 and 30% levels in a iso-protein and iso-caloric diet. Growth, measured by weight gain, was not significantly affected for the entire period (9 to 17 weeks of age).

Feed efficiency declined slightly with increasing levels of manure in the diet. Mortality was not affected, and no significant change was observed in the content of uric acid in plasma, but there was a marked increase of plasma phosphorus in the group fed rations containing 30% layer manure.

It can be concluded that feeding layer or other kind of poultry waste to turkeys appears to be possible and may contribute to savings on feed. The recommended level of layer manure for turkey laying hens is about 10%, and for growing turkeys up to a maximum of 30%. A careful balance of energy and minerals (Ca:P) is of great importance, because the higher the level of poultry wastes in the turkey diet, the more critical becomes the energy supply and mineral imbalance.

2.5 FEEDING CATTLE WASTE

2.5.1 Feeding cattle manure to cattle

The usual sequence involving refeeding cattle manure to cattle is indicated below:

This recycling situation results naturally in an inevitable accumulation of undigestibles (ash and structural carbohydrates) in the manure. Separating the liquid and solid fractions by mechanical means may offer a solution, as the liquid fraction would be suitable for high-yielding animals while the solid fraction could be used for maintenance or bedding material or eventually discarded.

Cattle manure can be fed either in dry form, chemically treated fresh manure or ensiled with forages, crop residues and other feed ingredients or wastes.

The most comprehensive cattle manure processing and refeeding studies have been carried out by Alabama scientists. Anthony (1969) fed different levels of silage (wastelage) based on 57% of fresh cattle manure and 47% of chopped hay. In experiments with washing, autoclaving, cooking and ensiling, the latter proved to be the most effective and also the most practical. The results indicated that cattle performed quite satisfactorily even when fed a very high level of dairy cattle manure. (6.34 kg DM/head/day). Anthony estimated that one full-fed feedlot steer produces enough manure to produce wastelage for one growing cow and one mature breeding cow.

Feedlot manure from beef cattle fed 80% concentrate and 20% roughage was tested by Braman (1976) as a feed component for heifers. The manure, scraped from concrete floors, contained 17.1% crude protein, 20.1% crude fibre and 9.6% ash. In a metabolism trial, the protein value of the manure (fed dehydrated) was compared to that of cottonseed meal. The protein value of the feedlot manure was that of maize, but only 60% of that of cottonseed meal. Nevertheless, relatively high DM digestibility was achieved: 82% for the maize/cottonseed-meal ration and 77% for the maize/manure ration. In a feeding trial, a mixture of 60% feedlot manure, 35% peanut hulls and 5% ground maize was ensiled and compared with a conventional ration comprising hay, maize silage and maize grain. The results, shown in Table 63, confirmed Anthony's earlier findings that cattle manure is a medium-quality forage substitute that can produce economies with a growing cattle herd.

Table 63
FEEDLOT MANURE: HEIFER FEEDING TRIAL RESULTS

Source: Braman, 1976.

Texas researchers Albin and Sherrod (1975) used composting processes to treat cattle waste. Feedlot manure scraped from the soil surface, stockpiled under aerobic conditions for about one month and then grouned through a hammermill (over a 6-mm screen), was fed at levels of 20, 40 and 60% in a high energy/protein ration. As the percentage of feedlot waste increased, apparent digestibility of nutrients decreased in a significant linear manner. Composting lowered the digestibility of organic matter and crude protein but, apparently due to compost-forming bacteria, cell-wall digestibility improved as compared with fresh unprocessed feedlot waste.

lowa researchers (Vetter and Burroughs, 1975a,b) fed cattle on an ensiled mixture of 50% cattle manure and 50% maize stover. Prior to feeding, the silage was balanced with additional protein and mineral/vitamin supplement. Beef cows consumed up to 14 kg of silage (DM) and their daily gain was 900 g, indicating sufficient intake and good palatability. The calculated TDN value of the conventional ration (hay, maize meal, lucerne hay and molasses) was 53%, while silage with manure had a TDN of 58% or possibly more. A mixture of manure and maize stover appears to be particularly suitable for wintering rations because its nutritive value is equivalent to a good quality hay.

The nutritive value and feeding potential of ensiled cattle manure were also evaluated by Long et al. (1976). The results indicated that cattle-waste-based diets balanced with high-moisture maize gave satisfactory performance and were economical substitutes for forage and soybbean meal.

Newton et al. (1977) reported results with feeding heifers (at initial weight 210 kg) a wastelage (silage) containing 40% fresh cattle manure. Heifers fed wastelage gained an average of 1.27 kg/day with a 5.40 feed conversion factor (feed/gain), while those fed control rations gained an average of 1.34 kg with a conversion factor of 5.02.

In a digestion trial on steers three diets were investigated: control ration without manure, wastelage and dried cattle manure. The experiment showed that fresh fermented manure in the form of wastelage was superior in digestibility parameters to dried cattle manure, particularly in terms of nitrogen utilization.

Schake et al. (1977) tested the use of cattle manure or water as a reconstitution medium for sorghum grain fed to steers. Sorghum reconstituted with cattle manure was more effective than with water: steers receiving it had significantly higher dressing percentages and their carcasses tended to higher fat content than the controls.

Research carried out at Oklahoma State University (Wagner, 1977) was concerned with feeding cattle manure collected in earlier phases. The process was continued for 4 phases. It was found that ash and fibre content, and to some extent protein levels, were higher in successive refeeding programmes. The reincorporated manure exhibited somewhat lower digestibilities of DM, organic matter and other constituents. It was concluded that cattle manure may have potential in growing and maintenance rations, but higher levels cannot be used for high-yielding animals.

It can be concluded that manure derived from cattle fed high-concentrate rations (dairy cattle, feedlot cattle) has good nutritive value and can be used as a forage substitute for growing and maintenance cattle as well as for dry beef cows. The level to be incorporated into ration of cattle varies from 15–60% of DM of the total ration, depending on the class and productivity of the cattle and the nutritive value of the manure. The plane of nutrition of cattle has a decisive effect on the chemical composition and the quantity of cattle manure that can be reused. Ensiling or chemical processing are the most economically suitable and safe treatments from the health standpoint.

2.5.2 Feeding cattle manure to pigs

As early as 1908 Henry, and later (1920), Henry and Morrison outlined the potential of recycling cattle manure to pigs (1–3 pigs per steer). Bohstedt et al. (1943) observed that free access to fresh cow manure permits pigs to avoid deficiencies in B-complex vitamins which may result “if only the usual 5% or less ground alfalfa hay is fed in the ration. A very interesting light is shed on the helpful supplementary effect of cattle manure which is not due to any whole undigested corn it may contain”.

Squibb and Salazar (1951) fed pigs a ration containing sun-dried fresh cow manure which was readily consumed. However, because of the energy imbalance of the ration (high fibre) the pigs' performance was poor.

Putnam (1971) reported experiments with feeding pigs with beef feedlot manure subjected to several treatments. Treated beef manure was successfully fed up to 85% of the total ration.

In Mauritius in 1976, cattle manure mixed with molasses (40% manure, 40% molasses and 20% conventional balancing ingredients) was readily consumed by pigs. The results were not comparable to those of commercial pig formula, but the economics were said to be in favour of a ration containing the mixture.

A cattle/pig recycling situation involving individual classes of pigs under a semi-intensive feeding system is outlined in Table 64. When rations are carefully balanced, substantial savings could be made on pig feed.

Table 64
FEEDING DAIRY AND BEEF MANURE TO PIGS

¹ At any time over a year;
² 880 kg (DM) of dairy or 657 kg (DM) of beef cattle manure produced per head per year.

In feeding cattle manure to pigs, it must be borne in mind that only manure from cattle fed high-concentrate rations will be suitable, while manure derived from higher roughage rations would contribute very little or could even produce negative results.

Cattle manure fed to pigs should be fresh and chemically treated. Ensiling is also practical. Molasses improves palatability and reduces the fibre content in the overall ration.

2.5.3 Feeding cattle manure to poultry

A large volume of literature on this subject goes back to the early 1940s. In 1942, Riley and Hammond observed that the development of testes and ovaries was retarded in chicks fed dried cow faeces, but was unaffected when the chicks were fed faeces from mature bulls.

Hammond (1942) suggested that the rumen contents may have been higher in vitamins than was the feed, and faeces may have several hundred times higher concentrations of vitamins than feed. He concluded that “cow manure” has a marked beneficial effect on growth of chicks when added to a riboflavin-deficient diet. It was found that cow manure contains a factor that stimulates comb growth in both male and female chicks.

Bird and Marvel (1943) reported great growth and hatchability improvement by feeding 10% faeces to battery-kept birds. Hammond (1944a) stated: “It has become increasingly evident to the writer that, because of the shortages of high grade alfalfa (lucerne) leaf meal and fish meal, cow manure or dried rumen contents may assume considerable practical importance in poultry feeding”. Also in 1944 Hammond reported that cow manure (fresh, and dried at 47°C, 80°C and 120°C) fed at 10% level to poultry replaced lucerne leaf meal in an adequate ration. Croschke et al. (1948) found that adding the unidentified dietary factor in cow manure to laying-hen diets improved hatchability and eliminated seasonal variations. The authors believed that coprophagy improved hatchability. Rubin and Bird (1946) suggested that cow manure contains a factor other than the vitamins or other factors previously reported. It is only this factor that has improved the growth-promoting properties of the basal diet. It is soluble in water or ethyl alcohol and can be extracted. Hens fed dried cow manure or fishmeal transfer enough of the substance to the egg to support optimal growth of chicks.

Whitson et al. (1946) reported that drying cow manure at 80°C produced better results with layers than at 45°C. The latter temperature affected egg production while the former did not. Hatchability was normal on either ration. Turner (1947) reported that the performance of male chicks fed manure from lactating cows was reduced when the manure exceeded 10% of the ration, while pullets responded well to 20%. Lillie et al. (1948) suggested that vitamin B₁₂ and the extract from cow manure reported by Rubin and Bird (1946) are closely related if not identical. Rubin et al. (1946) found a growth factor in cow manure and urine-free hen faeces that is apparently synthesized in the digestive system, because it was found even in faeces of hens lacking this factor in their diet. The following results were obtained:

Bird et al. (1948) reported that 5% of dried cow manure was an effective supplement in growing turkeys. The growing turkey has a critical need of an unknown dietary factor which occurs in cow manure, fishmeal and, probably in smaller quantities, in meat meal. The authors apparently referred to APF (animal protein factor), Slinger et al. (1949) reported that a supplement of 5% dried cow manure was effective when fed to turkeys in a maize/soybean ration. Palafox and Rosenberg (1951, 1952) observed that oven-dried or sun-dried cow manure, when substituted for mash, satisfactorily supported egg production and reproduction, but not at the 15% level. Lipstein and Bornstein (1971) observed that dried cow manure (36.4% ash) as a mineral supplement had no toxic effect when fed to chicks.

Under a UNDP/FAO programme in Singapore, 10% beef cattle manure (with wood shaving bedding) was successfully fed to layers (Müller, 1974) to economize on hen rations. The experiment is summarized in Table 65. The data in the table represent two 16-week periods; in the first, productivity was at a peak while in the second, overall productivity declined somewhat. The results showed a significant trend in both periods, and most of the observed parameters were in favour of the ration containing manure. The incorporation of cattle waste had great impact on feed cost reduction.

Table 65
FEEDING CATTLE MANURE TO LAYERS

Source: Müller, 1974.

Quantitative data and potential for feeding dried cattle manure to various classes of poultry are calculated in Table 66. Broiler under an intensive programme are naturally the most sensitive to the incorporation of cattle manure because of its high fibre content. Nevertheless, in rations for semi-intensive broiler feeding or for meat birds, higher levels (5–10%) can be incorporated providing that the diets are properly balanced. As for replacement birds, during the developing period the 15% level can be exceeded, while in early age (up to 6 weeks) the level should preferably be lower. Similarly, in layers and turkeys the level of incorporation of cattle manure depends on the composition of the ration. Milling by-products and other higher fibre, lower energy feeds should be excluded from the ration to ensure proper feed intake. Dried cattle manure can be thus recycled to poultry up to the 15% level or more, providing that diets are properly balanced in energy, fibre and other constituents.

Table 66
RECYCLING CATTLE WASTE TO POULTRY

¹ 4.5 batches/year for broilers; 2 batches/year for replacement birds and layers.

2.6 FEEDING PIG WASTE

Pig waste is a biomass that changes rapidly from the time of excretion. It creates a serious pollution problem because it is more offensive to the human environment that any other animal waste. Pig waste amounts to about 1% of weight of the pig, and from the nutrition standpoint it is much poorer than poultry waste. Approximately 15–20% of nutrients by-pass the digestion. Much however depends upon the plane of nutrition and other factors discussed in previous chapters.

There are several methods of recycling of pig manure for feeding:

1. feeding dry
2. adding oxidation ditch mixed liquor to a regular ration (2:1)
3. using ODML as drinking water
4. ensiling either alone or with other feeds or forages

The magnitude of the feeding potential has been evaluated in several studies. Diggs et al. (1965) fed dried pig manure collected from concrete floors to pigs; the results summarized in Table 67, indicate that incorporating the waste at the 30% level depressed growth and feed efficiency.

Table 67
REFEEDING PIG MANURE

Source: Diggs et al., 1965.

Orr et al. (1971, 1973), in experiments also involving dried pig manure, reported depression at any level. The differences in the findings of the two groups of researchers are attributable to differences in methods of collecting and processing the waste and formulating diets.

An interesting approach of lllinois scientists (Day and Harmon, 1969) using oxidation ditch products have brought a new element into pig waste recycling. They collected solids from an oxidation ditch after the liquid effluent was drained off. The solids contained 27.7% protein on DM and were tested on rats, where they replaced one half of the protein in soybean meal diet without reducing live weight gain.

In other experiments Harmon et al. (1973) tested another pig waste product derived from an anaerobic process (sludge). The sludge, after drying, was fed up to 30% to rats and pigs but, in both, it significantly reduced live weight gain and feed efficiency.

In another study, Harmon et al. (1972a) departed from the isolation of solids from the ODML, and used the whole biomass containing about 3% DM. The mixture was pumped into a holding tank (see Fig. 3, p. 90) for further aeration and mixed with a 12% protein (maize/soybean meal) formula at two parts liquid to one part feed. Water was available to pigs ad libitum. The results of five experiments clearly showed that pigs fed ODML mixed with feed gave results better than or at least similar to pigs on a conventional control diet.

A new approach was taken in another study (Harmon et al., 1973). The ODML refeeding system was even more simplified. The mixture of ODML was simply used as a source of water and no additional tap water was allowed for drinking. The results of experiments involving 6 replications on 120 pigs showed that the control group with conventional feed and water gained daily at an average of 660 g, while for pigs drinking ODML the daily gain was 730 g. This system may offer a completely closed cycle, and a continuous addition of water would help pig waste to maintain 3% DM and biological equilibrium. The far-reaching economic and environmental potential of utilizing all pig waste and water is nevertheless overshadowed by the possible health risks to pigs (accumulation of nitrites and nitrates, parasites, etc.). These risks could however be overcome by rigid control.

In Germany, Flachowsky (1975) fed 30 and 50% solids from pig semi-liquid manure to cattle to replace straw and protein concentrate in pelleted diets comprising wheat, barley, sugarbeet pulp. 1.5% urea and mineral-vitamin supplement. Prior to the experiment, the digestibility of the pellets was established on sheep, with results shown in Table 68.

Table 68
DIGESTIBILITY FOR LAMBS OF NUTRIENTS IN DRIED PIG FAECES

Source: Flachowsky, 1975.

The same diet was fed for 252 days to fattening bulls, with results shown in Table 69. The performance in all groups was quite satisfactory, although, the diet containing 50% pig manure, as could be expected, exhibited somewhat lower gain. Nevertheless, these experiments clearly demonstrated that pig waste, when processed and properly balanced with other ingredients, may become a potential feed substitute for cattle at levels up to 30%.

Table 69
FEEDING DRIED PIG FAECES TO FINISHING BULLS
(252 DAYS)

Source: Flachowsky, 1975.

¹ German feed unit.

Löhnert (1977), in a 84-day trial, fed 12 male calves (average initial live weight 47.2 kg) on a mixture of straw and pig slurry solids. As the percentage of straw and pig waste increased, the digestibility of the organic matter and the energy concentration declined significantly. The average daily live weight gain of the group fed 5% of the mixture was 875 g; the group on the mixture at 10% gained 825 g and the group on 15% 762 g.

In other studies, Flachowsky et al, reported (1977) that the nutritive value of pig slurry solids can be considerably affected by the method of separating solid and liquid fraction. Feeding trials showed that after a short adaptation period (1 to 3 days) the acceptance and thus the intake of wet or pelleted pig slurry solids (mixed with feed concentrates or fed as silage) improved. According to the ratio of pig waste to feed concentrate, daily gains varied from 1.00–1.40 kg/head of finishing bulls. As a result of these studies, a 10,000-pig farm has been integrated with a cattle feedlot, and a production plant erected for wet-bulk mixtures of pig waste and a cattle feed concentrate.

Hennig et al. (1977) reported results with pig slurry solids treated with 5% NaOH, decanted and pelleted. The waste was tested on wethers in two series of digestion trials. In both series, the alkaline treatment led to a significant increase in the apparent digestion coefficients for organic matter (24 vs. 36%), crude fibre (35 vs. 82%) and NFE (36 vs. 53%). The energy concentration of decanted solids increased from 370 to 414 feed equivelents (EFE) and that of pelleted solids from 343 to 431 kEFr (cattle) per kg DM.

Gruhn et al. (1977) studied the effect of solids from a semi-liquid pig manure on the carcass quality of cattle fed these solids at 35% level. The carcass investigation concentrated on the protein level and amino acids of the longissimus dorsi muscles of bulls and heifers fed either controlled rations (without pig waste) or rations containing 35% pig waste. The only difference attributable to the experimental feeding was a significantly lower DM and fat content in animals fed pig waste. The difference appeared to be related to the lower energy content of the pig-waste-based ration.

Berger et al. (1978), in a follow-up of previous research, ensiled 7 different silages based on different ratios of pig waste and hay (orchard grass). The arrangement of the experiment and some fermentation characteristics of mixtures before and after ensiling are shown in Table 70. The pH and the level of lactic acid indicated the quality of the ensiling process. The total bacteria count was substantially reduced by ensiling and faecal coliforms were totally eliminated.

Table 70
PIG MANURE HAY SILAGES: FERMENTATION CHARACTERISTICS

¹ Mean of two samples.
² Mean of six samples.

Source: Berger et al., 1976.

The results of digestibility studies carried out on gilts with the mixtures of 40:60 and 60:40 (faeces:hay) are shown in Table 71. The digestibility of DM, organic matter and crude protein for the control and rations containing the 40:60 silage were significantly higher than for rations containing the 60:40 silage. Gilts accepted all silages well, with some preference for the 40:60 silage.

Stanogias and Hendrosoekarjo (1977) conducted experiments with different levels of dry pig manure incorporated into ruminant rations. Steers fed 0, 15, 30 and 45% dried pig manure in pelleted from exhibited a linear decrease in DM digestibility.

Table 71
ENSILED PIG WASTE AND GROUND MAIZE GRAIN FED TO GILTS: APPARENT DIGESTIBILITY
(mean of 6 animals)

Source: Berger et al. (1978).

In other Australian studies Hendrosekarjo and Pearce (1978) reported on the utilization of dried pig faeces, high in copper, by sheep. The results suggested that pig faeces derived from pigs fed high copper levels were poorly utilized by sheep at both 15 and 30% faeces levels, and resulted in a marginal or toxic concentration of copper. The actual toxicity symptoms were observed by the authors at 30% pig faeces in the ration. Molybdenum used at 90 or 175 ppm had no apparent effect in offsetting the copper toxicity.

The quantitative recycling potential of pig waste within individual livestock species is outlined in Table 72. The level of waste to be recycled depends on the nutritive value of the waste, its contamination with trace elements (particularly copper) and antimicrobial drugs and on the treatment of the waste.

Recycling of pig waste to cattle, sheep and pigs is possible at 10–30% DM level in the ration providing the waste is properly balanced and processed, and the content of critical nutrients (cell walls, ash, copper, drugs and other undesired constituents) does not exceed the tolerance level beyond which the performance of livestock would be adversely affected.

2.7 FEEDING ANIMAL WASTES TO FISH

Intensive fish cultures, although a relatively new development, are rapidly expanding in developing countries. Feeding animal wastes to fish is an old practice; and the mechanism of manurefish recycling is illustrated in Figure 3.

Figure 3 — Manure-fish recycling

Table 72
RECYCLING PIG WASTE TO CATTLE AND PIGS

¹ Assumes 146 kg of pig waste (DM) per year.

New advances indicate that by controlling the rate of inflow of nutrients from animal wastes, it is possible to achieve optimum conditions for fast-growing fish in warm climates. Tropical and silver carp, catfish and Tilapia are the most popular, and their potential for utilizing animal wastes is enormous. Thus, for example Durham et al. (1966), who fed catfish in heavily overstocked ponds, replaced 50% of conventional feeds (grain and cottonseed cake) by feedlot manure. Ponds stocked with almost 60,000 fish per ha produced annually a net gain of 8.25 tonnes of fish biomass. There was no difference between yields from conventionally fed ponds and fish fed rations with 50% feedlot manure. Meyers (1977), in intensive aquaculture in Israel, fed cattle manure into fish ponds at daily rates of 250–400 litre/tonne of fish biomass, increasing fish production ten times (from 0.5 tonne to 5 tonnes per ha).

Other experiments of Meyers (1977) involving the use of cattle manure supplemented with chemical fertilizers are summarized in Table 73. The yields of common carp and Tilapia indicate that the potential of livestock manure in fish production is of great magnitude.

Table 73
GROWTH OF FISH IN MANURED PONDS¹
(110 days)

¹ Manure added five times per week, supplemented with superphophate (20%P) and ammonium (20% N) at 60 kg/ha/2 weeks.

Source: Meyers, 1977.

Meyer's research showed that about 45% of the cellulose decomposed within 2 weeks and that the celluloytic activity correlated positively with the increase of bacterial biomass.

Catfish cultures are also becoming very popular in the United States. Maximum gains of catfish are at 30°C, but good results are also obtained when the temperature varies between 26 to 34°C. Countries with tropical and subtropical climates have, in this respect, a great potential. Typical examples are Thailand and Philippines, where catfish production is integrated with livestock generating manure as the only source of feed for fish (see Section 2.1.4.1).

The nutrient requirements of catfish are generally much higher than those of broilers, and the high nutrient content of livestock manures can offer even more as fish feed than as broiler feed (see Table 74). The cost of these nutrients, which can be just the manure alone, is virtually zero. Moreover, the feed conversion ratio is similar in both fish and broiler feeding (1:2.5), if not even better for the fish species.

Table 74
NUTRIENTS REQUIREMENTS OF BROILERS AND CATFISH,
AND NUTRIENTS IN ANIMAL WASTES

Sources:¹ Deyoe and Tiemeier, 1968;
² NRC, 1977.

lllinois scientists (Buck et al., 1976) were apparently the first to utilize some Asian fish culture techniques in the USA to solve problems of animal wastes management, pollution control, and protein production. Their experiment was carried out in two ponds of similar size with nearby identical stockings of four Asian fish species and three native American species with differing amounts of pig manure. The first pond received the total waste from five growing pigs (about 39 pigs/ha of water area), the second pond received the waste from eight pigs (66 pigs/ha). The net increments in fish biomass over 170 days period were 2,971 and 3,834 kg/ha in the two ponds. The authors attributed the high fish biomass yield to the high plane of pig nutrition, a fortuitous choice of a fish stocking ratio, and effective water level management.

According to the estimates of Thai farmers, one pig generates enough manure to support the “direct feed” requirement of the fish, while the water-soluble inorganic nutrients of the manure fertilize the ponds, thus supporting the growth of algae, bacteria, and lower and higher aquatic plants.

From calculations obtained from Kamchai (10,000 pigs) and Praves (4,000 pigs), it appears that the manure from one pig produces about 20 to 38 kg of fish biomass per year. In Philippines, Eusebio (1976), in a small pilot pond with a closed recycling cycle, achieved 32.6 kg of biomass per pig at a somewhat lower production per area (587 kg/ha). The usual yields of fish ponds in Philippines and Thailand are about 1.2 tonnes/ha, manure being the only source of feed and nutrient supply for photosynthesis of aquatic plants and bacteria.

Some farmers in Asia build poultry cages or pig pens on a wooden platform above a fish pond; poultry or pig manure (or both), together with spilled feed, fall directly into the pond, where it is consumed by the fish. This system is very practical: no cleaning of poultry and pig house is necessary, and poultry or pigs situated above the fish pond enjoy an excellent air circulation which has a significant cooling effect for laying birds, particularly sensitive to heat stress; the same applies to pigs. This system, in terms of livestock waste management, increases the profit derived from fish and totally eliminates the pollution problem.

It is estimated that one laying hen (or weight equivalent of other classes of poultry) will produce enough manure to generate about 6–8 kg/year of fish biomass.

It can be concluded that fish cultures are an excellent outlet, closing circularly integrated recycling systems without further pollution discharge. This is even more true when fish ponds can be switched over to cropping every second year, a system quite commonly used in Asia. This practice supports both high production of disease-free fish and high crop yields.

Manure derived from individual, confined livestock species (annually) can support the following annual production range of fish biomass:

The conversion ratio of manure to fish biomass is related to numerous factors, particularly the fish species, climatic conditions and pond water management.