Abstract:
CITRUS PULP IN FORMULATED DIETS KEITH HUTTON* SUMMARY Most of the citrus fruits grown worldwide are oranges of various varieties. More than half of these are processed and have their juice extracted. The resultant wet citrus waste has been used for over 60 years as a source of feed for livestock. Most citrus pulp is now dried for convenience of storage and transport prior to feeding to ruminant livestock. Brazil and the U.S.A. are the largest exporters of dried citrus pulp in the world. Significant quantities are produced and utilized in Citrus pulp is primarily a low protein feed with a Australia. carbohydrate profile very different to the usual raw materials used by stockfeed manufacturers. It is a high energy feed, but contains virtually no starch and has more in common with dried spring forage, sugarbeet pulp or root crops than with cereal grains. As such 'it has advantages over cereal grains, particularly in formulated diets for ruminant animals. As a byproduct feed citrus from different sources vary Pulp may considerably in chemical composition, palatability and nutritive value. This variation is a characteristic of virtually all by-Product feeds. The level of utilization of citrus pulp in formulated feeds is very much dependent on availability and relative cost effectiveness of alternative raw materials. Dried citrus pulp from the Murrumbidgee Irrigation Area (MIA) is in strong demand for live sheep export pellets and general sheep, beef and dairy cow supplements with a limited quantity being included at low levels in sow feeds. Virtually none is used in rations for growing pigs or horses in Australia. poultry, INTRODUCTION current The annual world production of oranges is estimated at 43 million tonnes of which 65% are used for orange juice production. Around 12.5 million tonnes are produced in Brazil and 10 million tonnes in the U.S.A. in the former 85% an,d in the latter 60% of oranges are used for juice production. Australia is a relatively small producer. The total citrus fruit produced is estimated at about 650 thousand tonnes. Almost a third of these (30%) are used for fresh home consumption. A relatively small quantity of quality fruit (about 6%) is exported and the majority (64%) are used for juice. Oranges make up the major part (over 80%) of the Australian crop with lemons (7.5%), grapefruit (5%) and mandarins ( a r o u n5%) d making up the remainder. Most of the oranges grown in Australia are in the South-east (N.S.W. 38& Vic. 25$, S.A. 32%) with relatively minor contributions from Queensland (4%) and Western Australia (1%). Most of the orange crop in N.S.W. is grown in and around Leeton and Griffith in the MIA. 'Coprice Division, Ricegrowers' 297 Co-operative Ltd., Leeton 2705 wet citrus waste a t SC) li; m 0 i ~3 t u t* t\ t- t' p 1' t' s t' r1 t, s :\ p p r 0 s i 111 :'i 1. t? 1 y Ilalf the weight of fresh oranges :ind in the MlA hati tradi t-i onN lly bt?en dumped or fed to sheep, cattle and more rect?nt Ly goats r;ls produced with no further processing and with no protein nor However there is now cons idertible miriertil supyl~mentution. production of dried citrus pulp from the wet citrus waste by the Biocon Division of Ricegrowers' Co-operative Limited (RCL) at Griffith. In the MIA the potential amounts to around 8,500 tonnes dried orange pulp for stockfeed (dry matter 92%) in contrast to 50,000 of dumped wet waste. This is not a lot when compared to the dried citrus pulp exported out of Florida annually which amounts to around half a million tonnes and has been as high as 1 million tonnes in the late seventies and the early eighties before unseasonal frosts devastated production. However it represents around half a million Australian dollars in value as stockfeed. It is of special interest in the MIA because heat used to dry it is produced from combustion of rice hulls. Rice hulls are another MIA waste product which has caused disposal problems in the past. Over 120,000 tonnes of rice hulls are produced by the N.S.W. rice industry annually. Combustion of 110 tonnes of rice hulls can provide enough heat to produce 100 tonnes of dried citrus pulp and the residual silica ash (20% of original hulls) has many industrial applications and can be readily sold. The main outlets for ush are as a refractory agent in the steel industry and as a filter aid in the production of glucose syrups for the food industry. The integrated production of dried citrus pulp in the MIA using heat from combustion of rice hulls adds value to both the citrus and' rice crops while aiding in the prevention of two separate by-product waste disposal problems. lt is the intention in this paper to look at citrus pulp production in the .MIA and the utilization of dried citrus pulp particularly in the area of formulated diets for livestock and poultry. These results will be discussed in the light of extensive research and practical experience from all over the world. CITRUS PRODUCTION AND PROCKSSING In any consideration of utilization of by-products for livestock feeds, particularly where products of the livestock fed are destined for human consumption it is important to be aware of all production and processing conditions ussociwted with t 11 t;` particular by-product in order to eliminate any risks which may be associated with use of the material. For example the raw material may contain toxic factors which are concentrated in the by-product. These may be naturally occurring enzyme inhibitors or antimetabolites in the raw material such as occur in raw soyabeans, cottonseed and rapeseed which reduce animal, performance. There could be residues associated with control of weeds, fungus diseases and insect pests during growth and storage which could be concentrated in the by-product and later in animal products such as meat, milk or eggs and be potentially harmful to consumers. There may also be breakdown products resulting from 298 oxidation and rancidity which may be equally harmful to livestock There is increasing awareness of moulds and and consumers. Such contaminants affect mycotoxins. palatability H 11 d ft? tid conversion efficiency and may also t]Hact reproductive effici.e1~cy and thus profitability. At worst these residues tn:ly be ctit*.r ied consumer level. through to the All livestock producers, manufacturers and stockfeed professionals associated with production must livestock always be fully aware of these dangers in utilizing potential by-products and continually monitor husbandry, storage and processing methods and end product quality to eliminate all risks. Chemical spray recommendations are under strict control of State Departments of Agriculture. In the MIA the N.S.W. Department of Agriculture Orchard Calendar details Spray recommendations for citrus. The list covers treatments for control of various viruses, fungus diseases, moulds, mineral deficiencies, snails, mites and There insects. are also chemicals recommended to control fruit drop and post harvest decay. Nutrient supplements used to control mineral deficiencies are taken up through the tree leaves and residual levels wash off the fruit with rain. Trace amounts used are most unlikely to cause a problem in citrus waste. Fungicides are usually only used for post harvest packing. fruit The quantity of citrus treated with fungicides and subsequently used for juicing is therefore likely to be extremely low and there is not much risk associated with these chemicals in citrus waste. The use of pesticides in the MIA is not as widespread as in other places such as the coastal citrus growing areas. Although the Orchard Spray Calendar mentions around 13 pesticides for use with citrus most MIA farms use routinely only white oil for control of scale which is of no danger to stock or consumers. Chlordane is a particularly toxic chemical used on some young citrus trees to control ants, but such trees are not of fruit bearing age. As the spray is applied to the ground beneath the trees chlordane should not be a problem. Biological control with insect predators is preferred in the MIA and this is not compatible with use of insecticides. In addition to control of spraying all citrus fruit is thoroughly washed and scrubbed prior to juicing. Most juice factories use town water and a stiff brush but some use a sorbate bath to remove fungal spores. It follows that if the fruit is suitable for production of juice for human consumption then the resulting waste material is highly unlikely to be unfit for livestock feed use. Following the removal of juice the wet citrus wuste is transferred to the citrus pulp plant for further processing. All wet citrus waste destined for production of dried citrus pulp in the MIA is processed within 12-24 hours of juicing ensuring that rancidity and mould growth are virtually zero. 299 At the HCL Biocon plant wet citrus ~2123 ttp i k-3 t i p p t$ ti i fl t 0 u receival bay and conveyed to a vertical shredder following addition of a slurry of slaked lime which' facilitates water removal in a press prior to dehydration in a rice hull fired Dehydrated citrus pulp is then pelleted rotating drum dryer. while still hot and stored following cooling in bulk pellet storage silos prior to despatch to RCL Coprice Division Feedmill and other stockfeed mills. BY-PRODUCTS OF CITRUS The raw by-product of citrus juice manufacture is the wet citrus waste which includes everything from the citrus fruit except the expressed citrus juice. Wet citrus waste has caused disposal problems in the past. The major use for this material has been livestock feeding. It has been used for many years as produced with no further processing or as silage following a period of silo storage. Field dumped wet citrus waste is readily eaten by livestock but it doe& ferment readily, it attracts smells flies, strongly and cannot be easily stored and transported. Consequently dried citrus pulp has been produced in commercial quantities for over 50 years in Florida in an effort to overcome these problems (see Kesterson and Braddock 1976). In preparation of dried citrus pulp lime has to be added first to the wet waste to overcome the water holding capacity of the complex carbohydrates in the residue. The resultant material is then pressed to remove as much water as possible prior to drying. The press liquor from this process contains mostly soluble sugars and can be concentrated to produce citrus molasses which may then be added back to the pulp prior to pelleting. In the RCL Biocon process no molasses is recycled at present but awareness of the potential pollution problem and value of the press liquor will probably result in production of citrus molasses or utilization of the press liquor in some other way in the near future. Although most citrus waste finishes up as livestock feed there are many alternative commercial uses but no one method is envisaged as a competitor for stockfeed citrus products. In the MIA pectin for the food industry is being commercially produced at Griffith and in the U.S.AI there are a variety of items produced as added value products from citrus waste. For example d-limonene is the monocyclic terpene extracted for further use in the chemical industry. Synthetic odour materials including 1-carvone, a s.ynthetic spearmint oil flavour, are produced from d-limonene. In the plastics industry d-limonene is converted into resins and adhesives. As a solvent it is used in soaps and perfume manufacture and in the manufacture of rubber. There are many other applications for limonene and other citrus peel oils. Citrus oils are used in beverages, food, perfume, cosmetics, soap 9 pharmaceutical, paint, confectionery, condiment, ice cream, insecticides, rubber and textile industries and are also used for flavouring and scenting products. The major outlet is for flavouring. many other types of 300 A group of compounds known :I:! .f l:.tvotlo ids :r.b~o OCCVM i. n Hesperidin is a biologically active flavonoid used :~a a citrus. therapeutic agent in the pharmaceutical industry. It is also used as a base material for azo-dye wood stains. Naringin is the predominant flavonoid in grapefruit and is extracted for use as an additive to beverages. Like hesperidin it too is used in azomanufacture. Natural sweetening agents up to a thousand dye times sweeter than sucrose can also be extracted from citrus waste. Kesterson and Braddock (1976) have described in detail the history of the citrus industry in Florida and reviewed thoroughly the major developments and uses of by-products and speciality pkoducts of Florida citrus including fermentation products and waste disposal. COMPOSITION OF CITRUS PULP Wet citrus waste containing around .20% matter dry represents about half of the weight of fresh oranges, but this can vary from 50070% depending on species, variety, husbandry and processing techniques. The dry matter comprises mainly peel (600 65%) and segment pulp (30035%) with some residual seeds (040%). Variation depends largely on species and varieties within species. Chemical analyses have been used to give some indication of quality and feeding value of citrus waste for livestock and most of the published values have come from research carried out . in U.S.A. (see Harris et al. 1982). The average nutrient composition of dried citrus pulp shown in Table 1 summarizes results mainly obtained in Florida over wide range of samples. These values are not markedly different to values obtained in our own laboratory for MIA dried citrus pulp produced at RCL Biocon. TABLE 1 Estimated nutrient composition of dried citrus pulp A study of the composition of ci.trus Pulp in Spain indicated that Spanish dried citrus Pulp i S similar to Florida and MIA material and added acid dete re ent fibre and acid detergent lignin analyses which are also shown in Table le 301 Cell wall constituents or nwltral cictergent fibre levels in ruminant animal feeds appear to be a major factor in determining rumination time, at least as far as hays are concerned. Data on citrus pulp is limited but a level of around 27.28% neutral detergent fibre or CWC in dried citrus pulp has been found overseas (Welch and Smith 1971) and confirmed in Australia. Although citrus pulp is primarily used as a source of digestible energy in stockfeeds it does contain a significant amount of crude protein. Consequently it is of value in evaluating citrus pulp as a livestock feed to have some idea of the nature of this crude protein material. Amino acid profile data are limited and Table 2 shows a summary of data available at the present time. Only about half of the nitrogen in citrus pulp appears to be contributed by true protein. TABLE 2 Estimated amino acid composition of dried citrus pulp Although there are other chemical constituents in citrus pulp which may be of nutritional significance the analyses given in Tables 1 and 2 are those currently accepted by the majority of advisers and extension officers as being of most significance in comparing various feed ingredients as sources of nutrients for livestock. 302 CITRUS PULP FOR LIVESTOCK AND POULTRY One of the continuing responsibilities of nutritionists is the potential value of new or improved to determine feed ingredients. Almost every ingredient has some limitations, .but often they can be overcome. Soyabean meal for example was considered almost useless as a feed ingredient for poultry until it discovered that was proper heating inactivates the antinutritional factors in it. Chemical analyses are the firststage in nutritional evaluation. They are however of little use in predicting animal performance without animal acceptability data, digestibility trials and comparative feeding trials. The following section is concerned with trials carried out with live animals. Dried citrus pulp for poultry There is very little data on the use of citrus pulp in poultry diets, however a figure of 5.52 MJ/kg has been documented as a metabolizable energy value for use in formulating poultry feeds (Scott et al. 1976). It has been suggested that pullets and laying hens can utilize 5% dried grapefruit pulp with no effect on rate of growth or egg production, whereas even this low level gave unfavourable results with young poultry. Dried citrus pulp meal has been used in broiler diets up to 40% but feed consumption and feed conversion were both increased while weight gain was depressed when the inclusion of citrus pulp meal was raised from 20 to 40% (see El Moghazy and Boushy 1982). The pigment in orange and tangerine flavedo showed a 30.1% utilization for egg yolk pigmentation (see Kesterson and Braddock However it has also been claimed that 1976) in one laboratory. 2.5~5% dried citrus pulp can depress yolk colour even in the presence of 7.540% lucerne meal. Australian data suggests that MIA dried citrus pulp at a dietary level of 5% had neither beneficial nor adverse effects on egg yolk pigmentation either in t 11 e yrcsencie or absence of synthetic oxycurotenoids. However t h c2 r t? was 8 tendency for decreased production, WQ weight und feed intake irl these trials, the mat-nitude of which iu cause fatcaution, with hens fed 5% MIA dried citrus pulp (Karunajeewa The work on yolk pigmentation is further confused by data from trials in which citrus sludge was fed to layers. Yolks were described as ))rnore orange' as dietary citrus sludge levels were increased. No significant flavour differences were detected by a taste panel for either yolk or albumen in these experiments (Angalet et al. 1976). Dried citrus pulp is not generally used in poultry feeds in Australia. lg'[d) l Dried citrus DU~D for Digs As in the case of poultry very little work has been done on the use of citrus waste in pig diets. A digestible energy figure of IO.6 MJ/kg has been determined with pigs in metabolism cages (Farrell et ale 1983) which equates with a total digestible nutrients figure of 58e This is considerably higher than the figure of 45 total digestible nutrients for swine quoted in the Feedstuffs Yearbook. However it is much lower than the 303 Published work on amino acid availability from citrus pulp fed to pigs appears to be non-existent. Despite the limited published data dried citrus pulp is used in commercial balanced pig diets. A recommendation of 5% maximum is general in the stockfeed industry in Europe with none in creep feeds for baby RCL Coprice Division has successfully used dried citrus pigs. pulp in sow feeds for many years at a 5% level of inclusion. It is however important if using separate dry sow and lactating sow diets to include citrus in both, otherwise palatability problems may occur on changeover. Feedback from clients suggests 5% dried citrus pulp in sow feeds together with some ground rice hulls in dry sow feed aids in the prevention of constipation around farrowing. Furthermore there is no doubt that 5% dried citrus pulp in these fibrous feeds aids in production, enabling better quality pellets with less pellet breakdown to be produced in a shorter time with reduced energy costs. Dried citrus pulp for horses Citrus pulp had been fed to horses in Florida for many years without detrimental effect despite the fact that no published palatability data were available and no digestibility trials nor comparative feeding trials had been carried out specifically with horses fed citrus pulp prior to 1979 (E.A. Ott personal communication). However there was already a wealth of published information indicating that citrus pulp was a valuable feed ingredient for dairy cattle, fattening cattle and fattening Research work carried out at the University of Florida lambs. (Ott et al. 1979) has since shown that dried citrus pulp can be incorporated into horse diets as a substitute for oats without adversely affecting digestibility of the energy yielding components of the diet. However protein digestibility was Two acceptability trials, utilising eight mature horses reduced. were conducted to compare coarse grain concentrates containing zero or 30% citrus pulp as a substitute for oats. Acceptability of the 30% dried citrus pulp diet was a problem. Six horses refused the citrus pulp concentrate, consuming less than a tenth of the feed offered. horses were Four offered le75kg/lOOkg bodyweight of complete pelleted diets containing 0, 15 or 30% dried citrus Acceptability was goode Three of the horses consumed all Pulp. the feed offered while one horse refused 3% of the diet containing 30% Citrus. Apparent digestibility of organic mutter, ether extract and gross energy for the three diets were not significantly different. However apparent digestibility of acid detergent fibre and nitrogen free extract were higher for the dried citrus pulp diets and crude protein digestibility lower with the 30% dried citrus pulp diet. It was concluded that Florida dried citrus pulp is a suitable ingredient for inclusion in pelleted diets for mature horses at levels up to 15% as a replacement for OatS. 304 Horse feeds are of considerable significance to RCL mainly as an added tialue product for utilizing broken rice and rice milling Operations. rice Pollard fro.m Consequently, we have always endeavoured to improve our products where possible and provide products for which there is a strong market demand. During the drought of 1982/83 it became apparent that roughage was so expensive that horse owners in the Melbourne region were feeding very little of it and the ratio of pelleted feed to roughage fed was reaching undesirable levels. Digestive disturbances may occur in horses when supplementary cereal based pellets are fed, particularly in a group feeding situation when In order to overcome this a roughage is in short suPPlY* pelleted high fibre ration of relatively low energy was designed and this was tested by feeding 25 Victorian police horses in a trial at Attwood (Huntington and Hutton 1986). The horses were fed for four months on lucerne hay, grass hay and supplementary high fibre pellets. No untoward effects were noted during the trial and all horses maintained or improved their body condition. The pellets consisted of 22.5% broken brown rice, 20% rice Pollard, 25% ground rice hulls, 10% sunflower meal, 10% dried 8% lucerne meal, 2% bentonite, 0.5% dicalcium citrus pulp9 phosphate, 0.5% salt, 1.25% calcium carbonate and 0.25% of a micropremix designed to generously cover all known nutrient Rice hulls are a very cheap source of fibre requirements0 continuously available regardless of conditions of drought or Citrus provides plenty. digestible energy without Pulp additional starch and is an excellent pelleting aid ensuring high The specification of the high fibre pellets was quality pellets. gMJ/kg digestible energy, 10% crude protein, 5% crude fat, 18% crude fibre, 1.1% calcium, 0.7% salt and 0.57% phosphorus. The horses included in the trial were Thoroughbred or Thoroughbred Warmblood crosses of various ages. They included pregnant mares, growing horses, spelling horses and those doing light work. All had access to pasture, but the amount was variable. They were accustomed to a mixed supplementary diet. The basic feed was 4kg pellets and 3kg each of lucerne and grass hay daily. Body condition, pasture availability and type of work were factors leading to variation in this basic pattern. Feed acceptance was very good and horses were keen t o eat the pellets. Initially a number of horses had loose droppings, but these returned to normal quickly. No health problems were encountered throughout the trial. This work confirms Florida data obtained using citrus pulp in horse feeds and indicates that horses can be fe satisfactorily on a ration which includes ground rice hulls for extended periods. W'hen fed in combination with lucerne and grass hay, high fibre pellets containing considerable quantities of ground rice hulls and dried citrus pulp can provide a convenient, cheap, balanced safe, diet for horses. In group feeding situations and drought conditions such pellets would be much safer to feed than traditional cereal based pellets. 305 d In addition to the research at AttwoGd on high fibre diets p 0 1 i l'r e h 0 c 8 e s 9 it was decided to tt*ial. our standard mature hcl r:w p E' 1. 1. t) 2. $3 w.i 1. h t3 .i t h e c 1 '1 $ t' i 1. I' 11 3 \`\I 1 $1 L' 1' ;c `b :g t.: i t I' \I 3 p II L p TheBe t; I' i t4 1 rl w t.9 I.' It ? d t! 8 i 6: 11 (? d ~3 1~ tn p 1, y t 0 r t? p 1 :A c i ng broken rice. assess consumer acceptance a n d palat:lbiLity 01' the p e l l e t s &IT horses under commercial conditions. In the first series of trials the 15% citrus pellets were supplied to 8 owners and trainers for feeding a total of 27 horses. Horses included Showhacks Appaloosas, (Thoroughbred), Dressage horses (Thoroughbred) and Standardbreds. All horses were being worked, the work ranging from light exercise to heavy race training. Virtually all of the horses had been receiving our standard mature horse pellets prior to the trials. Most of the horses accepted the 15% citrus pellets initially but 8 horses did not and 4 of these refused completely. With the horses that did accept the 15% citrus pellets we noticed that feed was being left after 4-5 days and after a few more days at least half of these horses were refusing the pellets. In some cases if the experimental pellets were mixed 50:50 with our standard horse pellets acceptance was improved. Many trainers commented that the pellets tasted bitter and that was the reason for rejection after a number of days. f 0 Il In the second series of trials the 7.5% citrus pellets were supplied to 16 different trainers. Close on 70 horses were involved. The majority of these were Standardbreds but some Thoroughbreds and German Warmbloods were included. Initial acceptance was good with only 5 horses proving difficult. It maybe significant that 3 of these were yearlings. The only horses to completely reject the citrus ration were 7.5% yearlings. However in two cases trainers actually preferred the 7.5% citrus ration to the standard ration. After two weeks very little rejection occurred and the majority of the pellets were In 12 cases rejection of the 7.55 citrus pellets being consumed. was noticed.after a period of a few weeks. In all cases when the standard ration replaced the experimental pellets all horses accepted the feed change. Furthermore when the 7.5% citrus pellets were reintroduced they were readily accepted only to be rejected later by a few horses. Other horses which had not previously rejected 7.5% citrus pellets did so occasionally and with one horse rejection did not occur until 3 months later. However the majority of horses showed no indication of any problems. Dried citrus pulp even at the 7.5% level offers major benefits in feedmill efficiency. Throughput in our mill was doubled with 7.5% dried citrus pulp replacing 7.5% ground broken rice. Furthermore pellet durability was improved from 92.8% for the standard mature horse pellet to 95.8%e Despite these advantages and the observations from Florida that dried citrus pulp is a nutritious feed for horses it is clear that some horses do not appear to like it. Consequently as the horse feed market in Australia is so sensitive our policy is now not to use any citrus pulp in branded horse rations. 306 Citrus pulp for beef cattle In a digestion trial with dried grapefruit refuse with 4 steers, Neal et al. (1935) at the Florida Station found 24.8% of the crude protein, 71.5% of the crude fibre, 92.4% of the free extract nitrogen and 7 9 . 4 % o f the crude fat to be digestible. The dried grapefruit used yielded 1.2% digestible protein and 76% total digestible nutrients and was palatable. It was also noted that dried orange peel seemed to be as palatable as dried grapefruit refuse and that dried grapefruit and orange cannery refuses have a laxative action when fed as a large proportion of the ration. The general effects of the dried grapefruit refuse were noted as being favorable as indicated by thrifty appearance, gloss of the coat of hair, and improvement in thickness of flesh. These results were supported by Texas Agricultural Experiment Station (Jones et al. 1942). Dried citrus pulp, when fed to replace not more than 25% of the ear corn chop with husk, resulted in the production of practically equal gains but slightly higher finish than groups fed ear corn chop with husk as the carbohydrate concentrate portion of the ration. The replacement of as much as 60% of the daily allowance of ear corn chop with husk by dried citrus pulp produced a feed which was less palatable, and had slightly greater laxative effect, and reduced feed consumption, gains and finish. In these tests a mixture of 75 parts ear corn chop with husk and 25 parts dried citrus pulp as the carbohydrate concentrate produced satisfactory results. There were no distinguishing differences in the colour of fat between the check groups fed ear corn chop with husk and those which received the dried citrus pulp as replacement of varying amounts for ear corn chop with husk. Numerous trials have been reported since the pioneering studies from Florida, Texas and also California (see Jones et al. 1342) and they have consistently reported favourable KGTKiTS (Peacock and Kirk 1969; Kirk and Koger 1970). Furthermore a reduction in digestive disturbances with cattle on full feed including dried citrus pulp has been reported. Dried citrus pulp either loose or as pellets was found to result in reduced rumen ammonia levels for cattle fed urea supplements (Pineon and Wing The data from this trial suggested that citrus pulp at 19%). increased nitrogen utilization since it decreased urea 38055% nitrogen in the blood of these cattle. The inclusion of dried citrus pulp to replace corn meal in beef cattle rations was also shown to affect the fatty acid composition of carcass fat through its effect on the volatile fatty acid production in the rumen (Cabezas et al. 1965). Citrus pulp favoured acetate production at the expense of propionate and resultant carcase fat as measured over the ribs was harder for citrus fed cattle then those on corn diets. All these trials relate to trials from U.S.A. Material from Cyprus appears to be no different (Hadjipanayiotou and Louca The pattern of digestion of citrus pulp in ruminants 19%). whereby a highly . digestible material promotes an acetate fermentation 307 rather than the propionate fermentation associated with highly digestible starch based diets is interesting. In this context it has been observed recently that monensin which promotes propionate type fermentation in ruminants and decreases acetate was equally effective whether the primary energy source in beef cattle diets was corn or dried citrus .pulp (Vijchulata et al. 1980). Our own trials in the MIA have been somewhat limited. However it does appear that young growing cattle 8-12 months old weighing 2500350kg will gain 1.25kg per- head/day on good winter pasture with supplements of 3kg/head/day hay and 2kg/head/day of 14% protein pellets containing 25% dried citrus pulp. This rate of gain is similar to feedlot performance and was required to take purebred Red Poll cattle into the keenly sought 3500420kg yearling steer weight range in our trial. It is also worth noting here that wet citrus pulp is still fed to beef cattle in the MIA. Cattle appear to like it and eat it in the presence of fresh green irrigated feed or on dry feed in upland paddocks. Even when it has been standing around for days, or even weeks, in the hot sun and becomes hard and dry it appears to be readily eaten by beef cattle. Citrus pulp for dairy cattle It is clear from the previous discussion that beef catt