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Some factors affecting the future composition of UK compound animal feeds
Animal Feed Science and Technology, 6 (1981) 1--14 Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands
1
SOME FACTORS AFFECTING THE FUTURE COMPOSITION OF UK COMPOUND ANIMAL FEEDS
P.N. W I L S O N , T.D.A. B R I G S T O C K E
and N.H. C U T H B E R T
B O C M Silcock Ltd., Basing View, Basingstoke, Hants, RG21 2EQ (Gt. Britain) (Received 25 January, 1980; accepted for publication 25 August 1980)
ABSTRACT
Wilson, P.N., Brigstocke, T.D.A. and Cuthbert, N.H., 1981. Some factors affecting the future composition of UK compound animal feeds. Anita. Feed Sci. Technol., 6: 1--14. Changes in the livestock compound-feed industry are outlined. It is noted that the change to least-cost formulation of diets manufactured to a strictnutritional specification has increased the economic and biological efficiency with which different types of feed have been utilised by livestock. Nevertheless, the feeding of livestock continues to depend on large quantities of raw materials which are potentially food for humans. A number of reasons are given w h y crop by-products and other waste materials are not fully utilised by the c o m p o u n d trade, although considerable efforts have been made by the industry to find economic and acceptable alternative raw materials for c o m p o u n d diets. In the case of B O C M Silcock, once a raw material has been successfully evaluated at the Unilever Research Laboratories at Colworth House, extensive development work is conducted at two development farms. T w o different procedures are described and illustrated: (i) inclusion of the raw material in question at varying levels in a standard diet to assess effect on performance, and (ii)palatability test work, whereby a bland control-diet is partially replaced by the raw material under test, at levels appropriate to the likely commercial use of the test ingredient. However, the extent to which any waste material is eventually utilised will largely depend on its economic value, relative to the costs of competing raw materials. It appears unlikely that there will be any major availabilityof new cheap alternatives to cereals in the short term.
INTRODUCTION
Over the past 30 years, there have been dramatic improvements in livestock production and dramatic increases in compound-feed usage. For instance, the spectacular growth and intensification in the UK broiler industry (Richardson, 1976) has meant that farmers have bought more compound feed, because of its high quality nutritional specification and its convenient physical form. In addition, the change from "target" to "least cost" formulation of diets, manufactured to a strict nutritional specification, has also increased the efficiency with which the different types of feed have been utilised by livestock (Wilson, 1975).
0377-8401/81/0000--0000/$02.50, © 1981 -- Elsevier Scientific Publishing Company
In spite of these technical developments, the feeding of livestock still depends on large quantities of raw materials which are potentially useful as food for humans (Wilson, 1977) (Table I). There has been a general trend over the past 15 years for an erratic run
TABLE I I m p o r t s o f principal f e e d s grains i n t o t h e U.K. ( ' 0 0 0 t o n n e s )
Barley Maize Sorghum Feed wheat
Pre-war 1953154 average
Average of 1967/69
1973
1974
1975
1976
1977
1978
1979 forecast
903 3286 ---
315 3550 183 800
292 3389 72 900
812 3272 425 270
502 3029 475 530
646 3765 317 845
916 4106 169 690
350 3336 21 30*
360 3340 40 n/a
1275 1436 28 --
*Estimate. Year J u l y / J u n e 1 9 5 3 / 5 4 . 1973 o n w a r d s , calendar years. R e f e r e n c e s : A n n u a l R e v i e w o f Agriculture White Paper, A n n u a l R e v i e w o f A g r i c u l t u r e White Paper, A n n u a l R e v i e w o f Agriculture White Paper, A n n u a l R e v i e w o f A g r i c u l t u r e White Paper, U K A S T A ( 1 9 7 7 , 1979a).
1977. 1978. 1979. 1980.
Following the long-term trend, therefore, rather than the present short-term over-supply of world grain, there is good reason why all prudent steps should be taken to find and use alternative sources of energy for animal feeds. The Netherlands has been very successful in this respect by substituting cheaper sources of feed for expensive cereals (De Boer, 1978). Thus, Dutch cassavaimports have risen from 1.08 Mt in 1972 to 2.02 Mt in 1977. Indeed, the EEC as a whole increased the imports of cassava from 0.41 Mt in 1962, to 3.92 Mt in 1977 (Phillips, 1974;Waiters, 1978). Phillips {1979) has postulated that by 1985 cassava imports into the EEC will reach 6 Mr, unless political considerations result in artificial barriers to international trading in this commodity. There are already signs that such barriers are being effected as a result of political pressure from the "cereal lobby". Table II examines the percentage composition of compound feeds in UK by the main classes of ingredients. The increasing use of cereal by-products in cattle and sow rations should be noted [United Kingdom Agricultural Supply Trade Association (UKASTA) 1977 and 1979b]. Indeed, for the first 6 months of 1978, cereals contributed only 12% of the total composition of cattle grazing rations, whilst with diets for pregnant/lactating sows, the pro-
II
5 16
--
8 1 2
1 . -1
Animal proteins Meat and bone meal Fish/Herring meal Other Total animal proteins
Miscellaneous Molasses Fat Minerals and vitamins Cassava and cereal replacer pellets Other Total miscellaneous
1 5 3 3 12
Vegetable proteins Soya Groundnut/sheanut Rape Other Total vegetable proteins
.
8 2 5 5 6 5 31
Cereal by-products Wheatfeed/other milling offals Rice bran Dried grains/grain screenings Maize gluten Cereal pellets Other Total cereal by-products
7 2 3 10 2 24
3 4
1 .
3 2 6 3 14
9 2 5 6 1 7 30
--
-28
6
-40
1O 18
3
8
6 17
--
--
-. ---
1 4 1 4 10
1O 4 10 2 6 6 38
13 15 6 1 35
3 3
8 1 4 10 6 29
--
1 4 4 1 10
9 2 12 7 2 7 39
5 14 --19
5
4 1 1 -1 7
4
3 1
1 6
--
-.
19 1 1 -1 -22
27 24 7 3 61
.
1 2
1
3 1 2 7 -13
--
10 1 . -11
20 2 3 2 2 -29
12 32 1 -45
Pregnant sow 1976 1978
21 13
Pigs
Cattle Summer grazing 1976 1978
by main classes of ingredients.
Standard dairy 1976 1978
of British compounds
1977, 1979b)
Cereals Wheat Barley Maize Other Total cereals
1978 (UKASTA,
Percentage composition
TABLE
-1 4
1 1 1
2 3 1 6
12 . . 1 13
9 1 ---1 11
20 22 20 4 66
1976
.
1 2 1 3 1 8
1 2 5 8
. 16
16
1 -9
8
27 28 3 1 59
.
-1 5
1
3
4
--
--
1 3
1 . 1O
9
15 1 1 ---17
17 29 15 3 64
.
1 3 4
3 2 1 7 1 14
--
13 . . . 13
14 2 . 3 2 -21
11 36 1 -48
Finishing/ fattening 1976 1978
.
.
1 1
.
.
2 4
1 1
2 10 1 13
. 15
15 .
. .
. .
34 . 25 8 67
.
.
.
.
.
. .
.
.
.
1 6
.
. .
. 3 2
1 7 1 9
21
21
.
.
4 4
.
16 -60
44
.
.
.
.
. . 1 1
.
.
. 3 2 . 1 6
2 8 1 11
10
.
10
.
44 . 8 20 72
.
. 9 9
. 1 6
3 2
1 7 1 9
14
.
14
.
.
2 -62
60
Broiler fisnishers 1976 1978
in July/December
Broiler starter 1976 1978
Poultry
of survey results obtained
1978
----
Rearing
Comparison
.
.
.
.
.
2 11
1 -8
4 1 1 6
9
7 2
1 6
1
4
25 5 37 1 68
1976
.
Layers
1 8
1
5
1 11
1 9
--
--
4 1
1 13
12 --
--
5
1 63
21
37 4
1978
1976 and
portion of cereal by-products in compound feed had risen to 32%. Only in poultry formulations are traditional cereals still the main energy-rich ingredients (UKASTA, 1978). More recent data (UKASTA, 1980) show that little cassava is currently being used in compound feed rations and, consequently, cereal usage has tended to return to its pre-1978 level. Since the great majority of compound feed manufacturers use least-cost formulation, changes in ingredient prices will have a pronounced effect on the composition of compound feeds. In this respect, it must be realised that demand for any raw material by the animal feed manufacturer is determined by four factors. (i) The price of the ingredient in relation to its nutritional specification. (ii) The price of acceptable substitutes for the ingredient. Off) The upper and lower inclusion limits on the ingredient fixed by the compounder. (iv) Other considerations, such as handling and processing characteristics. (Crabtree, 1972; Wilson, 1980). H U M A N F O O D versus A N I M A L F E E D
It has been argued (e.g., Mellanby, 1975) that a change to a vegetarian type of diet in developed countries would lessen the apparent conflict between human food and animal feed. Only 50% of the total world grain-production is consumed directly by humans, 40% being given to livestock and the residual 10% being used for seed and other purposes (Anderson, 1975). As Holmes (1976) has shown, in terms of protein and energy yield, the most efficient food chain is that in which crops are consumed by humans. However, human beings are usually omnivores and not vegetarians, so it follows that social attitudes will determine that meat, milk and eggs remain important components of their diet. Indeed, certain essential nutrients, such as vitamin B12, are not found in vegetable protein sources. Dale (1979) noted that world meat-consumption in 1978 increased more rapidly than production, leading to some decrease in stocks. Survey work indicates that, throughout the world, meat consumption rises in direct relation to the increase in per capita gross national product. Animals are able to utilise crops, such as grass, straw and forage crops, which are considered unsuitable for human consumption. Wilkinson (1976) suggested that forage crops probably comprise the major feed of beef cattle in all major beef-producing areas. Even in the USA, where large quantities of cereal grain are given to beef animals, Wedin et al. (1975) indicated that forage crops account for 73% of total feed units 1. Furthermore, food crops destined for direct human consumption usually produce by-products unsuitable for human consumption, which can indirectly provide human food when given to animals. Sloneker (1976) calculated the amount of crop wastes ~Nutritional equivalent of 0.454 kg of maize grain.
in the US which could be given to livestock. These wastes, which a m o u n t to 300--500 Mt on a fresh weight basis, are mainly by-products and crop residues from maize, soya bean, wheat and sorghum production. The relationship between human and ruminant has generally been viewed as synergistic (Fitzhugh, 1978). However, the current pressures of a rapidly increasing world population, with an increasing expectation for an adequate diet, have led to an increasingly objective approach to evaluating ruminants as producers of human food (Blaxter, 1975; Pimmental et al., 1975; Wedin et al., 1975). Ruminants do not need to compete with humans in their dietary needs, whereas pigs and poultry usually do. Ruminants are able to graze areas inaccessible because of topography, climate, etc. Indeed, extensive ranching systems consume very little support energy and may, therefore, be considered energetically efficient. SEARCH F OR A L T E R N A T I V E ENERGY SOURCES TO TRA D I TI O N A L CEREALS
There are a n u m b e r of factors determining the extent, to which crop byproducts and other alternative sources of energy are utilised by the c o m p o u n d trade. These are: (i) availability of information about their composition and their nutritive value; (ii) availability of adequate handling and processing facilities; (iii) possible variations in composition; (iv) safety and efficacy of the raw material in question; (v) logistic problems of availability in quantity and seasonality of supply and (vi) need for transportation and processing. In this respect, Orskov (1977) suggested that the producers of crop byproducts may exert pressure for these to be utilised in animal feeds, largely in an to reduce a disposal problem, rather than to provide a potentially useful feed effort to reduce a disposal problem, rather than to provide a potentially useful feed ingredient. He suggested that by-products are sometimes included at a low t h e y make a meaningful contribution or not. He further noted that there was a wide variation in composition of such materials as distillery and brewery wastes. In this respect, it is interesting to examine the variability of a raw material, such as biscuit meal. In proximate analyses for samples from 8 different sources, the following means and standard deviations were obtained: oil 14.5% -+ 5.5; crude protein 10.2% + 1.6 and salt 1.2% + 0.7 (Wilson and Brigstocke, 1978, unpublished data). Wilson and Brigstocke (1977a) noted that the feasibility of recovering large quantities o f vegetable residues for animal feeding has been enhanced by the centraiisation of processing in large packing stations. The use of vegatable residues is likely to increase, but difficulties are posed by seasonal availability and the general problem that, as labour becomes scarcer and more expensive, the securing of the main crop will take priority over secondary operations in respect of residues.
Nevertheless, over the past decade, considerable efforts have been made b y the c o m p o u n d trade to find alternative raw materials for c o m p o u n d diets. Whilst this effort has n o t been entirely unrewarding, as illustrated by the success of up-grading of cereal straw (Wilson and Brigstocke, 1977b; Cuthbert et al., 1978; Thickett et al., 1980), there is no real prospect of finding large quantities of cheap by-products which could be directly incorporated into animal feeds as substitutes for traditional raw materials. Instead, a more systematic approach has been an initial assessment of the potential tonnage of material available followed by chemical evaluation and feeding trials with each potential raw material. However, the nutritive value of the material has often been found to be less than might have been expected from the gross chemical analysis. In many cases, the cost of preparing the by-product in a form for transport over long distances, and the additional costs of detoxification and/or up-grading the material to release its potential nutritional value, have been found to exceed its economic value relative to conventional raw materials ( R o b b , 1976). Williams (1978) has considered the future European feed industry and, in particular, the optimisation of raw material usage, noting that it is in relation to energy sources that the future of c o m p o u n d feeds will be most strongly influenced by EEC policy. Thus, the use of cassava and cereal replacer pellets (containing 49% cassava) in c o m p o u n d feeds could be seriously reduced if the recent EEC policy of maintaining high cereal prices whilst charging a low import d u t y on cassava is altered. This will have a major effect on attempts to lower the inclusion levels of cereal grains in the diets of farm livestock in the UK. Furthermore, Thailand, the world's largest exporter of cassava, is attempting to diversify its crop production with less dependence on this major cash crop, although cassava exports have been extremely successful in generating foreign capital, which in 1979 was valued at US $ 333 million (Phillips, 1979). E V A L U A T I O N OF NEW RAW MATERIALS BY THE COMPOUND FEED INDUSTRY
In the case of BOCM Silcock, once a raw material has been successfully evaluated at the Unilever Research Laboratories at Colworth House, extensive development work is conducted at one of the two BOCM Silcock Development Units. Two experimental procedures are employed: inclusion of the raw material in question at varying levels in a standard diet, and palatability test work, whereby a bland control-diet is partially replaced by the raw material under test, at levels appropriate to the potential commercial use of the test ingredient To illustrate these two procedures, two recent trials are discussed. T h e use o f cassava in a broiler d i e t
Creswell (1978), in a literature review of the use of cassava roots in pig and poultry diets, noted that cassava can contribute substantially to livestock
energy requirements, provided such diets are properly balanced in limiting nutrients (especially methionine) and the level of a potentially toxic glucoside in the cassava is minimised. Furthermore, if the diet is then pelleted to reduce volume and increase feed intake, and the "sweet '~ varieties are used, then cassava could replace up to 50% of the cereal portion of the diet. More recently, Oke (1978) described the problems of the use of cassava as animal feed. In a trial at the BOCM Silcock Poultry Development Farm at Stoke Mandeville, Marangos et al. (1978) evaluated cassava in a standard broiler finisher diet. Four thousand birds (Ross I) were fed on the same broiler starter to 21 days of age and then finished to 49 days on one of four experimental diets, containing 0, 7, 14 or 21% cassava. The composition of the diets are shown in Table III and their analyses in Table IV. Bird liveweights at the end of the trial were generally below average, but this was not related to any particular treatment. Performance data for the two sexes combined are given in Table V. Sex and diet interactions were not significant and, therefore, the combined figures can be considered to be representative of the performance of birds on each treatment. Weight gains between 22 and 49 days of age were not significantly different between treatment groups. However, there was a trend for liveweight gain to improve with the increase in the level of cassava. This improvement reached a m a x i m u m at the 14% inclusion level. Final liveweight was consisTABLE III Cassava in diets for broiler chicks: composition of experimental diets
Ingredients Wheat Wheatflour Cassava Extracted soya bean meal Herring meal Meat and bone meal Durabond Vegetable oil Animal fat oil Salt Premix*
Cassava (%) 0
7
14
21
47.24 25.00 0.00 10.97 5.19 4.72 2.00 3.20 1.00 0.13 0.55
38.11 25.00 7.00 12.90 5.20 4.70 2.00 3.40 1.00 0.14 0.55
28.80 25.00 14.00 15.00 5.20 4.60 2.00 3.70 1.00 0.15 0.55
19.58 25.00 21.00 17.00 5.20 4.50 2.00 4.00 1.00 0.17 0.55
*Premix (g/tonne): copper sulphate, 100; zinc oxide, 100; ferrous sulphate, 300; vitamin AD3,15; vitamin B6 (pyridoxine), 2; vitamin B~:, 12; vitamin D 3, 7; vitamin E, 20; choline chloride, 500; potassium iodide embamix, 2; vitamin B2, 5; calcium pantothenate, 15; folic acid, 1; nicotinic acid, 10; DL-methionine, 2120; L-lysine HCI, 880; manganous oxide, 125, vitamin K, 6 ; Payzone 25%, 41; Elancoban, 500; wheatfeed, 739.
TABLE IV T h e o r e t i c a l a n d a c t u a l analyses o f e x p e r i m e n t a l diets (%) Control Theo. Moisture Oil Protein Fibre Salt Calcium Phosphorus
Act.
12.32 6.02 19.25 2.42 0.45 0.86 0.60
7% Cassava
14% Cassava
21% Cassava
Theo.
Theo.
Theo.
12.90 5.90 19.40 1.68 0.43 0.85 0.63
Act.
12.12 6.26 19.25 2.55 0.45 0.86 0.60
12.80 6.01 19.60 2.02 0.43 0.85 0.60
11.92 6.51 19.25 2.69 0.45 0.86 0.55
Act. 12.70 6.34 19.40 2.20 0.46 0.88 0.53
11.72 5.76 19.25 2.83 0.45 0.86 0.55
Act. 13.00 6.35 19.60 2.56 0.40 0.89 0.53
Monensin
(mg/kg)
100
78.8
100
64.5
100
96.3
100
87.3
TABLE V P e r f o r m a n c e d a t a o f birds fed o n e x p e r i m e n t a l diets, 0 - - 4 9 days Cassava in diet (%)
Liveweight(kg) days:
Feed intake(kg) days:
Feed/gain for days:
Gain 22--49
0-21
22--49
0--49
0--21
22--49
0--49
1.822 1.863 1.879 1.875
1.372 1.398 1.421 1.404
0.754 0.756 0.759 0.761
2.888 2.878 2.917 2.943
3.642 3.634 3.677 3.704
1.679 1.627 1.662 1.622
2.114 2.068 2.062 2.106
2.004 1.955 1.962 1.981
0.013
0.017
0.016
0.002
0.014
0.015
0.045
0.027
0.016
NS
NS
NS
*
*
*
NS
NS
NS
21
49
0 7 14 21
0.450 0.465 0.458 0.471
SE of mean Significance of
difference *P< 0.05
t e n t with the effect on gains over the finishing period. A difference of 57 g was f o u n d between the control birds and those fed on the 14% cassava diet. The test for the main effect of the diet was close to significance for each of the feed intakes and the linear c o m p o n e n t of the effect was significant for the intake. Although differences in feed intake were of little consequence during the starter period, this relationship was appreciably greater after the cassava diets were introduced. Results suggest that intake increased with increasing levels of cassava. Similar findings have been found in work with dairy cows when comparing nil and 40% cassava inclusion levels in a standard compound diet (Brigstocke et al., 1979). For this broiler trial, regression equations
in which feed intake (g) was correlated with the proportion of cassava (C, %) were significant and are shown below. Intake ( 0--21 days) = 0.7544 + 0.00034 C Intake (22--49 days) = 2.8754 + 0.00291 C Intake ( 0--49 days) = 3.6296 + 0.00327 C As feed intake increased, the trend was for feed conversion efficiency to improve with the level of cassava inclusion, at least up to 14%, whereas at 21% the value approximated to that of the control. Feed costs at the time of the experiment (calculated on the basis of wheat at £85/t, cassava £64/t and soya bean meal £108/t) did n o t differ significantly between the treatments, even though the cassava-fed birds ate more feed. The margin over feed cost approached significance for the birds fed the cassava-containing diets as against the control, and averaged 2.47p/bird more than the control birds. This reflected the average improvement in carcase income of 2.21p/bird for the same birds.
The palatability o f dried coffee residue meal in a dairy cow c o m p o u n d diet Dried coffee residues are a by-product from the manufacture of instant or soluble coffee. The UK o u t p u t of dried coffee residues varies between 25 000 and 35 000 t / a n n u m on a dry basis. Ali et al. (1977) have shown t h a t this raw material has a high c o n t e n t of energy, fat and fibre, but d o u b t has been expressed about its digestibility and acceptibility by the ruminant. Coffee residue could be potentially useful as a raw material in ruminant c o m p o u n d feed because of its high oil content. Consequently, a palatability trial carried out at the BOCM Silcock Cattle Development Unit, Barhill, by Cuthbert and Thickett (1976) tested inclusion levels of 0, 2.5, 5, 7.5 or 10% dried coffee residue meal, formulated with a corresponding proportion of a bland basic cattle diet as shown in Table VI {diets A--E, respectively). Analysis of the coffee residue used is included in Table VI. Diets were manufactured as 9.5 mm extrusions. The trial involved 20 dairy cows and 10 heifers averaging 16 weeks post partum. Six blocks, each of 5 animals, were used in a latin square design. C o m p o u n d diets were given at 0.4 kg/kg of milk. Average yields at the start of the trial were 22.4 kg/day for cows (range 16.1--31.1) and 17 kg/day for heifers (range 11--18.6). The animals were fed on grass silage to appetite, and a minimum of 5 kg c o m p o u n d diet per head per day was given in two feeds. Any allocation over 9 kg of c o m p o u n d diet was given as a third feed at 22.00 hours. The rate of ingestion of 3.6 kg trial diets, weighed into containers from which the feed was subsequently consumed, was timed on three days of each test week. Refusals were recorded on all days. A refusal was defined as a failure to eat the prescribed anowance within 15 min. The 3.6 kg was given in one allocation in the afternoon and the balance of daffy compound, rationed according to milk yield, was given at a separate time. The trial lasted for 5 weeks and each cow received each test diet for 1 week.
10 TABLE VI Dried coffee residue meal in diets for dairy cows: formulation of experimental diets (%) Diet A
Dried coffee residue meal B
C
D
E
Basal diet* 100 Dried coffee residue meal 0
97.5 2.5
95.0 5.0
92.5 7.5
90.0 10
---
Theoretical analysis Oil Crude protein Crude fibre Salt Calcium Phosphorus
2.4 16.3 5.0 0.82 0.94 0.70
2.8 16.2 6.0 0.80 0.91 0.69
3.1 16.0 6.9 0.78 0.89 0.68
3.5 15.8 7.9 0.76 0.88 0.66
-------
Actual analysis - - C u m u l a t i v e farm samples** Moisture 13.0 12.8 12.8 Oil 2.1 2.4 3.0 Protein 16.9 17.0 16.8 Fibre 4.3 5.0 5.5 Salt 0.84 0.84 0.80 Calcium 0.74 0.70 0.66 Phosphorus 0.70 0.67 0.66 Sodium 0.35 0.33 0.33 Ash 5.7 5.6 5.3 Free fatty acids 17.4 15.0 14.1 Potassium . . . .
12.9 3.3 16.5 6.1 0.76 0.65 0.65 0.30 5.2 13.8 .
12.8 3.8 17.8 7.0 0.78 0.59 0.62 0.30 5.0 11.9
8.97 17.64 19.60 -0.08 0.16 0.07 0.06 --0.05
2.0 16.5 4.1 0.84 0.95 0.72
* Containing (%): wheat, 30; barley, 34.75; groundnut meal, 7; soya bean meal, 8; decorticated cottonseed meal, 7; molasses, 10; lime, 0.5; dicalcium phosphate, 2; salt, 0.5; premix, 0.25. Premix provided (g/t) COSO4.7H20 , 6; CuSO4.SH20, 30; ZnO, 45; KI, 9;MNO2, 186; vitamin AD3, 27; vitamin D3, 6; barley, 2191. **Protein levels rather higher than theoretical, particularly for diet E. Calcium levels below theoretical.
Results showed a similar eating rate for test diets with 2.5, 5 or 7.5% dried coffee residue inclusion compared to the control and the differences were a long way short of significance (Table VII). Only at the 10% inclusion level was there an appreciable reduction in eating rate, although this diet was still eaten relatively quickly. There were a number o f refusals of diet, including the control. The number o f refusals increased with increasing levels of dried coffee residue and initial introduction of high residue levels (i.e., 5--10%) was associated with increased unacceptability. There was no unacceptability associated with higher levels of dried coffee residue where cows had previously received trial diets containing lower levels.
11 TABLE VII Eating rates for diets containing dried coffee residue meal (refusals excluded) Diet A* B C D E SE of mean
Intake rate (g/min) 540.7 532.8 534.5 532.2 518.8 7.5
Time to eat 3.6 kg (min.) 6.66 6.76 6.74 6.76 6.94
*Control diet. This trial indicated t h a t dried coffee residue meal could be included in cattle diets, w i t h o u t serious risk of reduced acceptability or reduced eating rate, with inclusion levels up to 7.5%. An acclimatisation period is necessary, and initial introduction should be limited to 2.5%. Thereafter, levels could be increased to 7.5%. However, acceptability trials are n o t a substitute for experiments evaluating animal performance, and production trials need to be conducted before final decisions on raw material values and inclusion rates are made. THE ECONOMICS OF RAW MATERIALS The extent to which any raw material is utilised by the compounder will depend largely upon economics. In the trial discussed earlier (Marangos et al., 1978), the economic value of cassava depended on the relative cost of protein and energy in the formulation. Increasing levels of cassava were associated with increased inclusion of soya. Thus, when soya increases in price in relation to cereals, cassava becomes increasingly uneconomic. While soya remains relatively cheap, a combination with cassava will not only be economic, but may actually improve performance. A trial reported by Brigstocke et al. (1980), compared standard dairy cow c o m p o u n d diets with nil and 40% cassava inclusion given in conjunction with grass silage. The results indicated t h a t the diets containing the high level of cassava gave a slightly higher milk yield compared with the control diet (22.27 vs. 21.14 1/day), but this difference was not statistically significant. At the time this trial was carried out, the inclusion of cassava gave an economic saving of £3.50/t. It follows that any raw material c o m m o d i t y has two values. One is its "intrinsic value", dependent on its chemical composition, nutritional value etc., whilst the other is its " m a r k e t value", which is determined by its competitiveness with other raw materials at a given time in a given formulation. The " t r u e market value" of a material such as chemically treated straw is dependent upon competition with its relative position v/s & v/s all other raw
12 materials competing for "space" in the formula. Nevertheless, on any stable market, a given material will always bear some relationship to the current price of a few " m a j o r " alternatives {Wilson and Brigstocke, 1977b). T H E FUTURE
It follows from the above that the c o m p o u n d trade is aware of its ambivalent position and is seeking to optimise its raw material ingredient list witho u t adversely affecting performance. The relative inefficiency of animal production in providing f o o d for humans, and its apparent contribution to global maldistribution o f human foods, represent both a social and an economic dilemma with the economic argument at present prevailing {Greenhalgh, 1976). However, ruminants receive less than 30% of their energy requirements from concentrated feed. This small proportion, nevertheless, has a profound effect on their productivity in general, because it is consumed mainly b y the particular animal that is actually producing the most meat or milk. Indeed, as Holmes {1977) stated, only sheep, with a b o u t 6% of their ME derived from concentrates, are truly grassland animals under temperate conditions of relatively intensive animal husbandry. The replacement of cereals b y alternative materials, such as grass, does n o t automatically make more grain available for human consumption. Any land diverted from barley to grass will release the cereal for human consumption only if a smaller total area is required to produce the same quantity of animal products (Greenhalgh, 1976). If it proves feasible to replace a considerable a m o u n t of cereals at present given to livestock either indirectly (via c o m p o u n d feed) or directly with forages etc., without affecting productivity, then a large quantity of cereal grain is available for world trade and this is desirable in the long run to alleviate the apparent conflict between animals and humans. However, Spedding and H o x e y {1975) pointed out that cereals will continue to be given to animals when {i) there are over-riding economic considerations, {ii) land resources are not regarded as critically scarce and (iii) they are used as a small supplement, on which is based an overall level of efficiency of meat production leading to better resource use. CONCLUSION The prospects of finding acceptable and economical " n e w " raw materials for animal feeding are remote. This area has been well researched and there are few untried materials available on any scale. Many wastes which may superficially appear attractive would be uneconomical to process, store and transport. In addition, there is a grave danger of evaluating new raw materials merely on the basis of their chemical analysis. Often feeds which appear interesting on the basis of their chemical parameters, are less interesting when evaluated using the animal. Energy, protein and minerals may be in abundance, yet their digestibilities may be so low that their true nutritional value is trivial.
13
Clearly, the costs of processing such materials would outweigh their eventual return. While those involved in trading raw materials on the world markets can only be expected to provide an easily verified chemical description of their products, it is the responsibility of the feed manufacturer to ensure that the theoretical nutritive value of the final product is realised in terms of productive performance on the farm, expected by and acceptable to the livestock producer.
REFERENCES Ali, M.M., Topps, J.H. and Miller,T.B., 1977. Evaluation of dried coffee residues as a component of diets for ruminants. Proc. Nutr. Soc., 36: 67A. Anderson, W., 1975. More meat, or less,on the dinner table. Feedstuffs, 47 (19): 110--112. Annual Review of Agriculture White Paper, 1977. Cmnd. 6703, H M S O , London. Annual Review of Agriculture White Paper, 1978. Cmnd. 7058, H M S O , London. Annual Review of Agriculture White Paper, 1979. Cmnd. 7436, H M S O , London. Annual Review of Agriculture White Paper, 1980. Cmnd. 7812, H S M O , London. Blaxter, K.L., 1975. The energetics of British agriculture. Biologist, 22: 14--18. Brigstocke, T.D.A., Cuthbert, N.H., Thickett, W.S., Wilson, P.N. and Lindeman, M.A., 1979. Comparison of a standard dairy cow diet with nil and 4 0 % cassava fed in conjunction with a high intake of grass silage.Anim. Prod., 40:413 (Abstr.). Brown, L.R., 1977. The world food prospects. Longe Range Planning, 10: 26--34. Crabtree, J.R., 1972. The composition of compound feedstuffs under U K and E E C conditions. Grassl. Res. Inst. (Hurley)Tech. Rep. No. 11. Creswell, D.C., 1978. Cassava (Manihot esculenta Crantz) as a feed for pigs and poultry -- A review. Trop. Agric. (Trinidad), 55: 273--282, Cuthbert, N.H. and Thickett, W.S., 1976. Palatabilityof dried coffee residue meal. B O C M Silcock Dev. Rep. BS/76/15, unpublished. Cuthbert, N.H., Thickett, W.S., Wilson, P.N. and Brigstocke, T., 1978. The use of sodium hydroxide treated straw in rations for beef cattle. Anita. Prod., 27: 161--169. Dale, M.B., 1979. Current situation and outlook for selected livestock products and animal feeds. World Anim. Rev., 30: 43--47. De Boer, F., 1978. Food waste disposal in Dutch livestock husbandry. Paper presented at a National Industrial Materials Recovery Association (NIMRA) Conference on food for thought -- The recovery and re-use of food wastes. Fitzhugh, H.A., 1978. Bioeconomic analysis of ruminant production systems. J. Anim. Sci., 46: 797--806. Greenhalgh, J.F.D., 1976. The dilemma of animal feeds and nutrition. Anim. Feed Sci. Technol., 1 : 1--7. Holmes, W., 1976. The livestock of Great Britain as food producers. Nutrition (London), 29: 331--336. Holmes, W., 1977. Choosing between animals. Phil. Trans. R. Soc. London, Ser. B, 281 : 121--137. Marangos, A.G., Newlands, J., Pearson, J.E. and Jones, G., 1978. To evaluate cassava in a 2 stage broiler programme. BOCM Silcock Dev. Rep. BS/78/30, unpublished. Mellanby, K., 1975. Can Britain Feed Itself? Merlin Press, London. Oke, O.L., 1978. Problems in the use of cassava as animal feed. Anim. Feed Sci. Technol., 3: 345--380.
14 Orskov, E.R., 1977. Nutritional principles and evaluation of by-products, waste products and new feeds for ruminants. Livest. Prod. Sci., 4: 165--175. Phillips, T.P., 1974. Cassava utilisation and potential markets. International Development Research Centre, Ottawa, IDRC 020e, pp. 1--182. Phillips, T.P., 1979. Prospects for processing and marketing cassava products as animal feed. World Anim. Rev., 31: 36--40. Pimmental, D., Dritschilo, W., Krummel, J. and Kutzman, J., 1975. Energy and land constraints in food protein production. Science, New York, 190: 754--761. Richardson, D.I.S.,1976. The United Kingdom BroilerIndustry 1960--75. Production, Marketing and Consumption. Univ. of Manchester Dept. Agric. Econ., Agricultural Enterprise Studies in England and Wales No. 42. Sloneker, J.H., 1976. Agricultural residuesincluding feedlot wastes, Biotechnol. Bioeng. Symp. No. 6. Spedding, C.R.W. and Hoxey, A.M. 1975. The potentialfor conventional farm animals. In: D.J.A. Cole and R.A. Lawrie (Editors),Meat. Proc. 21st Easter School in Agric. Sci., Univ. of Nottingham, Butterworths, London, pp. 483--506. Thickett, W.S., Wilson, P.N., Cuthbert, N.H., Brigstocke,T.D.A. and Lindeman, M.A., 1980. A n evaluation of a 45% NaOH-treated straw diet fed ad lib in conjunction with grass silageto beef cattle.In: C. Thomas (Editor),Forage Conservation in the 80's. Occ. Symp. Eur. Grassl. Fed/Br. Grassl.Soc. No. 11, pp. 424--427. United Kingdom AgriculturalSupply Trade Association (UKASTA), 1977. Do you know? Facts and figuresabout the U K Compound Animal FeedingstuffsIndustry. U K A S T A , 1978. Composition of C o m p o u n d Feed Rations Jan.--June 1978. Feed Circular No. 78/149. U K A S T A , 1979a. Do you know? Facts and Figures about the U K compound animal feedingstuffs industry. UKASTA, 1979b. Composition of Compound Feed Rations July--December 1978. Feed Circular No. 79/96. UKASTA, 1980. Composition of Compound Feed Rations July--December 1979. Feed Circular No. 80/94. Waiters, P., 1978. Manioc poised for major UK compound role? agriTrade, June, pp. 20--22 and 62. Wedin, W.F., Hodgson, H.J. and Jacobson, N.L., 1975. Utilising plant and animal resources in producing human food. J. Anita. Sci., 41: 667--685. Wilkinson, J.M., 1976. Forage crops versus grain crops. In: J.C. Tayler and J.M. Wilkinson (Editors), Improving the Nutritional Efficiency of Beef Production. Report of a seminar in the EEC programme of co-ordination o f research on beef production. pp. 105--119. Williams, D.R., 1978. European feed industry's role in the optimisation of raw material usage. Milling Feed Fert., September, pp. 26--31. Wilson, P.N., 1975. The compound industry in animal production. Span, 18: 117--118. Wilson, P.N., The composition of animal feeds. J. Sci. F o o d Agric., 28: 717--737. Wilson, P.N., 1980. Concentrates. In: W.H. Broster and H. Swan (Editors), Feeding Strategy for the High Yielding Dairy Cow. EAAP Publ. No. 25, Granada, London, pp. 374--397. Wilson, P.N. and Brigstocke, T., 1977a. Recycling farm waste for animal feed. Agric. Prog., 52: 49--58. Wilson, P.N. and Brigstocke, T., 1977b. The commercial straw process. Process Biochem., 12: 17--21.
1
SOME FACTORS AFFECTING THE FUTURE COMPOSITION OF UK COMPOUND ANIMAL FEEDS
P.N. W I L S O N , T.D.A. B R I G S T O C K E
and N.H. C U T H B E R T
B O C M Silcock Ltd., Basing View, Basingstoke, Hants, RG21 2EQ (Gt. Britain) (Received 25 January, 1980; accepted for publication 25 August 1980)
ABSTRACT
Wilson, P.N., Brigstocke, T.D.A. and Cuthbert, N.H., 1981. Some factors affecting the future composition of UK compound animal feeds. Anita. Feed Sci. Technol., 6: 1--14. Changes in the livestock compound-feed industry are outlined. It is noted that the change to least-cost formulation of diets manufactured to a strictnutritional specification has increased the economic and biological efficiency with which different types of feed have been utilised by livestock. Nevertheless, the feeding of livestock continues to depend on large quantities of raw materials which are potentially food for humans. A number of reasons are given w h y crop by-products and other waste materials are not fully utilised by the c o m p o u n d trade, although considerable efforts have been made by the industry to find economic and acceptable alternative raw materials for c o m p o u n d diets. In the case of B O C M Silcock, once a raw material has been successfully evaluated at the Unilever Research Laboratories at Colworth House, extensive development work is conducted at two development farms. T w o different procedures are described and illustrated: (i) inclusion of the raw material in question at varying levels in a standard diet to assess effect on performance, and (ii)palatability test work, whereby a bland control-diet is partially replaced by the raw material under test, at levels appropriate to the likely commercial use of the test ingredient. However, the extent to which any waste material is eventually utilised will largely depend on its economic value, relative to the costs of competing raw materials. It appears unlikely that there will be any major availabilityof new cheap alternatives to cereals in the short term.
INTRODUCTION
Over the past 30 years, there have been dramatic improvements in livestock production and dramatic increases in compound-feed usage. For instance, the spectacular growth and intensification in the UK broiler industry (Richardson, 1976) has meant that farmers have bought more compound feed, because of its high quality nutritional specification and its convenient physical form. In addition, the change from "target" to "least cost" formulation of diets, manufactured to a strict nutritional specification, has also increased the efficiency with which the different types of feed have been utilised by livestock (Wilson, 1975).
0377-8401/81/0000--0000/$02.50, © 1981 -- Elsevier Scientific Publishing Company
In spite of these technical developments, the feeding of livestock still depends on large quantities of raw materials which are potentially useful as food for humans (Wilson, 1977) (Table I). There has been a general trend over the past 15 years for an erratic run
TABLE I I m p o r t s o f principal f e e d s grains i n t o t h e U.K. ( ' 0 0 0 t o n n e s )
Barley Maize Sorghum Feed wheat
Pre-war 1953154 average
Average of 1967/69
1973
1974
1975
1976
1977
1978
1979 forecast
903 3286 ---
315 3550 183 800
292 3389 72 900
812 3272 425 270
502 3029 475 530
646 3765 317 845
916 4106 169 690
350 3336 21 30*
360 3340 40 n/a
1275 1436 28 --
*Estimate. Year J u l y / J u n e 1 9 5 3 / 5 4 . 1973 o n w a r d s , calendar years. R e f e r e n c e s : A n n u a l R e v i e w o f Agriculture White Paper, A n n u a l R e v i e w o f A g r i c u l t u r e White Paper, A n n u a l R e v i e w o f Agriculture White Paper, A n n u a l R e v i e w o f A g r i c u l t u r e White Paper, U K A S T A ( 1 9 7 7 , 1979a).
1977. 1978. 1979. 1980.
Following the long-term trend, therefore, rather than the present short-term over-supply of world grain, there is good reason why all prudent steps should be taken to find and use alternative sources of energy for animal feeds. The Netherlands has been very successful in this respect by substituting cheaper sources of feed for expensive cereals (De Boer, 1978). Thus, Dutch cassavaimports have risen from 1.08 Mt in 1972 to 2.02 Mt in 1977. Indeed, the EEC as a whole increased the imports of cassava from 0.41 Mt in 1962, to 3.92 Mt in 1977 (Phillips, 1974;Waiters, 1978). Phillips {1979) has postulated that by 1985 cassava imports into the EEC will reach 6 Mr, unless political considerations result in artificial barriers to international trading in this commodity. There are already signs that such barriers are being effected as a result of political pressure from the "cereal lobby". Table II examines the percentage composition of compound feeds in UK by the main classes of ingredients. The increasing use of cereal by-products in cattle and sow rations should be noted [United Kingdom Agricultural Supply Trade Association (UKASTA) 1977 and 1979b]. Indeed, for the first 6 months of 1978, cereals contributed only 12% of the total composition of cattle grazing rations, whilst with diets for pregnant/lactating sows, the pro-
II
5 16
--
8 1 2
1 . -1
Animal proteins Meat and bone meal Fish/Herring meal Other Total animal proteins
Miscellaneous Molasses Fat Minerals and vitamins Cassava and cereal replacer pellets Other Total miscellaneous
1 5 3 3 12
Vegetable proteins Soya Groundnut/sheanut Rape Other Total vegetable proteins
.
8 2 5 5 6 5 31
Cereal by-products Wheatfeed/other milling offals Rice bran Dried grains/grain screenings Maize gluten Cereal pellets Other Total cereal by-products
7 2 3 10 2 24
3 4
1 .
3 2 6 3 14
9 2 5 6 1 7 30
--
-28
6
-40
1O 18
3
8
6 17
--
--
-. ---
1 4 1 4 10
1O 4 10 2 6 6 38
13 15 6 1 35
3 3
8 1 4 10 6 29
--
1 4 4 1 10
9 2 12 7 2 7 39
5 14 --19
5
4 1 1 -1 7
4
3 1
1 6
--
-.
19 1 1 -1 -22
27 24 7 3 61
.
1 2
1
3 1 2 7 -13
--
10 1 . -11
20 2 3 2 2 -29
12 32 1 -45
Pregnant sow 1976 1978
21 13
Pigs
Cattle Summer grazing 1976 1978
by main classes of ingredients.
Standard dairy 1976 1978
of British compounds
1977, 1979b)
Cereals Wheat Barley Maize Other Total cereals
1978 (UKASTA,
Percentage composition
TABLE
-1 4
1 1 1
2 3 1 6
12 . . 1 13
9 1 ---1 11
20 22 20 4 66
1976
.
1 2 1 3 1 8
1 2 5 8
. 16
16
1 -9
8
27 28 3 1 59
.
-1 5
1
3
4
--
--
1 3
1 . 1O
9
15 1 1 ---17
17 29 15 3 64
.
1 3 4
3 2 1 7 1 14
--
13 . . . 13
14 2 . 3 2 -21
11 36 1 -48
Finishing/ fattening 1976 1978
.
.
1 1
.
.
2 4
1 1
2 10 1 13
. 15
15 .
. .
. .
34 . 25 8 67
.
.
.
.
.
. .
.
.
.
1 6
.
. .
. 3 2
1 7 1 9
21
21
.
.
4 4
.
16 -60
44
.
.
.
.
. . 1 1
.
.
. 3 2 . 1 6
2 8 1 11
10
.
10
.
44 . 8 20 72
.
. 9 9
. 1 6
3 2
1 7 1 9
14
.
14
.
.
2 -62
60
Broiler fisnishers 1976 1978
in July/December
Broiler starter 1976 1978
Poultry
of survey results obtained
1978
----
Rearing
Comparison
.
.
.
.
.
2 11
1 -8
4 1 1 6
9
7 2
1 6
1
4
25 5 37 1 68
1976
.
Layers
1 8
1
5
1 11
1 9
--
--
4 1
1 13
12 --
--
5
1 63
21
37 4
1978
1976 and
portion of cereal by-products in compound feed had risen to 32%. Only in poultry formulations are traditional cereals still the main energy-rich ingredients (UKASTA, 1978). More recent data (UKASTA, 1980) show that little cassava is currently being used in compound feed rations and, consequently, cereal usage has tended to return to its pre-1978 level. Since the great majority of compound feed manufacturers use least-cost formulation, changes in ingredient prices will have a pronounced effect on the composition of compound feeds. In this respect, it must be realised that demand for any raw material by the animal feed manufacturer is determined by four factors. (i) The price of the ingredient in relation to its nutritional specification. (ii) The price of acceptable substitutes for the ingredient. Off) The upper and lower inclusion limits on the ingredient fixed by the compounder. (iv) Other considerations, such as handling and processing characteristics. (Crabtree, 1972; Wilson, 1980). H U M A N F O O D versus A N I M A L F E E D
It has been argued (e.g., Mellanby, 1975) that a change to a vegetarian type of diet in developed countries would lessen the apparent conflict between human food and animal feed. Only 50% of the total world grain-production is consumed directly by humans, 40% being given to livestock and the residual 10% being used for seed and other purposes (Anderson, 1975). As Holmes (1976) has shown, in terms of protein and energy yield, the most efficient food chain is that in which crops are consumed by humans. However, human beings are usually omnivores and not vegetarians, so it follows that social attitudes will determine that meat, milk and eggs remain important components of their diet. Indeed, certain essential nutrients, such as vitamin B12, are not found in vegetable protein sources. Dale (1979) noted that world meat-consumption in 1978 increased more rapidly than production, leading to some decrease in stocks. Survey work indicates that, throughout the world, meat consumption rises in direct relation to the increase in per capita gross national product. Animals are able to utilise crops, such as grass, straw and forage crops, which are considered unsuitable for human consumption. Wilkinson (1976) suggested that forage crops probably comprise the major feed of beef cattle in all major beef-producing areas. Even in the USA, where large quantities of cereal grain are given to beef animals, Wedin et al. (1975) indicated that forage crops account for 73% of total feed units 1. Furthermore, food crops destined for direct human consumption usually produce by-products unsuitable for human consumption, which can indirectly provide human food when given to animals. Sloneker (1976) calculated the amount of crop wastes ~Nutritional equivalent of 0.454 kg of maize grain.
in the US which could be given to livestock. These wastes, which a m o u n t to 300--500 Mt on a fresh weight basis, are mainly by-products and crop residues from maize, soya bean, wheat and sorghum production. The relationship between human and ruminant has generally been viewed as synergistic (Fitzhugh, 1978). However, the current pressures of a rapidly increasing world population, with an increasing expectation for an adequate diet, have led to an increasingly objective approach to evaluating ruminants as producers of human food (Blaxter, 1975; Pimmental et al., 1975; Wedin et al., 1975). Ruminants do not need to compete with humans in their dietary needs, whereas pigs and poultry usually do. Ruminants are able to graze areas inaccessible because of topography, climate, etc. Indeed, extensive ranching systems consume very little support energy and may, therefore, be considered energetically efficient. SEARCH F OR A L T E R N A T I V E ENERGY SOURCES TO TRA D I TI O N A L CEREALS
There are a n u m b e r of factors determining the extent, to which crop byproducts and other alternative sources of energy are utilised by the c o m p o u n d trade. These are: (i) availability of information about their composition and their nutritive value; (ii) availability of adequate handling and processing facilities; (iii) possible variations in composition; (iv) safety and efficacy of the raw material in question; (v) logistic problems of availability in quantity and seasonality of supply and (vi) need for transportation and processing. In this respect, Orskov (1977) suggested that the producers of crop byproducts may exert pressure for these to be utilised in animal feeds, largely in an to reduce a disposal problem, rather than to provide a potentially useful feed effort to reduce a disposal problem, rather than to provide a potentially useful feed ingredient. He suggested that by-products are sometimes included at a low t h e y make a meaningful contribution or not. He further noted that there was a wide variation in composition of such materials as distillery and brewery wastes. In this respect, it is interesting to examine the variability of a raw material, such as biscuit meal. In proximate analyses for samples from 8 different sources, the following means and standard deviations were obtained: oil 14.5% -+ 5.5; crude protein 10.2% + 1.6 and salt 1.2% + 0.7 (Wilson and Brigstocke, 1978, unpublished data). Wilson and Brigstocke (1977a) noted that the feasibility of recovering large quantities o f vegetable residues for animal feeding has been enhanced by the centraiisation of processing in large packing stations. The use of vegatable residues is likely to increase, but difficulties are posed by seasonal availability and the general problem that, as labour becomes scarcer and more expensive, the securing of the main crop will take priority over secondary operations in respect of residues.
Nevertheless, over the past decade, considerable efforts have been made b y the c o m p o u n d trade to find alternative raw materials for c o m p o u n d diets. Whilst this effort has n o t been entirely unrewarding, as illustrated by the success of up-grading of cereal straw (Wilson and Brigstocke, 1977b; Cuthbert et al., 1978; Thickett et al., 1980), there is no real prospect of finding large quantities of cheap by-products which could be directly incorporated into animal feeds as substitutes for traditional raw materials. Instead, a more systematic approach has been an initial assessment of the potential tonnage of material available followed by chemical evaluation and feeding trials with each potential raw material. However, the nutritive value of the material has often been found to be less than might have been expected from the gross chemical analysis. In many cases, the cost of preparing the by-product in a form for transport over long distances, and the additional costs of detoxification and/or up-grading the material to release its potential nutritional value, have been found to exceed its economic value relative to conventional raw materials ( R o b b , 1976). Williams (1978) has considered the future European feed industry and, in particular, the optimisation of raw material usage, noting that it is in relation to energy sources that the future of c o m p o u n d feeds will be most strongly influenced by EEC policy. Thus, the use of cassava and cereal replacer pellets (containing 49% cassava) in c o m p o u n d feeds could be seriously reduced if the recent EEC policy of maintaining high cereal prices whilst charging a low import d u t y on cassava is altered. This will have a major effect on attempts to lower the inclusion levels of cereal grains in the diets of farm livestock in the UK. Furthermore, Thailand, the world's largest exporter of cassava, is attempting to diversify its crop production with less dependence on this major cash crop, although cassava exports have been extremely successful in generating foreign capital, which in 1979 was valued at US $ 333 million (Phillips, 1979). E V A L U A T I O N OF NEW RAW MATERIALS BY THE COMPOUND FEED INDUSTRY
In the case of BOCM Silcock, once a raw material has been successfully evaluated at the Unilever Research Laboratories at Colworth House, extensive development work is conducted at one of the two BOCM Silcock Development Units. Two experimental procedures are employed: inclusion of the raw material in question at varying levels in a standard diet, and palatability test work, whereby a bland control-diet is partially replaced by the raw material under test, at levels appropriate to the potential commercial use of the test ingredient To illustrate these two procedures, two recent trials are discussed. T h e use o f cassava in a broiler d i e t
Creswell (1978), in a literature review of the use of cassava roots in pig and poultry diets, noted that cassava can contribute substantially to livestock
energy requirements, provided such diets are properly balanced in limiting nutrients (especially methionine) and the level of a potentially toxic glucoside in the cassava is minimised. Furthermore, if the diet is then pelleted to reduce volume and increase feed intake, and the "sweet '~ varieties are used, then cassava could replace up to 50% of the cereal portion of the diet. More recently, Oke (1978) described the problems of the use of cassava as animal feed. In a trial at the BOCM Silcock Poultry Development Farm at Stoke Mandeville, Marangos et al. (1978) evaluated cassava in a standard broiler finisher diet. Four thousand birds (Ross I) were fed on the same broiler starter to 21 days of age and then finished to 49 days on one of four experimental diets, containing 0, 7, 14 or 21% cassava. The composition of the diets are shown in Table III and their analyses in Table IV. Bird liveweights at the end of the trial were generally below average, but this was not related to any particular treatment. Performance data for the two sexes combined are given in Table V. Sex and diet interactions were not significant and, therefore, the combined figures can be considered to be representative of the performance of birds on each treatment. Weight gains between 22 and 49 days of age were not significantly different between treatment groups. However, there was a trend for liveweight gain to improve with the increase in the level of cassava. This improvement reached a m a x i m u m at the 14% inclusion level. Final liveweight was consisTABLE III Cassava in diets for broiler chicks: composition of experimental diets
Ingredients Wheat Wheatflour Cassava Extracted soya bean meal Herring meal Meat and bone meal Durabond Vegetable oil Animal fat oil Salt Premix*
Cassava (%) 0
7
14
21
47.24 25.00 0.00 10.97 5.19 4.72 2.00 3.20 1.00 0.13 0.55
38.11 25.00 7.00 12.90 5.20 4.70 2.00 3.40 1.00 0.14 0.55
28.80 25.00 14.00 15.00 5.20 4.60 2.00 3.70 1.00 0.15 0.55
19.58 25.00 21.00 17.00 5.20 4.50 2.00 4.00 1.00 0.17 0.55
*Premix (g/tonne): copper sulphate, 100; zinc oxide, 100; ferrous sulphate, 300; vitamin AD3,15; vitamin B6 (pyridoxine), 2; vitamin B~:, 12; vitamin D 3, 7; vitamin E, 20; choline chloride, 500; potassium iodide embamix, 2; vitamin B2, 5; calcium pantothenate, 15; folic acid, 1; nicotinic acid, 10; DL-methionine, 2120; L-lysine HCI, 880; manganous oxide, 125, vitamin K, 6 ; Payzone 25%, 41; Elancoban, 500; wheatfeed, 739.
TABLE IV T h e o r e t i c a l a n d a c t u a l analyses o f e x p e r i m e n t a l diets (%) Control Theo. Moisture Oil Protein Fibre Salt Calcium Phosphorus
Act.
12.32 6.02 19.25 2.42 0.45 0.86 0.60
7% Cassava
14% Cassava
21% Cassava
Theo.
Theo.
Theo.
12.90 5.90 19.40 1.68 0.43 0.85 0.63
Act.
12.12 6.26 19.25 2.55 0.45 0.86 0.60
12.80 6.01 19.60 2.02 0.43 0.85 0.60
11.92 6.51 19.25 2.69 0.45 0.86 0.55
Act. 12.70 6.34 19.40 2.20 0.46 0.88 0.53
11.72 5.76 19.25 2.83 0.45 0.86 0.55
Act. 13.00 6.35 19.60 2.56 0.40 0.89 0.53
Monensin
(mg/kg)
100
78.8
100
64.5
100
96.3
100
87.3
TABLE V P e r f o r m a n c e d a t a o f birds fed o n e x p e r i m e n t a l diets, 0 - - 4 9 days Cassava in diet (%)
Liveweight(kg) days:
Feed intake(kg) days:
Feed/gain for days:
Gain 22--49
0-21
22--49
0--49
0--21
22--49
0--49
1.822 1.863 1.879 1.875
1.372 1.398 1.421 1.404
0.754 0.756 0.759 0.761
2.888 2.878 2.917 2.943
3.642 3.634 3.677 3.704
1.679 1.627 1.662 1.622
2.114 2.068 2.062 2.106
2.004 1.955 1.962 1.981
0.013
0.017
0.016
0.002
0.014
0.015
0.045
0.027
0.016
NS
NS
NS
*
*
*
NS
NS
NS
21
49
0 7 14 21
0.450 0.465 0.458 0.471
SE of mean Significance of
difference *P< 0.05
t e n t with the effect on gains over the finishing period. A difference of 57 g was f o u n d between the control birds and those fed on the 14% cassava diet. The test for the main effect of the diet was close to significance for each of the feed intakes and the linear c o m p o n e n t of the effect was significant for the intake. Although differences in feed intake were of little consequence during the starter period, this relationship was appreciably greater after the cassava diets were introduced. Results suggest that intake increased with increasing levels of cassava. Similar findings have been found in work with dairy cows when comparing nil and 40% cassava inclusion levels in a standard compound diet (Brigstocke et al., 1979). For this broiler trial, regression equations
in which feed intake (g) was correlated with the proportion of cassava (C, %) were significant and are shown below. Intake ( 0--21 days) = 0.7544 + 0.00034 C Intake (22--49 days) = 2.8754 + 0.00291 C Intake ( 0--49 days) = 3.6296 + 0.00327 C As feed intake increased, the trend was for feed conversion efficiency to improve with the level of cassava inclusion, at least up to 14%, whereas at 21% the value approximated to that of the control. Feed costs at the time of the experiment (calculated on the basis of wheat at £85/t, cassava £64/t and soya bean meal £108/t) did n o t differ significantly between the treatments, even though the cassava-fed birds ate more feed. The margin over feed cost approached significance for the birds fed the cassava-containing diets as against the control, and averaged 2.47p/bird more than the control birds. This reflected the average improvement in carcase income of 2.21p/bird for the same birds.
The palatability o f dried coffee residue meal in a dairy cow c o m p o u n d diet Dried coffee residues are a by-product from the manufacture of instant or soluble coffee. The UK o u t p u t of dried coffee residues varies between 25 000 and 35 000 t / a n n u m on a dry basis. Ali et al. (1977) have shown t h a t this raw material has a high c o n t e n t of energy, fat and fibre, but d o u b t has been expressed about its digestibility and acceptibility by the ruminant. Coffee residue could be potentially useful as a raw material in ruminant c o m p o u n d feed because of its high oil content. Consequently, a palatability trial carried out at the BOCM Silcock Cattle Development Unit, Barhill, by Cuthbert and Thickett (1976) tested inclusion levels of 0, 2.5, 5, 7.5 or 10% dried coffee residue meal, formulated with a corresponding proportion of a bland basic cattle diet as shown in Table VI {diets A--E, respectively). Analysis of the coffee residue used is included in Table VI. Diets were manufactured as 9.5 mm extrusions. The trial involved 20 dairy cows and 10 heifers averaging 16 weeks post partum. Six blocks, each of 5 animals, were used in a latin square design. C o m p o u n d diets were given at 0.4 kg/kg of milk. Average yields at the start of the trial were 22.4 kg/day for cows (range 16.1--31.1) and 17 kg/day for heifers (range 11--18.6). The animals were fed on grass silage to appetite, and a minimum of 5 kg c o m p o u n d diet per head per day was given in two feeds. Any allocation over 9 kg of c o m p o u n d diet was given as a third feed at 22.00 hours. The rate of ingestion of 3.6 kg trial diets, weighed into containers from which the feed was subsequently consumed, was timed on three days of each test week. Refusals were recorded on all days. A refusal was defined as a failure to eat the prescribed anowance within 15 min. The 3.6 kg was given in one allocation in the afternoon and the balance of daffy compound, rationed according to milk yield, was given at a separate time. The trial lasted for 5 weeks and each cow received each test diet for 1 week.
10 TABLE VI Dried coffee residue meal in diets for dairy cows: formulation of experimental diets (%) Diet A
Dried coffee residue meal B
C
D
E
Basal diet* 100 Dried coffee residue meal 0
97.5 2.5
95.0 5.0
92.5 7.5
90.0 10
---
Theoretical analysis Oil Crude protein Crude fibre Salt Calcium Phosphorus
2.4 16.3 5.0 0.82 0.94 0.70
2.8 16.2 6.0 0.80 0.91 0.69
3.1 16.0 6.9 0.78 0.89 0.68
3.5 15.8 7.9 0.76 0.88 0.66
-------
Actual analysis - - C u m u l a t i v e farm samples** Moisture 13.0 12.8 12.8 Oil 2.1 2.4 3.0 Protein 16.9 17.0 16.8 Fibre 4.3 5.0 5.5 Salt 0.84 0.84 0.80 Calcium 0.74 0.70 0.66 Phosphorus 0.70 0.67 0.66 Sodium 0.35 0.33 0.33 Ash 5.7 5.6 5.3 Free fatty acids 17.4 15.0 14.1 Potassium . . . .
12.9 3.3 16.5 6.1 0.76 0.65 0.65 0.30 5.2 13.8 .
12.8 3.8 17.8 7.0 0.78 0.59 0.62 0.30 5.0 11.9
8.97 17.64 19.60 -0.08 0.16 0.07 0.06 --0.05
2.0 16.5 4.1 0.84 0.95 0.72
* Containing (%): wheat, 30; barley, 34.75; groundnut meal, 7; soya bean meal, 8; decorticated cottonseed meal, 7; molasses, 10; lime, 0.5; dicalcium phosphate, 2; salt, 0.5; premix, 0.25. Premix provided (g/t) COSO4.7H20 , 6; CuSO4.SH20, 30; ZnO, 45; KI, 9;MNO2, 186; vitamin AD3, 27; vitamin D3, 6; barley, 2191. **Protein levels rather higher than theoretical, particularly for diet E. Calcium levels below theoretical.
Results showed a similar eating rate for test diets with 2.5, 5 or 7.5% dried coffee residue inclusion compared to the control and the differences were a long way short of significance (Table VII). Only at the 10% inclusion level was there an appreciable reduction in eating rate, although this diet was still eaten relatively quickly. There were a number o f refusals of diet, including the control. The number o f refusals increased with increasing levels of dried coffee residue and initial introduction of high residue levels (i.e., 5--10%) was associated with increased unacceptability. There was no unacceptability associated with higher levels of dried coffee residue where cows had previously received trial diets containing lower levels.
11 TABLE VII Eating rates for diets containing dried coffee residue meal (refusals excluded) Diet A* B C D E SE of mean
Intake rate (g/min) 540.7 532.8 534.5 532.2 518.8 7.5
Time to eat 3.6 kg (min.) 6.66 6.76 6.74 6.76 6.94
*Control diet. This trial indicated t h a t dried coffee residue meal could be included in cattle diets, w i t h o u t serious risk of reduced acceptability or reduced eating rate, with inclusion levels up to 7.5%. An acclimatisation period is necessary, and initial introduction should be limited to 2.5%. Thereafter, levels could be increased to 7.5%. However, acceptability trials are n o t a substitute for experiments evaluating animal performance, and production trials need to be conducted before final decisions on raw material values and inclusion rates are made. THE ECONOMICS OF RAW MATERIALS The extent to which any raw material is utilised by the compounder will depend largely upon economics. In the trial discussed earlier (Marangos et al., 1978), the economic value of cassava depended on the relative cost of protein and energy in the formulation. Increasing levels of cassava were associated with increased inclusion of soya. Thus, when soya increases in price in relation to cereals, cassava becomes increasingly uneconomic. While soya remains relatively cheap, a combination with cassava will not only be economic, but may actually improve performance. A trial reported by Brigstocke et al. (1980), compared standard dairy cow c o m p o u n d diets with nil and 40% cassava inclusion given in conjunction with grass silage. The results indicated t h a t the diets containing the high level of cassava gave a slightly higher milk yield compared with the control diet (22.27 vs. 21.14 1/day), but this difference was not statistically significant. At the time this trial was carried out, the inclusion of cassava gave an economic saving of £3.50/t. It follows that any raw material c o m m o d i t y has two values. One is its "intrinsic value", dependent on its chemical composition, nutritional value etc., whilst the other is its " m a r k e t value", which is determined by its competitiveness with other raw materials at a given time in a given formulation. The " t r u e market value" of a material such as chemically treated straw is dependent upon competition with its relative position v/s & v/s all other raw
12 materials competing for "space" in the formula. Nevertheless, on any stable market, a given material will always bear some relationship to the current price of a few " m a j o r " alternatives {Wilson and Brigstocke, 1977b). T H E FUTURE
It follows from the above that the c o m p o u n d trade is aware of its ambivalent position and is seeking to optimise its raw material ingredient list witho u t adversely affecting performance. The relative inefficiency of animal production in providing f o o d for humans, and its apparent contribution to global maldistribution o f human foods, represent both a social and an economic dilemma with the economic argument at present prevailing {Greenhalgh, 1976). However, ruminants receive less than 30% of their energy requirements from concentrated feed. This small proportion, nevertheless, has a profound effect on their productivity in general, because it is consumed mainly b y the particular animal that is actually producing the most meat or milk. Indeed, as Holmes {1977) stated, only sheep, with a b o u t 6% of their ME derived from concentrates, are truly grassland animals under temperate conditions of relatively intensive animal husbandry. The replacement of cereals b y alternative materials, such as grass, does n o t automatically make more grain available for human consumption. Any land diverted from barley to grass will release the cereal for human consumption only if a smaller total area is required to produce the same quantity of animal products (Greenhalgh, 1976). If it proves feasible to replace a considerable a m o u n t of cereals at present given to livestock either indirectly (via c o m p o u n d feed) or directly with forages etc., without affecting productivity, then a large quantity of cereal grain is available for world trade and this is desirable in the long run to alleviate the apparent conflict between animals and humans. However, Spedding and H o x e y {1975) pointed out that cereals will continue to be given to animals when {i) there are over-riding economic considerations, {ii) land resources are not regarded as critically scarce and (iii) they are used as a small supplement, on which is based an overall level of efficiency of meat production leading to better resource use. CONCLUSION The prospects of finding acceptable and economical " n e w " raw materials for animal feeding are remote. This area has been well researched and there are few untried materials available on any scale. Many wastes which may superficially appear attractive would be uneconomical to process, store and transport. In addition, there is a grave danger of evaluating new raw materials merely on the basis of their chemical analysis. Often feeds which appear interesting on the basis of their chemical parameters, are less interesting when evaluated using the animal. Energy, protein and minerals may be in abundance, yet their digestibilities may be so low that their true nutritional value is trivial.
13
Clearly, the costs of processing such materials would outweigh their eventual return. While those involved in trading raw materials on the world markets can only be expected to provide an easily verified chemical description of their products, it is the responsibility of the feed manufacturer to ensure that the theoretical nutritive value of the final product is realised in terms of productive performance on the farm, expected by and acceptable to the livestock producer.
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