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An evaluation of the performance of weaner pigs fed diets incorporating fresh sweet liquid whey
ANIMAL FEED SCIENCE AND TECHNOLOGY
ELSEVIER
Animal Feed Science and Technology 54 ( 1995) 193-201
An evaluation of the performance of weaner pigs fed diets incorporating fresh sweet liquid whey S.M. Maswaure”, K.T. Mandisodza Pig Industry Board Experimental Farm, P.O. Box HG 297, Highlands, Harare. Zimbabwe
Received 3 May 1994; accepted 5 January 1995
Abstract Three hundred and eighty-five pigs from 77 litters weaned at 5 weeks of age were used to evaluate the consumption and nutritive value of fresh sweet liquid whey over a 4 week period. The diets were: control weaner diet, fed dry (Tl ); weaner diet + water, fed as a slurry mixed at a ratio of 1: 1 (T2); weaner diet + fresh whey, fed as a slurry mixed at a ratio of 1:1 (T3); weaner diet + fresh whey, fed as a slurry mixed at a ratio of 1:2 (T4) ; weaner diet + fresh whey, fed separately (T5). The pigs were fed to appetite at least five times a day. Treatments were replicated eight times, weekly, in groups of nine or ten pigs per treatment. Feeding slurry diets improved weaner diet intake by 3.8% in T2,6.8% in T3 and 3.4% in T4 when compared with the dry meal control (Tl). Feeding liquid whey ad libitum separately resulted in highest whey intake and reduced weaner diet consumption by 10.2%. Incidence of severe frothy diarrhoea during the first week after weaning was higher (P < 0.01) in pigs fed slurry diets or fresh whey separately (9-14%) than in those fed the control dry meal (5%). The proportion of pigs with severe diarrhoea decreased as the pigs grew older and diarrhoea had no adverse effects on pig performance. Daily liveweight gains were higher in whey supplemented treatments than in control treatments (Tl and T2) during the first and second week postweaning (P
* Corresponding author at: Kyushu National Agricultural Experiment Station, Kikuchi-Gun, Nishigoshi-Machi, Suya 2421. Kumamoto 861-11, Japan. 0377-8401/95/$09.50 0 1995 Elsevier Science B.V. All rights reserved ssDf0377-8401(95)00775-x
194
S. M. Maswaure. K.T. Mandosodza / Animal Feed Science and Technology 54 (1995) 193-201
1. Introduction
Whey is of high nutritional value for farm animals, in particular for pigs, and is often utilized in the three forms dried whey, concentrated whey or liquid whey. Fresh whey has a very low total solids content, averaging only 6-7%, which consists mainly of lactose and protein. Although the composition of whey varies essentially with the type of cheese of which it is a by-product, the method of preservation or the origin of the milk (Thivend, 1977)) the chemical composition of the dry matter may be of the order of 35% crude protein (N X 6.34), 50% lactose, 4.5% fat, and 6.0% ash (Cinq-Mars et al., 1986). The high proportion of lactose in whey is a good source of energy, while its relatively high protein content is of good biological value (Ministry of Agriculture, Fisheries and Food (MAFF) , 1978). In addition, whey is also a good source of water-soluble vitamins of the B group and its ash fraction is a good source of calcium and phosphorus. Fresh liquid whey has been traditionally fed in moderation to growing and fattening pigs and has only been included in diets of early weaned pigs in the dried form. The inclusion of small amounts of dried whey in maize-soyabean based diets has been shown to improve daily liveweight gains and feed efficiency of piglets weaned at 2-4 weeks of age (Kornegay et al., 1974; Pals and Ewan, 1978; Graham et al., 1981; Schingoethe, 1988). Cinq-Mars et al. (1986) have shown that feeding a wet weaner maize-soyabean diet containing whey protein concentrate, a product from ultrafiltration process, improves the performance of early weaned pigs. However, the feeding of liquid fresh whey to weaner pigs is not a normal practice presumably because of fears for a decline in feeding hygiene and increased risks of postweaning diarrhoea. Further constraints in the utilization of fresh liquid whey are linked to high transportation costs of the bulky liquid and the lack of drying facilities and as a result most of it is discarded or wasted. The objective of the present study was to investigate practical ways of incorporating varying proportions of fresh sweet whey into the diets of weaner pigs (5 weeks of age) in order to improve their growth and performance.
2. Materials and methods 2.1. Animals and experimental procedures A total of 385 crossbred pigs from 77 litters, weaned at an age of approximately 35 days and an average liveweight of 7.1 kg, were utilized in the experiment. Piglets from each litter were allocated to five groups of nine or ten pigs each. The groups were balanced for litter, sex and liveweight, and replicated weekly over a period of 8 weeks. The pigs were housed on a bedded concrete floor in conventional, naturally ventilated fattening pens. Drinking water was provided at all times via nipple drinkers. The five dietary treatments were randomly allocated weekly to five groups of weaned pigs and were evaluated over a 4 week period as follows: Treatment 1 (Tl ) , Control, weaner diet (fed in a dry meal form) ; ‘IT, Weaner diet + water, mixed at a ratio of 1: 1 ( w/w) ; T3, Weaner diet + whey, mixed at ratio of 1:l w/w; T4, Weaner diet + whey, mixed at ratio of 1:2 (w/w) ; T5, Weaner diet + whey, fed ad libitum separately.
SM. Maswaure, K.T. Mandosodza /Animal Feed Science and Technology 54 (1995) 193-201
195
Table 1 Composition and chemical analysis (as fed) of the piglet weaner diet Ingredients/constituent
g kg-’
Formulation
Milled pearl millet Soyabean meal Limestone flour Mono-calcium phosphate Antibiotic preparation (DB 1/TSP)” DB 1 vitamin and mineral premixa,b
643 310 15 20 2 10
Determined chemical analysis
Dry matter Crude protein Crude tibre Ether extracts Nitrogen-free extracts Ash
880 206 78 44 469 81
Calculated chemical composition
Metabolizable energy (MJ kg-‘) Total digestible nutrients Protein Oil Crude fibre Lysine Methionine Methionine + cystine Threonine Calcium Total phosphorus Sodium
11.02 647 207 24 61 10 10 13 7 8 6 2
a Antibiotic preparation and mineral and vitamin mix were supplied by Hemish Cameron, Harare. The antibiotic preparation was a combination drug containing 10% sulphachloropyridazine sodium and 2% trimethoprim. b DB 1 vitamin and mineral premix for creep feed provided the following per kg of diet: methionine 400 mg, vitamin A 8000 IU, vitamin D 1000 IU. vitamin E 40 IU, nicotinic acid 15 mg, pantothenic acid 15 mg, vitamin Bz 5 mg, vitamin B,a 0.02 mg, choline 500 mg, copper 250 mg, iron 180 mg, zinc 100 mg, manganese 60 mg. iodine 2 mg, selenium 0.2 mg, sodium chloride 4 g.
The diets in T2, T3 and T4 were offered as a slurry, the dry meal portion of the diet being weighed separately and then thoroughly mixed by hand with the corresponding amounts of water or whey. To avoid the build-up of stale food in the feeders, pigs were fed to appetite, in small amounts, at least five times per day. The formulation and chemical composition of the weaner diet are shown in Table 1. The fresh whey was collected from a cheese factory weekly in 50-l carboys and kept in cold storage at -20°C and was thawed at room temperature before being fed. The fresh whey contained 58 g total solids kg-‘. The chemical analysis (g kg-‘) of the total solids was: crude protein, 174.5; fat, 189.7; lactose, 520.3; ash, 115.5.
196
S.M. Maswaure, K.T. Mandosodza /Animal Feed Science and Technology 54 (1995) 193-201
2.2. Data collection Daily feed intake was recorded for each pen and the pigs were individually weighed every 7 days. The effects of dietary treatments on the incidence and severity of diarrhoea were assessed using a subjective diarrhoea score. The scores were taken daily on a per pen basis, based on observations of individual animals and the proportion of faeces indicating type of diarrhoea. Firmness of faeces was evaluated according to the following scores: 0, normal faeces; 1, soft faeces, possibly slight diarrhoea; 2, definitely unformed moderately fluid faeces; 3, severe watery or frothy diarrhoea (Ekstrom et al., 1976). The pigs were not given additional veterinary treatment for diarrhoea but an antibiotic was included in the diet. 2.3. Chemical analysis The whey and weaner diet were analysed for their proximate chemical composition. Dry matter (DM) was determined by drying the samples to constant weight at 105°C. Nitrogen content was determined using the micro-Kjeldahl digestion procedure. For both the whey and diet the values presented are means of duplicate analyses; crude protein was calculated as nitrogen (N) content X 6.34 for whey and N content X 6.25 for the weaner diet. Ash content was determined by combustion of 3.0 g samples in porcelain dishes at 600°C for 5 h. Fat in the diets was determined as ether extracts using the soxhlet procedure, by continuously evaporating petroleum ether. Fat content of the whey was determined volumetrically using the Gerber method. Crude fibre in the diet was determined according to the method of the Association of Official Analytical Chemists ( 1984). Lactose in whey and nitrogen free extracts in the diet were determined by difference. 2.4. Statistical analysis Data for weekly liveweight, daily feed intake, feed conversion daily liveweight gains and faecal scores were subjected to analysis of variance and differences between individual treatment means were determined using the t-test after a significant F test (Snedecor and Cochran, 1967),
3. Results and discussion 3.1. The effect of including liquid whey in the diet on feed consumption Data on weaner diet consumption are presented in Table 2. Weaner diet consumption did not differ significantly between control treatments (Tl and T2) ; however, the inclusion of water in T2 increased diet intake by 3.8% during the 4 week experimental period. The inclusion of fresh sweet whey into the weaner diet to form a whey/meal mix at a ratio 1:1 (T3), resulted in an increase in weaner diet intake that was significantly greater (P < 0.05) than that of the controls (Tl and T2) during Weeks 1 and 3 of the trial. Overall the inclusion of whey in T3 resulted in a 6.8% increase in total meal intake during the 4 week trial period.
S. M. Maswaure, K. T. Mandosodza /Animal Feed Science and Technology 54 (1995) 193-201
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Table 2 Daily feed intake of piglet weaner diet (kg DM per day per pig) SEM P
Treatment Tl Week 1 postweaning Week 2 postweaning Week 3 postweaning Week 4 postweaning Total weaner diet intake (kg) Percentage weaner diet intake versus control (Tt)
T3
T2
0.33 0.56”” 0.77ab
0.34” 0.57” 0.81”
1.OO”
1.04”
18.62 0.0
19.32 + 3.8
T4 0.37b 0.56”” 0.83” 1.05”
19.88 +6.8
T5 0.36b 0.54” 0.80* 1.05”
19.25 +3.4
0.34” 0.016 * 0.48b’ 0 018 * 0.72b 0:028 0.09 0.85”y 0.031 *** 16.73 - 10.2
-
-
Values are of piglet weaner diet intakes, excluding added whey in T3, T4 and T5. Treatments: control weaner diet, fed dry ( Tl ) ; weaner diet + water, fed as a shmy mixed at a ratio of 1:I (T2) ; weaner diet + fresh whey, fed as a slurry mixed at a ratio of 1:1 (T3); weaner diet + fresh whey, fed as a shmy mixed at a ratio of 1:2 (T4) or weaner diet + fresh whey, fed ad libitum separately (T5). Estimates of dry matter contributed by liquid whey were calculated from the amounts of whey fed or mixed with the piglet weaned diet (Table 3) and the dry matter content of the whey presented in Table 1. Treatment means within same row with different superscripts differ: abP<0.05; “.‘P
When liquid whey was mixed with the weaner meal at a ratio 2: 1 (T4), weaner diet intake was greater than the control treatments during Week 1 (P < 0.05) and Week 2 (P < 0.01). The increase in total meal intake in T4 during the 4 week trial period was 3.4% greater than in Tl. When whey was provided ad libitum separately (T5), the provision of whey resulted in a reduction in total meal intake ( - 10.2%)) and daily meal intake was significantly lower than in the control treatment (P < 0.05) during Weeks 2, 3 and 4 of the trial. From the results in Table 2, it appears that the mixing of small amounts of whey with a cerealsoyabean basal diet to form a slurry enhances the consumption of the weaner meal. This enhanced meal consumption is probably due to the improved palatability of the diet and is greater than the increase caused by mixing the weaner diet with water alone (i.e. T2 vs. T3 and T4). However, when considerable amounts of whey are offered, as in T5, a substitutive effect between the whey and the meal is observed, which resulted in a 10.2% saving on meal consumption. This is in general agreement with other reports in which consumption of large quantities of whey led to considerable savings on feed (see Cieslak et al., 1986; Modler, 1988; Schingoethe, 1988), especially if transport costs from the processing plant to the farm are low. The amounts of water and whey consumed during the experiment as part of the diet, treatments are shown in Table 3. In T3, T4 and T5 the corresponding contribution of whey solids to the total dry matter (TDM) intake was 6.3%, 12.5% and 25.4%, respectively. The percentage contribution of whey solids to DM intake observed with the pigs fed ad libitum (T5) falls at the lower limit of the 24.0-58.5% range reported by Cieslak et al. ( 1986) when fresh sweet whey was provided as a protein supplement to maize based diets fed to growing-finishing pigs. This should be expected as older pigs have generally been known to be better utilizers of fresh whey (MAFF, 1978). In the present study there was a sevenfold increase in daily whey intake by pigs with ad libitum access to whey (T5) between
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S.M. Maswaure. K.T. Mandosodza /Animal Feed Science and Technology 54 (1995) 193-201
Table 3 Mean daily whey (and water, R) consumption on as-fed basis and on total solid basis Treatmenmt Tl
T2
T3
T4
T5
Fresh whey consumption (kg per &y per pig)
Week 1 postweaning Week 2 postweaning Week 3 postweaning Week 4 postweaning Total whey consumption
-
0.61 0.88 1.12
0.42 0.61 0.89 1.17
0.80 1.19 1.73 2.24
-
21.00
21.63
41.72
0.39
0.66
1.91 3.24 4.72 73.71
Whey solids consumption (kg per day per pig)
Week 1 postweaning Week 2 postweaning Week 3 postweaning Week 4 postweaning
-
Total whey solids intake (kg per pig)
-
-
0.024 0.036 0.05 1 0.067
0.046 0.069 0.100 0.130
0.111 0.183 0.273
1.246
2.415
4.242
0.039
Treatments: control weaner diet, fed dry (T 1) ; weaner diet + water, fed as a slurry mixed at a ratio of 1:1 (T2) ; weaner diet + fresh whey, fed as a slurry mixed at a ratio of 1:1 (T3); weaner diet + fresh whey, fed as a slurry mixed at a ratio of 1:2 (T4); weaner diet + fresh whey, fed ad libitum separately (T5).
the ages of 5 and 9 weeks, which corresponds to an increase in whey consumption from 0.66 to 4.7 1 per pig per day during the 4 week duration of the experiment. 3.2. Dietary effects on the incidence and severity of piglet diarrhea Fewer pigs fed the control diet (Tl) had diarrhoea and it was less severe than when slurry diets (T2, T3 or T4) were fed or when whey was fed ad libitum separately (T5). The incidence of severe frothy diarrhoea (diarrhoea score 3) decreased with time postweaning and was higher in slurry and ad libitum whey fed pigs than in the dry meal control diet (Tl). The proportion of pigs showing this type of diarrhoea in Tl-T5, respectively, were: Week1,0.05,0.14,0.09,0.14,0.12(SEM0.018,P<0.01);Week2,0.05,0.11,0.08,0.11, 0.11 (standarderrorofthemean (SEM) 0.016,P=0.08);Week3,0.04,0.09,0.06,0.09, 0.11 (SEMO.018, P=O.O7); Week4,0.04, 0.07,0.04,0.03,0.10 (SEM0.21, P=O.O9). The most severe cases of diarrhoea were with treatments T2, T4 and T5, whereas the dry meal control treatment (Tl ) had the least incidence of severe diarrhoea. Between 77% and 82% of the pigs did not contract diarrhoea, soft or fluid faeces during the first week, and the numbers increased to between 84% and 90% during Week 4 postweaning. This may explain the lack of differences in animal performance, between treatments, observed in the present study. The effects of diarrhoea on food utilization and performance of young pigs are well documented; for example, diarrhoea has been reported to lead to a reduced feed intake and lower liveweight gains. Some studies have reported that diarrhoea occurs less frequently with pigs fed simple diets (Bailey and Carson, 1970; Ball and Aherne, 1982). However, in the study by Ball and Aherne ( 1982)) the decrease in gain and reduced gain:feed
S.M. Maswaure, K.T. Mandosodza /Animal Feed Science ana’Technology 54 (1995) 193-201
199
Table 4 Liveweight (kg) of weaner pigs during and after the experiment Treatment
SEM
P
NS ** *** *** **
Tl
T2
T3
T4
T5
7.09 8.58” 10.62”” 14.68”“” 18.49”
7.07 8.60” 10.78”“” 14.83”” 18.55’”
7.07 8.75” 11.38”bv 15.61b 19.93”
7.07 9.12bv 11.76”’ 16.34y 20.01bY
7.05 8.90 11.93by 15.7gby 19.64”
0.023 0.111 0.175 0.245 0.321
47.60a 59&V 70.92
47.37” 59.00” 69.76
50.37b 62.92b 73.86
50.17b 62.41” 73.45
49.1 7b 61.36b 71.71
0.805 0.963 1.244
Experiment period
Week 0 postweaning Week 1 postweaning Week 2 postweaning Week 3 postweaning Week 4 pestweaning Postexperimentperiod
Week 10 postweaning Week 12 postweaning Week 14 postweaning
* * NS
Treatment means within same row with different superscripts differ: “.bP< 0.05; “.“P< 0.01; ‘;+‘P< 0.001.
owing to diarrhoea was only slightly significant. In the present study, the occurrence of severe and frothy diarrhoea was highest during the first 2 weeks of the trial. Thereafter, the difference between treatments decreased and the proportion of pigs producing normal faeces increased, except for animals in T5 which showed persistent signs of relatively more severe diarrhoea. Despite the number of cases of severe or frothy diarrhoea reported, mortality was very low with only two pigs (0.2%) being lost from the experiment-one from T2 and one from T3. The contribution of diarrhoea to reduced pig performance was not assessed. Based on the performance of the pigs during the trial and at 10 weeks posttrial, it can be deduced that substantial benefits in pig performance and feed savings can be made from feeding fresh liquid whey to weaner pigs even if this may be done only for a relatively short period of time.
ratio
3.3. Effect of inclusion of liquid whey in the diet on piglet pe$ormance Weekly liveweight and mean daily liveweight gains of pigs in the experiment are shown in Table 4. At all stages of the feeding trial pigs fed whey supplemented diets were heavier than their contemporaries fed the control diets containing no whey. The mean liveweights in T3, T4 and T5 at the end of the feeding trial were 1.44, 1.52 and 1.15 kg greater than in Tl. However, the amount of whey included in a weaner diet or the method by which the whey was fed did not have a significant influence on piglet growth, except during Week 1 when T4 > T3 (P < 0.05)) and during Week 2 when T4 5: T5 > T3 (P < 0.001). Pigs from whey treatments had some residual benefits from the treatments since they continued to grow faster during the post-trial period when experimental animals were mixed and fed the same grower-finishing diet (see Table 4). By 10 or 12 weeks postweaning, when pigs reached porker weight, pigs fed weaner diets previously incorporating whey were still heavier than those fed control diets (P < 0.05). The corresponding liveweights were 50.4, 50.2 and 49.2 kg for T3, T4 and T5, respectively, compared with the control groups which weighed 47.6 kg (Tl) and 47.4 (T2). The results in Table 2 demonstrate that the inclusion
200
S,M. Maswaure, K.T. Mandosodza /Animal Feed Science and Technology 54 (1995) 193-201
of relatively small amounts of whey in diets (T3 and T4) enhanced the consumption of weaner diet (whereas when adequate whey was provided (T5), there was a depression in weaner diet intake), possibly because of the palatability of the whey. Data on mean daily liveweight gains showed a significant improvement (P < 0.01) during the first 2 weeks postweaning when pigs from T2, T4 and T5 had higher liveweight gains than control treatments. During Weeks 3 and 4 of the trial daily liveweight gains of pigs were similar (P > 0.05) across treatments. When the daily liveweight gains are interpreted in conjunction with the liveweight data presented in Table 4, they suggest that the nutrition of the piglet is critical during the immediate first or second week postweaning, and any advantage gained during this period is likely to persist into later life. In conclusion, the results from the present study demonstrate that fresh sweet whey can be incorporated into the diets of weaner pigs, and fed as slurry or ad libitum separately, resulting in an improvement in pig performance and with no serious incidence of diarrhoea. The increase in whey consumption as the pig grows suggests that better utilization of fresh whey can be obtained with older pigs. The most obvious benefit of feeding fresh liquid whey separately appears to be the saving in weaner diet, particularly when large amounts of whey are being consumed.
Acknowledgments
The authors express their thanks to Kadoma Dairy for the generous gift of fresh whey and to Mr. C. Chirume for his help and corporation. Funds, equipment and facilities for the study were provided by the Pig Industry Board of Zimbabwe.
References Association of Official Analytical Chemists, 1984. Official Methodsof Analysis, 14thEdn. Associationof Official Analytical Chemists, Arlington, VA. Bailey, H.S. and Carson, W.E., 1970. Comparisonof simple and complex diets for baby pigs; effect of form of feed and of glucose addition. J. Anim. Sci., 30: 394. Ball, R.O. and Aheme, F.X., 1982. Effect of diet complexity and feed restrictionon the incidence and severity of diarrhoeain early-weaned pigs. Can. J. Anim. Sci., 62: 907. Cieslak, D.G., Benevenga, N.J. and G~ntnter, R.H., 1986. Evaluationof fresh sweet as a proteinsupplementto maize for growing pigs. Anim. Feed Sci. Technol., 14: 171-181. Cinq-Mars,D., B’elanger, G., Lachance, B. and Btisson, G.J., 1986. Performanceof early weaned piglets fed diets containing various amountsof whey proteinconcentrate.1. Anim. Sci., 63: 145. Ekstrom,K.E.. Grummer,R.H. and Benevenga, N.J., 1976. Effects of a diet containing40% dried whey on the performanceand lactase activities in the small intestines and caecum of the Hampshireand ChesterWhite pigs. J. Anim. Sci., 42: 106. Graham,P.L., Mahamad,D.C. and Shields, Jr., R.G., 1981. Effect of starterdiet and length of feeding regimen on performanceand digestive enzyme activity of two week old weaner pigs. 1. Anim. Sci., 53: 299. Komegay, ET., Thomas, H.R. and Kramer,C.Y., 1974. Evaluationof the potentiallevels and milk productsfor pig starterdiets. J. Anim. Sci.. 39: 527. Ministry of AgricultureFisheries and Food (MAFF), 1978. Whey as a Feeding Stuff. ADAS PublicationNo. 615, Middlesex. Modler,H.W., 1988. The use of whey as an animal feed and fertilizer.Nutr. Abstr.Rev. Ser. B, 58: 2246.
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Pals, D.A. and Ewans, R.C., 1978. Utilisationof the energy of dried whey and wheat middilings by young swine. J. Anim. Sci., 46: 402. Schingoethe, D.I., 1988. Whey products in fed for swine. Nutr. Abstr. Rev. Ser. B, 58: 2398. Snedecor, G.W. and Co&ran, W.G., 1967. Statistical Methods. Iowa State University Press, Ames, 1A. Thivend, P.. 1977. Use of whey in feeding ruminants with particular reference to pollution problems. World Anim. Rev., 23: 20-24.
ELSEVIER
Animal Feed Science and Technology 54 ( 1995) 193-201
An evaluation of the performance of weaner pigs fed diets incorporating fresh sweet liquid whey S.M. Maswaure”, K.T. Mandisodza Pig Industry Board Experimental Farm, P.O. Box HG 297, Highlands, Harare. Zimbabwe
Received 3 May 1994; accepted 5 January 1995
Abstract Three hundred and eighty-five pigs from 77 litters weaned at 5 weeks of age were used to evaluate the consumption and nutritive value of fresh sweet liquid whey over a 4 week period. The diets were: control weaner diet, fed dry (Tl ); weaner diet + water, fed as a slurry mixed at a ratio of 1: 1 (T2); weaner diet + fresh whey, fed as a slurry mixed at a ratio of 1:1 (T3); weaner diet + fresh whey, fed as a slurry mixed at a ratio of 1:2 (T4) ; weaner diet + fresh whey, fed separately (T5). The pigs were fed to appetite at least five times a day. Treatments were replicated eight times, weekly, in groups of nine or ten pigs per treatment. Feeding slurry diets improved weaner diet intake by 3.8% in T2,6.8% in T3 and 3.4% in T4 when compared with the dry meal control (Tl). Feeding liquid whey ad libitum separately resulted in highest whey intake and reduced weaner diet consumption by 10.2%. Incidence of severe frothy diarrhoea during the first week after weaning was higher (P < 0.01) in pigs fed slurry diets or fresh whey separately (9-14%) than in those fed the control dry meal (5%). The proportion of pigs with severe diarrhoea decreased as the pigs grew older and diarrhoea had no adverse effects on pig performance. Daily liveweight gains were higher in whey supplemented treatments than in control treatments (Tl and T2) during the first and second week postweaning (P
* Corresponding author at: Kyushu National Agricultural Experiment Station, Kikuchi-Gun, Nishigoshi-Machi, Suya 2421. Kumamoto 861-11, Japan. 0377-8401/95/$09.50 0 1995 Elsevier Science B.V. All rights reserved ssDf0377-8401(95)00775-x
194
S. M. Maswaure. K.T. Mandosodza / Animal Feed Science and Technology 54 (1995) 193-201
1. Introduction
Whey is of high nutritional value for farm animals, in particular for pigs, and is often utilized in the three forms dried whey, concentrated whey or liquid whey. Fresh whey has a very low total solids content, averaging only 6-7%, which consists mainly of lactose and protein. Although the composition of whey varies essentially with the type of cheese of which it is a by-product, the method of preservation or the origin of the milk (Thivend, 1977)) the chemical composition of the dry matter may be of the order of 35% crude protein (N X 6.34), 50% lactose, 4.5% fat, and 6.0% ash (Cinq-Mars et al., 1986). The high proportion of lactose in whey is a good source of energy, while its relatively high protein content is of good biological value (Ministry of Agriculture, Fisheries and Food (MAFF) , 1978). In addition, whey is also a good source of water-soluble vitamins of the B group and its ash fraction is a good source of calcium and phosphorus. Fresh liquid whey has been traditionally fed in moderation to growing and fattening pigs and has only been included in diets of early weaned pigs in the dried form. The inclusion of small amounts of dried whey in maize-soyabean based diets has been shown to improve daily liveweight gains and feed efficiency of piglets weaned at 2-4 weeks of age (Kornegay et al., 1974; Pals and Ewan, 1978; Graham et al., 1981; Schingoethe, 1988). Cinq-Mars et al. (1986) have shown that feeding a wet weaner maize-soyabean diet containing whey protein concentrate, a product from ultrafiltration process, improves the performance of early weaned pigs. However, the feeding of liquid fresh whey to weaner pigs is not a normal practice presumably because of fears for a decline in feeding hygiene and increased risks of postweaning diarrhoea. Further constraints in the utilization of fresh liquid whey are linked to high transportation costs of the bulky liquid and the lack of drying facilities and as a result most of it is discarded or wasted. The objective of the present study was to investigate practical ways of incorporating varying proportions of fresh sweet whey into the diets of weaner pigs (5 weeks of age) in order to improve their growth and performance.
2. Materials and methods 2.1. Animals and experimental procedures A total of 385 crossbred pigs from 77 litters, weaned at an age of approximately 35 days and an average liveweight of 7.1 kg, were utilized in the experiment. Piglets from each litter were allocated to five groups of nine or ten pigs each. The groups were balanced for litter, sex and liveweight, and replicated weekly over a period of 8 weeks. The pigs were housed on a bedded concrete floor in conventional, naturally ventilated fattening pens. Drinking water was provided at all times via nipple drinkers. The five dietary treatments were randomly allocated weekly to five groups of weaned pigs and were evaluated over a 4 week period as follows: Treatment 1 (Tl ) , Control, weaner diet (fed in a dry meal form) ; ‘IT, Weaner diet + water, mixed at a ratio of 1: 1 ( w/w) ; T3, Weaner diet + whey, mixed at ratio of 1:l w/w; T4, Weaner diet + whey, mixed at ratio of 1:2 (w/w) ; T5, Weaner diet + whey, fed ad libitum separately.
SM. Maswaure, K.T. Mandosodza /Animal Feed Science and Technology 54 (1995) 193-201
195
Table 1 Composition and chemical analysis (as fed) of the piglet weaner diet Ingredients/constituent
g kg-’
Formulation
Milled pearl millet Soyabean meal Limestone flour Mono-calcium phosphate Antibiotic preparation (DB 1/TSP)” DB 1 vitamin and mineral premixa,b
643 310 15 20 2 10
Determined chemical analysis
Dry matter Crude protein Crude tibre Ether extracts Nitrogen-free extracts Ash
880 206 78 44 469 81
Calculated chemical composition
Metabolizable energy (MJ kg-‘) Total digestible nutrients Protein Oil Crude fibre Lysine Methionine Methionine + cystine Threonine Calcium Total phosphorus Sodium
11.02 647 207 24 61 10 10 13 7 8 6 2
a Antibiotic preparation and mineral and vitamin mix were supplied by Hemish Cameron, Harare. The antibiotic preparation was a combination drug containing 10% sulphachloropyridazine sodium and 2% trimethoprim. b DB 1 vitamin and mineral premix for creep feed provided the following per kg of diet: methionine 400 mg, vitamin A 8000 IU, vitamin D 1000 IU. vitamin E 40 IU, nicotinic acid 15 mg, pantothenic acid 15 mg, vitamin Bz 5 mg, vitamin B,a 0.02 mg, choline 500 mg, copper 250 mg, iron 180 mg, zinc 100 mg, manganese 60 mg. iodine 2 mg, selenium 0.2 mg, sodium chloride 4 g.
The diets in T2, T3 and T4 were offered as a slurry, the dry meal portion of the diet being weighed separately and then thoroughly mixed by hand with the corresponding amounts of water or whey. To avoid the build-up of stale food in the feeders, pigs were fed to appetite, in small amounts, at least five times per day. The formulation and chemical composition of the weaner diet are shown in Table 1. The fresh whey was collected from a cheese factory weekly in 50-l carboys and kept in cold storage at -20°C and was thawed at room temperature before being fed. The fresh whey contained 58 g total solids kg-‘. The chemical analysis (g kg-‘) of the total solids was: crude protein, 174.5; fat, 189.7; lactose, 520.3; ash, 115.5.
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2.2. Data collection Daily feed intake was recorded for each pen and the pigs were individually weighed every 7 days. The effects of dietary treatments on the incidence and severity of diarrhoea were assessed using a subjective diarrhoea score. The scores were taken daily on a per pen basis, based on observations of individual animals and the proportion of faeces indicating type of diarrhoea. Firmness of faeces was evaluated according to the following scores: 0, normal faeces; 1, soft faeces, possibly slight diarrhoea; 2, definitely unformed moderately fluid faeces; 3, severe watery or frothy diarrhoea (Ekstrom et al., 1976). The pigs were not given additional veterinary treatment for diarrhoea but an antibiotic was included in the diet. 2.3. Chemical analysis The whey and weaner diet were analysed for their proximate chemical composition. Dry matter (DM) was determined by drying the samples to constant weight at 105°C. Nitrogen content was determined using the micro-Kjeldahl digestion procedure. For both the whey and diet the values presented are means of duplicate analyses; crude protein was calculated as nitrogen (N) content X 6.34 for whey and N content X 6.25 for the weaner diet. Ash content was determined by combustion of 3.0 g samples in porcelain dishes at 600°C for 5 h. Fat in the diets was determined as ether extracts using the soxhlet procedure, by continuously evaporating petroleum ether. Fat content of the whey was determined volumetrically using the Gerber method. Crude fibre in the diet was determined according to the method of the Association of Official Analytical Chemists ( 1984). Lactose in whey and nitrogen free extracts in the diet were determined by difference. 2.4. Statistical analysis Data for weekly liveweight, daily feed intake, feed conversion daily liveweight gains and faecal scores were subjected to analysis of variance and differences between individual treatment means were determined using the t-test after a significant F test (Snedecor and Cochran, 1967),
3. Results and discussion 3.1. The effect of including liquid whey in the diet on feed consumption Data on weaner diet consumption are presented in Table 2. Weaner diet consumption did not differ significantly between control treatments (Tl and T2) ; however, the inclusion of water in T2 increased diet intake by 3.8% during the 4 week experimental period. The inclusion of fresh sweet whey into the weaner diet to form a whey/meal mix at a ratio 1:1 (T3), resulted in an increase in weaner diet intake that was significantly greater (P < 0.05) than that of the controls (Tl and T2) during Weeks 1 and 3 of the trial. Overall the inclusion of whey in T3 resulted in a 6.8% increase in total meal intake during the 4 week trial period.
S. M. Maswaure, K. T. Mandosodza /Animal Feed Science and Technology 54 (1995) 193-201
197
Table 2 Daily feed intake of piglet weaner diet (kg DM per day per pig) SEM P
Treatment Tl Week 1 postweaning Week 2 postweaning Week 3 postweaning Week 4 postweaning Total weaner diet intake (kg) Percentage weaner diet intake versus control (Tt)
T3
T2
0.33 0.56”” 0.77ab
0.34” 0.57” 0.81”
1.OO”
1.04”
18.62 0.0
19.32 + 3.8
T4 0.37b 0.56”” 0.83” 1.05”
19.88 +6.8
T5 0.36b 0.54” 0.80* 1.05”
19.25 +3.4
0.34” 0.016 * 0.48b’ 0 018 * 0.72b 0:028 0.09 0.85”y 0.031 *** 16.73 - 10.2
-
-
Values are of piglet weaner diet intakes, excluding added whey in T3, T4 and T5. Treatments: control weaner diet, fed dry ( Tl ) ; weaner diet + water, fed as a shmy mixed at a ratio of 1:I (T2) ; weaner diet + fresh whey, fed as a slurry mixed at a ratio of 1:1 (T3); weaner diet + fresh whey, fed as a shmy mixed at a ratio of 1:2 (T4) or weaner diet + fresh whey, fed ad libitum separately (T5). Estimates of dry matter contributed by liquid whey were calculated from the amounts of whey fed or mixed with the piglet weaned diet (Table 3) and the dry matter content of the whey presented in Table 1. Treatment means within same row with different superscripts differ: abP<0.05; “.‘P
When liquid whey was mixed with the weaner meal at a ratio 2: 1 (T4), weaner diet intake was greater than the control treatments during Week 1 (P < 0.05) and Week 2 (P < 0.01). The increase in total meal intake in T4 during the 4 week trial period was 3.4% greater than in Tl. When whey was provided ad libitum separately (T5), the provision of whey resulted in a reduction in total meal intake ( - 10.2%)) and daily meal intake was significantly lower than in the control treatment (P < 0.05) during Weeks 2, 3 and 4 of the trial. From the results in Table 2, it appears that the mixing of small amounts of whey with a cerealsoyabean basal diet to form a slurry enhances the consumption of the weaner meal. This enhanced meal consumption is probably due to the improved palatability of the diet and is greater than the increase caused by mixing the weaner diet with water alone (i.e. T2 vs. T3 and T4). However, when considerable amounts of whey are offered, as in T5, a substitutive effect between the whey and the meal is observed, which resulted in a 10.2% saving on meal consumption. This is in general agreement with other reports in which consumption of large quantities of whey led to considerable savings on feed (see Cieslak et al., 1986; Modler, 1988; Schingoethe, 1988), especially if transport costs from the processing plant to the farm are low. The amounts of water and whey consumed during the experiment as part of the diet, treatments are shown in Table 3. In T3, T4 and T5 the corresponding contribution of whey solids to the total dry matter (TDM) intake was 6.3%, 12.5% and 25.4%, respectively. The percentage contribution of whey solids to DM intake observed with the pigs fed ad libitum (T5) falls at the lower limit of the 24.0-58.5% range reported by Cieslak et al. ( 1986) when fresh sweet whey was provided as a protein supplement to maize based diets fed to growing-finishing pigs. This should be expected as older pigs have generally been known to be better utilizers of fresh whey (MAFF, 1978). In the present study there was a sevenfold increase in daily whey intake by pigs with ad libitum access to whey (T5) between
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Table 3 Mean daily whey (and water, R) consumption on as-fed basis and on total solid basis Treatmenmt Tl
T2
T3
T4
T5
Fresh whey consumption (kg per &y per pig)
Week 1 postweaning Week 2 postweaning Week 3 postweaning Week 4 postweaning Total whey consumption
-
0.61 0.88 1.12
0.42 0.61 0.89 1.17
0.80 1.19 1.73 2.24
-
21.00
21.63
41.72
0.39
0.66
1.91 3.24 4.72 73.71
Whey solids consumption (kg per day per pig)
Week 1 postweaning Week 2 postweaning Week 3 postweaning Week 4 postweaning
-
Total whey solids intake (kg per pig)
-
-
0.024 0.036 0.05 1 0.067
0.046 0.069 0.100 0.130
0.111 0.183 0.273
1.246
2.415
4.242
0.039
Treatments: control weaner diet, fed dry (T 1) ; weaner diet + water, fed as a slurry mixed at a ratio of 1:1 (T2) ; weaner diet + fresh whey, fed as a slurry mixed at a ratio of 1:1 (T3); weaner diet + fresh whey, fed as a slurry mixed at a ratio of 1:2 (T4); weaner diet + fresh whey, fed ad libitum separately (T5).
the ages of 5 and 9 weeks, which corresponds to an increase in whey consumption from 0.66 to 4.7 1 per pig per day during the 4 week duration of the experiment. 3.2. Dietary effects on the incidence and severity of piglet diarrhea Fewer pigs fed the control diet (Tl) had diarrhoea and it was less severe than when slurry diets (T2, T3 or T4) were fed or when whey was fed ad libitum separately (T5). The incidence of severe frothy diarrhoea (diarrhoea score 3) decreased with time postweaning and was higher in slurry and ad libitum whey fed pigs than in the dry meal control diet (Tl). The proportion of pigs showing this type of diarrhoea in Tl-T5, respectively, were: Week1,0.05,0.14,0.09,0.14,0.12(SEM0.018,P<0.01);Week2,0.05,0.11,0.08,0.11, 0.11 (standarderrorofthemean (SEM) 0.016,P=0.08);Week3,0.04,0.09,0.06,0.09, 0.11 (SEMO.018, P=O.O7); Week4,0.04, 0.07,0.04,0.03,0.10 (SEM0.21, P=O.O9). The most severe cases of diarrhoea were with treatments T2, T4 and T5, whereas the dry meal control treatment (Tl ) had the least incidence of severe diarrhoea. Between 77% and 82% of the pigs did not contract diarrhoea, soft or fluid faeces during the first week, and the numbers increased to between 84% and 90% during Week 4 postweaning. This may explain the lack of differences in animal performance, between treatments, observed in the present study. The effects of diarrhoea on food utilization and performance of young pigs are well documented; for example, diarrhoea has been reported to lead to a reduced feed intake and lower liveweight gains. Some studies have reported that diarrhoea occurs less frequently with pigs fed simple diets (Bailey and Carson, 1970; Ball and Aherne, 1982). However, in the study by Ball and Aherne ( 1982)) the decrease in gain and reduced gain:feed
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199
Table 4 Liveweight (kg) of weaner pigs during and after the experiment Treatment
SEM
P
NS ** *** *** **
Tl
T2
T3
T4
T5
7.09 8.58” 10.62”” 14.68”“” 18.49”
7.07 8.60” 10.78”“” 14.83”” 18.55’”
7.07 8.75” 11.38”bv 15.61b 19.93”
7.07 9.12bv 11.76”’ 16.34y 20.01bY
7.05 8.90 11.93by 15.7gby 19.64”
0.023 0.111 0.175 0.245 0.321
47.60a 59&V 70.92
47.37” 59.00” 69.76
50.37b 62.92b 73.86
50.17b 62.41” 73.45
49.1 7b 61.36b 71.71
0.805 0.963 1.244
Experiment period
Week 0 postweaning Week 1 postweaning Week 2 postweaning Week 3 postweaning Week 4 pestweaning Postexperimentperiod
Week 10 postweaning Week 12 postweaning Week 14 postweaning
* * NS
Treatment means within same row with different superscripts differ: “.bP< 0.05; “.“P< 0.01; ‘;+‘P< 0.001.
owing to diarrhoea was only slightly significant. In the present study, the occurrence of severe and frothy diarrhoea was highest during the first 2 weeks of the trial. Thereafter, the difference between treatments decreased and the proportion of pigs producing normal faeces increased, except for animals in T5 which showed persistent signs of relatively more severe diarrhoea. Despite the number of cases of severe or frothy diarrhoea reported, mortality was very low with only two pigs (0.2%) being lost from the experiment-one from T2 and one from T3. The contribution of diarrhoea to reduced pig performance was not assessed. Based on the performance of the pigs during the trial and at 10 weeks posttrial, it can be deduced that substantial benefits in pig performance and feed savings can be made from feeding fresh liquid whey to weaner pigs even if this may be done only for a relatively short period of time.
ratio
3.3. Effect of inclusion of liquid whey in the diet on piglet pe$ormance Weekly liveweight and mean daily liveweight gains of pigs in the experiment are shown in Table 4. At all stages of the feeding trial pigs fed whey supplemented diets were heavier than their contemporaries fed the control diets containing no whey. The mean liveweights in T3, T4 and T5 at the end of the feeding trial were 1.44, 1.52 and 1.15 kg greater than in Tl. However, the amount of whey included in a weaner diet or the method by which the whey was fed did not have a significant influence on piglet growth, except during Week 1 when T4 > T3 (P < 0.05)) and during Week 2 when T4 5: T5 > T3 (P < 0.001). Pigs from whey treatments had some residual benefits from the treatments since they continued to grow faster during the post-trial period when experimental animals were mixed and fed the same grower-finishing diet (see Table 4). By 10 or 12 weeks postweaning, when pigs reached porker weight, pigs fed weaner diets previously incorporating whey were still heavier than those fed control diets (P < 0.05). The corresponding liveweights were 50.4, 50.2 and 49.2 kg for T3, T4 and T5, respectively, compared with the control groups which weighed 47.6 kg (Tl) and 47.4 (T2). The results in Table 2 demonstrate that the inclusion
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of relatively small amounts of whey in diets (T3 and T4) enhanced the consumption of weaner diet (whereas when adequate whey was provided (T5), there was a depression in weaner diet intake), possibly because of the palatability of the whey. Data on mean daily liveweight gains showed a significant improvement (P < 0.01) during the first 2 weeks postweaning when pigs from T2, T4 and T5 had higher liveweight gains than control treatments. During Weeks 3 and 4 of the trial daily liveweight gains of pigs were similar (P > 0.05) across treatments. When the daily liveweight gains are interpreted in conjunction with the liveweight data presented in Table 4, they suggest that the nutrition of the piglet is critical during the immediate first or second week postweaning, and any advantage gained during this period is likely to persist into later life. In conclusion, the results from the present study demonstrate that fresh sweet whey can be incorporated into the diets of weaner pigs, and fed as slurry or ad libitum separately, resulting in an improvement in pig performance and with no serious incidence of diarrhoea. The increase in whey consumption as the pig grows suggests that better utilization of fresh whey can be obtained with older pigs. The most obvious benefit of feeding fresh liquid whey separately appears to be the saving in weaner diet, particularly when large amounts of whey are being consumed.
Acknowledgments
The authors express their thanks to Kadoma Dairy for the generous gift of fresh whey and to Mr. C. Chirume for his help and corporation. Funds, equipment and facilities for the study were provided by the Pig Industry Board of Zimbabwe.
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Pals, D.A. and Ewans, R.C., 1978. Utilisationof the energy of dried whey and wheat middilings by young swine. J. Anim. Sci., 46: 402. Schingoethe, D.I., 1988. Whey products in fed for swine. Nutr. Abstr. Rev. Ser. B, 58: 2398. Snedecor, G.W. and Co&ran, W.G., 1967. Statistical Methods. Iowa State University Press, Ames, 1A. Thivend, P.. 1977. Use of whey in feeding ruminants with particular reference to pollution problems. World Anim. Rev., 23: 20-24.