Nutritive Value of Potato Processing Wastes in Total Mixed Rations for Dairy Cattle I CHRIS ONWUBUEMELI, 2 J. T. HUBER? K. J. KING, and C.O.L.E. JOHNSON Department of Animal Science Michigan State University East Lansing 48824 ABSTRACT The nutritive value of wet potato pro- cessing waste for dairy cattle was deter- mined in two experiments. In Experiment 1, rations contained, on a dry matter basis, O, 10, 15, and 20% potato waste and were substituted for high moisture corn in diets for 32 lactating Holstein cows for 12 wk. Substituting potato waste for corn did not significantly affect milk yield, milk composition, milk pro- duction persistency, or dry matter intake. Cows fed 20% potato waste tended to de- crease in milk fat percent and to shift molar proportions of rumen volatile fatty acids toward a decrease in acetate: propio- hate ratio. In Experiment 2, six steers were used in a 3 x 3 Latin square design to test digestibility and nitrogen utilization of potato waste substituted for high mois- ture corn at 0, 10, and 20% of the ration dry matter. A second group of four steers with rumen fistulas were used in a 4 × 4 Latin square to test rumen fermentation parameters. Diets contained 0, 10, 20, and 30% potato wastes and were similar to Experiment 1. Potato waste did not significantly affect digestibility of crude protein or dry matter, but at 20% sub- stitution digestibility of acid detergent fiber decreased. Rumen ammonia, ace- tate, acetate to propionate ratios, and total volatile fatty acids were lower at Received September 13, 1984. 1Published with approval of the Director of the Agricultural Experiment Station as Journal Article No. 11411. 2Federal Livestock Department, Kano, Nigeria. 3Department of Animal Science, University of Arizona, Tucson, AZ 85721. high intakes of potato waste and pH was increased. The shift in rumen fermenta- tion when large amounts of potatoes were fed explains the depressed butter fat on these rations. INTRODUCTION A large number of by-products of the food industry are used in livestock feed. Crop resi- dues and by-products currently fed advanta- geously to livestock include corn stalks, apple pomace, beet pulp, corn distiller's grain, fresh carrots, small grain straws, sugarcane baggasse, and others (9, 10). By-products of potato processing have been used to a limited extent in cattle feeding (2, 3, 5). Depending on the processing plant, potato by-products may be potato pulp, peeling slivers, potato culls, potato chips, and fragments. Potato wastes are a disposal problem, but if properly incorporated into animal rations, they are valuable as livestock feed (12). About 1 million tons of potato wastes are produced an- nually in the US. Crude protein and fiber con- tent of potato wastes vary greatly depending on processing methods and range between 4 and 8% and 1.6 and 17.5%, respectively (2, 3, 5). The pH of wastes falls rapidly to about 3.7 at which pH it remains stable for long periods. Starch losses of up to 56% may occur during storage due to enzymatic and bacterial action (3, 7). In the past, potato wastes or by-products were fed to livestock as potato meal or dried pulp. Because of large expenditures for drying, current interest is centered on utilization of wet wastes. Substitution of wet potato waste for concentrates in dairy feeds appears feasible, particularly with completely mixed rations. Data by Brown et al. (2) indicated that wet corn and potato chipping by-products may be fed to dairy cattle without adverse effects. Our 1985 J Dairy Sci 68:1207-1214 1207
Transcript
Nutri t ive Value of Potato Processing Wastes in Total Mixed Rations for Dairy Catt le I
CHRIS ONWUBUEMELI, 2 J. T. HUBER? K. J. KING, and C.O.L.E. JOHNSON
Department of Animal Science Michigan State University
East Lansing 48824
ABSTRACT
The nutritive value of wet potato pro- cessing waste for dairy cattle was deter- mined in two experiments. In Experiment 1, rations contained, on a dry matter basis, O, 10, 15, and 20% potato waste and were substituted for high moisture corn in diets for 32 lactating Holstein cows for 12 wk. Substituting potato waste for corn did not significantly affect milk yield, milk composition, milk pro- duction persistency, or dry matter intake. Cows fed 20% potato waste tended to de- crease in milk fat percent and to shift molar proportions of rumen volatile fatty acids toward a decrease in acetate: propio- hate ratio.
In Experiment 2, six steers were used in a 3 x 3 Latin square design to test digestibility and nitrogen utilization of potato waste substituted for high mois- ture corn at 0, 10, and 20% of the ration dry matter. A second group of four steers with rumen fistulas were used in a 4 × 4 Latin square to test rumen fermentation parameters. Diets contained 0, 10, 20, and 30% potato wastes and were similar to Experiment 1. Potato waste did not significantly affect digestibility of crude protein or dry matter, but at 20% sub- stitution digestibility of acid detergent fiber decreased. Rumen ammonia, ace- tate, acetate to propionate ratios, and total volatile fatty acids were lower at
Received September 13, 1984. 1 Published with approval of the Director of the
Agricultural Experiment Station as Journal Article No. 11411.
2 Federal Livestock Department, Kano, Nigeria. 3Department of Animal Science, University of
Arizona, Tucson, AZ 85721.
high intakes of potato waste and pH was increased. The shift in rumen fermenta- tion when large amounts of potatoes were fed explains the depressed butter fat on these rations.
INTRODUCTION
A large number of by-products of the food industry are used in livestock feed. Crop resi- dues and by-products currently fed advanta- geously to livestock include corn stalks, apple pomace, beet pulp, corn distiller's grain, fresh carrots, small grain straws, sugarcane baggasse, and others (9, 10).
By-products of potato processing have been used to a limited extent in cattle feeding (2, 3, 5). Depending on the processing plant, potato by-products may be potato pulp, peeling slivers, potato culls, potato chips, and fragments.
Potato wastes are a disposal problem, but if properly incorporated into animal rations, they are valuable as livestock feed (12). About 1 million tons of potato wastes are produced an- nually in the US. Crude protein and fiber con- tent of potato wastes vary greatly depending on processing methods and range between 4 and 8% and 1.6 and 17.5%, respectively (2, 3, 5). The pH of wastes falls rapidly to about 3.7 at which pH it remains stable for long periods. Starch losses of up to 56% may occur during storage due to enzymatic and bacterial action (3, 7).
In the past, potato wastes or by-products were fed to livestock as potato meal or dried pulp. Because of large expenditures for drying, current interest is centered on utilization of wet wastes. Substitution of wet potato waste for concentrates in dairy feeds appears feasible, particularly with completely mixed rations. Data by Brown et al. (2) indicated that wet corn and potato chipping by-products may be fed to dairy cattle without adverse effects. Our
1985 J Dairy Sci 68:1207-1214 1207
1208 ONWUBUEMELI ET AL.
study determined the feeding value for dairy cows of potato processing waste obtained from a processing plant in Michigan.
MATERIALS AND METHODS
The potato processing waste (PPW) con- sisted, on a dry matter (DM) basis, of 60% peel and sludge, 30% raw potato screenings, and 10% cooked packaging wastes. Steam treatment was used for peeling of potatoes with no added alkali. Whole cull potatoes were minced to pieces less than 1 cm prior to delivery. Analysis of waste is shown in Table 1.
The study consisted of two experiments: 1) one with lactating cows and 2) a digestibility and rumen metabolism trial with young, grow- ing steers.
Experiment 1
Lactation Trial. Thirty-two lactating Hol- stein cows were blocked for milk yields during a 2 wk pretreatment and allotted to a ran- domized block design. There were four cows per block and eight per treatment. The four rations (A, B, C, and D) provided 0, 10, 15, or 20% PPW (of DM) as substitute for high mois- ture corn (HMC). All rations contained 25% corn silage, 25% haylage, and approximately 14% CP. Ingredient and chemical analyses of total mixed rations are in Table 2.
For the 12-wk experimental period cows were fed twice daily and housed in confinement stalls at the Michigan State University Dairy Cattle Center. Orts were weighed once daily and feed was adjusted to allow for about 10% orts.
Cows were milked twice daily and milk weights recorded. At biweekly intervals, a.m. and p.m. milk samples were composited and analyzed for fat, protein, and total solids. On
day 60 of treatment, rumen contents were sampled through a stomach tube and blood from the tail vein. Rumen contents were strained through four layers of cheesecloth, pH was taken, and 25 ml were acidified with .5 ml 50% sulfuric acid, centrifuged, and frozen at - 5 ° C until analyzed. Blood samples were collected in heparinized, oxalated tubes, and centrifuged at 800 × g and plasma was frozen at - 5 ° C until analyzed.
Experiment 2
Ration Digestibility. In a 3 × 3 Latin square design six yearling steers were used to test di- gestibility and nitrogen utilization of rations in which PPW replaced HMC at 0, 10, or 20% of DM. Ingredient composition and analyses of total mixed rations are in Table 3.
Steers, housed in metabolism stalls at the Michigan State University Beef Cattle Research Center, were adapted to the rations for 7 days, and feces and urine were collected for 5 days. Steers were weighed at 0800 h on the beginning and last day of each collection period. Rations were fed ad libitum once daily in the morning and feed and orts were sampled daily. Urine was collected in a metal funnel connected to plastic jars by rubber tubing. To each jar 50 ml concentrated sulfuric acid were added daily just after urine sampling for preventing nitrogen loss.
Rumen Metabolism. Four steers fitted with rumen fistulas were used in a 4 × 4 Latin square design. Three rations were the same as in trial 1 and the fourth contained 30% of the DM as PPW (Table 3). All rations were fed at 5% in excess of consumption to ensure ad libitum in- take. Steers were adapted to rations for 9 days, and on day 10 rumen contents were sampled at 0, 2, 4, and 8 h postfeeding. Samples were strained through four layers of cheesecloth into
TABLE 1. Chemical analysis of potato processing waste used in the study.
TABLE 2. Ingredient and chemical composi t ion of rations used in the lactation experiment .
1 2 0 9
Ingredients
Rations, % PPW ~ 0 10 15 20
Corn silage, % of DM 2 25 25 25 25 Haylage, % of DM 25 25 25 25 High mois ture corn, % of DM 42 32 27 22 Protein supplement , 3 % of DM 7 7 7 7 Trace mineralized salt, 4 % of DM 1 1 1 1 PPW, % of DM 0 10 15 20
Chemical composi t ion DM 48.15 44.12 40.70 36.70 Crude protein 14.25 14.17 14.23 13.97 Acid detergent fiber 19.63 19.65 19.70 19.73
PPW = Potato processing waste.
2 DM = Dry matter . 3 Guaranteed analysis: m i n i m u m crude protein, 44.0%; m a x i m u m crude fiber, 8.0%; m i n i m u m calcium, 2.9%;
m i n i m u m phosphorus , 1.5%; m i n i m u m sodium chloride, 1.8%; m i n i m u m vitamin A, 15,000 USP units / lb (.45 kg); m i n i m u m vitamin D3, 3,000 USP units / lb (.45 kg); m i n i m u m manganese, .200%; m i n i m u m copper, .005%; m i n i m u m iodine, .007%.
4 Guaranteed analysis: m i n i m u m zinc, .350%; m i n i m u m iron, .030%; m i n i m u m cobalt, .005%; m i n i m u m salt, 96.00%.
p las t i c vials c o n t a i n i n g .1 m l m e r c u r i c c h l o r i d e to s t o p f e r m e n t a t i o n . T h e p H o f r u m e n f l u i d w a s d e t e r m i n e d i m m e d i a t e l y , a n d 2 m l o f r u m e n f l u id w e r e m i x e d w i t h 2 m l o f 10%
s o d i u m t u n g s t a t e a n d 2 ml 1 N s u l f u r i c ac id . T h e m i x t u r e w a s c e n t r i f u g e d a t 1 2 0 0 × g a n d t h e s u p e r n a t a n t was f r o z e n at - 5 ° C u n t i l a n a l y z e d .
TABLE 3. Ingredient and chemical composi t ion of rations fed in digestibility and rumen fermenta t ion experiment.
Ingredients 0
Rations, % PPW I'2
10 20 30
Corn silage, % of DM 3 25 25 25 25 Haylage, % DM 25 25 25 25 High mois ture corn, % DM 43 33 23 13 PPW, % DM 0 10 20 30 Protein supplement , a % DM 7 7 7 7
Chemical composi t ion DM 50.17 46.05 43.05 36.60 Crude protein 14.13 14.07 14.01 13.77 Ac id detergent fiber 19.53 19.61 19.74 19.77
1 PPW = Potato processing waste. Rat ions 0, 10, and 20 were fed in digestibility trial. All rations were fed in the rumen fermenta t ion trial.
3 DM = Dry matter . 4 Guaranteed analysis: m i n i m u m crude protein, 44.0%; m a x i m u m crude fiber, 8.0%; m i n i m u m calcium, 2.9%;
m i n i m u m phosphorus , 1.5%; m i n i m u m sodium chloride, 1.8%; m i n i m u m vitamin A, 15,000 USP units / lb (.45 kg); m i n i m u m vitamin D3, 3,000 USP units / lb (.45 kg).
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Cbernical Analysis. Dry matter was deter- mined on complete rations by comminuting in a food chopper and placing about 50 g of mate- rial in a forced-air oven set at 100°C for 24 h. For PPW and feces, DM was determined at 60°C for 48 h. Crude protein was determined on all samples by the macro-Kjeldahl method and acid detergent fiber by the method of Van Soest (19). Milk samples were analyzed for fat, protein, and total solids by infrared spectro- scopy at the Michigan Dairy Herd Improvement Milk Testing Laboratory. Plasma glucose was determined by the glucose-oxidase method (15). Rumen fluid was analyzed for acetate, propionate, and butyrate by gas chromatog- raphy in a column packed with 10% SP 1200/ 1% phosphoric acid (H3PO4) on 100/120 chromosorb. Rumen ammonia was determined by the method of Chaney and Marbach (4).
Statistical Analysis. Data were analyzed statistically by analysis of variance methods de- scribed by Gill (6) for randomized block, split plot, or Latin square designs.
RESULTS AND DISCUSSION
Experiment 1
Lactation Trial. Ration DM decreased as percent PPW in the ration increased due to the higher moisture in PPW than HMC. There were no differences between treatments in mean DM
intakes. This contrasts with Brown et al. (2), who reported a significant decrease in DM intake as percent of corn-potato by-product in the ration increased.
Total milk production, 4% fat-corrected milk, and milk production persistency were not different between control and PPW rations (Table 4). Milk production was highest at the highest PPW. This contrasts with Brown et al. (2) and may be attributed to the differential effect of PPW on DM intake in the two studies. However, the studies may not be directly com- parable because Brown et al. (2) substituted more by-product (24 and 36% of ration DM). Moreover, their by-product was composed of both potato chipping and corn wastes.
Milk fat percent tended to decrease with in- creased PPW. The decreasing trend in milk fat percent may be explained in part by low fiber in PPW. Also, about 10% of the PPW was cooked waste. Inclusion of steamed potatoes into lactating rations previously decreased milk fat percent (16). Milk protein percent was not different among treatments. Likewise, plasma glucose was not affected by treatments, and values were similar to those in the literature (1, 11).
Cows fed PPW gained slightly more weight than controls but differences were small. Effi- ciency of feed utilization did not differ among treatments, suggesting that DM from potato waste is utilized as efficiently for milk produc- tion as that from HMC.
Eight cows per treatment for 12 wk. a Means on same row were not significantly different (P>.05).
There were no significant d i f ferences be- tween t r ea tmen t s in concen t ra t ions o f rumen acetate , p rop iona te , and bu tyra te , or in aceta te : p rop iona te (C2 :C3) ratios (Table 5), bu t a t rend toward higher p rop iona te and lower C2:C3 was no ted as PPW increased, which may have been responsible for the decrease in milk fat percent .
Experiment 2
Ration Digestibility. A p p a ren t p ro te in diges- t ibil i ty was no t d i f fe ren t among rat ions (Table 6). Nicholson and Friend (13) r epor ted 31% di- gest ibi l i ty for crude pro te in in po ta to pulp fed to sheep" Ryan and Balls (14) isolated an inhibi- tor to c h y m o t r y p s i n f rom po ta to juice.
TABLE 6. Nutrient digestibility, nitrogen (N) balance, 1 weight change, and efficiency of feed utilization of steers fed potato processing wastes (PPW).a
Rations, % PPW Items 0 10 20 SEM
Dry matter (DM) intake, kg/day 5.69 c 5.78 c 4.45 d .4 Apparent DM digestibility, % 78.6 79.3 80.4 1.26 Apparent protein digestibility, % 72.8 74.4 71.3 2.03 Acid detergent fiber digestibility, % 54.8 e 54.9 e 48.6 f 2.66 N intake, g/day 129.6 a 124.8 a 99.2 b 6.4 Urinary N, g/day 49.6 43.2 32.0 11.2 Fecal N, g/day 34.7 c 32.0 c 29.6 d 1.47 Digested N, g/day 94.1 90.7 70.1 8.1 N retained, g/day 44.8 51.2 38.4 12.8 Urinary N, % digested 52.3 43.8 48.0 15.57 Fecal N, % digested N 38.0 c 35.5 d 40.9 f 3.58 Fecal N, % N intake 27.0 25.8 28.7 2.02 Weight gain, g/day 444.2 541.6 430.8 148.3 Weight gain/DM digested, g/kg 110. 0 130.0 130.0 40.0 Weight gain/N digested, g/g 5.1 6.2 4.6 1.47
a'bMeans in same row with different superscripts differ (P<.05). C'dMeans in same row with different superscripts differ (P<. 10). e'fMeans in same row with different superscripts differ (P<.25). 1 Values are means of treamaents. 2 Six steers per treamaent in a 3 × 3 Latin square design.
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TABLE 7. Rumen fermentation characteristics I of steers fed potato processing wastes (PPW).2
Rations, % PPW Items O 10 20 30 SEM
Total VFA, 3 mM 52.26 a 51.05 a 44.97 b 46.12 b .36 Acetate, mM 33.74 a 31.75 a 27.60 b 26.48 b .28 Propionate, mM 12.60 e 12.34 e 11.60 f 13.41g .08 Butyrate, mM 5.92 6.96 5.77 6.23 .08 Acetate:propionate 2.74 h 2.65 h 2.50 h 2.01 i .16 Rumen ammonia, mg/dl 4.88 h 3.98 h 2.98 i 2.35 i .58 pH 5.78 e 6.06 f 6.28 f 6.13 f .20 DMI, 4 kg/day 4.21 a 4.38 b 3.99 e 3.17 d .06
a'b'C'dMeans in same row with different superscripts differ (P<.025). e'f'gMeans in same row with different superscripts differ (P<. 10). h'iMeans in same row with different superscripts differ (P<.O05). 1 Values are means of treatment that include all sampling times.
Four steers/treatment in a 4 × 4 Latin square design. 3 VFA = Volatile fatty acids. 4 DMI = Dry matter intake.
The PPW tended to lower (P<.25) A D F di- gestibility. Previous studies with po ta to waste did not measure fiber digestibili ty. Diets high in readily digestible carbohydrates , which depress rumen pH, of ten decrease rumen pH and cellu- lose digestibil i ty (17); however, rumen pH was not lowered by PPW.
The PPW is pr imari ly an energy source and contains an amoun t of starch similar to high mois ture corn for which it subst i tuted. How- ever, po ta to starch may have been more rap- idly digested than corn starch. The depres- sion in A D F digestibil i ty might be associated with an increased rate of rumen fe rmenta t ion .
Differences be tween t rea tments in DM diges- tibili t ies were small, but values rended to in- crease as PPW increased. Pota to pulp in sheep rations decreased fecal DM (13) and increased the digestible DM.
Nitrogen Balance. Fecal ni t rogen decreased (P<.10) at 20% PPW, but ur inary ni t rogen did not differ be tween t rea tments (Table 6). Nei ther was ni t rogen re tent ion affected. Nitro- gen retained as percent of digested ni t rogen was numerical ly higher for the PPW rations, bu t variat ion among t rea tments was large.
Daily weight gains and eff ic iency of DM and protein ut i l izat ion were no t affected by PPW addi t ion to rations, nor was ut i l izat ion of dietary DM or o f dietary protein.
Rumen Metabolism. Inclusion of 20 and 30% PPW decreased (P<.025) total rumen VFA, acetate, and acetate to p rop iona te ratios. Higher (P<.10) propionate than on the cont ro l rat ion was observed for 30% but no t 20% PPW (Table 7). The decrease in total tureen V F A at 20 and 30% PPW may be explained .by de- creased DM intakes. Tota l V F A increased with t ime after feeding and was inversely related to rumen pH (Table 8), which agrees wi th I-Ioogen- doorn and Grieve (8). The shift in rumen fer- menta t ion toward lower acetate and C~:C3 ratios at 20 and 30% PPW was associated with the decreased milk fat percent observed in Exper iment 1.
The higher percentages of dietary PPW de- creased (P<.005) rumen ammon ia concentra- tions, which peaked 2 h postfeeding. Addi t ion of more fe rmentable carbohydrate , such as starch, to ruminant rations causes a decrease in rumen ammonia (18) probably due to a greater uptake of ammonia by rumen microorganisms in suppor t of enhanced microbial growth. How- ever, the lower V F A concent ra t ions on high PPW contrasts with such an effect.
Data f rom this s tudy indicate tha t PPW can replace up to 20% of the grain in to ta l mixed rations for lactating dairy cattle. However , milk fat may be depressed if 20% or more of the rat ion DM comes f rom PPW. Feeding up to 20%
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NUTRITIVE VALUE OF POTATO PROCESSING WASTES 1213
TABLE 8. Effect of time of sampling on volatile fatty acids (VFA) and pH of steers fed potato processing wastes (PPW).
of the rat ion DM as PPW will no t adversely af- fect nu t r i en t digestibil i ty, bu t 20% or more o f the rat ion DM as PPW may depress ADF diges- t ibil i ty and cause a shif t in rumen f e r m e n t a t i o n toward higher C2 :C3 ratios.
ACKNOWLEDGMENT
This s tudy was partially suppor t ed by Ore- Ida Foods, Inc., Boise, ID.
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