UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA THE DIGESTIBILITY OF GROUND PRUNES, WINERY POMACE, AVOCADO MEAL, ASPARAGUS BUTTS, AND FENUGREEK MEAL A. H. FOLGER BULLETIN 635 February, 1940 UNIVERSITY OF CALIFORNIA BERKELEY, CALIFORNIA CONTENTS PAGE Digestion trial with prunes 3 Digestion trial with dried winery pomace 5 Digestion trial with avocado meal ; 7 Digestion trial with dried asparagus butts 9 Eesults obtained with fenugreek meal 10 Summary 11 THE DIGESTIBILITY OF GROUND PRUNES, WINERY POMACE, AVOCADO MEAL, ASPARAGUS BUTTS, AND FENUGREEK MEAL 1 A. H. FOLGER 2 In the effort to assist livestock men in their search for satisfactory feeds, the Division of Animal Husbandry of the University of California has conducted tests on certain by-product materials that have appeared on the market recently, or about which many inquiries have been re- ceived. The present paper gives the results of digestion trials conducted on dried prunes, dried winery pomace, avocado meal, and dried aspara- gus butts, together with some information on fenugreek meal. As in previous trials, wether sheep were used as test animals because they are especially suited to digestion- trial work, being easy to handle and care for and having feces that are easily collected and processed. When the sheep were being prepared for the various trials a preliminary feed- ing period of 10 days was used ; then, during the 15 days immediately following, the feces were collected. They were taken immediately to the drying room and the dry weight recorded after removal from the oven. All analyses of feces were calculated to the moisture-free basis. Further detailed procedure for these trials has been given in Bulletin 409. 3 Tables presenting the results in detail are given in connection with each trial, while a comparison of the digestible nutrients determined with those found in various common feeds is given in table 16. DIGESTION TRIAL WITH PRUNES Because of economic conditions the prune growers have been encumbered recently with a large surplus of prunes that they have desired to with- hold from the market. Hoping to dispose of a large portion of these to the stockmen, the growers asked the Agricultural Experiment Station to investigate their value as stock feed. After considerable preliminary work it was decided that in the diges- tion trial the best results would be obtained by feeding a mixture of the 1 Received for publication August 24, 1939. 2 Superintendent Official Advanced Registry Tests ; resigned September 16, 1939. 3 Mead, S. W., and H. R. Guilbert. The digestibility of certain fruit by-products as determined for ruminants. Part I. Dried orange pulp and raisin pulp. California Agr. Exp. Sta. Bui. 409 : 1-11. 1926. (Out of print. ) [3] 4 University of California — Experiment Station ground prunes with oat hay of known digestibility, since this procedure gave a uniform mixture of known composition that could be easily han- dled and fed. This product, "prune meal," proved palatable to the ani- mals. The results are presented in tables 1, 2, and 3. TABLE 1 Total Feed Consumed and Total Feces Collected in Trial with Prune Meal Animal number Oat hay Prunes Feces (dry) 5 grains 6,900 6,900 6,900 grams 5,850 5,850 5,850 grams 4,960 6 5,120 7 4,960 TABLE 2 Chemical Analyses of Feces and Feeds in Trial with Prune Meal Animal number or feed analyzed Feces: 5 6 7 Feeds: Oat hay Prunes. Dry matter per cent 100.00 100.00 100.00 92.61 85.30 Crude protein per cent 10.14 9.86 10.75 6.60 5.70 Nitrogen-free extract per cent 40.84 40.43 39.89 45.37 75.30 Ether extract per cent 1.70 1.73 1.99 2.18 2.30 Crude fiber per cent 35.20 37.18 36.18 30.62 12.00 TABLE 3 Coefficients of Digestibility of Ground Prunes* Animal number Dry matter Crude protein Nitrogen-free extract Ether extract 5 per cent 59.41 56.20 59.41 per cent 15.90 15.29 6.78 per cent 81.55 80.55 82.62 per cent 81.58 6 78.38 7 70.88 58.34 12.66 81.57 76.95 The results for crude fiber showed negative digestibility. Although, for this trial, it was considered desirable to feed the prunes in ground form, the usual procedure under farm conditions is to supply the prunes whole in bunks, mangers, or on a feeding floor. Subsequently about 30 tons of whole prunes were given to all classes of livestock in the Station flocks and herds during the winter of 1938-39; they Were eaten with relish and with no unfavorable results. The various classes of livestock have several ways of dealing with the Bul. 635] Digestibility of Various By-products prune pits. Hogs crack the pits and consume the entire prune. Sheep, on the other hand, reject most of such seeds, though a few are swallowed and pass through the digestive tract relatively unchanged. Cattle, how- ever, swallow the entire prune which goes directly to the rumen, later to be regurgitated with the cud. When prunes are first fed, the cattle reject these regurgitated pits.; but soon they learn to crack and resWallow them, and thus utilize the food value of the kernels. DIGESTION TRIAL WITH DRIED WINERY POMACE Although some of the pomace discharged from the wineries has been used as fertilizer, much of it has not been utilized in any way, so that its dis- posal has been a problem. TABLE 4 Total Feed Consumed and Total Feces Collected in Trial with Winery-Pomace Samples A and B Animal number Alfalfa hay Winery pomace Feces (dry) grams 7,500 6,750 7,500 5,250 8,250 5,250 3,750 7,500 grams 13,500 12,000 10.500 6,000 9,000 9,000 5,250 6,000 grams 11,521 10,353 9,776 5,779 9,039 8,270 4,962 6,305 In the last three or four years several firms have been marketing this pomace dried and ground under the name of "grape meal" either with or without added molasses, as a feed for livestock. Because of the enormous supply of this material available and because of the numerous inquiries concerning its usefulness the Station has conducted digestion trials on three different lots of dried pomace, none of which contained molasses. Tests were made with three different meals ; samples A and B were used in 1938 and fed in conjunction with alfalfa hay of known digestibility. Sample C was used in 1939 and fed without supplement. The results of the trials are presented in tables 4-9. A feeding trial with dairy cows in milk was planned to accompany the 1939 digestion trial. It was not conducted, however, because of inability to induce the cows to consume sufficient pomace for the purposes of the experiment. This result was in contrast to the experience with sheep ; there was never any difficulty in getting them on feed even when pomace alone was fed. University of California — Experiment Station TABLE 5 Chemical Analyses or Feces and Feeds in Trial with Winery-Pomace Samples A and B Animal number or feed analyzed Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber Feces: r i per cent 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 88.78 89.68 92.82 per cent 15.94 16.31 15.52 14.07 14.56 15.26 14.17 14.85 19.40 13.05 11.76 per cent 37.91 37.69 38.66 35.96 37.13 39.52 38.02 35.28 33.29 36.87 39.11 per cent 4.42 3.52 3.52 3.16 4.62 4.84 4.42 4.46 1.72 6.49 8.05 per cent 34.27 Sample A J 2 35 16 1 3 35 04 u 38.01 [5 34.91 Sample B I 8 31.18 1 7 35.41 8 37.27 Feed: 23.84 27.52 27.45 TABLE 6 Coefficients of Digestibility of Winery-Pomace Samples A and B Animal number Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber f 1 per cent 24.95 24.15 22.02 24.27 23.85 23.85 21.40 23.15 30.50 24.73 per cent 12.40 9.07 10.72 22.40 13.65 6.09 0.13 9.83 8.82 6.22 per cent 25.98 25.70 20.02 27.68 24.85 26.00 20.73 24.76 34.32 26.45 per cent 51.80 63.25 62.26 68.72 61.51 55.56 53.14 58.38 59.77 56.71 per cent 18.63 Sample A I 2 14.99 1 3 13.48 [ 4 6.19 Average ( 5 13.32 13.47 Sample B J 6 21.84 j 7... 10.18 [ 8 13.50 Average 14.75 Average of both samples 24.29 9.93 25.65 59.11 14.04 TABLE 7 Total Feeds Consumed and Total Feces Collected in Digestion Trial with Winery- Pomace Sample C Animal number Winery pomace Feces (dry) 1 grams 12,270 20,430 10,890 grams 7,800 2 13.600 3 7,000 Bul. 635] Digestibility of Various By-products TABLE 8 Chemical Analyses of Feces and Feeds in Trial with Winery-Pomace Sample C Animal number or feed analyzed Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber Feces: 1 per cent 100.00 100.00 100.00 89.25 per cent 14.68 14.17 16.01 11.54 per cent 41.02 45.23 39.57 35.34 per cent 3.38 3.88 3.22 7.98 per cent 33.57 2 30. 4S 3 34.38 Feed: 29.15 TABLE 9 Coefficients of Digestibility of Winery-Pomace Sample C Animal number Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber j per cent 28.7 25.4 27.9 per cent 19.1 18.3 10.8 per cent 26.2 14.8 28.0 per cent 73.0 67.6 74.1 per cent 26.8 2 30.4 3 24.2 27.3 16.1 23.0 71.6 27.1 Judging from the results, dried winery pomace is decidedly low in total digestible nutrients ; it is high in fiber and low in protein, and in feeding value is inferior to good roughage. DIGESTION TRIAL WITH AVOCADO MEAL The avocado growers, through the Calavo Growers of California, have begun to dispose of surplus and off-grade avocados by crushing the fruit to extract the oil, which has a ready sale for use in cosmetics. Since the residual material, when ground, has been suggested for use as a stock feed, the Station was requested to conduct a digestion trial with the meal. Oat hay, the digestibility of which we had previously determined, was fed as a supplement. The results are presented in tables 10-12. It is concluded that the avocado meal used was reasonably palatable, since there was no particular difficulty in getting the animals on feed. Because of its low total digestible nutrient vaue its feeding value is but little more than that of a good-quality hay. The meal used in this trial had been treated with solvents for the extraction of the fat ; produced by the usual pressure extraction process it would, of course, have had a higher total digestible nutrient value because of the higher fat content. University of California — Experiment Station TABLE 10 Total Feed Consumed and Total Feces Collected in Trial with Avocado Meal Animal number Oat hay Avocado meal Feces (dry) grams 7,250 7,975 6,750 8,250 6,750 6,750 grams 5,800 6,525 5,250 6,750 5,250 5,250 grams 4,740 2 5,490 3 4,610 4 5,310 5 4,630 6 4,510 TABLE 11 Chemical Analyses of Feces and Feeds in Trial with Avocado Meal Animal number or feed analyzed Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber Feces : per cent 100.00 100.00 100.00 100.00 100.00 100.00 91.49 91.45 per cent 18.70 18.83 18.83 18.95 19.37 18.92 7.41 20.41 per cent 39.15 38.06 38.84 38.22 37.55 37.61 46.18 39.26 per cent 1.80 2.04 1.91 1.98 2.03 2.14 2.85 1.25 per cent 26.65 2 26.60 3 26.95 4 26.85 5 27.39 6 27.05 Feed: 33.10 19.27 TABLE 12 Coefficients of Digestibility of Avocado Meal Animal number Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber 1 per cent 68.1 64.2 63.1 70.2 62.7 65.2 per cent 47.3 44.1 41.8 48.7 39.1 43.2 per cent 75.5 74.2 71.8 79.2 74.3 76.4 per cent 95.1 73.0 81.8 85.7 72.8 69.0 per cent 90.5 2..'.' 85.1 3./ 83.7 4 91.6 5 81.1 6..... 85.9 Average 65.6 44.0 75.2 79.6 86.3 Bul. 635] Digestibility of Various By-products DIGESTION TRIAL WITH DRIED ASPARAGUS BUTTS Cull asparagus and trimmings from the canneries have, for some time, been a waste product about which there has been considerable discussion, as this form of material is difficult of disposal. After some minor attempts to determine the feasibility of using the material in the green form, a digestion trial was conducted with the dried material as a basis for further investigation. Several hundred pounds of the dried asparagus butts prepared by one of the canneries were run through a hammer mill and coarsely ground. Because the animals available were already accustomed to winery po- mace, the dried ground asparagus butts were fed in the trial, along with the pomace reported above as sample C. The results appear in tables 13-15. TABLE 13 Total Feed Consumed and Total Feces Collected in Trial with Asparagus Butts Animal number Winery pomace Asparagus Feces (dry) l grams 9,540 13,620 6,518 grams 8,160 9,540 7,868 grams 10,230 2 13,500 5 7,700 TABLE 14 Chemical Analyses of Feces and Feeds in Trial with Asparagus Butts Animal number or feed analyzed Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber Feces : 2 5 Feeds: Winery pomace Asparagus per cent 100.00 100.00 100.00 92.17 90.96 per cent 14.47 14.22 13.97 11.94 15.64 per cent 38.61 39.22 41.23 40.22 35.46 per cent 4.41 4.12 3.08 5.46 0.99 per cent 33.90 34.38 34.09 29.38 31.91 TABLE 15 Coefficients of Digestibility of Asparagus Butts Animal number Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber 1 per cent 48.3 49.6 53.4 per cent 58.9 62.8 65.6 per cent 65.6 68.2 58.6 per cent 62.5 63.5 82.5 per cent 45.3 2 25.7 5 51.1 50.4 62.4 64.1 69.5 40.7 10 University of California — Experiment Station Whereas the sheep were induced to eat the butts without much diffi- culty and in quantities sufficient for a satisfactory trial, as with the winery pomace, dairy cows did not relish the material. The results indicate that dried asparagus butts possess a feeding value comparable to the fair-quality roughages. Being relatively high in fiber they could be substituted for roughages. RESULTS OBTAINED WITH FENUGREEK MEAL Fenugreek has been used for some time as a covercrop and for green- manuring ; recently, however, there has been some attempt to promote its growth for seed, mainly for use as another source of vegetable oil. When this led to considerable interest in its feeding value, a digestion trial was attempted. TABLE 16 Total Digestible Nutrients of Various Common Feeds Compared with the Feeds Used in These Trials* Feed Total dry matter in 100 pounds Digestible nutrients in 100 pounds Crude protein Total Alfalfa hay, all analyses Oat hay Cottonseed meal, 43 per cent Coconut meal, old process Linseed meal, old process Barley, Pacific Coast states Prunes Winery pomace, average of samples A and B . Winery pomace, sample C Avocado meal Asparagus butts pounds 90.4 88.0 93.5 pounds 10.6 4.5 35.0 18.7 30.6 6.9 0.7 1.3 1.9 9.0 9.7 pounds 50.3 46.3 75.5 80.8 78.2 78.8 66.1 24.5 30.7 57.3 47.1 * Data for alfalfa hay, oat hay, cottonseed meal, coconut meal, linseed meal, and barley taken from: Morrison, F. B. Feeds and feeding, 20th ed. Appendix table 1. 1050 p. The Morrison Publishing Co., Ithaca, N.Y.,1936. Although the fenugreek meal was decidedly palatable, even serving as an appetizer for less-relished feeds, it was also very laxative. Partly, at least, because of this fact, the results of the trial were most unsatis- factory, and no reliable digestion coefficients could be obtained. Bul. 635] Digestibility of Various By-products 11 SUMMARY Judging from these trials, dried prunes are very palatable and have, on the basis of total digestible nutrients, a feed value equivalent to about 85 per cent of that of barley. Since, however, they furnish less than 1 per cent digestible protein, prunes must be fed along with protein-rich roughages or concentrates ; and because of their laxative nature they should not be overfed. No ill effects were noted when the hogs and cattle consumed the entire prune, including the pit. Digestion trials have been completed with three different samples of commercial dried winery pomace or "grape meal." All proved to be low in total digestible nutrients, none containing more than 2 per cent di- gestible protein and 31 per cent total digestible nutrients. There seems to be considerable difference in the palatability for sheep and cattle. Al- though invariably the sheep ate the meal readily, a milk-production trial had to be discontinued because of inability to induce the cows to consume enough. Although the 9 per cent digestible protein content of avocado meal corresponds to that found in the grains, the total digestible-nutrient content of 57.3 is only slightly better than that of good hay, perhaps because the sample tested had been extracted by the solvent process and may therefore have been extremely low in fat. Most oil meals are ex- tracted by pressure. The meal was reasonably palatable. The use of asparagus waste as a feed is still in the experimental state. Judging from the data obtained in the trial, it has approximately the feed value of oat hay. Good oat hay, however, is superior in palatability. Fenugreek meal, because of its laxative properties, could not be fed in sufficient quantities to yield accurate data on its digestibility. Total dry matter and digestible nutrients in the products tested in these experiments are given in table 16, together with similar data on alfalfa hay and some other common feeds for comparison. 12m-4, '40(3089)