Fiber digestibility by black lemurs (Eulemur macaco macaco).

Black lemurs, Eulemur macaco, are classified as generalist feeders, consuming a proportion of fruits and leaves that varies with seasonal availability. It is hypothesized that black lemurs are capable of using neutral detergent fiber (NDF) as a source of energy through fiber fermentation in the cecum and large intestine. In captivity, they are typically fed a diet of commercially available primate biscuits and readily available produce, both of which are limited in NDE Digestibility trials were conducted on 14 black lemurs; 12 were housed in groups (four, three, three, and two) and 2 were individually housed. The lemurs were fed four manufactured feeds differing in fiber form and content. A commercially available primate biscuit, containing approximately 27% NDF, served as the control diet. The second diet contained the same primate biscuits, which were ground and then incorporated into a fiber-based gel matrix. The third and fourth diets were formulated using soybean hulls or ground corncobs as the fiber source, resulting in 53% and 47% NDF, respectively. Produce was added to the diet at 36% (dry matter basis). Dry matter digestibility differed significantly among all diets. Neutral detergent fiber digestibility was highest for the ground biscuit in gel and lowest for the two high-fiber gel diets, with biscuit digestibility values falling between the two extremes. The high-fiber gel diets were successful in increasing the NDF concentrations of the primate diets; however, black lemurs were capable of only limited fiber digestion.     

Low-quality roughages in high-concentrate pelleted diets for sheep: digestion and metabolism characteristics as affected by corncob and(or) rice hull additions

Two trials were conducted to determine effects of feeding corncobs, rice hulls or a combination of both on nutrient digestion and flow of digesta through the gastrointestinal tract of multiple-cannulated sheep (55-kg Rambouillet X Dorset rams; trial 1; 4 X 4 Latin square) as well as ruminal, digestive and metabolic characteristics of early-weaned lambs (24.1-kg crossbred rams; trial 2; randomized complete block design; 3 periods) fed pelleted 75% concentrate-25% roughage diets. In trial 1, apparent total tract dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF) digestibilities decreased and N digestibility increased as percentage of dietary corncobs decreased and percentage of rice hulls increased. Site of NDF digestion appeared to shift from the upper to the lower digestive tract as percentage of corncobs decreased and percentage of rice hulls increased. In trial 2, apparent DM digestibility decreased as corncobs were replaced with rice hulls in the diet. Neutral detergent fiber digestibility was not affected by diet except in larger lambs at higher intakes, with NDF digestibility generally decreasing as percentage of dietary rice hulls increased. Nitrogen digestibility was not affected by replacing corncobs with rice hulls in the diet. Ruminal pH decreased as rice hulls replaced corncobs in the diet. These data are interpreted to indicate that rice hulls can be effectively substituted for corncobs in sheep diets when added at levels up to 25% of the total diet.     

Effects of roughage particle size on site of nutrient digestion and digesta flow through the gastrointestinal tract of sheep fed corncob-concentrate diets

An experiment examining nutritional effects of dietary corncob particle size was conducted using ruminal-, duodenal- and ileal-cannulated sheep in a 4 X 4 Latin square design. Site of nutrient digestion and digesta flow were the principal criteria evaluated. Analyses of dry matter (DM), N, starch and neutral detergent fiber (NDF) were performed on feed, feces and digesta samples. Chromic oxide-impregnated paper was used as an external marker to estimate digestibilities at different sites along the gastrointestinal tract. Ruminal pH and volatile fatty acid molar proportions were also determined. All diets (74.9% concentrates: 25.1% corncobs) were pelleted and were similar in ingredient composition but varied in corncob particle size (corncob mean particle sizes were 6.5, 5.4, 1.4 or .8 mm). Dietary crude protein levels differed little among treatments. Starch concentration was higher in diets containing the larger corncob particles while NDF, acid detergent fiber (ADF), cellulose and hemicellulose concentrations were lower in diets containing larger particles, suggesting a reaction between starch and fiber moieties during the pelleting process. Starch flow past the duodenum decreased (P less than .05) as dietary corncob particle size decreased. Apparent NDF digestion before the duodenum was highest for sheep fed diets containing 1.4-mm corncobs (P less than .05). Apparent starch digestion in the small intestine decreased (P less than .05) as dietary corncob particle size decreased. A considerable amount of NDF was apparently digested in the small intestine of sheep consuming diets containing 5.4- and .8-mm corncobs. Likewise, a substantial amount of NDF was apparently digested in the large intestine. Few differences in apparent total tract digestibilities were noted.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of roughage particle size on ruminal, digestive and metabolic characteristics of early-weaned lambs fed pelleted corncob-concentrate diets

Two experiments were conducted to determine effects of feeding corncobs of various mean particle size (MPS) on ruminal, digestive and metabolic characteristics of early-weaned lambs fed pelleted 74.9% concentrate:25.1% corncob diets. The MPS of corncobs in diets was 6.5, 5.4, 1.4 and .8 mm, respectively. As particle size decreased, percentage starch decreased and percentage neutral detergent fiber (NDF), acid detergent fiber (ADF) and cellulose increased. In Exp. 1, 28 crossbred rams (seven/treatment, avg initial wt, 15.3 kg) were used in a randomized complete-block design. In Exp. 2, lambs from Exp. 1 were re-weighed (avg initial wt, 16.8 kg) and fed the same diets as in Exp. 1. In Exp. 1 and 2, lambs ingested dry matter (DM) equal to 2.68 and 3.74% of body weight, respectively. In Exp. 1, apparent DM digestibility was unaffected by corncob MPS; however, in Exp. 2, DM digestibility was highest (68.8%) for lambs fed the 6.5-mm diet and lowest (63.8%) for those fed the .8-mm diet. Apparent starch digestibility was high (greater than 98.8%) in both experiments. Neutral detergent fiber and ADF digestibilities were highest for lambs fed the 1.4-mm diet (50.5 and 43.6%, Exp. 1; 39.6 and 28.9%, Exp. 2). A dramatic increase (6.8 to 39.1%) in acid detergent lignin (ADL) digestibility was observed in Exp. 1 as corncob MPS decreased. In Exp. 2, ADL digestibilities were similar for lambs fed the 6.5-, 5.4- or 1.4-mm diets (avg value, 5.9%) and highest for those fed the .8-mm diet (29.7%). Nitrogen metabolism was unaffected by corncob MPS. In Exp. 1, digestible energy intake, corrected for urinary losses, did not differ among treatments but in Exp. 2, lambs consuming the 6.5-mm diet had higher corrected digestibility energy intakes (1,926.6 kcal/d) than did those fed other diets (avg, 1,832.4 kcal/d). Ruminal pH sampled 4 h post-feeding was highest for lambs consuming the 6.5-mm diet (6.25) in Exp. 1 and the 1.4-mm diet (5.89) in Exp. 2. Lowest ruminal pH (5.30 and 5.36, respectively) was for lambs consuming the .8-mm diet in Exp. 1 and the 5.4-mm diet in Exp. 2. Ruminal lactate concentrations were variable within and among treatments. Total ruminal volatile fatty acid (VFA) concentrations were similar across treatments but in Exp. 2, there was a shift in molar proportions from acetate to propionate as corncob MPS decreased.(ABSTRACT TRUNCATED AT 400 WORDS)     

Low-quality roughages in high-concentrate pelleted diets for sheep: digestion and metabolism of nitrogen and energy as affected by dietary fiber concentration

Two trials were conducted to evaluate effects of, and interactions between, level and source of fiber in the diet on ruminal environment, microbial protein synthesis, nutrient digestion and flow of digesta through the gastrointestinal tract of multiple-fistulated sheep (trial 1; 4 X 4 Latin square design) and on ruminal, digestive and metabolic characteristics of early-weaned lambs (trial 2; randomized complete block design; 3 periods). All diets tested were pelleted and were formulated to contain either 39% or 25% neutral detergent fiber (NDF), with corncobs or cottonseed hulls (CSH) as the major NDF (roughage) sources. In trial 1, dry-matter (DM) and organic-matter (OM) digestibilities were not different (P greater than .05) among treatments. Digestibility of NDF was higher (P less than .05) with high-fiber. Bacterial N synthesis (g N/kg OM truly digested) was not different (P greater than .05) among treatments. Molar proportion acetate was higher (P less than .05) and molar proportion propionate lower (P less than .05) when sheep were fed high-fiber diets. In trial 2, apparent DM digestibility was higher (P less than .05) for lambs fed diets containing corncobs. Energy digestibility was higher (P less than .05) at the low-fiber level and for lambs fed diets containing corncobs. Apparent NDF digestibility by lambs was higher (P less than .05) at the high-fiber level and for lambs fed diets containing corncobs. Nitrogen retained (percentage of N intake) was higher (P less than .05) for lambs fed diets containing CSH. Ruminal pH and molar proportion acetate were higher (P less than .05) and molar proportion propionate lower (P less than .05) for lambs fed high-fiber diets. Although responses to corncob vs CSH inclusion in high-energy pelleted diets differ, both roughages are effective as fiber sources in sheep diets.     

Associative effects of sorghum silage and sorghum grain diets

A metabolism trial was conducted to quantitate associative effects between sorghum silage and sorghum grain, and to identify responsible factors. Diets were formulated by mixing ground sorghum grain (0, 15, 30, 45 and 60% of diet dry matter) with sorghum silage and were adjusted to 15.0% crude protein with soybean meal. Cannulated Beefmaster-cross steers (300 kg) were adapted to diets for 14 d followed by 5 d of fecal collection during which digestibility of components was determined. Intake of digestible dry matter and digestibilities of dry matter and neutral detergent fiber increased with increases in diet grain content (linear effect: P less than .01, P less than .01, P less than .05, respectively; quadratic effect: P less than .05, P less than .005, P less than .06, respectively). Digestibilities of starch, crude protein and hemicellulose were not significantly affected by grain level. Ruminal pH averaged 6.0 and was not significantly affected by grain level or time of sampling. Ruminal in situ digestion of neutral detergent fiber and acid detergent fiber at 48 h decreased (linear contrast, P less than .001) with increasing grain content. Rate of passage of liquid digesta was not affected by grain level in the diet. The rate of passage of particulate digesta decreased linearly (P less than .005, orthogonal contrast) with increasing levels of grain. Low levels of sorghum grain (15 and 30%) improved digestibility and intake of digestible dry matter of sorghum silage-based diets, whereas higher rates of grain supplementation (45 and 60%) did not result in further improvement.     

Feeding value of diets containing almond hulls

Four mature geldings were used in a 4 X 4 Latin Square digestion experiment to determine the digestibility of pelleted diets containing 0. 15, 30 and 45% Nonpareil almond hulls. The four isonitrogenous treatments consisting of almond hulls, oat hay, and alfalfa hay provided approximately 94% dry matter (DM), 11% crude protein (CP), 23-32% acid detergent fiber (ADF) and 4100 kcal/kg gross energy (GE). Each horse consumed a different diet during each of four 14-day trial periods. Horses were fed 10 kg of their assigned diet per day. The horses gained an average of 15 kg over the course of the 8-week study. No feed was refused in any of the trials and there were no signs of adverse reactions to any of the diets. The digestibilities of the four dietary components (DM, CP, ADF and GE) were not affected by horse or trial period. Dry matter and GE digestibilities increased (P<.05) as the almond hull content increased in the four diets (59, 63, 64 and 68% DM digestibility and 57, 61, 61 and 64% GE digestibility, respectively). Acid detergent fiber digestibility was not affected by almond hull content (39, 39, 39 and 42% digestibility, respectively) while CP digestibility decreased as the almond hull content increased in the four diets (69, 62, 66 and 56% digestibility, respectively). Almond hulls appear to be a safe and palatable feed for horses and can be fed up to levels of 45%.     

不同粗饲料组合对山羊饲粮养分表观消化率及氮平衡的影响

本试验旨在研究不同粗饲料组合对山羊饲粮养分表观消化率及氮平衡的影响。选取4只体重为(26.63±2.60)kg的波尔山羊×徐淮山羊(波杂羊),采用4×4拉丁方设计,基础饲粮采用稻草(A)为粗饲料,试验饲粮分别采用大豆皮(B)、金针菇菌渣(C)及大豆皮+金针菇菌渣(D)替代部分稻草,4组饲粮等氮、等能、等纤维。试验分为4期,每期15 d,其中预试期10 d,正试期5 d。结果表明:1)4组饲粮的干物质(DM)、酸性洗涤纤维(ADF)、磷以及总能的表观消化率差异不显著(P0.05)。2)与饲粮A相比,饲粮D显著提高了有机物(OM)和中性洗涤纤维(NDF)的表观消化率(P0.05),饲粮B与饲粮A差异不显著(P0.05);饲粮B、饲粮C和饲粮D的钙表观消化率差异不显著(P0.05),但显著高于饲粮A(P0.05)。3)与饲粮A相比,饲粮B、饲粮C和饲粮D显著提高了氮沉积率和氮生物学价值(P0.05)。综合得出,与单独采用稻草为粗饲料相比,采用大豆皮、金针菇菌渣或二者联合与稻草组合提高了山羊OM、NDF、钙的表观消化率,氮沉积率以及氮生物学价值;本试验条件下,采用大豆皮和金针菇菌渣联合与稻草组合为粗饲料效果最优。     

Soybean hulls as a dietary fiber source for dogs.

In Exp. 1, soybean hull samples were obtained from nine sources across the United States and analyzed for nutrient content to determine their suitability for inclusion in dog diets. Compositional data revealed variation in both the amount of total dietary fiber (TDF; 63.8 to 81.2%) in the soybean hulls and the ratio of insoluble:soluble fiber (5.0:1 to 15.4:1). Crude protein content varied widely among sources, ranging from 9.2 to 18.7%. An in vivo trial (Exp. 2) was conducted using a premium dog diet containing 3.0, 4.5, 6.0, 7.5, or 9.0% soybean hulls (DM basis). There was a negative linear effect (P < .05) of soybean hull inclusion in the diet on DM, OM, TDF, and GE total-tract digestibilities, as well as on calculated ME. Crude protein and fat digestibilities were unaffected by treatment. Based on these results, ileally cannulated dogs were fed diets containing 6.0, 7.5, or 9.0% soybean hulls (DM basis) in addition to diets containing either 0% supplemental fiber or 7.5% beet pulp (Exp. 3). Nutrient digestion at the ileum was unaffected by inclusion of supplemental fiber. Total tract digestion of DM, OM, and GE was lower ( P < .05) for diets containing supplemental fiber when compared with the diet containing 0% fiber. Crude protein and fat digestibilities were unaffected by treatment. There was no difference in nutrient digestibility between those diets containing soybean hulls and a diet containing beet pulp. Soybean hull inclusion in the diet resulted in a negative linear effect (P < .05) on calculated ME, in addition to lowering ME (P < .05) when compared with the 0% fiber control diet. Calculated ME for dogs fed a 7.5% beet pulp-containing diet was lower (P < .05) than that for dogs fed the soybean hull-containing diets. Results indicate that soybean hulls can be an effective dietary fiber source in dog diets.     

Effect of supplemental niacin or niacinamide and soybean source on ruminal bacterial fermentation in continuous culture

Effects of niacin or niacinamide in diets containing either soybean meal, raw whole soybeans or whole soybeans extruded at 132 and 149 C on ruminal bacterial fermentation were examined with a dual-flow continuous culture system. In Exp. 1, soybean sources each provided 50% of total crude protein in diets comprised of 52% concentrate mix, 36% corn silage and 12% alfalfa hay (dry-matter basis). Each diet was supplemented with 0 or 100 mg/kg niacin. Niacin supplementation increased (P less than .05) total nonstructural carbohydrate digestibility and lowered (P less than .05) butyrate concentration. There was also an increase (P less than .10) in amino acid effluent flow from 8,413.3 to 8,665.3 mg/d with addition of niacin to the diet. In Exp. 2, diets were supplemented with 0 or 100 mg/kg of niacin or niacinamide. The total mixed diet was comprised of 60% concentrate mix, 20% corn silage and 20% alfalfa hay (dry matter basis). Acid detergent fiber and cellulose digestibilities and total amino acid effluent flow were higher (P less than .10) with niacinamide supplementation. Niacin or niacinamide had no effect on dry matter and organic matter digestibilities, ammonia-N, total VFA concentration or crude protein degradation. Contrary to results found in other studies, niacin or niacinamide supplementation had no effect on bacterial protein synthesis.     

Evaluation of corn fiber, cottonseed hulls, oat hulls and soybean hulls as roughage sources for ruminants

An in situ trial (randomized complete block design) using cows, and a site and extent of digestion trial (Latin square design) using sheep were conducted to study the potential of corn fiber (CF), cottonseed hulls (CSH), oat hulls (OH) and soybean hulls (SH) as roughage sources for ruminants. Two feedlot trials with steers and one with lambs (completely randomized design with factorial arrangements of treatments) were conducted to study the potential of CF and SH as energy supplements relative to corn. In situ rate of ruminal dry matter (DM) disappearance (3 to 36 h) and extent of DM disappearance (36 h) indicated that CF and SH were more fermentable in the rumen compared with OH or CSH, with SH being the most fermentable. Total tract digestibilities of DM, organic matter (OM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were above 70% for sheep fed CF and SH diets, and were 50% or less for sheep fed OH and CSH diets. A ranking of by-products in terms of nutritive value followed the trend: CF greater than SH greater than OH greater than CSH. Lamb feedlot trial data showed that CF was of similar nutritive value to corn and of higher nutritive value than SH at the 50% level of supplementation. Corn-fed lambs responded better than CF- or SH-fed lambs at the 70% level of supplementation. Data from steer feedlot trials showed that CF was of similar quality to corn and of higher quality than SH. Dramatic differences exist in by-product feed utilization by ruminants. All by-products tested appeared to have some usefulness as dietary components.     

Digestibility of fiber components and reproductive performance of sows fed high levels of alfalfa meal

Two experiments were conducted with second-parity sows fed either 5 or 50% alfalfa meal diets (Exp. 1) or 5, 50 or 95% alfalfa meal diets (Exp. 2) beginning 30 d after breeding and continuing through lactation, 21 d postpartum. Diets in both experiments were calculated to be equal in crude protein, but different in metabolizable energy content. Feed intake was restricted to 2 kg/d during gestation and ad libitum during lactation. Sows were tethered in metabolism crates 45 d after breeding. Total feces were collected during two 5-d collection periods, 60 and 100 d after breeding. Digestibilities of dry matter, fiber components (neutral detergent fiber, acid detergent fiber, hemicellulose and cellulose), protein and energy were determined in both experiments for all diets and periods of gestation. In both experiments, there was a reduction (P less than .05) in digestibility of dry matter, fiber components, protein and energy with increasing fiber levels for both periods of gestation. In Exp. 1, the decrease in digestibility of dry matter, neutral detergent fiber, acid detergent fiber, cellulose and energy was greater at 100 d gestation than at 60 d in sows fed 50% alfalfa. In Exp. 2, 50 and 95% dietary alfalfa reduced 60-d digestibilities of dry matter, all fiber constituents, energy and protein; these digestibilities were further reduced (P less than .05) at 100 d of gestation. In Exp. 1, weight gains of sows fed 5 and 50% alfalfa diets from breeding to 109 d gestation, were 42 and 18 kg/sow (5 greater than 50% level, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Castor beans hulls as a replacement for Tifton 85 hay in lamb diets

The objective of this study was to evaluate the effect of replacing Tifton 85 hay (0, 33, 66, or 100 %) with by castor bean hulls on the intake and nutrient digestibility and performance of 28 noncastrated lambs, averaging 7 months in age, 19.5?±?2.0 kg average live weight, fed on diets based on forage cactus. The animals were housed in individual pens for 100 days. The digestibility trial occurred 40 days after the start of the performance using LIPE® as an external indicator for estimating fecal dry matter production. The replacement of hay with Castor beans hulls linearly decreased the intakes of dry matter, neutral detergent fiber, organic matter, and crude protein and reduced the digestibility coefficients of the dry matter, neutral detergent fiber, organic matter content, crude protein, and total digestible nutrient content. The hot carcass and true carcass yields were not influenced by the treatments and the feed conversion increased linearly. The empty body weight, live weight at slaughter, hot and cold carcass weights, total gain, and average daily gain decreased linearly with the replacement. The replacement of Tifton 85 hay with castor bean hulls reduced the intake of dry matter, crude protein and energy, consequently reducing the performance of the animals. However, as the regression coefficients were of low magnitude, data were subjected to analysis of variance and means were compared using the Dunnett test with diet without castor bean hulls set as the control treatment. The Tifton 85 hay can be replaced up to 66 % by castor bean hulls in finishing diets for lambs.     

Influence of sodium bicarbonate and magnesium oxide on digestion and metabolism in yearling beef steers abruptly changed from high forage to high energy diets

Eight rumen-cannulated steers (initial wt 330kg) were adapted to a mixed alfalfa-grass hay diet for 30 d and abruptly changed to complete mixed diets of corn silage, snapped ear corn and a corn-based supplement to determine the effects of buffers on diet adaptation, digestion and ruminal metabolism. The diets contained: 1) no buffer, 2) .5% magnesium oxide (MgO), 3) 1.0% sodium bicarbonate (NaHCO3) and 4) .5% MgO and 1.0% NaHCO3, as a percentage of diet dry matter (DM). Digestion, metabolism and ruminal characteristics were measured in each of 2 wk immediately after the diet change. The animals were then adapted to the mixed alfalfa-grass hay diet, re-randomized and assigned to the four diets, thus four steers consumed each diet. Intakes and digestibilities of DM were generally greater for the diets containing buffers. The most notable differences were a greater DM intake with added NaHCO3 and an improved DM digestibility with added MgO. The higher DM digestibility with MgO was apparently related to improved neutral detergent fiber (NDF) and starch digestion. Fecal pH was significantly increased with MgO addition. Because of the greater intake and digestibilities, the amount of DM, NDF, and starch digested tended to be greater for the buffered diets. There were no diet X week interactions for intake and digestibilities, thus the responses observed existed during both wk 1 and 2 after the change in diets. In general, intake and digestibilities were greater in wk 2 than in wk 1 for all diets.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of corn processing and dietary fiber source on feedlot performance, visceral organ weight, diet digestibility, and nitrogen metabolism in lambs

In Exp. 1, early-weaned Targhee and Polypay crossbred lambs (60 ewes and 66 rams; initial BW 24 +/- 1.0 kg) were used in a 2 x 3 factorial experiment to determine the effects of corn processing (whole shelled corn [WSC] or ground and pelleted corn [GC]) in combination with supplemental fiber (none [control]; soybean hulls, SBH [highly digestible]; or peanut hulls, PH [highly indigestible]) on DMI, ADG, feed efficiency, and visceral organ weight. For the total trial, WSC resulted in a 4% increase (P < .01) in ADG vs GC, and supplemental fiber resulted in increased (P < .01) DMI and ADG vs the control diet. Experiment 2 was conducted using 12 Targhee and Polypay crossbred wether lambs (initial BW 25 +/- 7 kg) to determine the effects of corn processing and fiber source in high-concentrate diets on diet digestibility and N retention using the same diets as in Exp. 1. Lambs fed WSC had greater (P < .001) apparent N digestion, true N digestion, and N retention (P < .01) than those fed GC. The apparent digestibilities of DM, OM, and NDF were greater (P < .001) for WSC than for GC diets. Peanut hulls resulted in decreased (P < .01) DM, OM, and NDF apparent digestibilities compared with the control and SBH diets. Starch digestion was not affected (P > .10) by diet. Whole corn resulted in improved DM, OM, NDF, and N digestibility compared with GC. Overall, both the SBH and PH diets resulted in greater DMI and ADG than the control diet, which lacked supplemental fiber.     

Effects of Feeding Distiller's Dried Grains with Solubles on Growth and Feed Efficiency of Weanling Horses

The effects of replacing corn and soybean meal with distiller's dried grains and solubles in the weanling horse diet were examined. Sixteen weanling horses, 12 fillies and four colts, were fed completely pelleted diets consisting of 50% alfalfa in addition to 50% of a concentrate containing either corn and soybean meal (CS), or 30% of the concentrate replaced with distiller's dried grains with solubles (DDGS). There were no significant differences (P > .05) between the two diets in either average daily gain or gain-to-feed ratio. The CS diet had a higher apparent dry matter digestibility (P < .0001), and higher apparent digestibility of crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF) (P < .01). It was concluded that replacing a portion of the corn and soybean meal with distiller's dried grains with solubles in the weanling horse diet did not lead to significant growth depression. However, the diet containing DDGS had reduced apparent digestibility of dry matter, CP, and fiber. Therefore, it was concluded that it may not be advisable to replace more than 30% of the concentrate portion or 15% of the total diet with distiller's dried grains and solubles when alfalfa is used as the forage source constituting 50% of the weanling diet. Even less DDGS may be desirable to substitute for corn and soybean meal in weanling horse diets if the forage source is one with lower protein quality than alfalfa. It is possible that using DDGS for less than 30% of the concentrate portion of the diet along with high-quality alfalfa forage may produce comparable gain and feed efficiency results with less depression of apparent digestibility of dry matter, crude protein, and fiber.     

Effects of whole cottonseed, cottonseed oil or animal fat on digestibility of wheat straw diets by steers

Two completely random digestion trials were conducted, each with 12 beef steers (325 kg initial weight), to measure changes in digestibilities of fat and of forage components when fat was added to diets containing 62 to 76% wheat straw. Trial 1 diets contained either no added fat or 6.3% added fat from whole cottonseed (30% of the diet), cottonseed oil or animal fat; diets were formulated to contain equal levels of cottonseed hulls and cottonseed meal. Trial 2 diets contained 0, 2, 4 or 8% added animal fat. In all forms and at all levels, added fat increased apparent digestibility of dietary lipid (P less than .05). However, estimated true digestibility of lipid decreased (from 94 to 71%) as added fat was increased from 0 to 8% (P less than .05). Up to 6.3% added fat increased digestible energy (DE) content of the diet. Fat additions of 2 and 4% increased daily DE intake (P less than .05) and did not depress digestibility of diet components (P greater than .05). Fat additions of 6.3% or greater, either as free fats or as whole cottonseed, reduced (P less than .05) mean acid detergent fiber digestibility from 40 to 28%. In addition to depressing fiber digestibility, 8% added fat reduced (P less than .05) digestibilities of dry matter (from 54 to 47%), organic matter (60 to 52%) and gross energy (60 to 51%). Oil fed as whole cottonseed caused digestibility depressions similar to free fat addition at the same level.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tifton hay, soybean hulls, and whole cottonseed as fiber source in spineless cactus diets for sheep

The objective of this paper was to evaluate the effect of three different sources of fiber (tifton hay, soybean hulls, and whole cottonseed) in spineless cactus diets for sheep in the semiarid region of northeastern Brazil. Twenty-one sheep in finishing phase with indeterminate breed, non-castrated, and with initial weight of 18.90?±?1.07 kg were randomly distributed to individual stalls where they were confined for the duration of the experiment. The intakes of dry and organic matter, total carbohydrates, and total digestive nutrients were not influenced (P?>?0.10) by the different fiber sources (1.10, 0.97, 0.73, and 0.80 kg/day, respectively). However, sheep which received the whole cottonseed diet were characterized by a lower (P?<?0.10) intake of crude protein and neutral detergent fiber and greater (P?<?0.10) intake of ether extract (0.11, 0.29, and 0.048 kg/day, respectively). The different sources of fiber resulted in similar times spent feeding (P?>?0.10), although the rumination time was greater for tifton hay (P?<?0.10) (429.05 min/day). The digestibility coefficient of dry and organic matter differed between the treatments (P?<?0.10), with the soybean hull diet showing a higher level of digestion (83.23 and 86.72 %, respectively). The whole cottonseed diet gave the smallest digestibility coefficient of crude protein (68.95 %) and greatest for ether extract (85.94 %). The daily weight gain of animals fed on whole cottonseed was significantly lower (P?<?0.10). On the basis of these findings, we recommend the use of tifton hay or soybean hulls as important additional source of fiber in forage spineless cactus diets for sheep in finishing phase.     

Growth, nutrient utilization and intestinal morphology of pigs fed high-fiber diets

Two trials (24 and 48 pigs; 9.7 kg initial body weight) were conducted to determine the effects of dietary fiber on growth, nutrient utilization and intestinal morphology of young pigs. The four diets fed were: basal corn-soybean meal (B), 15% oat hulls (OH), 15% soybean hulls (SH), and 20% alfalfa meal (AM). Fiber source did not have major effects on performance in a 35-d feeding trial. Balance trials (7-d duration) were conducted 32 d (Trial 1) or 6 d (Trial 2) after completion of the feeding trials. Feed intakes were equalized at 8.7% (Trial 1) or 10.3% (Trial 2) of initial body weight (kg.75). All fiber sources decreased apparent digestibilities of N, energy and dry matter (P less than .05) with no effect on N retention. Apparent digestibilities of neutral and acid detergent fiber, cellulose, and hemicellulose were reduced by OH and AM (P less than .01), but not by SH. Fiber sources did not affect apparent Ca, P, Zn or Mn absorption or retention, or Mg absorption, but decrease Mg retention (P less than .05). Apparent Na absorption was decreased by OH and increased by AM (P less than .05) but was unaffected by SH. All fiber sources increased K intake, but only SH and AM increased apparent K absorption (P less than .05). Fiber sources did not affect Na or K retention. The OH increased Cu intake and balance (P less than .05). All fiber sources increased Fe intake, but only SH and AM increased (P less than .05) Fe balance. Villus shape and surface morphology in jejunum and ileum examined by scanning electron microscopy (Trial 1 only) appeared to be independent of diet. However, jejunum villus morphologies of two pigs fed AM were characterized by loss of epithelial cells and microvilli at the villus apex, and ileum villi were blunted and frequently folded in one pig fed SH. Fiber sources at the levels included in a corn-soybean meal diet fed in this study had only a minimal impact on performance and utilization of minerals and N and intestinal structure, although apparent energy utilization was decreased.     

Nitrogen utilization and digestibility by growing steers and goats of diets that contain monensin and low crude protein

Two digestion and metabolism experiments were conducted to determine effects of monensin in low-protein diets. Monensin supplementation (27 mg/kg of diet dry matter) of steers (303 kg) fed 8.7% crude protein increased (P less than .01) apparent N digestibility and N retention and decreased (P less than .01) percentage of N apparently absorbed lost in urine. Apparent digestibilities of dry matter, gross energy and acid detergent lignin were increased (P less than .05). Digestibilities of neutral detergent and acid detergent fibers were not affected by monensin. In growing wether goats (15 kg) fed 8.5% crude protein, monensin (23 mg/kg of diet dry matter) improved (P less than .01) apparent N digestibility and apparent N absorption. However, urinary N excretion also increased (P less than .05), resulting in no difference in N retention. Monensin did not affect digestibilities of dry matter or gross energy. Efficiency of feed conversion and average daily gain were improved with monensin supplementation of growing goats fed a low-protein, high-roughage diet. Monensin resulted in typical shift of acetate-to-propionate ratio in both experiments. Results suggest that improved N utilization may account for some benefits of feeding monensin.