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PubMed1987

Rumination and vomiting in Prader-Willi syndrome.

Inability to vomit has been cited as characteristic of Prader-Willi syndrome (PWS). Although post-prandial vomiting after gastric by-pass surgery has been reported, neither vomiting under "typical" circumstances or rumination have been described. Prompted by the discovery of several cases of vomiting and rumination, a questionnaire was sent to members of the PWS Association. Approximately 36% (113/313) of affected individuals reportedly experienced at least one episode of vomiting. Induced vomiting was unsuccessful in 9 of 14 cases in whom results were known. However, no complications of Ipecac were reported. We suggest that there is an alteration in the physiologic set-point at which vomiting occurs, leading to a decreased propensity to vomit. Liberal and strict definitions of rumination yielded 15.7% and 10.2% positive responses, respectively. Rumination was associated with a history of vomiting. Enamel deterioration consistent with rumination has been observed, and such changes should be looked for in all PWS children. In several instances, rumination was found to decrease when very strict weight control was lessened. Certain individuals may ruminate under too strict a weight control program, and weight control goals should be evaluated to achieve a reasonable compromise between ideal weight and obesity. Vomiting and rumination do not rule out the diagnosis of PWS.

Adolescent↗
PubMed1995

Differentiation of ruminal and human Streptococcus bovis strains by DNA homology and 16s rRNA probes.

Streptococcus bovis is commonly present in the rumen, but strains of S. bovis have also occasionally been isolated from human blood or fecal samples. Studies were undertaken with 16s rRNA gene sequences and DNA hybridizations to define the genetic relationships between these two groups of strains. Ruminal strains were found to yield genomic DNA restriction endonuclease digest patterns different from human strains when either the 16s rRNA gene amplified from ruminal S. bovis strain JB1 or a conserved universal 23s rRNA fragment was used as probes. A DNA probe based on the V1 region of the 16s rRNA of S. bovis JB1 was found to hybridize to DNAs of other ruminal S. bovis strains (K27FF4, 21-09-6C, five new ruminal isolates, and weak hybridization was found with DNAs from S. bovis 33317 (type strain), S. equinus 9812, and six other ruminal isolates. No hybridization occurred with strains representing different major human biotypes/homology groups (43143, 43144, 27960, V1387). All ruminal S. bovis strains had a guanosine plus cytosine DNA content of 37.4-38.8 mol% and, based on DNA-DNA genomic hybridizations, could be separated into two homology groups, one of which included S. equinus 9812 and S. bovis 33317. Both ruminal groups had less than 38% DNA homology to the human strains, indicating ruminal strains are clearly two separate species distinct from the human strains.

Animals↗
PubMed1979

A food satiation and oral hygiene punishment program to suppress chronic rumination by retarded persons.

Food satiation and oral hygiene punishment were used to treat the non-life-threatening rumination of two institutionalized profoundly retarded persons. Satiation consisted of allowing the clients to eat until a satiation criterion of food refusal was achieved or until two full meal portions were consumed. The oral hygiene procedure consisted of cleansing the clients' teeth and gums with Listerine for 2 minutes following each instance of rumination. In the formal study, three conditions--baseline, satiation, and satiation plus oral hygiene--were used following the lunch meal in a multiple-baseline across-subjects design. One client's rumination decreased from an average of 89.5% during baseline to 48.8% during the satiation condition and to 3% during satiation plus oral hygiene. The second client's rumination decreased from a baseline average of 49.9% to 7.9% during satiation and to 1.4% during satiation plus oral hygiene. Generalization probes taken following the breakfast and dinner meals showed a systematic decline in rumination as the various conditions were implemented following the lung meal. In the 16-week follow-up, rumination was treated following all meals with oral hygiene, and satiation was used at one of the daily meals for 1 week on a rotating basis. Rumination remained at a near-zero level following all meals throughout the follow-up. Thereafter, a maintenance program was conducted by the ward staff. The satiation plus oral hygiene punishment treatment program appears to be an immediate, effective, enduring, and humane method of treating the non-life-threatening rumination of retarded individuals.

Adult↗
PubMed2001

Systematics and evolution of ruminal species of the genus Prevotella.

Bacterial species of the genus Prevotella represent a numerically dominant microbial population in the rumen of cattle. They belong to the phylogenetic division Cytophaga-Flexibacter-Bacteroides (CFB) which is a large group of ecologically diverse bacteria with only a few shared traits. The phylogenetic descent from a common ancestor seems to be unquestionable, however, as judged from the small subunit ribosomal RNA analysis. Only 4 ruminal Prevotella species have been described to date, even though the sequence analysis of directly retrieved 16S rRNA genes indicates a large genetic diversity within this group of rumen bacteria. The closest relatives of ruminal Prevotella spp. are not surprisingly other species of the genus Prevotella, typically inhabiting the gastrointestinal tract, oral cavity and genital areas of other animals and man. The previous phylogenetic analysis showed that species of the genus Prevotella can be split into two groups or superclusters, the "ruminal" and the "non-ruminal prevotellas". One of 4 currently described ruminal Prevotella spp., i.e. P. albensis, has been placed outside the supercluster containing ruminal Prevotella spp. and within the supercluster containing the non-ruminal Prevotella spp. However, the number of available small subunit rRNA sequences from this species represents only a fraction of all known ruminal Prevotella sequences.

Animals↗
PubMed2005

Chewing activities and oesophageal motility during feed intake, rumination and eructation in camels.

It was the aim of this study to characterize rumination behaviour, eructation and oesophageal motility in camels to identify similarities and differences between camels and domestic ruminants. Recordings were carried out in five camels fed on a hay-based diet. On an average, the duration of rumination, feeding and resting was 8.3, 5.6 and 10.1 h per 24 h, respectively. Rumination activity peaked in the morning between 9:00 and 11:00 and in the night between 02:00 and 04:00 a.m. During rumination periods, on an average 67 boluses were regurgitated per hour. Each bolus was chewed for an average of 45 s with 68 chews per min. The pause between two rumination cycles lasted on an average 9 s. Hay intake took 61 min/kg dry matter (DM), rumination lasted 71 min/kg DM of hay consumed. The regurgitation of a bolus started with a contraction of cranial compartment 1 (C 1) during a B-sequence, followed by a deep inspiration with closed glottis. Digesta enters the oesophagus, and an antiperistaltic wave transported the bolus orally. Eructation starts with a contraction of the caudal C1 during a B-sequence when the cranial C1 is relaxed. After entering the oesophagus, a rapid antiperistaltic wave transports the gas orally. Results revealed that the parameter values obtained in the camels were remarkably similar to those in domestic ruminants despite profound morphological differences and different patterns of forestomach motility.

Animals↗
PubMed2005

Aflatoxin B1 binding to sorbents in bovine ruminal fluid.

A recent approach to the problem of contamination of agricultural products by aflatoxin B(1) (AFB(1)) is to add non-nutritional adsorbents to animal diets in order to sequester ingested aflatoxins. We conducted in vitro experiments to develop a rapid and cheap model using ruminal fluid to assess the ability of sorbent materials to bind AFB(1). Seven sorbents (hydrated sodium calcium aluminosilicate; clinoptilolite; zeolite; two types of bentonite; sepiolite; and PHIL 75), commonly added to bovine diets were incubated in water and ruminal fluid in the presence of AFB(1). Hydrated sodium calcium aluminosilicate, sepiolite and one of the bentonites bound 100% of the AFB(1) in the presence of both ruminal fluid and water; clinoptilolite bound about 80% of AFB(1) in both liquids; whereas the affinities for the mycotoxin of zeolite (50%) and the other sample of bentonite (60%) in water seem to be increased by about 40% in ruminal fluid incubations. PHIL 75 had the poorest binding ability: about 30% in water and 45% in ruminal fluid. In view of the differences in toxin binding in water and ruminal fluid, it is preferable to use the ruminal fluid model for the in vitro pre-screening of sorbent materials potentially useful as adjuvants to ruminant feeds.

Adsorption↗
PubMed1975

Energy exchanges associated with eating and rumination in sheep given grass diets of different physical forms.

1. Energy exchanges and other physiological functions associated with eating and rumination were determined in four experiments. Sheep were given chopped, dried grass (DGC), pelleted, dried grass (DGP) or fresh grass (FGC). 2. In Expt I a preliminary study was made using all three diets. The dry matter (DM) of DGP was eaten significantly faster than that of chopped diets. Sheep salivated most during eating and ruminated longest when given DGC. Rates of contraction for the reticulo-rumen did not differ significantly between diets during idling and rumination, but were significantly faster during eating with DGP. The apparent energy costs of eating were 17, 109 and 176 kJ/kg DM eaten for DGP, DGC and FGC respectively, but these probably underestimated the true energy cost. 3. Expt 2 compared DGP and DGC at two levels of intake. The mean energy costs of eating DGP and DGC were 23.5 and 267 kI/kg DM respectively. The mean energy costs of eating between the energy cost of eating and the duration of the meal. The proportion of time the sheep spent ruminating DGC was about 23% but less than 1% for DGP. There was no significant relationship between heat production and the time spent ruminating. 4. In Expt 3 four sheep were offered fresh grass and, later, an equivalent DM intake after the material had been dried. The sheep ate the dried meal significantly faster. The mean energy costs of eating were 208 and 346 kJ/kg DM for DGC and FGC respectively. In this experiment the sheep ruminated significantly longer when given FGC, and the energy cost of rumination was 0.11 kJ/min. 5. Increases in heat production during and after fistula-feeding only 2-8% of those obtained during eating, indicating that nearly all the increase in heat production during eating could be attributed to the energy cost of eating per se. 6. The contribution of the energy costs of eating and rumination to the heat increment of feeding and the energy requirement for maintenance of sheep are discussed.

Animal Feed↗
PubMed1967

The relative significance of acetate and glucose as precursors for lipid synthesis in liver and adipose tissue from ruminants.

1. The incorporation of labelled glucose into lipid by liver slices from sheep and cows is considerably less than that by liver slices from the rat, although oxidation to carbon dioxide occurs to a similar extent. ATP citrate lyase and NADP malate dehydrogenase are inactive in both sheep and cow liver but active in rat liver. The absence of the citrate-cleavage pathway of lipogenesis in ruminant liver has been confirmed by the negligible amounts of C-3 of aspartate incorporated into fatty acids. 2. Considerable amounts of [(14)C]acetate are incorporated into fatty acids and non-saponifiable lipid in rat and ruminant liver. Acetyl-CoA synthetase, the initial enzyme in the metabolism of acetate, has a high activity in liver from rat and ruminants. 3. In adipose tissue from ruminants more acetate than glucose is converted into lipids, whereas the converse is true in rat adipose tissue. The greater incorporation of [(14)C]acetate into fatty acids in adipose tissue from the ruminant as compared with the non-ruminant may be caused, in part, by the higher activity of acetyl-CoA synthetase activity in the ruminant. 4. The results suggest that, in both liver and adipose tissue from ruminants, acetate is a more important source of lipid than glucose. 5. Two enzymes of the hexose monophosphate shunt, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, are active in both tissues and from the three species.

Acetates↗
PubMed2000

Polyamines in the gastro-intestinal tract of goat kids and in the regenerating ruminal epithelium of sheep.

The aim of the present study was to investigate whether temporal changes in polyamine concentration and synthesis could be found in the luminal content and wall tissue of the rumen and abomasum, two organs which have entirely different growth patterns during the first month of life. In the abomasal mucosa there was a marked gradual decrease in the ornithine decarboxylase (ODC) activity during the first month of life, while the ODC activity in the ruminal mucosa was low during the whole experimental period. However, injury of the rumen wall was followed by increased ODC activity. The ODC activity in duodenal mucosa was about 10 times higher than in the ileal mucosa and the ruminal epithelium. In ruminal liquid a clear peak in ODC activity was observed during the period 51-70 days after birth. The polyamine concentration did not parallel the ODC activity, in either the ruminal epithelium or the ruminal liquid. Of the polyamines, the spermine concentration was always highest, and with the exception of duodenal mucosa, the putrescine concentration was lowest. In liver a clear decrease in spermidine concentration from day 1 to about day 60 after birth was observed. Otherwise no marked temporal changes in tissue polyamine concentrations were observed. Two and a half hours after oral administration of 14C-labelled spermine, nearly all of the radioactivity was found in the lumen of the gastrointestinal tract. On the other hand, 1 h after intravenous injection of polyamines the walls of the gastrointestinal tract were strongly labelled. In conclusion, the polyamines needed for ruminal epithelial development seem to come from sources other than the ruminal epithelium itself or the ruminal lumen.

Abomasum↗
PubMed1975

[Results of chewing and ruminant activity of cows fed rations of cereal straw of various physical forms and after chemical treatment with sodium lye].

3 trials were conducted with adult cows. The animals received different types of coarse fodder (straw, lucerne) which was subjected to chemical treatment (liquid NaOH) and mechanical treatment (pelleting, wafering); then, the chewing and ruminating activity of the cows was measured. Different criteria were used, i.e. movements of the jaws during food intake and rumination and number of regurgitated bits of food. On the average, one movement of jaws lasted 0.94 sec. and swallowing and regurgitation took 5.5 sec. From this, the duration of the rumination process was determined. No differences in ruminating activity were found between lucerne and chopped/chaffed food while the the case of wheat straw about 30% of additional ruminating activity was performed in comparison with pelleted lucerne and chaffed food. This structural effect was even a bit more pro nounced when the straw was first ground and then wafered. Preceding chemical treatment of the straw with liquid NaOH reduced the ruminating activity in the case of chopped food by 53%, with pellets by 40% and with straw pressed into blocks by 62%. The finess of the feed was in no case found to be related to rumination activities, while hardness of the food particles as well as physical and chemical treatment of the food had an importent influence on the rumination activity.

Animal Nutritional Physiological Phenomena↗
PubMed1996

Influence of barley and buffer supplements on quantitative aspects of ruminal fiber digestion of cows.

Four Jersey cows, fitted with ruminal and duodenal cannulas, were used to assess the specific effects of changes in ruminal pH that were induced by barley addition to a hay diet on ruminal fiber digestion. Cows received successively 100% unchopped cocksfoot hay (diet H), 65% hay and 35% pelleted ground barley (diet HB), and HB plus a continuous intraruminal infusion of bicarbonate salt solution (diet HBB). Cows were limit-fed once daily at 7 kg of DM day-1. The ruminal fractional passage rate of the liquid and hay was respectively estimated from a single administration of Cr-EDTA and Eu labeled on hay fiber. Duodenal fiber flow was estimated both by the double marker method (Yb-acetate/Cr-EDTA) and by multiplying the fractional passage rate of Eu-labeled hay by ruminal pool size. Barley supplement decreased ruminal NDF and ADF digestion compared with diet H, but passage rates of the solid and fluid fractions in the rumen were not affected. The depressive effect of barley supplement on in situ degradability of hay NDF and ADF decreased the degradation rates and increased the 72-h undegradable fraction. Compared with diet HB, ruminal NDF and ADF digestion was improved with buffer supplementation but was less than that of diet H, even though ruminal pH was similar to that of diet H. Passage rates of the fluid and particle fractions were depressed and unaffected, respectively, with buffer addition. Higher in situ degradability of hay with the buffer supplement resulted in an increase in the 72-h undegradable fraction, but the fractional degradation rate was unaffected.

Animals↗
PubMedDate not supplied

Co-rumination in the friendships of girls and boys.

This research addresses a new construct, co-rumination. Co-rumination refers to extensively discussing and revisiting problems, speculating about problems, and focusing on negative feelings. Friendship research indicates that self-disclosure leads to close relationships; however, coping research indicates that dwelling on negative topics leads to emotional difficulties. Co-rumination is a single construct that integrates both perspectives and is proposed to be related both to positive friendship adjustment and problematic emotional adjustment. Third-, fifth-, seventh-, and ninth-grade participants (N = 608) responded to questionnaires, including a new measure of co-rumination. Co-rumination was related to high-quality, close friendships and aspects of depression and anxiety. Girls reported co-ruminating more than did boys, which helped to account for girls' more positive friendship adjustment and greater internalizing symptoms. Other analyses addressed whether co-rumination and the related constructs of self-disclosure and rumination had different relations with friendship and emotional adjustment.

Affect↗
PubMed2002

Transport of ketone bodies and lactate in the sheep ruminal epithelium by monocarboxylate transporter 1.

Due to intensive intracellular metabolism of short-chain fatty acids, ruminal epithelial cells generate large amounts of D-beta-hydroxybutyric acid, acetoacetic acid, and lactic acid. These acids have to be extruded from the cytosol to avoid disturbances of intracellular pH (pH(i)). To evaluate acid extrusion, pH(i) was studied in cultured ruminal epithelial cells of sheep using the pH-sensitive fluorescent dye 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein. Extracellular addition of D-beta-hydroxybutyrate, acetoacetate, or lactate (20 mM) resulted in intracellular acidification. Vice versa, removing extracellular D-beta-hydroxybutyrate, acetoacetate, or lactate after preincubation with the respective monocarboxylate induced an increase of pH(i). Initial rate of pH(i) decrease as well as of pH(i) recovery was strongly inhibited by pCMBS (400 microM) and phloretin (20 microM). Both cultured cells and intact ruminal epithelium were tested for the possible presence of proton-linked monocarboxylate transporter (MCT) on both the mRNA and protein levels. With the use of RT-PCR, mRNA encoding for MCT1 isoform was demonstrated in cultured ruminal epithelial cells and the ruminal epithelium. Immunostaining with MCT1 antibodies intensively labeled cultured ruminal epithelial cells and cells located in the stratum basale of the ruminal epithelium. In conclusion, our data indicate that MCT1 is expressed in the stratum basale of the ruminal epithelium and may function as a main mechanism for removing ketone bodies and lactate together with H+ from the cytosol into the blood.

Acids↗
PubMed1990

Influence of roughage source on kinetics of digestion and passage, and on calculated extents of ruminal digestion in beef steers fed 65% concentrate diets.

Roughage sources were compared in flaked milo-based diets that contained 35% chopped alfalfa hay (AH, control diet) or with cottonseed hulls (CSH) or chopped wheat straw (WS) replacing half the AH. Latin square experiments were used to measure total tract digestion coefficients, particulate passage rates (rare earths), liquid turnover rates (Co-EDTA), and rumination time in six growing steers (Exp. 1) and in situ digestion of DM and NDF, ruminal pH and ruminal DM distribution in three mature, ruminally cannulated steers (Exp. 2). Rates of passage from Exp. 1 and rates and extents of digestion from Exp. 2 were used to calculate apparent extent of ruminal digestion (AED). In Exp. 1, total tract digestibilities of DM and NDF were lower (P less than .05) by 7 and 22%, respectively, when CSH, but not WS, were included in the diet. Digestibility of cell solubles was not different (P greater than .10) among diets. Inclusion of WS increased (P less than .10) rumination time by 36%, and CSH increased intake (P less than .10) by 17% over the control diet. In Exp. 2, there tended to be (P less than .20) increased in situ digestion of milo and AH in the WS diet. Measures of ruminal pH were similar for all diets. The AED for AH and milo DM and NDF, and the proportion of total tract NDF digestion occurring in the rumen (50, 47 and 62% for control, CSH and WS diets, respectively), were highest (P less than .05) for the WS diet. This resulted in similar total tract digestibilities for the WS and AH diets. The two low-digestibility roughages had different effects at this concentrate level; wheat straw enhanced apparent extent of ruminal digestion for NDF of other ingredients in the mixed diets, but cottonseed hulls did not.

Animal Feed↗
PubMed1990

Influence of forage diets on ruminal particle size, passage of digesta, feed intake and digestibility by steers.

To assess the influence of forage diets on particle size of digesta in the rumen, three ruminally fistulated steers were fed alfalfa, orchardgrass or switchgrass hays in a 3 x 3 Latin square design. Mean sieve size of ruminal digesta for alfalfa, orchardgrass and switchgrass diets was 671, 652 and 466 microns, respectively. A second experiment examined the influence of ruminal particle size on digesta passage, digestibility and intake. Four ruminally fistulated Angus-Hereford steers were given ad libitum access to different proportions of alfalfa and switchgrass in a 4 x 4 Latin square design. Either a 100% alfalfa, 50% alfalfa:50% switchgrass, 25% alfalfa:75% switchgrass or 100% switchgrass diet was offered once daily. Mean sieve sizes of the ruminal digesta of these diets responded cubically (P less than .01; 1,066, 946, 1,003 and 925 microns, respectively). Mean ruminal turnover times were 24.3, 24.8, 24.7 and 29.8 h, respectively. Dry matter intake increased linearly (P less than .10) as the proportion of legume in the diet increased; no influence of diet on DM digestibility was observed. Passage rate of dosed nylon particles 1, 3 and 5 mm in length was influenced (P less than .01) by size; however, no difference in the passage rates of the nylon particles due to diet was evident. Particle size of ruminal digesta did not respond in a linear manner to the proportion of legume in the diet. A smaller ruminal particle size was not associated with a faster turnover of digesta.

Animal Feed↗
PubMed1993

Determination of the ruminal escape value and duodenal amino acid flow of rapeseed meal.

A 4 x 4 Latin square metabolism trial was conducted to evaluate protein escape potential, duodenal amino acid (AA) flows, and ruminal digestion effects of rapeseed meal (RSM) when fed with non-endophyte-infected tall fescue (Festuca arundinacea) hay. Four Holstein steers (average BW = 400 +/- 6.5 kg), each equipped with ruminal and duodenal cannulas, were fed twice daily at 0700 and 1900. Protein supplements compared with RSM, soybean meal (SBM), blood meal (BM), and a negative control based on urea (U). Diets were formulated to contain 14% CP. Rapeseed meal-supplemented steers had lower (P < .01) ruminal NDF and OM digestibilities than steers fed SBM. Based on in situ data, the lower NDF, DM, and OM digestibilities that occurred when RSM was fed than when SBM and BM were fed were possibly due to the reduced digestibility of the hulls in the RSM. Ruminal pH was not different (P > .05) among treatments. Blood meal supplementation decreased (P < .01) ruminal and total tract CP digestibilities compared to all other supplements. Ruminal liquid and particulate passage rates were not changed (P > .05) by supplement source. Urea supplementation resulted in the highest (P < .01) ruminal ammonia concentration, whereas BM supplementation resulted in the lowest ruminal ammonia concentration (P < .01). Blood meal resulted in greater (P < .01) dietary protein flow to the duodenum than the other treatments. However, microbial efficiencies, as well as microbial DM and protein flows to the duodenum were not different (P > .05) among treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1993

The effects of feeding regimen and dietary sucrose supplementation on natural abundance of 15N in some components of ruminal fluid and plasma of sheep.

An experiment was conducted to investigate the effects of changes in ruminal conditions arising from feeding and sucrose supplementation to the diet on the natural abundance of 15N (delta 15N value) of some biological components and of feces and urine in sheep. Four wethers fitted with ruminal fistulas were fed on alfalfa hay cubes with or without sucrose either 2 or 12 times daily. With twice-daily feeding, the delta 15N values of ruminal ammonia and plasma urea decreased after feeding, whereas only small changes were observed throughout the sampling period with 12 times daily feeding. With 12 times daily feeding with and without sucrose, the delta 15N values of ruminal ammonia were higher (P < .05) than those of the diet and plasma urea. The delta 15N values of ruminal bacteria were lower (P < .05) than those of ruminal ammonia but higher (P < .05) than those of the diet. The delta 15N values for feces were higher (P < .05) than those of the diet, and no differences (P > .25) were observed between the delta 15N values of urine and those of the diet. Dietary sucrose supplementation lowered (P < .05) the delta 15N values of ruminal ammonia but had no effect (P > .10) on values for ruminal bacteria and plasma urea. Nitrogen excretion in urine was decreased (P < .05) by sucrose supplementation to the diet, but the delta 15N value of urine showed no effect (P > .25) of sucrose addition.(ABSTRACT TRUNCATED AT 250 WORDS)

Ammonia↗
PubMed1993

Intestinal supply of amino acids in steers fed ruminally degradable and undegradable crude protein sources alone and in combination.

The objective of this study was to examine the effect of combining ruminally degradable and undegradable CP sources on ruminal microbial protein synthesis and postruminal N and amino acid (AA) flows in steers. Six steers fitted with ruminal, duodenal, and ileal cannulas were fed diets containing corn silage and high-moisture corn supplemented with urea, soybean meal (SBM), dry corn gluten feed (DCGF), a combination of corn gluten meal and blood meal (CB), or SBM and DCGF in combination with CB. Estimated ruminal N escapes for SBM, DCGF, and CB were 32, 25, and 68%, respectively. Supplemental CP sources supplied 35 to 40% of diet CP (12.5% CP diets). Dry matter intake was adjusted to 2.3% of BW for each steer in each period. Total N flow at the duodenum decreased (P < .01) when the diet was supplemented with urea vs other proteins due to decreased (P < .01) flow of nonmicrobial N. However, microbial N and AA flows were greater (P < .05) for urea than for other protein supplements. Disappearance of OM and NDF in the stomach decreased (P < .07) or was numerically lower but nonmicrobial N at the duodenum increased (P < .08) as CB replaced SBM or DCGF in the diet. Protein source had little effect on ruminal fermentation characteristics except that ruminal ammonia N (NH3N) concentration was higher (P < .05) for urea than for other treatments. Total AA and essential AA flows to and disappearance from the small intestine increased (P < .06) as CB replaced DCGF. However, substituting CB for SBM had little effect on intestinal flows and disappearance of AA. These data suggest that source of ruminally degradable CP can influence the efficacy of feeding ruminally degradable and undegradable CP in combination. In general, source of supplemental CP had a greater effect on the quantity than on the profile of absorbable AA supplied to the duodenum.

Amino Acids↗