scholarly journals 292 Altering the particle size of supplemental zeolite (clinoptilolite): Effects on nitrogen utilization and nutrient digestibility in backgrounding cattle

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 213-213
Author(s):  
Caitlin Klaeui ◽  
Mario de Haro Martí ◽  
Mireille Chahine ◽  
Gwinyai E Chibisa
Keyword(s):  
Particle Size ◽  
Latin Square ◽  
Nutrient Digestibility ◽  
Neutral Detergent Fiber ◽  
Beef Heifers ◽  
Plasma Urea ◽  
Spot Urine ◽  
Post Feeding ◽  
N Utilization ◽  
D 20

Abstract The objective of this study was to evaluate the effects of feeding supplemental clinoptilolite with a particle size of either 30 microns or 400 microns (US 40 mesh) on measures of nitrogen (N) utilization and nutrient digestibility in backgrounding cattle. Six ruminally cannulated beef heifers were used in a replicated 3 × 3 Latin square design with 21-d periods. The dietary treatments were: 1) a basal forage-based backgrounding TMR with no supplement (CON), 2) CON + 30-micron clinoptilolite (CL-30), and 3) CON + 400-micron clinoptilolite (CL-400). Clinoptilolite was top-dressed (2.5% of diet DM) during morning feeding (1100 h). Ruminal fluid (d 19 at 2, 3, 4, 6 and 12 h post-feeding), spot urine and grab fecal (d 19 at 1400 and 1900; d 20 at 0300, 0700, 1500, and 2300 h; d 21 at 0500 and 1100 h), and blood samples (d 21 at 3 h post-feeding) were collected and analyzed for nutrients and metabolites. There was no diet effect (P = 0.50) on ruminal ammonia-N (NH3-N) and plasma urea-N (PUN) concentrations. Similarly, urine N and urea-N (UUN), and fecal N excretion did not differ (P ≥ 0.28) across diets. There was no diet effect (P ≥ 0.11) on dry matter (DM) and organic matter (OM) intake, and apparent total tract DM, crude protein (CP), and neutral detergent fiber (NDF) digestibility. However, although it did not differ for the CL-400 compared to CON and CL-30 heifers, apparent total tract OM digestibility was greater for CL-30 than CON heifers. In summary, although feeding supplemental clinoptilolite with a particle size of either 30- or 400-microns to beef heifers did not enhance N utilization, apparent total tract OM digestibility was greater for heifers fed supplemental 30-micron but not 400-micron clinoptilolite compared to the CON diet.

scholarly journals PSVI-8 Effects of feeding ensiled or dried grape pomace on measures of nitrogen utilization in backgrounding cattle

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 428-428
Author(s):  
Gwinyai E Chibisa ◽  
Cody Ream ◽  
Allison Stevens
Keyword(s):  
Latin Square ◽  
Polyphenolic Compounds ◽  
Grape Pomace ◽  
Plasma Urea ◽  
Spot Urine ◽  
Post Feeding ◽  
Preservation Method ◽  
N Utilization ◽  
D 20 ◽  
Dietary Treatments

Abstract Because of its content of polyphenolic compounds, feeding grape pomace (GP) could alter nitrogen (N) utilization in cattle in a manner that limits urinary N excretion and, thus, reactive N emissions. However, the preservation method used for GP, whose shelf-life is limited when fresh, could potentially cause changes in the bioactivity of the polyphenolic compounds. This study evaluated the effects of feeding either ensiled or sun-dried GP on ruminal ammonia-N (NH3-N) and plasma urea-N (PUN) concentrations, and route of N excretion in backgrounding cattle. Six ruminally-cannulated beef heifers were used in a replicated 3 × 3 Latin square design with 21-d periods. Dietary treatments were (DM basis): 1) a typical backgrounding diet (CON), 2) CON + 15% ensiled GP, and 3) CON + 15% sun-dried GP. Grape pomace partially replaced triticale silage in the diet. Ruminal fluid (d 19 at 3 h post-feeding), blood (d 21 at 3 h post-feeding), and fecal grab and spot urine samples (d 19 at 0900, 1500, and 2100; d 20 at 0300, 1200, and 1800 h; d 21 at 0000 and 0600 h) were collected and analyzed for metabolites. Data was analyzed using PROC MIXED in SAS. There was no diet effect (P ≥ 0.48) on N intake, and ruminal NH3-N and PUN concentrations. Urine N (g/d and % of N intake) and urea-N (g/d) output were lower (P < 0.01) for heifers fed GP-containing diets than the CON diet. However, fecal N excretion (g/d and % of N intake) was greater (P = 0.01) for heifers fed GP-containing diets than the CON diet. In summary, although there was no diet effect ruminal NH3-N and PUN concentrations, feeding GP irrespective of preservation method, was effective in changing the route of N excretion from urine to feces, which is beneficial from an environmental standpoint.

PSIII-11 The effect of feeding supplemental zeolite (clinoptilolite) of two different particle sizes on measures of nitrogen utilization and nutrient digestibility in finishing beef heifers

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 287-287
Author(s):  
Cheyanne A Myers ◽  
Mario de Haro Marti ◽  
Mireille Chahine ◽  
Gwinyai E Chibisa
Keyword(s):  
Particle Size ◽  
Nutrient Intake ◽  
Nutrient Digestibility ◽  
Particle Sizes ◽  
Sample Collection ◽  
Beef Heifers ◽  
Plasma Urea ◽  
Ruminal Ph ◽  
N Utilization

Abstract Clinoptilolite (CLN), could potentially improve nitrogen (N) utilization when fed to beef cattle as it can bind ruminal-ammonia-N (NH3-N), limiting its loss and subsequent detoxification into urea-N, which is released into blood and is excreted in urine. However, the effectiveness of CLN is influenced by physical properties such as particle size. Although decreasing the particle size has been shown to increase the binding of ammonium in-vitro, this remains to be evaluated in vivo. Therefore, the objective of this study was to determine the effects of feeding CLN of two different particle sizes (30 and 400 µm) on ruminal NH3-N and plasma-urea-N (PUN) concentrations, ruminal pH, and nutrient intake and apparent total-tract digestibility. Six ruminally-cannulated beef heifers (mean initial BW± SD, 620.8 ± 30.15) were used in a replicated 3 × 3 Latin square design with 21 d periods (sample collection from d 15 to 21). Dietary treatments were: 1) finishing ration with no supplement (CON), 2) CON +30-µm CLN (CL-30), and 3) CON + 400-µm CLN (CL-400). Clinoptilolite was top-dressed (2.5% of diet DM) during morning feeding. Intake was measured daily. Ruminal fluid was collected on d 19 for NH3-N analysis and blood was collected 3 h post-feeding on d 21 for PUN analysis. Indwelling pH loggers were used to measure ruminal pH (d 15 to 21) and grab fecal samples were collected from d 19 to 21 to determine total-tract nutrient digestibility. Statistical analysis was conducted using PROC MIXED in SAS. There was no treatment effect (P ≥ 0.13) on ruminal NH3-N and PUN concentrations, ruminal pH, and nutrient (DM, OM, NDF, ADF and CP) intake and apparent total tract digestibility. In conclusion, feeding CLN to finishing heifers had no effect on measures of N utilization, ruminal pH and nutrient intake and apparent total-tract digestibility.

scholarly journals Milk Potential of Pantaneira Cows, a Local Breed, at Organic System

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1079
Author(s):  
Willian Biazolli ◽  
Marcus Vinicius Morais de Oliveira ◽  
Dirce Ferreira Luz ◽  
Leonardo de Oliveira Seno ◽  
Alysson Martins Wanderley ◽  
...  
Keyword(s):  
Body Weight ◽  
Milk Yield ◽  
Milk Fat ◽  
Latin Square ◽  
Nutrient Digestibility ◽  
Organic Production ◽  
Neutral Detergent Fiber ◽  
Organic System ◽  
Plasma Urea ◽  
Organic Systems

Pantaneiro cattle (Bos taurus taurus) is a breed locally adapted to the Brazilian Pantanal. Local breeds are essential for the quality production of organic systems based on planned grazing practices, because of their results in resilient and productive ecosystems, enhancing biodiversity. This study aimed to evaluate the performance of Pantaneira primiparous cows, and systems with reduced use of concentrate, simulating organic production conditions. Five animals, with an average body weight of 396.2 ± 43.5 kg, were kept in individual continuous grazing regimes and supplemented with different concentrate levels (1.2%, 0.9%, 0.6%, 0.3%, and 0.0% of body weight). The animals were allocated at random in a 5 × 5 Latin square design repeated twice during the study time. The cows had a low dry matter and nutrient intake with a reduction in concentrate level, with improvement in neutral detergent fiber digestibility and a reduction in total nutrient digestibility. No changes were observed in plasma glucose levels or urea excretion, but the plasma urea nitrogen decreased with reductions in concentrate levels. There was a reduction in milk yield, but the energy-corrected milk was not affected by the reduction in concentrate levels; furthermore, the milk yield efficiency was not affected. The milk fat content improved with the reduction in concentrate levels. The Pantaneira breed has the genetic potential for the maintenance of competitive production and quality in organic systems.

scholarly journals Feeding strategies for improving productivity of growing steers fed grass silage

2008 ◽  
Vol 88 (4) ◽  
pp. 685-692
Author(s):  
D. R. Ouellet ◽  
L. Faucitano ◽  
D. Pellerin ◽  
M. D’Amours ◽  
R. Berthiaume
Keyword(s):  
Particle Size ◽  
Soybean Meal ◽  
Nitrogen Balance ◽  
Average Daily Gain ◽  
Latin Square ◽  
Feeding Strategies ◽  
Beef Steers ◽  
Plasma Urea ◽  
Grass Silage ◽  
Ground Corn

Two experiments were conducted to determine the relationship between corn particle size and soybean meal treatment on growth, diet digestibility, and nitrogen balance of growing steers. In the first experiment, 40 medium-frame beef steers (250 ± 11 kg) were fed individually for 140 d a diet based on grass silage offered for ad libitum consumption and supplemented with either 3.5 kg of DM d-1 of cracked corn (CC) or ground corn (GC) and with 450 g of DM d-1 of solvent extracted (SS) or lignosulfonate-treated soybean meal (Soypass™ SP). Dry matter intake was not affected by treatments and averaged 8.6 ± 0.3 kg d-1 (P > 0.10). Average daily gain was higher for animals receiving the ground corn than those fed cracked corn. Feed to gain ratio was not affected by treatments. There was an interaction between treatments for plasma urea-N concentration, with source of soybean meal having no effect with CC. When compared with SS, SP supplement reduced plasma urea-N when fed with GC. No effect of soybean meal and its interaction with corn processing was observed on growth performance. In the second experiment four additional steers were used in a 4 × 4 Latin square design to evaluate diet digestibility and nitrogen balance. There was an interaction between treatments for starch apparent digestibility and N retained, the values being respectively, 90, 86, 93, and 92% (SEM = 1.2; P < 0.01) and 36, 42, 44 and 41 g d-1 (SEM = 2.8; P < 0.03) for CCSS, CCSP, GCSS and GCSP, respectively. Altogether, the results indicate a slight advantage to reduce particle size of corn in growing steers fed grass silage. However, soybean meal treatment resulted in limited effects on growth and digestion. Key words: Rumen carbohydrate, undegradable protein, performance, steers

scholarly journals Effect of stage of maturity at harvest for forage pea (Pisum sativum L.) on eating behavior, ruminal fermentation, and digestibility when fed as hay to yearling beef heifers

2019 ◽  
Vol 4 (1) ◽  
pp. 149-158 ◽  
Author(s):  
Alex A Pursley ◽  
Bill Biligetu ◽  
Tom Warkentin ◽  
Herbert A Lardner ◽  
Gregory B Penner
Keyword(s):  
Pisum Sativum ◽  
Eating Behavior ◽  
Latin Square ◽  
Neutral Detergent Fiber ◽  
Starch Digestibility ◽  
Ruminal Fermentation ◽  
Beef Heifers ◽  
Passage Rate ◽  
Ruminal Ph ◽  
Pisum Sativum L

Abstract The objective of this study was to evaluate the stage of maturity at harvest for pea hay (Pisum sativum L., c.v. CDC Horizon) on dry matter intake (DMI), eating behavior, ruminal fermentation, and digestibility when fed to beef heifers. Pea hay was cut at EARLY (defined to occur when flat pods were on one or more nodes), MID (when seeds filled the pods at one or more nodes and the leaves were changing from green to gold), and LATE (yellow dry seeds filled pods on most or all of the nodes and the pods and leaves had a yellow color) phases, and was cured in the field and baled. Six ruminally-cannulated Speckle Park heifers were used in a replicated 3 × 3 Latin square design with three 18-d periods including 12 d for adaptation, 2 d for measurement of ruminal pool sizes, and 4 d for the collection of eating behavior, ruminal pH, ruminal digesta, and feces. For all treatments, the respective pea hay was included at 40% of the dietary DM. Stage of maturity at harvest for pea hay did not affect total DMI, pea hay DMI, or the total short-chain fatty acid concentration in ruminal fluid with averages of 8.6 kg/d, 3.2 kg/d, and 96.55 mM, respectively. The duration of time spent ruminating decreased with advancing pea hay maturity when reported as min/d, min/kg DMI, and min/kg neutral detergent fiber (NDF) (P ≤ 0.01). Mean ruminal pH also decreased with advancing pea maturity (P &lt; 0.01). The ruminal DM and undigested NDF corrected for OM pools were not affected by stage of maturity (P ≥ 0.55) nor was the rate of digestion for NDF. However, NDF passage rate decreased by 0.21%/h with advancing pea hay maturity (P = 0.02). Apparent total tract digestibility of NDF (average = 16.30%, P = 0.41) was not affected, but starch digestibility decreased from 96.10% to 93.08% with advancing pea hay maturity (P = 0.07). Overall, stage of maturity at harvest for pea hay does not appear to affect DMI or NDF digestibililty but decreases chewing activity, apparent total tract starch digestibility, ruminal pH, and ruminal NDF passage rate.

scholarly journals Effects of source and concentration of neutral detergent fiber from roughage in beef cattle diets on feed intake, ingestive behavior, and ruminal kinetics

2020 ◽  
Vol 98 (5) ◽  
Author(s):  
Rodrigo S Goulart ◽  
Ricardo A M Vieira ◽  
Joao L P Daniel ◽  
Rafael C Amaral ◽  
Vanessa P Santos ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Feed Intake ◽  
Dry Matter ◽  
Latin Square ◽  
Nutrient Digestibility ◽  
Corn Silage ◽  
Neutral Detergent Fiber ◽  
Ingestive Behavior ◽  
Rumen Content ◽  
Residence Times

Abstract The objectives of this research were to evaluate the effects of source and concentration of α-amylase-treated neutral detergent fiber (aNDF) from roughage on feed intake, ingestive behavior, and ruminal kinetics in beef cattle receiving high-concentrate diets. Six ruminally cannulated Nellore steers (408 ± 12 kg of body weight) were randomly assigned to a 6 × 6 Latin square design with six diets: 10% aNDF from corn silage (10CS); 20% aNDF from corn silage (20CS); or four diets containing 10% aNDF from corn silage and 10% aNDF from one of the following sources: sugarcane (SC), sugarcane bagasse (SCB), soybean hulls (SH), or low oil cottonseed hulls (LOCH). The parameters of passage and degradation kinetics were estimated based on a two-compartmental model with gamma- and exponential-distributed residence times. The nonlinear models were fitted by nonlinear least squares, and a linear mixed-effects model was fitted to all variables measured from the Latin square design that were related to intake, digestibility, digestion kinetic parameters, and residence times. Mean particle size (MPS) between roughage sources (CS, SCB, and SC) and coproducts (SH and LOCH) was affected (P &lt; 0.05). Dry matter intake (DMI) was not affected (P &gt; 0.05) by 20CS, SC, SH, or LOCH. Steers fed 20CS or LOCH diets had 16% and 20% greater DMI, respectively, (P &lt; 0.05) than steers fed 10CS diet. Steers fed SCB consumed the least dry matter (DM). The SH and LOCH diets had lower MPS values (about 8.77 mm) in comparison to 20CS, SCB, and SC diets (about 13.08 mm) and, consequently, affected (P &lt; 0.05) rumen content, ruminal in situ disappearance, nutrient digestibility, and solid fractional passage rate. Chewing time was affected (P &lt; 0.05) by roughage sources and concentration. Lower values of distance travel inside the rumen (min/cm) were observed (P &lt; 0.05) for the SCB and SC diets in comparison with any other diet. Except for SCB, there was no difference (P &gt; 0.05) in rumen fill, among other treatments. Mean daily ruminal pH was not affected (P &gt; 0.05) by 20CS, SCB, SC, and LOCH diets, and it ranged from 6.1 to 6.23. Total short-chain fatty acids concentration was affected (P &lt; 0.05) by roughage source and concentration. Based on our results, we recommend that under Brazilian finishing diets, replacing roughage sources, except for SCB, based on aNDF concentration of the roughage in high-concentrate diets containing finely ground flint corn does not affect DMI.

scholarly journals Nutritional value of high moisture corn silage in the diet of Holstein cows

2014 ◽  
Vol 66 (5) ◽  
pp. 1495-1503 ◽  
Author(s):  
P. Persichetti Júnior ◽  
G.A. Almeida Júnior ◽  
C. Costa ◽  
P.R.L. Meirelles ◽  
J.P.F. Silveira ◽  
...  
Keyword(s):  
Plasma Glucose ◽  
Latin Square ◽  
Nutrient Digestibility ◽  
Corn Silage ◽  
Neutral Detergent Fiber ◽  
Holstein Cows ◽  
High Moisture ◽  
Linear Effect ◽  
Five Phases ◽  
High Moisture Corn

Five Holstein cows were distributed in a 5x5 latin square design to assess the effect of replacement levels of dry ground corn grain (DGCG) by high moisture corn silage (HMCS) on intake, total nutrient digestibility and plasma glucose, according to the following treatments: 1) 100% DGCG; 2) 75% DGCG and 25% HMCS; 3) 50% DGCG and 50% HMCS; 4) 25% DGCG and 75% HMCS; 5) 100% HMCS. The experiment lasted 70 days, divided into five phases of 14 days each. The digestibility was obtained using chromic oxide (Cr2O3) as the indicator. Fecal samples were collected twice daily and blood samples were collected on the last day of each period before the first meal (0h) and 2h, 4h, 6h and 12h after the meal. There was no effect (P>0.05) on the intake of dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF) and starch. The total apparent digestibility of DM, crude protein (CP), NDF and ADF were not affected (P>0.05) by the treatments, as well as the plasma glucose concentration. However, there was a decreased linear effect (P<0.05) for the protein intake and increased linear effect (P<0.05) for starch digestibility, as the level of HMCS was increased in the diets.

Feeding either palm oil or sunflower oil on nutrient digestibility and blood metabolites in crossbred Thai native x Brahman bull

2016 ◽  
Author(s):  
Wantanee Polviset ◽  
Nattiya Prakobsaeng
Keyword(s):  
Beef Cattle ◽  
Palm Oil ◽  
Sunflower Oil ◽  
Low Density Lipoprotein ◽  
Latin Square ◽  
Density Lipoprotein ◽  
Nutrient Digestibility ◽  
Neutral Detergent Fiber ◽  
Blood Metabolites ◽  
Dietary Treatments

This experiment was conducted to investigate the effect of palm oil and sunflower oil supplementations on digestibility and blood metabolites in crossbred Thai native x brahman bulls fed on TMR used rice straw as a roughage source. Four, 2 year old crossbred Thai native x Brahman bulls were randomly assigned in a 2x2 factorial in 4 x 4 latin square design. Each period of feeding lasted for 21 days to receive four dietary treatments; 3% palm oil, 6% palm oil, 3% sunflower oil and 6% sunflower oil. All animals were fed with TMR ad-libitum. It was found that supplementation of palm oil and sunflower oil had no effect on digestibility of dry matter (DM), organic matter (OM), neutral detergent fiber (NDF) and crude protein (CP). Supplementation resulted in significant (P<0.05) lower acid detergent fiber (ADF) digestibility when feeding with palm oil on the other hand feeding beef cattle with 6% from palm oil and sunflower oil were higher Ether extract (EE) digestibility than 3% from twice oils (P<0.05). Blood glucose, blood urea nitrogen, cholesterol, triglyceride, high density lipoprotein and low density lipoprotein were not significant different among treatments. Based on this study, supplementing TMR sunflower oil in diets was suitable in beef cattle without any effect ruminal digestibility and blood metabolites.

scholarly journals Effect of Corn Particle Size on the Particle Size of Intestinal Digesta or Feces and Nutrient Digestibility of Corn–Soybean Meal Diets for Growing Pigs

Animals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 876
Author(s):  
Qingtao Gao ◽  
Feng Zhao ◽  
Fangkun Dang ◽  
Hu Zhang ◽  
Ya Wang
Keyword(s):  
Particle Size ◽  
Soybean Meal ◽  
Enzyme Activities ◽  
Digestive Enzyme ◽  
Nutrient Digestibility ◽  
Growing Pigs ◽  
Neutral Detergent Fiber ◽  
Duodenal Fluid ◽  
Digestive Enzyme Activities ◽  
Corn Particle Size

This study was conducted to evaluate the effect of corn particle size on the particle size of intestinal digesta or feces and nutrient digestibility of corn–soybean meal diets. Twenty-four growing barrows (initial BW: 21.9 ± 1.62 kg) were randomly divided into 4 groups of 6 pigs. A T-cannula was surgically placed in the anterior duodenum (about 50 cm from pylorus) of pigs in Groups 1 and 2 or in the distal ileum of pigs in Groups 3 and 4. Corn used to formulate diets had mean particle size (MPS) of 365 µm (Corn 1) or 682 µm (Corn 2), resulting in diets with MPS of 390 µm (Diet 1) or 511 μm (Diet 2). Diet 1 or 2 were randomly assigned within pig Groups 1 or 2 and 3 or 4. The digestive enzyme activities of duodenal fluid, particle size of intestinal digesta and feces, as well as nutrient digestibility, were determined for each pig as the experiment unit. The MPS of duodenal digesta (181 vs. 287 µm, p < 0.01), ileal digesta (253 vs. 331 µm, p < 0.01), and feces (195 vs. 293 µm, p < 0.01) was significantly reduced for pigs fed Diet 1 vs. Diet 2, respectively. Compared with Diet 2, Diet 1 significantly reduced the proportion of particles above 0.5 mm, but significantly increased the proportion of particles between 0.072 and 0.5 mm (p < 0.01) in digesta and feces (p < 0.01). Diet 1 significantly increased solubles percentage (<0.072 mm) in duodenal digesta (p < 0.05) but did not affect solubles percentage in ileal digesta and feces. The MPS of diet did not affect the activities of amylase, trypsin, and chymotrypsin in the duodenal fluid and the apparent total tract digestibility (ATTD) of dry matter, gross energy, crude protein, ether extract, neutral detergent fiber (NDF) and acid detergent fiber (ADF) in pigs offered Diet 1 compared to Diet 2. The in vitro digestible energy (IVDE) (3706 vs. 3641 kcal/kg; p = 0.03) was greater for Corn 1 vs. Corn 2. However, no significant difference was observed in IVDE (3574 vs. 3561 kcal/kg; p = 0.47) for Diet 1 vs. Diet 2. In conclusion, the particle size of digesta and feces was dependent on the dietary particle size. However, the digestive enzyme activities of duodenal fluid and ATTD of energy and nutrients were not affected by reducing dietary MPS from 511 to 390 µm.

scholarly journals Processing index of barley grain and dietary undigested neutral detergent fiber concentration affected chewing behavior, ruminal pH, and total tract nutrient digestibility of heifers fed a high-grain diet

2021 ◽  
Vol 99 (1) ◽  
Author(s):  
Tao Ran ◽  
Atef M Saleem ◽  
Karen A Beauchemin ◽  
Gregory B Penner ◽  
Wenzhu Yang
Keyword(s):  
Barrier Function ◽  
Latin Square ◽  
Barley Grain ◽  
Nutrient Digestibility ◽  
Neutral Detergent Fiber ◽  
Blood Metabolites ◽  
Fiber Concentration ◽  
Finishing Cattle ◽  
Ruminal Ph ◽  
Grain Processing

Abstract The objective of this study was to investigate the effects of processing index (PI) of barley grain and dietary undigested neutral detergent fiber (uNDF) concentration on dry matter (DM) intake, chewing activity, ruminal pH and fermentation characteristics, total tract digestibility, gastrointestinal barrier function, and blood metabolites of finishing beef heifers. The PI was measured as the density after processing expressed as a percentage of the density before processing, and a smaller PI equates to a more extensively processed. Six ruminally cannulated heifers (average body weight, 715 ± 29 kg) were used in a 6 × 6 Latin square design with three PI (65%, 75%, and 85%) × 2 uNDF concentration (low and high; 4.6% vs. 5.6% of DM) factorial arrangement. The heifers were fed ad libitum a total mixed ration consisting of 10% barley silage (low uNDF), or 5% silage and 5% straw (high uNDF), 87% dry-rolled barley grain, and 3% mineral and vitamin supplements. Interactions (P &lt; 0.01) of PI × uNDF were observed for DM intake, ruminating and total chewing time, and DM digestibility in the total digestive tract. Intake of DM, organic matter (OM), starch, and crude protein (CP) did not differ (P &gt; 0.14) between low and high uNDF diets, but intakes of NDF and acid detergent fiber were greater (P = 0.01) for high uNDF diets regardless of barley PI. Heifers fed high uNDF diets had longer (P = 0.05) eating times (min/d or min/kg DM) and tended (P = 0.10) to have longer total chewing times (min/kg DM) than those fed low uNDF diets. Additionally, heifers sorted (P = 0.01) against long particles (&gt;19 mm) for high uNDF diets but not for low uNDF diets. Altering PI of barley grain did not affect (P &gt; 0.12) total volatile fatty acid (VFA) concentration, molar percentages of individual VFA, or duration of ruminal pH &lt; 5.8 and &lt;5.6. Total VFA concentration was less (P = 0.01), acetate percentage was greater (P = 0.01), and duration of ruminal pH &lt; 5.8 and &lt;5.6 was less (P = 0.05) for high compared with low uNDF diets. Digestibility of DM, OM, and CP was greater (P = 0.02) for low vs. high uNDF diets with PI of 65% and 75%, with no difference between low and high uNDF diets at PI of 85%. Blood metabolites and gastrointestinal tract barrier function were not affected (P ≥ 0.10) by the treatments. These results suggest that increasing dietary uNDF concentration is an effective strategy to improve ruminal pH status in finishing cattle, regardless of the extent of grain processing, whereas manipulating the extent of barley processing did not reduce the risk of ruminal acidosis.

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