Neutral Detergent Fiber Intake Research Articles

Effect of forage quality and narasin inclusion on ruminal fermentation, nutrient intake, and total tract digestibility of Nellore steers.

The study aimed to evaluate the effects of forage quality and narasin inclusion on intake, digestibility, and ruminal fermentation of Nellore steers. Twenty-eight rumen-cannulated Nellore steers (initial body weight [BW] = 350 ± 32.4kg) were allocated to individual pens in a randomized complete block design, with 7 blocks, defined according to the fasting BW at the beginning of the experiment. The steers were randomly assigned within blocks to 1 of 4 experimental diets in 2 × 2 factorial arrangements, being the first-factor forage quality (MEDIUM = 81g of CP/kg of dry matter [DM], and HIGH = 153g of CP/kg of DM), and the second factor was the inclusion (N13 = diet plus 13mg/kg of DM of narasin) or not (N0) of narasin (Zimprova; Elanco Animal Health, São Paulo, Brazil). The experiment consisted of a 28-d period with 22 d for adaptation and the last 6d for data collection. No haylage quality × narasin interaction (P ≥ 0.68) was observed on DM and nutrient intake. Haylage quality affected (P ≤ 0.01) DM intake, with greater values observed for steers fed HIGH compared with MEDIUM haylage. There was an increase (P < 0.001) in OM, NDF, hemicellulose, and CP intake for steers consuming HIGH vs. MEDIUM haylage. Including N13 did not affect (P > 0.39) DM and nutrient intake of steers. No haylage quality × narasin interactions were detected (P ≥ 0.60) for total tract nutrient digestibility. However, steers fed with HIGH haylage showed an increase (P > 0.001) in DM and digestibility of all nutrients compared with MEDIUM. Steers fed a MEDIUM haylage had a greater (P < 0.01) proportion of acetate compared with steers fed HIGH during all evaluated hours. Steers fed HIGH haylage had a greater (P < 0.01) proportion of propionate at 0h compared with steers consuming MEDIUM, whereas at 12h, steers consuming MEDIUM hay had a greater (P < 0.01) proportion of propionate vs. HIGH haylage. A haylage quality × narasin and haylage quality × time of collection interactions were detected (P ≤ 0.03) for rumen ammonia concentration, which was reduced (P < 0.03) in N13 vs. N0 steers consuming HIGH haylage. Collectively, high-quality haylage allows increased consumption and digestibility, with more energy-efficient ruminal fermentation. In addition, narasin might be an important nutritional tool in forage-based diets to enhance the ruminal fermentation parameters of Bos indicus Nellore steers.

The Effect of Supplementing White Sweet Lupine Grain Meal (Lupinus albus L.) on Blood and Milk Metabolites, Milk Yield, and Quality of Dairy Cows in Ethiopia

Feed is the cornerstone of dairy production, serving as a crucial input for sustainable milk production. This trial aimed to investigate the effect of white sweet lupine grain meal inclusion on feed intake, blood and milk metabolites, milk yield, and quality. The experimental cows had a parity of 2±0.71 (mean ± SD), a daily milk yield of 12.72 ± 0.9, and an average body weight of 412.6 ± 21.5 kg. The varying proportions of treatment diets were: 75, 50, 25 and 0% (T1, T2, T3 and T4) treatment groups respectively. Data collected during the study were subjected to analysis of variance to determine significant differences. Cows fed diet T1 showed a better dry matter (10.39 kg/day), organic matter (7.31 kg/day), nitrogen (2.42 kg/day), and NDF intakes (3.75 kg/day) that had significant difference on (p&lt;0.05). When lupine inclusions dropped from 75 to 50 and even to 25%, the N digestibility decreased from 76.63, 70.66, and 65.6%, respectively, and the digestibility of N in all treatment diets significantly decreased (p &lt; 0.01). Once more, cows fed T1 diet had the highest (p&lt;0.01) plasma glucose concentration (116.81 mg/dl) among the four experimental groups. Cows fed T2 and T4 diets showed significant variation at (p&lt;0.05) in plasma glucose levels, with values of 108.7 and 110.16 mg/dl, respectively. Cows fed T1 had relatively lower plasma beta-Hydroxybutyric acid and non-esterified fatty acid concentrations (p&lt;0.05) than others, with mean values of 3.23 and 1.28 mg/dl respectively. The partial inclusion of white sweet lupine grain meal up to the level of 75% is highly suggested as a better alternative feed source.

How neonatal diet affects the long-term development of rumination behavior, rumen fermentation and feed digestion in dairy calves fed a high milk level?

This study was to investigate growth performance, rumination development, rumen fermentation and feed digestion in young calves provided high volumes (about 20% of calf birth weight) of milk with or without forage inclusion and how these parameters correlate with each other. Immediately after birth, 160 newborn Holstein female calves (41.6 ± 4.2 kg of initial BW) were randomly divided into 2 treatments: 1) starter (CON, only starter) and 2) starter and hay (HAY, both starter and hay). The calves were fed their respective experimental diets from d 4 to 84, after which they were all introduced to similar diets until the end of the experiment on d 196. Treatment had no effect on growth and structural measurements throughout the experimental period. However, treatment had an effect on the other parameters, mainly during the post-weaning period. Forage supplementation tended to reduce starter dry matter intake (P = 0.05), while increasing the forage intake (P < 0.01) and the feed-to-gain ratio (P < 0.01). HAY calves had increased neutral detergent fiber (NDF) and physically effective NDF (peNDF) intakes (P < 0.05) and tended to lower (P < 0.01) starch intake compared to CON calves. The HAY calves had a higher rumination time (P < 0.01), ruminal pH (P < 0.01), and acetate-to-propionate ratio (P = 0.05) compared to the CON calves. Spearman correlation analysis showed that rumination time was positively related to the ruminal pH at d 84 (P = 0.01) and 196 (P = 0.02). The HAY calves had similar apparent total-tract digestibility of dry matter (DM), NDF and ether extract (EE), but lower digestibility of organic matter (OM, P = 0.03), crude protein (CP, P < 0.01) and starch (P < 0.01) compared to those of the CON calves at week 12. Furthermore, there were no positive relationships between rumination time and nutrient digestibility or between rumination time per kilogram DM and nutrient digestibility. In conclusion, feeding hay to calves fed a high milk level improved rumination during the post-weaning period only, without a concomitant effect on growth performance throughout the experimental period, suggesting no detrimental effect of feeding forage in calves fed high milk level.

Unveiling microbial biomarkers of ruminant methane emission through machine learning.

Enteric methane from cow burps, which results from microbial fermentation of high-fiber feed in the rumen, is a significant contributor to greenhouse gas emissions. A promising strategy to address this problem is microbiome-based precision feed, which involves identifying key microorganisms for methane production. While machine learning algorithms have shown success in associating human gut microbiome with various human diseases, there have been limited efforts to employ these algorithms to establish microbial biomarkers for methane emissions in ruminants. In this study, we aim to identify potential methane biomarkers for methane emission from ruminants by employing regression algorithms commonly used in human microbiome studies, coupled with different feature selection methods. To achieve this, we analyzed the microbiome compositions and identified possible confounding metadata variables in two large public datasets of Holstein cows. Using both the microbiome features and identified metadata variables, we trained different regressors to predict methane emission. With the optimized models, permutation tests were used to determine feature importance to find informative microbial features. Among the regression algorithms tested, random forest regression outperformed others and allowed the identification of several crucial microbial taxa for methane emission as members of the native rumen microbiome, including the genera Piromyces, Succinivibrionaceae UCG-002, and Acetobacter. Additionally, our results revealed that certain herd locations and feed composition markers, such as the lipid intake and neutral-detergent fiber intake, are also predictive features for methane emissions. We demonstrated that machine learning, particularly regression algorithms, can effectively predict cow methane emissions and identify relevant rumen microorganisms. Our findings offer valuable insights for the development of microbiome-based precision feed strategies aiming at reducing methane emissions.

Assessing the In Vitro and In Vivo Effect of Supplementation with a Garlic (Allium sativum) and Oregano (Origanum vulgare) Essential Oil Mixture on Digestibility in West African Sheep.

This study assessed the impact of a mixture of garlic (Allium sativum) and oregano (Origanum vulgare) essential oils (EOGOs) on in vitro dry matter digestibility (IVDMD) and in vivo apparent nutrient digestibility. Different EOGO inclusion levels were evaluated to assess the dose response and potential effects of the mixture. Three EOGO inclusion levels (0.5, 0.75, and 1 mL/kg of incubated dry matter) were evaluated in vitro, while four treatments (0.5, 0.75, and 1 mL/day of EOGO and a control group) were tested in vivo on 12 West African sheep. A randomized controlled trial was conducted using a 4 × 4 design. Blood parameters (glucose, blood urea nitrogen, and β-hydroxybutyrate) were measured to observe the effect of EOGO on the metabolism. The results showed that the inclusion of EOGO significantly enhanced IVDMD at low levels (p < 0.052) compared with the highest levels in treatments containing 0.5 and 0.75 mL/kg of EOGO dry matter. A higher intake of dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF) (p < 0.05) was observed in the in vivo diets with the inclusion of EOGO. In terms of in vivo apparent digestibility, significant differences were found among treatments in the digestibility coefficients of DM, CP, and NDF. EOGO inclusion increased the digestibility of DM. CP digestibility displayed a cubic effect (p < 0.038), with the lowest values of digestibility observed at 1 mL EOGO inclusion. Additionally, NDF digestibility showed a cubic effect (p < 0.012), with the highest value obtained at 0.75 mL of EOGO inclusion. The inclusion levels above 0.75 mL EOGO showed a cubic effect, which indicates that higher concentrations of EOGO may not be beneficial for the digestibility of CP and NDF. Although no significant difference was observed in total digestible nutrients, a linear trend was observed (p < 0.059). EOGO improved the intake of DM, CP, and NDF. EOGO supplementation improved the digestibility of DM and NDF, with optimal levels observed at 0.5 mL/day. No significant effects were observed in the blood parameters. These results suggest that EOGO has the potential as an additive in ruminal nutrition to improve food digestibility and serve as an alternative to antibiotic additives. The use of EOGO potentially improves fiber digestion and may reduce the use of antibiotics in livestock production. Garlic (A. sativum) and oregano (O. vulgare) essential oils effectively modulated fiber digestibility at 0.75 mL/day. Garlic (A. sativum) and oregano (O. vulgare) essential oils have the potential to improve digestibility at low inclusion levels and serve as an alternative to antibiotic additives. The effectiveness of essential oils is greater in a mixture and at lower doses.

Effects of forage quality and particle size on feed intake and ruminoreticulum content of goats.

The aim was to evaluate the effect of particle size and hay quality on feed intake, granulometric profile, and composition of the ruminoreticulum content in goats. We used 54 Alpine bucks in a completely randomized design with a factorial arrangement of 3 × 3. Treatments were a combination of Bermuda grass hay (Cynodon dactylon) with three quality levels: high (35 days), medium (50 days), and low (65 d) harvested at regrowth times. Were evaluated three particle sizes: small (16% ≥4.76 mm), medium (48% ≥4.76 mm), and large (75% ≥4.76 mm), which accounted for 66%, 75%, and 94% of physically effective fiber, respectively. Samples of offered diet, intake, and ruminoreticulum content were used to generate the granulometric profile. The offered diet, intake, and ruminoreticulum content presented different granulometric profiles regarding hay quality and particle size. Dry matter intake (DMI) and neutral detergent fiber intake (NDFI) increased (P < 0.05) when low-quality hay and large particles were offered. However, when particle size in low-quality hay was reduced, DMI and NDF decreased (P < 0.05). When analyzing the ruminoreticulum content (DM, NDF, peNDF, and indigestible DM), we did not observe any effect (P > 0.05) of hay quality or particle size on the variables. Thus, reducing hay quality and increasing particle size increase dry matter and fiber intake, presenting an interaction between forage quality and particle size. Forage quality and particle size promote intense selective behavior and chewing, which leads to a homogeneous content of particle profile in ruminoreticulum and a uniform average retention time.

Effect of feeding Pleurotus pulmonarius-treated empty fruit bunch on nutrient digestibility and milk fatty acid profiles in goats.

This study aimed to evaluate the effect of feeding P. pulmonarius-treated empty fruit bunch (FTEFB) on the nutrient intakes, digestibility, milk yield and milk profiles of lactating Saanen goats. A total of nine lactating Saanen goats were used in an incomplete cross-over experimental design. The balanced dietary treatments contain different replacement levels of Napier grass with FTEFB at 0% (0-FT), 25% (25-FT) and 50% (50-FT). The FTEFB contained crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) at 4.10, 94.6, 70.8 and 19.4% DM, respectively. The replacement of FTEFB in 25-FT did not alter dry matter, NDF, hemicellulose, ADL, ether extract and gross energy intakes when compared to the control fed group (0-FT). The ADF and cellulose intake was higher in 25-FT than in the others (P < 0.001). The digestibility of hemicellulose, cellulose and ADL were not changed in 25-FT compared to the control group (P < 0.05) whereas when 50% FTEFB was incorporated to the diet, intermediate digestibility was decreased significantly (P < 0.05). Milk yield and protein content did not differ between the goat received 25-FT and the control group (P > 0.05). There are no differences in milk fatty profiles between dietary treatments (P > 0.05), except for OCFA. Goat fed with 25-FT had the lowest OCFA (P < 0.01) and significantly reduced the lauric acid concentration (P < 0 .05) when compared to the control group. Thus, replacement of NG in 25-FT does not adversely affect nutrient intake, fibre digestibility (cellulose and hemicellulose), milk yield, milk composition and milk fatty acid profiles. Overall, FTEFB may have potential to be used in the dairy goat diet as a roughage source to replace Napier grass.

Performance of grazing sheep kept on tamani grass supplemented with Parkia platycephala pods replacing corn in the multiple supplements

ABSTRACT This study aimed to evaluate the effect of Parkia platycephala pods in the supplements for grazing sheep on intake, digestibility, and animal performance. Twenty-four sheep (21.26 ± 2.87 kg) were used by a completely randomised design with six animals per treatment. The evaluated treatments were mineral salt (MS), mineral salt + urea/ammonium sulfate (urea-supplement; UR), multiple supplements based on corn + soybean meal (MSCS), and multiple supplements in which P. platycephala pods replaced 50% of corn (MSPP). The supplements evaluated did not affect pasture intake, and total dry matter (DM) intake was higher for animals fed multiple or UR than those fed with MS. Sheep fed multiple supplements presented 55.57% higher crude protein (CP) intake than those fed MS or UR. Neutral detergent fibre intake was 17.76% lower in sheep fed MS than those fed other supplements. Animals fed multiple supplements presented higher digestibility for DM and CP than those fed MS or US. Animals fed multiple supplements presented 54.61% higher total body weight gain and 54.79% higher average daily gain than those fed MS or US. Thus, Parkia platycephala pods can replace 50% of corn in multiple supplements without compromising the performance of grazing sheep.

Thermoregulatory responses and ingestive behavior of sheep subjected to water restriction and high- and low-energy diets in a semi-arid environment

The aim of the study was to evaluate the effect of water restriction and low- and high-energy diets on sheep's thermoregulatory responses and ingestive behavior. Forty sheep, non-castrated, with an average body weight of 18.85 kg (SD = 2.80 kg) and an average age of 5 months were assigned to a 2 × 2 factorial arrangement, comprising 2 diets (high- and low-energy) and 2 water offers (ad libitum and 50% water restriction), with 10 replicates. Thermoregulatory responses were evaluated in two periods (morning and afternoon). There was an interaction effect of Diet x Water supply x Periods on respiratory rate (P < 0.05). High-energy diets resulted in increased heart rate, idleness, dry matter feeding and rumination efficiency, and water intake. Low-energy diets increased feeding time, rumination time, the number of ruminal cuds, chews per day, total chewing time, neutral detergent fiber intake and rumination efficiency, number of ruminations per day, average duration of rumination, and defecation frequency. Water supply affected heart rate and idleness (P < 0.05). Sheep had higher values of heart rate and rectal and surface temperatures during the afternoon (P < 0.05). Water restriction combined with a low-energy diet and high environmental temperature leads to a reduction in the respiratory rate of Santa Inês crossbred sheep. Regardless of the dietary energy value, water restriction by 50% of the daily requirement of sheep reduces dry matter intake and increases idleness.

211 Evaluation of Beef Heifer Variability in the Ability to Eat and Digest a High Forage Diet

Abstract This study evaluated beef heifers selected for high or low digestible fiber intake (DFI) and investigated its relationship with methane production, residual feed intake (RFI), and total tract digestibility. Sixteen recently weaned black Angus beef heifers (n = 8/treatment) were selected from a group 64 heifers (224 ± 17.2 kg) fed a high forage-based diet [70% barley silage:30% pelleted concentrate (DM basis)]. The 64 heifers were fed in 6 outdoor pens equipped with GrowSafe bunks to monitor feed intake for 60 d (14 d adaptation + 46 d for data collection). Individual fecal samples and BW, and feed samples were taken once weekly. Fecal samples were pooled by animal. Feed and fecal samples were analyzed for dry matter (DM), neutral detergent fibre (NDF), and undigested neutral detergent fiber (uNDF) content. The internal marker uNDF was used to estimate total tract diet DM and NDF digestibility. The 8 heifers with the greatest and the 8 with the least digestible NDF intake (g/kg BW0.75) were selected and used for methane measurements using the GreenFeed system (42 d) and in a total-tract digestibility trial with total fecal and urine collection using the same high forage based diet. Results from the GrowSafe selection trial indicated no differences between the average BW of low and high DFI heifers (264 vs. 274 kg, P = 0.20). Heifers selected for high DFI had greater (P &amp;lt; 0.01) DM and NDF intake (kg/d or % of BW), and digestibility (49.6 vs. 42.1% NDF digestibility). The heifer groups differed in RFI (P &amp;lt; 0.01), with high DFI categorized as inefficient (+0.84 RFI) and low DFI as efficient (-0.34 RFI). No differences in ADG were observed between low and high DFI heifers during this short 46 d study period (0.614 vs 0.773, P = 0.16). High DFI heifers had lower methane production than low DFI heifers (15.9 vs. 19.0 g/kg of DMI, P = 0.02). The results of the total-tract digestibility trial showed that the high DFI heifers had a greater DMI compared with the low DFI heifers (10.9 vs. 10.2 kg/d; P = 0.04). The DMI intake was not different between groups when expressed as a % of BW (2.06 vs 2.04, P = 0.65). There was also no difference observed for DM digestibility (73.0 vs 73.1%) between the two groups. It is important to note that in the digestibility study, the DMI was less than in the GrowSafe selection trial (2.5 vs 3.2% BW) and this may have influenced results. Heifers with high DFI were heavier than low DFI heifers (533 vs. 505, P = 0.02) during the digestibility trial. Results suggest that selecting heifers for high DFI may increase growth rate and reduce methane production.

PSXIII-17 Feeding Sorghum Silage: Effects of Grain Processing on Intake and Apparent Total Tract Digestibility of Backgrounding Beef Heifers

Abstract This study evaluated the effect of processing sorghum silage (SS) at harvest on dry matter intake and nutrient digestibility of beef cattle. A dual-purpose sorghum (ADV2450IG, Advanta seeds, Irving, TX) was harvested (Claas Jaguar 930, Harsewinkel, Germany) at the late-dough stage of grain maturity and processed (PRO) or not (NPR) with a specific SS cracker (196 mm rolls of 125 teeth each, 40% speed differential, 1.1 mm roll gap). Whole-plant was chopped at 15 mm and ensiled in polyethylene ag-bags (60 m long and 2.74 m diameter) for 60 d until the beginning of a performance trial which was followed by the digestibility trial. From a performance trial with eight heifers/pen and 12 pens total (six per treatment), one heifer (13 ± 1.5 mo and 251,4 ± 36.3 kg of BW) by pen was randomly selected for the digestibility trial. Two backgrounding diets containing (DM basis), 90.5% SS either PRO or NPR, 6.5% soybean meal (expeller) and 3% supplement (ROC90, Provimi, Argentina); continued to be offered ad libitum for an extra 3 d of adaptation, while feed and feces were collected the next 4 d. Feed was individually offered once daily, and orts were collected the following day. Fecal samples were collected twice daily and apparent total tract digestibility was determined using uNDF240h as a marker. Data were analyzed as a completely randomized design using pen as the experimental unit, and initial BW as a covariate. Dry matter (DM) and organic matter (OM) intake tended (P &amp;gt; 0.07) to be greater, while starch intake was greater (P &amp;lt; 0.03) for the NPR treatment. intake of NDF, ADF and CP were not affected by treatments. No differences (P &amp;gt; 0.10) were detected for DM, OM, NDF, ADF and CP digestibility, while starch digestibility was greater (P &amp;lt; 0.001) by processing (93.55 vs. 86.48 for PRO and NPR, respectively). In conclusion, processing sorghum silage at harvest increased apparent total tract digestibility of starch when SS was fed to backgrounding beef heifers.

PSXIII-18 Feeding One-Year Stored Sorghum Silage: Effects of Grain Processing on Intake and Apparent Total Tract Digestibility of Backgrounding Beef Heifers

Abstract This study evaluated the effect of feeding sorghum silage after one-year of storage (SS) based diets, on dry matter intake and nutrient digestibility of beef cattle. A dual-purpose sorghum (ADV2450IG, Advanta seeds, Irving, TX) was harvested (Claas Jaguar 930, Harsewinkel, Germany) at the late-dough stage of grain maturity and processed (PRO) or not (NPR) with a specific SS cracker (196 mm rolls of 125 teeth each, 40% speed differential, 1.1 mm roll gap). Whole-plant was chopped at 15 mm and ensiled in polyethylene ag-bags (60 m long and 2.74 m diameter), for 388 d until the beginning of a 60 d-performance trial which was followed by the digestibility trial. From a performance trial with eight heifers/pen, and 12 total (six per treatment), one heifer (13.5 ± 1 mo and 259,4 ± 38 kg of BW) by pen was randomly selected for the digestibility trial. Two backgrounding diets containing (DM basis), 90.5% SS either PRO or NPR, 6.5% soybean meal (expeller) and 3% supplement (ROC90, Provimi, Argentina); continued to be offered ad libitum for an extra 3 d of adaptation while feed and feces were collected the next 4 d. Feed was individually offered once daily, and orts were collected the following day. Fecal samples were collected twice daily and apparent total tract digestibility (TTD) was determined using uNDF240h as a marker. Data were analyzed as a completely randomized design using pen as the experimental unit, and initial BW as a covariate. No differences among treatments were detected for DM, OM, NDF, ADF, CP and starch intake (P &amp;gt; 0.35). No effects of treatment were observed (P &amp;gt; 0.40) for DM, OM, NDF, ADF, CP and starch TTD. In conclusion, no effects of processing on apparent total tract digestibility were detected when feeding a one-year stored sorghum silage to backgrounding beef heifers.

PSXIII-21 Effects of Bacterial Direct-Fed Microbial Mixtures on Beef Cattle Feeding Behavior

Abstract The effects of bacterial direct-fed microbial (DFM) mixtures on beef cattle feeding behavior were evaluated. Six ruminally cannulated crossbred Angus steers (BW = 520 ± 30 kg) were used in a replicated 3 × 3 Latin Square design. Steers were offered a steam-flaked corn-based finishing diet to ad libitum during three, 28 d periods (21-d adaptation and 7-d collection). Treatments assigned were: 1) Control (no DFM, lactose carrier only); 2) Treat-A [L. animalis, P. freudenreichii; B. subtilis; and B. licheniformis, at 1:1:1:3 ratio, respectively; totaling 6 × 109 CFU (50mg)/animal-daily minimum (Chr.Hansen]; and 3) Treat-B, the same DFM combination, but with doses at 1:1:3:1 ratio. Bacterial counts were approximately 30% greater than the minimum expected. The DFM diluted mixtures and carrier (Control) were pre-weighed and stored at -20°C until incorporated into the diet (2 g· animal-1· /day-1) 10 min prior to feeding. For mixing, approximately 1 kg (as is) of the diet being offered was removed from the individual recipient, DFM was mixed by hand, and the mixture was incorporated into the feed allocated for the day. The feeding behavior assessment consisted of a 24 h continuous visual observation (every 5 min) performed by trained personnel. Animals were assessed on d 26 of each period (no other management other than cleaning of the stall), while time spent eating, ruminating, resting, active, and drinking were taken. Time spent chewing was accounted for by adding time spent eating and ruminating. In addition, records allowed the count of the number of meals taken, as well as the time spent on each meal. Data were analyzed using the GLIMMIX procedure of SAS, with animal considered as the experimental unit, the fixed effects of treatment, and random effect of square, period, and animal (square). F-test protected pre-planned orthogonal contrasts was used to compare Control vs. Treat-A and Control vs. Treat-B. Meal number (16/d) and length (8 min/meal) were not affected by treatments (P ≥ 0.54). Main feeding behavior variables consisting of rumination (198 min/d), eating (117 min/d), chewing (315 min/d), drinking (22 min/d), resting (929 min/d), and active (174 min/d) were not affected (P ≥ 0.24) by treatments. A tendency was observed (P = 0.08) where animals offered the Treat-B spent numerically less time ruminating per unit of digestible DM and OM intake compared with Control (13.5 vs. 15.5, and 13.7 vs 15.6 min/kg, respectively). Other behaviors measured in min/kg of DM, NDF, and ADF intake were not affected (P ≥ 0.17) by treatments [rumination (11.5, 60.2, and 181), eating (6.5, 34.4, and 104), chewing (18, 94.6, and 285), and drinking (1.2, 6.6, and 19.8) min/kg, respectively]. The bacterial DFM mixtures offered appear not to directly affect the feeding behavior of beef cattle consuming a steam-flaked corn-based finishing diet.

363 Effect of Protein and Starch Supplementation Level on Intake and Digestibility By Steers Consuming Low-Quality Forage: I. Bos Taurus Taurus

Abstract A deficiency of ruminally available N (RAN) caused by a basal diet of low-quality forage depresses forage utilization. Supplemental protein improves forage utilization by increasing RAN, resulting in increased intake and potentially improving digestion. Addition of starch to a supplement can increase total digestible OM intake (TDOMI); however, too much starch decreases RAN creating competition between fiber and starch fermenting bacteria potentially decreasing forage utilization. Our objective was to determine the effect of starch supplementation on intake and digestion in Bos taurus taurus steers. Accordingly, five ruminally cannulated Angus steers (BW 375 ± 45 kg) were used in a 4 × 4 Latin square to evaluate the effect of decreasing supplemental starch when consuming King Ranch Bluestem hay (3.5% CP, 73% NDF). Steers received four isonitrogenous (130 mg N/ kg BW) supplements providing increasing levels of starch (2% starch = 100% soybean meal; 20% starch = 26.3% corn, 73% soybean meal, 0.7% urea; 38% starch = 51.6% corn, 47% soybean meal, 1.4% urea; 56% starch = 78.6% corn, 19% soybean meal, 2.4% urea). Five 14-d periods were conducted, consisting of 9 d adaptation and 4 d to measure intake and digestion, and 1 d for ruminal fermentation. As designed, supplement OM intake (SOMI) increased linearly (P &amp;lt; 0.01) as starch level increased. Forage OM intake (FOMI) decreased linearly with increasing starch (P &amp;lt; 0.01). Increases in SOMI and decreases in FOMI combined to result in no significant (P ≥ 0.14) differences in total OMI (TOMI) between starch levels. Total digestible OMI (TDOMI) responded quadratically (P = 0.05) to increasing starch and was 45.8, 49.4, 48.4 and 41.9 g TDOMI/kg BW0.75 for 2, 20, 38, and 56% starch, respectfully. Total DOMI was 18% greater when steers were provided 20% starch supplement compared with 56% starch. Similarly, total digestible NDF intake responded quadratically (P = 0.05) and was maximized with 20% starch. Total tract OM digestion and NDF digestion were not significantly affected (P ≥ 0.15) by starch level in the supplement. In conclusion, providing supplemental starch over 20% decrease forage utilization. Decreases in FOMI with starch inclusion may be attributed to competition for RAN between fiber fermenting and starch fermenting bacteria.

Nitrogen Utilization in Goats Consuming Buffelgrass Hay and Molasses-Based Blocks with Incremental Urea Levels.

The use of goats for meat production faces challenges from environmental and nutritional factors. Urea is an affordable non-protein nitrogen source commonly utilized in ruminant nutrition. The objective of this study was to investigate nitrogen utilization in goats fed low-quality hay supplemented with molasses blocks containing urea. Twenty Anglo-Nubian doelings were individually housed in metabolic cages and provided with chopped Buffelgrass (Cenchrus ciliaris) hay ad libitum. Goats were randomly assigned to four urea levels (0, 2, 4, and 6%; n = 5 per treatment) in molasses blocks for a duration of 30 days. A negative nitrogen balance (-2.458 g/day) was observed in doelings consuming blocks without urea, compared with a positive balance (0.895 g/d) for those consuming the 6% urea blocks. Block nitrogen intake significantly increased with urea level, but urea supplementation did not affect dry matter (DM) or neutral detergent fiber (NDFom) intake or digestibility. A minimum crude protein (CP) requirement of 8% for maintenance in doelings consuming low-quality forage with a urea-based supplement was determined through regression analysis between CP intake (% of DM) and N balance (r2 = 0.479; p < 0.002). The value of 8% of CP obtained in this study is similar to several previous studies reported in the literature, but in this case, the increments in CP came exclusively from urea. In this study, increasing the urea content of molasses blocks up to 6% significantly increased nitrogen intake, retention, and balance in goats. These results contribute to a better understanding of nitrogen utilization in goats fed low-quality hay with urea supplementation.

Predicted essential fatty acid intakes for a group of dairy cows also apply at individual animal level

The ruminant requirements for essential fatty acids (EFAs), particularly linoleic acid (LA) and alpha-linolenic acid (ALA), have not been fully determined, although evidence suggests that an adequate supply of polyunsaturated fatty acids (FAs) could improve immunity and reproduction in transition cows. In previous studies, we predicted EFA intake for a group of cows based on animal characteristics and milk EFA secretions. However, to support precision livestock feeding, we need to match the nutrient requirements and intakes of each cow as closely as possible. Our group-level predictions may not be accurate enough to estimate the EFA intake of an individual cow, due to inter-individual variations in EFA digestion and metabolism related to differences in feed intake, intake patterns, and the composition and functioning of the rumen microbiota. To address this issue, here we set out to establish specific equations that predict EFA intake for an individual cow based on the difference (i.e. the residuals) between observed EFA intake and the predicted EFA intake based on our group-level equations. We studied a database of individual dairy cows (26 experiments; 503 datapoints from three research teams) and we predicted the residuals from (1) dietary and animal-related factors (i.e. full predictions) and (2) animal-related factors only (i.e. field predictions), which are considered more field-amenable. The variance of predicted LA and log ALA intake was explained to 68% by observed LA intake and 66% by observed log ALA intake, respectively. The residuals of LA intake were predicted by dietary ALA content, total FA intake, BW, milk yield and fat content in full predictions, and by BW, feeding level, milk yield and fat content, and sum of milk C4:0 to C14:0 FA in field predictions. The log residuals of ALA intake were predicted by dietary NDF and total FA contents, NDF intake, BW, milk protein, LA and ALA contents, and fat yield in full predictions, and by BW, DM intake, milk LA and ALA contents, and fat yield in field predictions. The field predictions showed a moderate loss of accuracy compared to full predictions based on RMSE of prediction (from 38 to 54 g/d for LA and from 0.090 to 0.12 log (g/d) for ALA). This work is the first to predict the EFA intake of an individual cow based on previously established group-level predictions of EFA intake adjusted for dietary and animal-related factors.

Effects of Dietary Corn Malt-Sactic Mixed Concentrate with Rice Straw and Corn Husk on Rumen Fermentation, Nutrient Digestibility, Blood Metabolites and Growth Performance in Growing Beef Heifers

The enhancement of protein content in grains is interesting because starch is the main energy component used in beef cattle feeds. Corn malt-sactic is a modified corn grain with increase protein content and improve digestibility through the process of malt germination and microbial fermentation. Therefore, the effects of feeding malt-sactic from corn grain as a high protein energy source in diet were investigated on rumen fermentation, nutrient digestibility, blood metabolites, and growth performance in beef heifers. Sixteen of 1-year-old Brahman crossbred growing beef heifers with an initial weight of 220 ± 24.5 kg were randomly assigned into 4 different rations according to completely randomized design (CRD). Experimental treatments were corn grain or corn malt-sactic mixed concentrates with roughage sources as follow, T1; corn grain mixed concentrate with corn husk, T2; con grain mixed concentrate with rice straw, T3; malt-sactic mixed concentrate with corn husk, and T4; corn malt-sactic mixed concentrate with rice straw. The results showed that total feed intake and digestibility of dry matter, crude protein, NDF and ADF were significantly higher in the heifers fed corn malt-sactic mixed concentrate diet than corn mixed concentrate diet (p &lt; 0.05). Ruminal pH post-feeding, blood urea nitrogen, and blood glucose were not different among treatments (p &gt; 0.05). Body weight gain and average daily gain were significantly higher (p &lt; 0.05), while feed conversion ratio was lower in corn malt-sactic mixed concentrate diet as compared with corn mixed concentrate diet (p &lt; 0.05). The source of roughage did not affect rumen fermentation, nutrient digestibility, blood metabolites, or growth performance (p &gt; 0.05). Results indicated that using corn malt-sactic as an ingredient in beef heifer diets can improve digestibility and growth performance. HIGHLIGHTS The addition of corn malt-sactic enhances both malt germination and microbial fermentation. Incorporating a corn malt-sactic mixed concentrate diet boosts heifers' feed intake and improves digestibility. Utilizing a corn malt-sactic mixed concentrate diet leads to improved Average Daily Gain (ADG) and Feed Conversion Ratio (FCR) in heifers. GRAPHICAL ABSTRACT

Modeling Gastrointestinal Tract Wet Pool Size in Small Ruminants.

The gastrointestinal tract (GIT) wet pool size (GITwps) refers to the total amount of wet contents in GIT, which in small ruminants can reach up to 19% of their body weight (BW). This study aimed to develop models to comprehensively predict GITwps in small ruminants using a meta-regression approach. A dataset was created based on 21 studies, comprising 750 individual records of sheep and goats. Various predictor variables, including BW, sex, breed, species, intake level, physiological states, stages and types of pregnancy, dry matter intake, and neutral detergent fiber intake (NDFI), were initially analyzed through simple linear regression. Subsequently, the variables were fitted using natural logarithm transformations, considering the random effect of the study and residual error, employing a supervised forward selection procedure. Overall, no significant relationship between GITwps and BW (p = 0.326) was observed for animals fed a milk-based diet. However, a strong negative linear relationship (p < 0.001) was found for animals on a solid diet, with the level of restriction influencing GITwps only at the intercept. Furthermore, the prediction of GITwps was independent of sex and influenced by species in cases where individuals were fed ad libitum. Pregnant females showed a noticeable reduction in GITwps, which was more pronounced in cases of multiple pregnancies, regardless of species (p < 0.01). The composition of the diet was found to be the primary factor affecting the modulation of GITwps, with NDFI able to override the species effect (p < 0.0001). Overall, this study sheds light on the factors influencing GITwps in small ruminants, providing valuable insights into their digestive processes and nutritional requirements.

Effects of offering free-choice hay for the first 5 days postpartum on productivity, serum inflammatory markers, gut permeability, and colon gene expression in fresh dairy cows

The objective of the present study was to evaluate the effects of offering free-choice hay to cows during the first 5 d immediately after calving on feed intake, milk yield, plasma metabolites, serum inflammatory markers, rumination, gut permeability, and colon gene expression. It was hypothesized that cows offered free-choice hay would have lower gut permeability, lower inflammation, and higher milk production, compared with cows not offered hay. Thirty-two multiparous cows were fed a closeup total mixed ration (TMR; 21.5% starch, 32.1% forage neutral detergent fiber [NDF] on a dry matter basis) until calving. In the postpartum period, all cows were fed a fresh cow TMR (26.8% starch and 23.4% forage NDF) from calving until 21 DIM, and were assigned randomly to receive 1 of 2 treatments as follows: (1) free-choice timothy hay (61.6% NDF; 9.6% crude protein), offered outside of the TMR in a separate manger, for the first 5 d postpartum (FCH; n = 20), or 2) no free-choice hay (NH; n = 12). The FCH cows tended to have lower serum haptoglobin concentration on d 3, compared with NH (0.95 vs. 1.52 mg/mL). Within the FCH group, cows with greater hay intake had a smaller increase in serum amyloid A from d 1 to 3 after calving (r = 0.37), and tended to have a smaller increase in serum haptoglobin concentration (r = 0.36). Cows in the FCH group had a lower ratio of starch intake (kg) to forage NDF intake (kg) on d 1 and 2, compared with NH (0.91 vs. 1.14 ± 0.03), and cows that had a lower starch:forage NDF ratio tended to have a smaller increase in serum haptoglobin concentration from d 1 to 3 after calving (r = 0.32). Cows in the FCH group had lower TMR dry matter intake (DMI; 15.0 vs. 17.1 ± 0.93 kg/d) and lower total DMI (TMR + hay DMI; 15.9 vs. 17.1 ± 0.87 kg/d), from d 1 to 5 when free-choice hay was offered, compared with NH. However, the hay treatment did not affect plasma energy metabolite concentration, gut permeability, colon gene expression, milk yield, rumination time, or change in body weight or body condition score. Overall, these findings suggest that offering free-choice hay for the first 5 d after calving may reduce serum inflammatory marker concentration, but milk yield may not increase, due to lower intake.

Effects of complete substitution of dietary grain and protein sources with by-products on the production performance of mid-lactation dairy cows fed diets based on barley silage under heat-stress conditions

This study evaluated the effects of replacing cereal grains and soybean meal with by-products (BY) on production performance, nutrient digestibility, ruminal fermentation, nutrient recovery, and eating and chewing behavior of moderate-producing dairy cows under heat-stress conditions. Twelve multiparous Holstein cows (116.7 ± 12.01 d in milk; 42.7 ± 5.06 kg/d milk yield; 665 ± 77 kg body weight; mean ± SD) were used in a replicated 3 × 3 Latin square with 28-d periods (21 d for diet adaptation and 7 d for sampling and data collection). Cows were fed a total mixed ration containing a 39.2:60.8 ratio of forage to concentrate throughout the experiment. All diets were formulated to be isoenergetic and isonitrogenous, with different concentrates. Diets were (1) control diet based on cereal grains (CON: ground corn and ground barley, plus soybean meal); (2) sugar-rich BY diet (S-BY-CM: beet pulp, citrus pulp, and liquid molasses, plus canola meal); and (3) cereal grain BY diet (CG-BY: rice bran, corn germ meal, wheat bran, barley sprout, and broken corn). Our results showed that replacing grains with BY increased neutral detergent fiber intake and digestibility but decreased starch intake, human-edible energy, and human-edible protein. Milk yield and dry matter intake (DMI) decreased more in cows fed the CG-BY diet compared with the other 2 treatments. In contrast, no significant differences were observed between the CON and S-BY-CM diets in terms of milk yield and DMI. The S-BY-CM diet increased energy-corrected milk production compared with the CG-BY diet (36.2 vs. 34.3 kg/d), but CG-BY enhanced feed conversion efficiency compared with the other 2 treatments. Although the S-BY-CM diet prolonged the eating and sorting of small particles, neither of the dietary treatments affected chewing activity or ruminal pH 4 h after feeding. Furthermore, both diets containing BY contributed to an increase in milk fat content in comparison to the CON group. Additionally, the CG-BY and S-BY-CM diets demonstrated better performance than the CON diet in terms of human-edible feed conversion efficiency for protein and energy. The results indicated that S-BY-CM can completely replace barley and corn grain in the diet of mid-lactating dairy cows exposed to heat-stress conditions without any negative effect on production and ruminal pH. However, the inclusion of CG-BY did impair DMI, milk yield, and digestibility of nutrients and is not recommended during heat-stress conditions.