Total Digestibility Research Articles

Sugarcane, corn silage and concentrate levels in cattle diet

This study evaluated two roughage types (sugarcane and corn silage) and two concentrate feed levels (0 and 25% of the total dry matter) in the cattle diet, in a 2x2 factorial design, and compared passage rate measurements (indicator and rumen evacuation). Four Holstein-Zebu heifers cannulated in the rumen and ileum were evaluated, in a 4x4 Latin square design. Stool samples (8th - 10th day) and rumen fluid (8th day) were collected and the rumen was emptied (14th and 16th day). Treatments were compared by contrast, evaluating the effects of roughage, concentrate feed and interaction between these factors. Dry matter (DM) intake and neutral detergent fiber corrected for ash and protein (apNDF) were highest for animals fed corn silage, and DM and organic matter (OM) intake were highest when fed concentrate. There was no roughage effect on ruminal mass, but concentrate decreased ruminal NDF in the total digesta mass. The coefficients of total digestion of crude protein (CP), apNDF and non-fiber carbohydrates (NFC) were higher for sugarcane than corn silage. Concentrate feed improved the total digestibility of OM and NFC. Passage rates evaluated by the marker technique and rumen evacuation were similar. Corn silage or 25% concentrate in the cattle diet improved consumption, intake rate and nutrient digestibility. The particle passage rate can be estimated by rumen evacuation or by adjusting a nonlinear mathematical model.

What is the impact of neutral detergent fibre digestibility on productive performance of beef cattle fed tropical forages?

Our objective was to quantify the relationship between total neutral detergent fibre (NDF) digestibility and nutritional and productive characteristics in cattle fed tropical forages using a meta-analytical approach. The dataset used to develop this work was compiled from 24 experiments carried out with beef cattle in Brazil, published between 2005 and 2020, and totalising 115 treatment means. All the experiments were carried out using change-over designs and included a control treatment (i.e., only forage). There was a linear and positive relationship (P<0.01) between total NDF digestibility and voluntary forage intake. We estimated a 0.17 g/kg body weight increase in forage intake for each percentage point (i.e., 0.01 g/g) of improvement in NDF digestibility. On average, increasing total NDF digestibility caused a linear improvement (P<0.01) in rumen microbial nitrogen production (NMIC) and in dietary digested organic matter (DOM). The total NDF digestibility was linear and positively associated with nitrogen balance (NB, P<0.01). However, the increment in NB as a response to total NDF digestibility was more prominent as dietary NDF decreased (P<0.01). In summary, we concluded that increasing NDF digestibility in cattle fed tropical forage-based diets improves the voluntary forage intake and the supply of energy and metabolisable protein. This simultaneous effect causes an increase in the animal's nitrogen accretion and weight gain, but this effect will be more prominent as the dietary content of neutral detergent fibre decreases.

Effects of chicken slurry inclusion on apparent total tract macronutrient digestibility, palatability, and fecal characteristics, microbiota, and metabolites of healthy adult dogs.

"Premium" pet foods are often formulated with meat slurries. Meat slurries are believed to be of higher quality than rendered meals, but inadequate research has been performed to test how their inclusion affects palatability, digestibility, or indicators of gastrointestinal health. Therefore, the objectives of this study were to determine how chicken slurry inclusion affected the palatability and apparent total tract macronutrient digestibility (ATTD) of dog foods and to assess their effects on the fecal characteristics, metabolites, and microbiota of dogs. A replicated 3x3 Latin square design digestibility study was conducted using 9 healthy adult dogs (age = 5.44 ± 0.53 yr) to test diets containing 0% (control; CON), 8% (low inclusion; LOW), and 16% (high inclusion; HIGH) chicken slurry. The experiment comprised three 21-day experimental periods (14 days of adaptation, 5 days of total fecal collection (used for ATTD calculations), and 2 days of blood collection). On the first day of fecal collections, one fresh sample was collected for measurement of pH, dry matter (DM) content, fermentative metabolite concentrations, and microbiota populations. A 2-day palatability study (n=20 dogs) was also conducted to compare CON vs. HIGH. Data were analyzed statistically by Mixed Models using SAS 9.4, with P<0.05 being significant. In the palatability study, dogs were shown to prefer (P<0.05) the HIGH diet by a ratio of 2:1. In the digestibility study, fecal output, scores, pH, and DM percentage were not different among diets. The ATTD of protein was higher (P<0.05) for the HIGH diet (84.6%) than for the LOW (82.7%) or CON (82.6%) diets. The ATTD of other nutrients and energy were not different among diets (all over 80%). Fecal propionate, butyrate, and total short-chain fatty acid concentrations were higher (P<0.05) in dogs fed the LOW diet (122.0, 67.4, and 408.2 βmol/g, respectively) than those fed the HIGH diet (89.0, 46.9, and 338.2 βmol/g, respectively). The other fecal metabolites (acetate, branched-chain fatty acids, ammonia, phenol, and indole) were not different among treatments. Few changes to the fecal microbiota were noted. However, the relative abundance of fecal Fusobacterium was higher (P<0.05) in dogs fed the CON diet than those fed the HIGH diet (25.% vs. 20.0% relative abundance). In summary, chicken slurry inclusion improved palatability but had minimal effects on nutrient digestibility and fecal characteristics, metabolites, and microbiota.

Evaluating NIRS for predicting faecal fibre, protein fractions and digestibility in dairy sheep and goats fed alfalfa hay and concentrate

This study evaluated the effectiveness of near-infrared spectroscopy (NIRS) in predicting faecal fibre, protein fractions and total tract apparent digestibility in dairy sheep and goats fed varying ratios of alfalfa-hay and concentrate. A total of 180 faecal samples from dairy sheep and goats were collected and chemically analysed. Faecal samples underwent also NIRS spectral acquisition and calibration models were obtained through modified partial least square regression and tested for robustness. The NIRS provided excellent estimations for N and CP as % as is (R 2 ExV 0.91 and 0.91, RPD 3.16 and 3.33, respectively), good estimation for N, CP and ND soluble CP % DM (R 2 ExV 0.90, 0.90 and 0.85, RPD 3.14, 2.90 and 2.48) and ND soluble CP expressed as % as is (R 2 ExV 0.87, RPD 2.55), approximative quantitative prediction for acid detergent insoluble crude protein (ADICP) and ADIN % acid detergent fibre (ADF) (R 2 ExV 0.79 and 0.71, RPD 1.93 and 1.78, respectively) and ADICP as % as is (R 2 ExV 0.67, RPD 1.70) but resulted to be less effective when predicting all the other components. The prediction models for total-tract digestibility (ttD) of ADICP performed best among the developed equations (R 2 ExV 0.57, RPD 1.38), but the model was not sufficient for precise predictions, suggesting a good capacity of NIRS to predict faecal N excretion but also intrinsic limitations of faecal spectra due to the partial residual nutrients content, compared to the diet. Increasing the number of calibration samples and values, the forage species, and the F:C ratios in the diet offered to the animals could improve the NIRS performance.

Spring water discharge and metal enrichment in urban soils

Abstract Urban centers have inherited a unique mix of persistent contamination that impacts interactions among urban soil and groundwater systems. In particular, the potential for urban groundwater to transport contaminants from surface sources through the subsurface environment and ultimately to soils is not well understood. Studies have focused on specific ‘natural’ mechanisms driving distribution of metals in urban soils. However, very few studies have examined the accumulation of contamination in soils at groundwater discharge locations (springs) and the potential for groundwater to redistribute urban legacy contaminants far from the source. Soil transects straddling four groundwater springs in Pittsburgh, Pennsylvania were sampled to evaluate patterns resulting from contaminated groundwater discharge on urban soils. Metal concentrations were measured in pore water and compared with concentrations observed in total digestions and exchangeable extractions (acetic acid) of the soil. Across the springs Co, Cr, Ni, and V (metals often used in steel alloys) were elevated downslope, suggesting contaminated groundwater discharge enriches trace metals in these locations. These processes create unexpected biogeochemical patterns on the landscape and have the potential to create hotspots of soil metal contamination at predictable points across the urban landscape.

Dog Breed and Starch Gelatinisation Correlation in Food Digestibility and Faecal Traits.

Large dog breeds commonly produce unformed faeces. The present study hypothesised that foods for large dog breeds require higher starch gelatinisation (SG) to reduce organic matter flow to colon. Fifteen Rottweilers (Ro; 49.4 ± 6.12 kg), 18 Beagles (Be; 12.13 ± 1.75 kg) and 20 Shih-Tzus (ST; 4.62 ± 1.15 kg) were fed one of three diets, all based on the same sorghum formulation, processed to obtain three levels of SG: SG90 (91.8% SG), SG50 (50.7% SG) and SG30 (27.4% SG). Foods were provided for 23 days, and the coefficient of total tract apparent digestibility (CTTAD) of nutrients, faecal production and fermentation products, Na, K and Cl apparent absorption and gastrointestinal transit time (GTT) were evaluated. Results were submitted to analysis of variance considering SG, breed and their interactions, and means compared by the Tukey test (p < 0.05). All dogs promptly ate the foods. Faeces scores were lower for Ro than for Be and ST, and lower for SG30 than SG90 (p < 0.05). Faeces pH was higher, and total short-chain fatty acids were lower for SG90 than for SG50 and SG30 (p < 0.01), regardless of breed. No diet effect was observed for GTT (p > 0.05), but it was lower for Ro (41.7 ± 6.2 h) than for ST (48.7 ± 8.6 h). The CTTAD of nutrients was lower for SG30, intermediary for SG50 and higher for SG90 (p < 0.05), and among breeds CTTAD was higher for Be than ST and Ro (p < 0.05), which did not differ from each other, except for crude protein CTTAD which was lower for Ro (p < 0.05). The apparent absorption of Na and K was higher for the SG90 treatment, and for Be in comparison with Ro and ST (p < 0.05). Food SG had a remarkable influence on Ro faeces formation and on the CTTAD in all breeds. Greater fermentation in the colon and lower protein CTTAD may be involved in Ro unformed faeces formation.

Marine microalgae meal (Schizochytrium sp.) influence on intake, in vivo fermentation parameters and in vitro gas production and digestibility in sheep diets is dose-dependent

The objective of this study was to evaluate the dry matter intake (DMI), intake of nutrients and in vivo ruminal fermentation in wethers fed diets without or with 2 or 4% of marine microalgae meal (Schizochytrium sp.) as a source of docosahexaenoic polyunsaturated fatty acid (DHA; C22:6 n-3), as well as the total gas production and digestibility of the experimental diets using in vitro techniques. Six Santa Inês wethers with a body weight of 55.6 ± 5.20kg and 18 months of age fitted with a ruminal cannula, were used and housed in individual stalls. The experimental design consisted of a double 3 ×3 Latin square (three treatments and three periods) with each experimental period lasting 21 days (14 days for adaptation to diets, 5 days for sample collection and 2 days of blank time between periods), for a total of 63 days. Animals fed 4% microalgae meal showed lower DMI (P<0.05; 1,14 vs. 0,86kg/d) and lower intake of nutrients (P<0.05), except for ether extract (EE; P=0.967), compared to animals not fed microalgae. Wethers that were not fed marine microalgae had lower ruminal pH just two hours after feeding (P=0.042) and lower concentrations of ammoniacal nitrogen (NH3-N) in the ruminal fluid at all sampling times (P=0.011) compared to wethers fed diets with 2 and 4% level inclusion. The addition of marine microalgae meal did not have an effect on heat production and in vitro gas production (P>0.05). The in vitro digestibility of non-fibrous carbohydrates (NFC) increased (P=0.033) with the inclusion of marine microalgae in the diet, being higher in the 4% treatment compared to the others. Additionally, marine microalgae meal significantly reduced (P=0.002; 0.55 to 0.47g/g of DM) the in vitro digestibility of neutral detergent fiber corrected for ash and protein (NDF). The inclusion of marine microalgae meal Schizochytrium sp. as a DHA source did not negatively affect ruminal fermentation. However, it compromised dry matter and nutrients intake, as well as NDF digestibility in animals fed 4% microalgae while a reduction on DMI as well as intake of nutrients at 2% inclusion was not significant. Therefore, it is recommended to use marine microalgae meal in the feeding of wethers under tropical conditions at a concentration of 2% of the diet.

PSLBI-9 The growth performance and total tract starch digestibility of finishing Nelore bulls fed flint corn-based diets are improved by the corn processing method and urea source

Abstract The aim of this study was to evaluate the flint corn processing method (CPM) and urea source for finishing Nellore bulls fed corn-based diets. In this study, 80 Nellore bulls [initial body weight (BW) = 388 ± 45.7 kg] were allocated into 28 pens (7 pens/treatment; 6 pens with 3 bulls + 1 pen with 2 bulls). A completely randomized design with a 2 × 2 factorial arrangement of treatments was used to test two CPMs: dry ground corn (DGC) and reconstituted and ensiled corn (REC), and two US: feed-grade urea (FGU) and post-ruminal release urea (PRU). Dietary inclusion (% DM) of flint corn (vitreousness = 86.0%) was 61.3% (DGC or REC), and urea source addition was 0.5% as non-protein nitrogen (NPN; as FGU or PRU). The PRU source (Trouw Nutrition, Netherlands) contained 82% urea on a DM basis. In an in vitro assay, 27% of this urea was released into the rumen. Experimental period lasted 100 d (with 14 d of adaptation). Fecal samples from each bull were collected in two periods of three consecutive days (d 44 to 46 and 94 to 96) at different time (0600, 1200, and 1800 h). Samples were composited by pen and analyzed for fecal starch (FS) and indigestible NDF as markers for fecal excretion. At the end of the experiment, bulls were slaughtered and the jejunum and pancreas were sampled from one bull per pen. Interaction effects were not found (P ≥ 0.31) for any feedlot growth performance variables (Table 1). Final BW, average daily gain, and feed efficiency (gain to feed; G:F) were greater for bulls fed REC and PRU than for those fed DGC and FGU (P &amp;lt; 0.02), respectively. As a result, observed dietary net energy (NE) for maintenance and BW gain were about 7.0% and 9.0% greater for bulls fed REC diets, and 4.3% and 5.6% greater for bulls fed PRU diets, respectively. Bulls fed DGC had 2.2 times greater FS compared with bulls fed REC, resulting in lower fecal pH and total tract starch digestibility (TSD) for bulls fed DGC compared with those fed REC (P &amp;lt; 0.01). Interestingly, a similar trend was observed in bulls fed PRU compared with those fed diets with FGU (P &amp;lt; 0.06). Jejunal gene expression of SLC5A1 was not affected by treatments (P &amp;gt; 0.14). Nevertheless, bulls fed diets with PRU presented greater jejunal α-amylase activity (P = 0.02). Pancreatic α-amylase activity was less when bulls were fed DGC + PRU diet. In conclusion, REC markedly improved TSD and growth performance compared with DGC. Additionally, independent of CPM, PRU inclusion as NPN source increased G:F and dietary NE concentration due to the positive effects on jejunal amylase activity and TSD.

PSIX-5 Performance of black soldier fly larvae meal as secondary protein sources in extruded dog diets

Abstract Black soldier fly larvae meal (BSFL) has gained market exposure with ties to sustainability and novelty. Graded inclusions of BSFL were assessed for nutrient digestibility, stool quality, and palatability in adult dogs. The BSFL was included at 0%, 5% and 10% in chicken-based extruded dog diets (formulated to 22% crude protein, 13% crude fat, 3% crude fiber). The study was approved by the facility’s Institutional Animal Care and Use Committee. A standard 2-bowl palatability test over a 2-d period was executed (n = 30 dogs each) to determine intake ratios between diets (0% vs. 5%, 0% vs. 10%, and 5% vs. 10%). Total tract nutrient digestibility was evaluated (n = 6 dogs per diet) with 5 d acclimation followed by 5 d total fecal collection. Stool quality was evaluated on a 1 to 5 scale. Palatability data were analyzed using paired t-test. To test for mean differences in digestibility and stool quality outcomes between 0%, 5%, and 10% BSFL dogs, we applied the Kruskal-Wallis test. Statistical significance was set at 5% type 1 error rate. Dry matter, protein, fat, and energy digestibility, and stool quality were similar between all diets (P &amp;gt; 0.05). Palatability was improved (P &amp;lt; 0.05) with inclusion of BSFL (i.e., preference for 5% and 10% vs. 0% inclusion) and improved (P &amp;lt; 0.05) at 10% vs. 5% inclusion. The BSFL tested showed merit as a palatable ingredient source that maintains stool quality and digestibility in adult dogs.

PSVI-29 Effect of pig weight and exogenous enzyme supplementation on ileal endogenous amino acid losses and standardized ileal amino acid digestibility of soybean meal produced from Kentucky-grown soybeans

Abstract There is increasing interest in using locally sourced soybeans and soybean meal. Ileal amino acid digestibility (IAAD) of soybean meal from Kentucky-grown soybeans was evaluated in 25- and 50-kg cannulated pigs. The experiment used sixteen pigs in a randomized complete block design consisting of four treatments with 4 pigs per treatment. This was repeated in time resulting in eight replicates per treatment for both body weight (BW)groups. After cannulation at about 20 kg BW, all pigs were allowed to recover from the surgery and were fed a corn-SBM-based diet that met all nutrient and energy requirements. The experimental diets consisted of two nitrogen-free diets [NFD] with or without exogenous enzyme supplementation (phytase and a combination of phytase and carbohydrase enzymes) and two semi-purified diets containing soybean meal from Kentucky-grown soybeans as the only source of protein with or without exogenous enzyme supplementation. Each diet was fed for 7 consecutive d with 10-h ileal digesta collection on d 6 and 7. The same diets were fed to the same set of pigs at about 50 kg BW. Data were analyzed as a factorial arrangement of treatments (BW x diet) for ileal endogenous amino acid losses (IEAAL), apparent IAAD and standardized IAAD (SIAAD). Data from the NFD were used to determine the SIAAD from the AIAAD values. Exogenous enzyme supplementation increased (P &amp;lt; 0.05) IEAAL except for Gly and Pro while samples collected during phase 2 had greater (P &amp;lt; 0.05) IEAAL (10 amino acids). Pig BW did not influence IEAAL. Enzyme supplementation did not increase AIAAD except for Arg, Ala, Gly, N, and total AA while apparent ileal N, Met, Thr, and Val digestibility was greater (P &amp;lt; 0.05) in 50 kg pigs. Interactions between BW and diets showed that 50 kg pigs fed the SBM diet containing enzyme supplementation had greater (P &amp;lt; 0.05) N, Arg, and total AA digestibility compared with 50 kg pigs without enzyme supplementation. Digestibility of Val and Asp was greater (P &amp;lt; 0.05) in samples collected during phase 2. After correction for basal IEAAL, 50 kg pigs had greater (P &amp;lt; 0.05) SIAAD values for 12 of the AA analyzed while exogenous enzyme supplementation resulted in greater (P &amp;lt; 0.05) SIAAD for 9 of the AA analyzed. The SIAAD values for four AA (His, Phe, Val, and Asp) were greater (P &amp;lt; 0.05) for samples collected in phase 2. Results from this study showed that exogenous enzyme supplementation increased IEAAL and that IAAD of SBM produced from Kentucky-cultivated soybeans was high and that exogenous enzyme supplementation improved the SIAAD values of several amino acids. The IAAD values of SBM produced from soybeans cultivated in KY was high and are similar to values reported in the literature.

PSIX-10 Effects of Bacillus subtilis ATCC PTA-122264 on macronutrient digestibility and fecal characteristics, metabolites, and microbiota of healthy adult dogs subjected to an abrupt diet change

Abstract Probiotic use in dogs is increasing, with spore-forming Bacillus species gaining interest due to their viability during processing, storage, and in the gastrointestinal tract. B. subtilis is known for its adaptable metabolism that may be useful in pets subjected to abrupt dietary changes. The objective of this study was to determine dietary apparent total tract macronutrient digestibility (ATTD) and fecal characteristics, metabolites, and microbiota of healthy adult dogs supplemented with B. subtilis ATCC PTA-122264. All procedures were approved by the University of Illinois IACUC prior to experimentation. Dogs [n = 12; 6 ± 1 yr; 8.71 ± 0.91 kg body weight (BW)] were used in a replicated 3x3 Latin square design (n = 12/group) and fed to maintain BW. In each 42-d experimental period, dogs were allotted to one of three treatments: Control (kibble diet only), Low [kibble diet + 1×109 colony-forming units (CFU) of B. subtilis], and High (kibble diet + 5×109 CFU of B. subtilis). After a 22-d adaptation phase, a 5-d fecal collection phase was followed by a blood collection phase. On d 28, dogs were abruptly changed to a canned diet and fed for 14 d, with fecal samples collected on d 30 (2 d post change), 34 (6 d post change), 38 (10 d post change), and 42 (14 d post change). Fecal microbiota data were evaluated using QIIME2. All other data were analyzed using the Mixed Models procedure of SAS, with P &amp;lt; 0.05 being considered significant. B. subtilis supplementation of the kibble diet did not influence food or energy intake, fecal output, ATTD, most serum metabolites, hematology, fecal characteristics, fecal bacterial alpha and beta diversity indices, and dysbiosis index, demonstrating the safety of the strain in dogs. However, fecal Streptococcus and Blautia abundances were higher in High dogs than Low or Control dogs, while E. coli abundance was less in Low dogs than High and Control dogs. The abrupt change to a canned diet led to significant alterations in fecal characteristics, dysbiosis index, and bacterial abundances, which were not influenced by B. subtilis supplementation. Bacterial alpha diversity measures were affected, with observed ASV (amplicon sequence variants) and the Fisher Index reducing, and the Shannon Index increasing by dietary change. The abrupt dietary change caused a distinct shift in microbial communities, as evidenced by principal coordinates analysis plots. The relative abundances of various fecal bacterial taxa, including Bifidobacterium, Faecalibaculum, Turicibacter, and Lactobacillus were decreased, while Collinsella, Ruminococcus gnavus group, and Escherichia-Shigella were increased with the dietary change. Our data support the notion that daily supplementation of 1 – 5×109 CFU of B. subtilis ATCC PTA-122264 in healthy dogs is safe and does not affect markers of general health and fecal characteristics, warranting further exploration.

401 Effect of protein and starch supplementation level on intake and digestibility by steers consuming low-quality forage: I. Bos 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 organic matter (OM) intake (TDOMI); however, too much starch decreases RAN and pH potentially decreasing forage utilization. Our objective was to determine the effect of starch supplementation on intake and digestion in Bos taurus indicus steers. Accordingly, five ruminally cannulated Brahman steers [body weight (BW) = 420 ± 55 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. Other measures of intake, including forage OM intake (FOMI), total OM intake (TOMI), and total neutral detergent fiber intake (TNDFI) decreased in a cubic manner in response to increasing starch (P ≤ 0.04). Forage OMI also responded with a cubic decrease (72.2, 68.9, and 69.5 g/kg BW0.75) when the protein supplement contained 2, 20, and 38% starch, respectively, but decreased to 61.2 g/kg BW0.75 when the 56% starch supplement was provided. Similarly, TOMI decreased 5.3% when starch inclusion increased from 38 to 56%. Total tract OM digestion and NDF digestion were not significantly affected (P ≥ 0.86) by starch level in the supplement; therefore, despite TOMI and TNDFI decreasing, there was no effect on total digestible OM intake and (TDOMI) and total digestible NDF intake (TDNDFI). In conclusion, providing supplemental starch over 38% decreased forage utilization. Decreases in FOMI with starch inclusion may be attributed to competition for RAN between fiber fermenting and starch fermenting bacteria.

250 Effects of corn processing on growth performance, starch digestibility, and blood metabolites in receiving beef steers

Abstract Corn is the most common grain ingredient fed to feedlot cattle in the U.S. and most corn goes through some processing to increase the energy availability. This study examined the effects of a novel corn processing method on the growth performance, starch digestibility, and blood metabolites of growing steers compared with traditional corn processing methods. Angus-cross steers [n = 218; body weight (BW) = 230 ± 18.5 kg] were sorted into pens of 6 or 7 steers upon arrival and fed a common receiving diet for 2 d prior to being weighed, processed, and starting dietary treatments (n = 12 pens/treatment) on d 0. Treatments included diets with dry rolled corn (ROLL), steam flaked corn (FLAKE), and high shear dry extruded corn (EXT; High-Gel Insta-Pro International, Grimes, IA). Corn was included at 30% DM of a corn silage and SweetBran-based diet. Due to illness concerns, diets were adjusted to reduce corn in the diet to 25% on d 5; in feed antibiotic was fed d 5 to 9, and all calves were weighed and administered Draxxin (1.1 mL/45.45 kg) on d 17. Final BW were collected on d 37 and 38 and serum (glucose, insulin) and fecal samples (total tract starch digestibility) were collected from one steer per pen. Data were analyzed using the Mixed procedure of SAS 9.4 (Cary, NC) with pen as the experimental unit. Treatment did not affect midpoint (d 17) BW or average daily gain (ADG) from d 0 to 17 (P ≥ 0.31). Final BW, ADG, and dry matter intake were not different between treatments (P ≥ 0.15). Feed efficiency (gain:feed) was greatest in EXT (0.261) compared with ROLL (0.232) with FLAKE (0.259) being intermediate and not different from other treatments (P = 0.007). Total tract starch digestibility was determined using the equations from Zinn et al. (2007) and was increased in EXT and FLAKE compared with ROLL (P = 0.0002). Serum glucose and insulin on d 36 were not affected by treatment (P ≥ 0.19). Overall, a growing diet of 25% high shear dry extruded corn increased feed efficiency and total tract starch digestibility over dry rolled corn and resulted in similar performance to steers fed steam flaked corn.

249 Effects of sorghum silage kernel processing on growth performance and blood metabolites of beef heifers

Abstract Our previous studies suggested that using a shredlage (SHRD) processor or a conventional (CONV) sorghum kernel processor leads to similar apparent total tract nutrient digestibility of whole plant sorghum silage (WPSS). This study evaluated the effects of feeding WPSS harvested using different kernel processors (CONV vs. SHRD), on growth performance of beef heifers. Grain sorghum (ADV2450IG; Advanta Seeds, Argentina) was harvested at the hard-dough stage with a Class Jaguar 950 (Harsewinkel, Germany), switching the kernel processor to generate the forage material for the two treatments: CONV and SHRD. The material was bagged in two 2.7 m diameter bags and allowed to ferment for 3 mo. Black Angus heifers [n = 96; body weight (BW) = 15 ± 1 mo, 249.6 ± 28.6 kg] were blocked by initial BW, and randomly assigned to pens (8 heifers/pen, 6 pens/treatment). Diets consisted, all in DM basis, of WPSS of each respective type (SHRD or CONV) at 90.5%, expeller soybean meal at 7.0%, and a vitamin-mineral-NNP concentrate at 2.5%. The experiment consisted of a 14-d adaptation period, followed by a 56-d growing period; and feed was offered once daily. Data were analyzed as a randomized complete block design, using pen as the experimental unit, with the fixed effect of treatment and the random effect of block. No differences were observed (P &amp;gt; 0.10) for final BW, dry matter intake, and residual feed intake. However, CONV fed heifers tended to gain more BW per day (ADG, 0.83 vs. 0.77 kg/d; P = 0.07) and had greater gain to feed ratio (GF, 0.083 vs. 0.075 kg/kg; P = 0.05) and greater Kleiber ratio (KR, 12.1 vs 11.2 g/kg; P = 0.05) as compared with SHRD fed heifers. Furthermore, performance calculated dietary Net Energy of gain (NEg) in CONV fed heifers tended to be greater than that for SHRD (0.70 vs. 0.65 Mcal/kg of diet DM, respectively; P = 0.06). Moreover, blood serum from CONV fed heifers had 16% greater total bilirubin (P = 0.04), 12% greater cholesterol (P = 0.02), and slightly greater non esterified fatty acids (P = 0.03) concentrations. Noteworthy, serum concentrations of total bilirubin were correlated (P ≤ 0.03) with ADG, GF, KR and NEg. In conclusion, the type of kernel processor utilized for the harvest of sorghum silage may have an impact on feed efficiency of beef cattle. These differences could be related to changes on the site of utilization of nutrients, particularly starch; what could also explain the differences on blood metabolites. However, further research is needed to help explain these findings.

290 Effects of chicken-based protein source on apparent total tract macronutrient digestibility, palatability, and fecal characteristics, microbiota, and metabolites of healthy adult dogs

290 Effects of chicken-based protein source on apparent total tract macronutrient digestibility, palatability, and fecal characteristics, microbiota, and metabolites of healthy adult dogs

Effects of Different Defatting Methods of Black Soldier Fly (Hermetia illucens) Larvae Meal on the Metabolic Energy and Nutrient Digestibility in Young Laying Hens.

This study aimed to investigate the effects of different defatting methods of black soldier fly (Hermetia illucens) larvae meal (BSFM) on the metabolic energy and nutrient digestibility in laying hens. Sixty young laying hens (Hy-Line W-36) aged 63 days were randomly divided into two groups (G1 and G2), each with five replicates of six hens housed in individual cages. Group G1 was fed 25% pressed black soldier fly meal (BSFMp) and 75% basal diet, and Group G2 was fed 25% extracted black soldier fly meal (BSFMe) and a 75% basal diet. Both diets included 5 g/kg chromium oxide as an external marker. A 7-day preliminary trial was followed by a 4-day experimental period. The results indicate that pressing and extracting significantly affected the digestibility of crude fat and total energy in BSFM, with BSFMp showing significantly higher crude fat digestibility than BSFMe. Similarly, total energy digestibility was also significantly higher in BSFMp. However, there were no significant differences in dry matter, organic matter, and crude protein digestibility between the two processing methods. The apparent metabolic energy values of BSFMp and BSFMe were 16.34 and 12.41 MJ/kg, respectively, showing a significant difference. The nitrogen-corrected metabolic energy values were 15.89 MJ/kg in BSFMp and 11.93 MJ/kg in BSFMe, indicating a highly significant difference. The digestibility of arginine and leucine in BSFMp was significantly higher than in BSFMe, while differences in lysine, cystine, threonine, tryptophan, and isoleucine were not significant. In conclusion, both defatting methods of BSFM had no adverse effects on the metabolic energy and nutrient digestibility in young laying hens, but BSFMp demonstrated better effects on the digestibility of metabolic energy and nutrients in the feed for young laying hens.

Digestive characterization and its relationship with digestibility, performance traits of local breed Mexican Cuino mini-pigs

The effect of sex on the characteristics of the digestive tract and its relationship with the apparent total tract digestibility (ATTD) and performance traits was studied in 14 Mexican Cuino (MC) mini-pigs averaging 57.2 ± 8.1 kg, fed ad libitum a diet based on sorghum and soybean meal. Nitrogen ATTD was significantly better in females than in castrated male pigs. A trend was found for the relative weight of the entire digestive tract to be heavier in castrated males than in female pigs. Large intestine contribution to total digestive tract weight was relatively high in both sexes, 48.7 and 50.8%, respectively, for castrated males and females. A significant, though not strong relationship between large intestine relative weight and ATTD of dry matter (DM) was observed. These results indicate that sex would appear to be a factor influencing digestive processes in MC mini-pigs.

Fermented total mixed ration enhances nutrient digestibility and modulates the milk components and fecal microbial community in lactating Holstein dairy cows.

Fermented total mixed ration (FTMR) is an effective method of preserving high-moisture byproducts with higher aerobic stability after fermentation. FTMR has the potential to fulfill the daily nutritional requirements of cattle and enhance their production performance. The objective of this research was to examine the influence of FTMR on lactation performance, total tract apparent digestibility, fecal microbiota communities, and fermentation profiles in lactating dairy cows. A total of 12 cows were randomly assigned into two groups: the TMR group and the FTMR group. The TMR group was fed a total mixed ration (TMR) diet, and the FTMR group was fed an FTMR diet. The FTMR did not impact milk yield in dairy cows despite a decrease in dry matter intake, which increased the efficiency of the feed. In contrast to that in the TMR group, the milk fat content in the FTMR group was greater. The FTMR group showed greater digestibility of neutral detergent fiber (NDF), organic matter (OM), dry matter (DM), crude protein (CP), and acid detergent fiber (ADF) in the total digestive tract than did the TMR group. The FTMR increased the concentration of butyrate in the fecal matter and reduced the pH of the feces. The Chao1, ACE, and Shannon indices of the archaeal community in dairy cow feces were significantly higher in cow fed the FTMR compared to those fed the TMR. LefSe analysis revealed higher levels of Oscillospira, Lactobacillus, Prevotella, and Dehalobacterium in the feces of dairy cows fed the FTMR than in those fed the TMR. However, the abundances of Roseburia, rc4-4, Bulleidia and Sharpea exhibited the opposite trend. The abundances of Halobacteria, Halobacteriales, and Halobacteriaceae, which are biomarkers for distinguishing fecal archaea in the TMR from the FTMR, were substantially greater in the feces of dairy cows that consumed the TMR than in those that consumed the FTMR. Therefore, FTMR can improve the milk fat content, total tract apparent feed digestibility efficiency, and diversity of archaea in the feces. Additionally, this work provides a theoretical basis for the feasibility of FTMR feeding for dairy cows.

Impact of Partial Oil Removal on Energy Content of Distillers Grains Plus Solubles for Finishing Cattle.

Two experiments evaluated the impact of the reduction in the percentage of corn oil remaining in distillers grains plus solubles (DGS) after the ethanol plant de-oiling process or by adding corn oil back to DGS following de-oiling on finishing cattle performance and nutrient digestion. Experiment 1 utilized 320 yearling steers (initial BW = 413 kg; SD = 25 kg) fed in 32 pens (10 steers/pen) and assigned to one of four treatments (n = 8 pens/treatment). The four treatments consisted of a blended DRC:HMC corn control diet (CON), de-oiled modified distillers grains plus solubles included at 40% of diet DM (DODGS), de-oiled modified distillers grains plus solubles included at 38% of diet DM plus 2% added corn oil (DODGS + Oil), and full-fat modified distillers grains plus solubles included at 40% of diet DM (FFDGS). The DODGS product contained 8.9% fat while the FFDGS product contained 11.6% fat. Dry matter intake (DMI) was impacted by treatment (p = 0.01) with steers fed DODGS having the greatest DMI and steers fed CON, DODGS + Oil, and FFDGS having lower DMI. Dietary treatment tended to impact ADG (p = 0.06) with steers fed DODGS and DODGS + Oil having greater gains than CON, with FFDGS being an intermediate. As a result of increased ADG, G:F differed between treatments (p < 0.01) with the greatest feed efficiency observed for steers fed DODGS + Oil and FFDGS. Including MDGS in the diet improved G:F by 6 to 11% compared to feeding DRC:HMC corn blend, with an improvement in G:F of 4.9 and 1.2% for DODGS + Oil and FFDGS, respectively, compared to DODGS. Hot carcass weight was impacted by dietary treatment (HCW; p = 0.05), with DODGS- and DODGS + Oil-fed steers having the heaviest HCW, CON steers having the lightest HCW, and FFDGS being an intermediate. Experiment 2 was a 5 × 4 unbalanced Latin rectangle digestion experiment with four diets, five ruminally cannulated steers, and five periods that utilized the same treatments as Exp. 1. Dietary fat measured 4.2, 6.0, 7.9, and 7.1% for CON, DODGS, DODGS + Oil, and FFDGS, respectively. Intakes of DM, OM, and energy as well as total tract fat digestibility and DE (Mcal/d) were not impacted by dietary treatment (p ≥ 0.46). When corn oil was added back to de-oiled MDGS, there was a negative impact on digestibility of OM (p < 0.01) and NDF (p = 0.07) compared with DODGS, FFDGS, and CON. Partially removing oil from modified distillers grains plus solubles did not significantly impact cattle performance, carcass traits, energy content, or digestibility when MDGS was included at approximately 40% of diet DM.

Handheld Near-Infrared Spectroscopy for Undried Forage Quality Estimation.

This study investigates the efficacy of handheld Near-Infrared Spectroscopy (NIRS) devices for in-field estimation of forage quality using undried samples. The objective is to assess the precision and accuracy of multiple handheld NIRS instruments-NeoSpectra, TrinamiX, and AgroCares-when evaluating key forage quality metrics such as Crude Protein (CP), Neutral Detergent Fiber (aNDF), Acid Detergent Fiber (ADF), Acid Detergent Lignin (ADL), in vitro Total Digestibility (IVTD)and Neutral Detergent Fiber Digestibility (NDFD). Samples were collected from silage bunkers across 111 farms in New York State and scanned using different methods (static, moving, and turntable). The results demonstrate that dynamic scanning patterns (moving and turntable) enhance the predictive accuracy of the models compared to static scans. Fiber constituents (ADF, aNDF) and Crude Protein (CP) show higher robustness and minimal impact from water interference, maintaining similar R2 values as dried samples. Conversely, IVTD, NDFD, and ADL are adversely affected by water content, resulting in lower R2 values. This study underscores the importance of understanding the water effects on undried forage, as water's high absorption bands at 1400 and 1900 nm introduce significant spectral interference. Further investigation into the PLSR loading factors is necessary to mitigate these effects. The findings suggest that, while handheld NIRS devices hold promise for rapid, on-site forage quality assessment, careful consideration of scanning methodology is crucial for accurate prediction models. This research contributes valuable insights for optimizing the use of portable NIRS technology in forage analysis, enhancing feed utilization efficiency, and supporting sustainable dairy farming practices.