Ruminal Ammonia Concentration Research Articles

80 Substitution of dried distiller’s grains with soybean meal on beef cattle diets: Effects on ruminal ammonia and volatile fatty acid concentrations

Abstract The objective of this study was to evaluate the effects of substitution of dried distiller grains with soybean meal on beef cattle diets in ruminal ammonia and volatile fatty acid (VFA) concentrations. Red Angus steers [n = 4; body weight (BW) = 360 ± 9 kg] with ruminal, duodenal, and ileal cannulas, were used in a 4 × 4 latin square. Diets (TMR) consisted of dry-rolled corn (70%), hay (10%), liquid supplement (5%), and test ingredients (15%). Treatments were [dry matter (DM) basis]: 1) 15.0% DDGS (CON); SBM in replacement of 50% of DDGS (SBM50); SBM in replacement of 75% of DDGS (SBM75), and SBM in replacement of 100% of DDGS (SBM100). Each period lasted 18-d, consisting of a 7-d diet adaptation followed by an 11-d collection period. Rumen fluid was collected at -2, 0, 2, 4, 6, 8, 10, and 12 h post-feeding on d 16. Ruminal digesta was strained through two layers of cheesecloth and two 10-mL aliquots of ruminal fluid were collected and stored at −20°C until further analysis of ammonia and VFA concentrations. Data were analyzed as repeated measures using the MIXED procedure of SAS with treatment, sampling time, and their interaction as fixed effects, and animal and period as random effects. No treatment by day interactions (P ≥ 0.84) were observed for ammonia or VFA. Ammonia concentrations were greater (P ≤ 0.01) for SBM75 compared with SBM100 and CON, with intermediate values observed for SBM50 (Table 1). Moreover, ammonia was greater (P ≤ 0.01) at 0h compared with 6, 8, and 12h post-feeding. Acetate was greater (P ≤ 0.01) for SBM75 and SBM100 compared with CON and SBM50. Concentrations of propionate were greatest (P ≤ 0.01) for SBM100 and least for CON, with SBM50 and SBM75 being intermediate. Further, propionate was greater (P ≤ 0.01) at 16h compared with 0 and 2 h post-feeding, with all other times being intermediate. Isobutyrate was less (P ≤ 0.01) for CON than all other treatments, and greater concentrations (P ≤ 0.01) were observed at -2 compared with 14 and 16 h post-feeding. Butyrate was greatest (P ≤ 0.01) in SBM75, followed by CON and SBM50; SBM50 was similar to SBM100. Butyrate concentrations were similar -2 and 0 h post feeding, which were less (P ≤ 0.01) than all other times. Isovalerate was greater (P ≤ 0.01) for CON than SBM50 and SBM75, and similar to SBM100. Valerate was greatest (P ≤ 0.01) for SBM75 and SBM100 followed by SBM 50 and CON which had the least valerate value. Overall, our results show that SBM75 resulted in greater concentrations of ammonia, acetate, propionate, butyrate, isobutyrate, and valerate compared with CON. These data suggest that 75% substitution of DDGS with SBM has the potential to optimize microbial fermentation. To complement these results, we are currently evaluating rumen protein degradation profiles and amino acid flow to small intestine.

PSVI-5 Extruded blend of Nannochloropsis oculata microalgae and flaxseed and its effects on ruminal fermentation and nutrient digestion

Abstract Omega-3 fatty acids are essential nutrients for mammals, and are required for cellular growth and synthesis of numerous cellular signaling molecules. NBO3 Technologies, LLC (Manhattan, KS) has developed an omega-3 supplement consisting of an extruded blend of flaxseed and Nannochloropsis oculata microalgae (GreatOplus; GOP). Our objective was to evaluate effects of GOP on dry matter intake (DMI), water intake (WI), ruminal metabolism, and apparent total tract nutrient disappearance in cannulated Holstein steers (n = 11; initial body weight 586.4 ± 49.7 kg). Treatments consisted of backgrounding diets (40% roughage, 60% concentrate) containing 0% (CON) or 10% GOP (dry basis). Feed and water intake were recorded using an Insentec Roughage and Water monitoring system (Hokofarm Group; Emmeloord, The Netherlands). Steers were utilized in a cross-over design with two 19-d periods. Each period consisted of a 15-d adaptation phase and a 4-d collection phase. Ruminal contents, duodenal digesta, and feces were collected at 8-h intervals for 4 d starting at 1000 h on d 16. The sampling schedule was advanced by 2 h with each subsequent sampling day, thus generating a 24-h profile at 2-h intervals post-feeding over the 4-d sampling phase. Titanium dioxide (15 g) was dispensed directly into the rumen of each steer 15 min before feeding and to estimate apparent ruminal flow and fecal excretion of nutrients. There was a Treatment X Day interaction for DMI (P < 0.001); DMI was greater for steers fed GOP some of the days during the adaptation phase compared with steers fed the control diet, but intakes were similar during the collection phase. Ruminal fluid pH, ruminal ammonia concentration, and WI were not affected by treatment (P > 0.10). As expected, ruminal outflows of total fatty acids (195.6 vs 338.1 g/d for CON and GOP, respectively) and α-linolenic acid (ALA; 1.6 vs 6.3 g/d, respectively) were greater for steers fed GOP compared with steers fed CON (P < 0.05); however, ruminal disappearance (i.e., biohydrogenation) of ALA was extensive, with only 8% and 4.7% of ALA intake exiting the rumen for CON and GOP, respectively. Apparent total tract digestion of organic matter was not impacted by diet (P > 0.20; 78.1 and 76.8% for CON and GOP, respectively). Supplementing an extruded blend of flaxseed and microalgae can effectively increase the amount of α-linolenic acid available for absorption in the small intestine, but overall recovery of dietary α-linolenic acid is relatively low due to extensive biohydrogenation by microbes within the rumen.

Nutritional Performance of Grazing Beef Cattle Supplemented with High-Protein Distillers' Dried Grain.

The objective was to evaluate the effects of including high-protein distillers dried grains (HP-DDG; 430 g/CP) in supplements for beef cattle in an intensive finishing pasture system. Five Nellore bulls with an average body weight (BW) of 413.5 ± 32 kg were distributed in a 5 × 5 Latin square design. The animals were randomly allocated to Marandu palisade grass paddocks (Urochloa brizantha cv. Marandu), with 0.32 ha each. Protein-energy supplements were evaluated and formulated with different replacement levels (0, 250, 500, 750 and 1000 g/kg) of soybean meal (SBM) by HP-DDG. Supplements were offered once a day in the amount of 6.0 kg/animal. Replacing SBM with HP-DDG had no effect (p > 0.10) on the intake of total and pasture DM, OM, CP, NDFap, digestible organic matter (DOM), metabolizable protein and CP:DOM ratio. Total and pasture DM intake averaged 6.07 and 11.54 kg/day, respectively. Replacing SBM with HP-DDG reduces and increases, respectively, the intake of degradable (RDP) and undegradable (RUP) protein in the rumen (p < 0.10) with a consequent linear reduction in ruminal ammonia concentration (RAN), nitrogen excretion in urine and serum N concentration (SUN) (p < 0.10). In supplements offered in the amount of 6.0 kg animal/day, SBM can be completely replaced by HP-DDG.

Impact of dietary supplementation with β-alanine on the rumen microbial crude protein supply, nutrient digestibility and nitrogen retention in beef steers elucidated through sequencing the rumen bacterial community

This study investigated the effects of β-alanine (β-Ala) on rumen fermentation, nutrient digestibility, nitrogen (N) metabolism, plasma biochemical parameters, and rumen bacterial communities in beef steers. Six steers with initial liveweight of 252.8 ± 5.2 kg and 3 treatments of supplementing with 0, 30, or 60 g β-Ala per day to basal diet were allocated in a replicated 3 × 3 Latin square design. Each experimental period was 20 d, of which the first 15 d were for adaptation and the subsequent 5 d were for sampling. The results showed that β-Ala linearly increased the ruminal concentration of microbial crude protein (MCP) (P = 0.005), but it did not affect the ruminal concentrations of ammonia N and total volatile fatty acids (P > 0.10). β-Ala also linearly increased the dry matter (DM) (P = 0.009), organic matter (OM) (P = 0.017) and crude protein (CP) (P = 0.043) digestibility, tended to decrease the acid detergent fiber digestibility (P = 0.077), but it did not affect the neutral detergent fiber digestibility (P = 0.641). β-Ala quadratically increased the relative abundance of ruminal Bacteroidota (P = 0.021) at the phylum level, and increased Prevotella (P = 0.028) and Prevotellaceae_UCG-003 (P = 0.014), and decreased the relative abundance of NK4A214_group (P = 0.009) at the genus level. Feeding steers with β-Ala linearly increased the urinary N (P = 0.006), urea excretions (P = 0.002) and the N retention (P = 0.004), but it did not affect the N utilization efficiency (P = 0.120). β-Ala quadratically increased the plasma concentration of the total antioxidant capacity (P = 0.011) and linearly increased the plasma concentration of insulin-like growth factor-1 (P < 0.001). In summary, dietary supplementation with β-Ala improved the rumen MCP supply and increased the digestibility of DM, OM, CP and the N retention. Further research is necessary to verify the ruminal degradability of β-Ala and to investigate the mechanism of the impact of absorbed β-Ala on the anti-oxidative ability in steers.

Effects of bacterial direct-fed microbial combinations on beef cattle growth performance, feeding behavior, nutrient digestibility, ruminal morphology, and carcass characteristics.

The effects of the dietary inclusion of a mixture of bacterial direct-fed microbial (DFM) on feedlot beef cattle growth performance, carcass characteristics, nutrient digestibility, feeding behavior, and ruminal papillae morphology were evaluated. Crossbred-Angus steers (n = 192; initial body weight (BW) = 409 kg ± 8kg) were blocked by BW and randomly assigned into 48 pens (4 steers/pen and 16 pens/treatment) following a randomized complete block design. A steam-flaked corn-based fishing diet was offered to ad libitum intake once daily for 153 d containing the following treatments: (1) Control (no DFM, lactose carrier only); (2) treat-A (Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus subtilis, and Bacillus licheniformis), at 1:1:1:3 ratio, respectively; totaling 6 × 109 CFU (50mg)/animal-daily minimum; and (3) treat-B, the same DFM combination, but with doses at 1:1:3:1 ratio. Bacterial counts were ~30% greater than the minimum expected. Data were analyzed using the GLIMMIX procedure of SAS, with pen as the experimental unit, the fixed effect of treatment, and the random effect of BW-block, while preplanned contrasts comparing Control × treat-A or treat-B were used. Steers offered treat-A had increased carcass-adjusted average daily gain (P = 0.03) by 6.7%, gain efficiency (P < 0.01) by 6%, tended (P = 0.07) to have increased carcass-adjusted final BW by 15kg, and hot carcass weight (P = 0.07) by 10kg, while treat-B did not differ (P ≥ 0.17) from control. Overall dry matter (DM) intake (P = 0.36) and other carcass traits (P ≥ 0.13) were not affected by treatments. Steers offered treat-A tended to have increased digestibility of DM (P = 0.07) by 3%, neutral detergent fiber (P = 0.10), and hemicellulose (P = 0.08) by 9% compared with control, while treat-B did not differ (P ≥ 0.10) from control. No treatment × period interactions (P ≥ 0.21) or main effects of treatment (P ≥ 0.12) were observed during 24-h feeding behavior. Steers ruminated, ate, chewed, and were more active (P ≤ 0.01) during the second behavioral assessment (day 113), while drinking behavior was not affected (P ≥ 0.88). Ruminal papillae morphology and ruminal ammonia concentration (ruminal fluid collected at slaughter facility) were not affected by treatment (P ≥ 0.39). Steers offered the DFM treat-A had improved growth performance and it positively affected carcass weight and nutrient digestion. The DFM combinations did not seem to affect feedlot cattle feeding behavior or ruminal papillae morphology.

Effect of wheat middling incorporation into wet corn distillers grains with solubles on apparent diet digestibility and ruminal fermentation characteristics in growing and finishing diets.

Two separate cross-over experiments were conducted to evaluate the effects of incorporating wheat middlings into wet corn distillers grains with solubles (WDGS) on apparent diet digestibility and ruminal fermentation characteristics in growing and finishing diets. In experiment 1, four ruminally cannulated heifers (313 ± 42.9kg) were limit fed a high-energy growing diet that included WDGS (CON) or WDGS + wheat middlings (CON + WM) at 40% of diet dry matter (DM). The diet also contained (DM basis) 39.5% dry-rolled corn, 7.5% supplement, and 13% warm-season grass hay. In experiment 2, four ruminally cannulated Holstein steers (321 ± 17.4kg) were fed a finishing diet that included WDGS (CON) or WDGS + wheat middlings (CON + WM) at 30% of diet DM. The diet also contained (DM basis) 60.3% dry-rolled corn, 2.7% supplement, and 7.0% warm-season grass hay. Experiments consisted of two 15-d periods that were conducted concurrently. Each period included 10 d of diet adaptation, 4 d of fecal collection, and 1 d of ruminal fluid collection. Fecal samples were collected on days 11 to 14 of each period and composite samples were analyzed for chromium to estimate apparent diet digestibility. On day 15, ruminal fluid samples were collected prior to feeding and again at 2, 4, 6, 8, 12, 18, and 24-h post-feeding. In experiment 1, DM, organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) intake did not differ (P ≥ 0.11) between diets; however, starch intake was greater (P = 0.03) for heifers fed CON + WM compared with CON. Apparent DM, OM, NDF, and starch digestibilities were similar between diets (P ≥ 0.13), but feeding CON + WM tended to lead to lesser (P = 0.06) apparent ADF digestibility. Ruminal pH and total volatile fatty acid concentrations did not differ between diets (P ≥ 0.16); however, ruminal ammonia concentrations tended to be less (P = 0.09) for CON + WM compared with CON. In experiment 2, DM intake did not differ (P = 0.65) between diets. Apparent DM digestibility was greater (P = 0.01) for CON + WM compared with CON but the difference was small. Intake and apparent digestibility of OM, NDF, ADF, and starch did not differ (P ≥ 0.25) between diets. Ruminal ammonia concentrations were lesser (P = 0.03) while ruminal pH was greater (P = 0.02) for CON + WM compared with CON. Overall, incorporation of wheat middlings into WDGS had minimal impacts on feed intake, apparent diet digestibility, and ruminal fermentation characteristics when fed to growing and finishing cattle.

Influence of the concentration and nature of total dissolved solids in brackish groundwater on water intake, nutrient utilization, energy metabolism, ruminal fermentation, and blood constituents in different breeds of mature goats and sheep

Brackish water is being progressively utilized in livestock farming across the globe where freshwater is scarce, potentially leading to detrimental consequences for animal health and performance. This study was conducted to determine effects of different brackish groundwater types on water and feed intake, nutrient utilization, ruminal fluid characteristics, and blood constituent concentrations in different breeds of goats and sheep in a 6 (animal types; AT) × 6 (water treatments; WT) Latin square design. Six AT (Boer, Spanish, and Tennessee Stiff-Leg does and Dorper, Katahdin, and St. Croix ewes) consumed drinking water differing in total dissolved solids (TDS) and mineral composition. Six WT were fresh water (FRW; 287 mg TDS/kg), a natural brackish water (BR) alone (100-BR; 5734 mg TDS/kg), BR with concentrations of all minerals increased by about 100 % (200-BR; 10,603 mg TDS/kg), FRW added with NaCl having similar TDS level (6654 mg/kg) as 100-BR (100-SL), FRW added with NaCl having similar TDS (12,197 mg/kg) as 200-BR (200-SL), and water with similar TDS (10,643 mg/kg) level as 200-BR by adding NaCl to 100-BR (200-BR/SL). Water treatment only affected (P < 0.05) water intake, total volatile fatty acids in ruminal fluid, blood phosphorus, blood aldosterone, and plasma osmolality. Water intake was greater (P < 0.05), but total ruminal volatile fatty acid concentrations were lower (P < 0.05) for 200-SL than other WT. Plasma osmolality and aldosterone concentrations were lower (P < 0.05) for 200-SL and 200-BR/SL than FRW. There were no significant interactions between WT and AT for any variable. Water and feed intake, digestibilities, ruminal ammonia concentration, and methane emission were similar among AT (P > 0.05). There were differences (P < 0.05) among AT for many ruminal fermentation and blood characteristics. Although there were some differences among WT, no AT seemed adversely affected by water with a TDS level near or slightly above 10,000 mg/kg regardless of mineral sources.

Digestibility of western Canadian finishing beef cattle diets when short-season, high-moisture shelled corn and snaplage partially replace dry-rolled barley grain and barley silage

The objective of this study was to determine the effects of substituting barley grain with short-season, high-moisture shelled corn, and barley grain and barley silage with snaplage on ruminal fermentation and the site and extent of digestion in beef cattle fed finishing diets. Six ruminally and duodenally cannulated heifers (420 ± 16.4 kg body weight) were fed a barley grain and silage finishing diet (BG), a diet where half of the barley grain was replaced with high-moisture shelled corn (HC), or a diet where the barley silage and a portion of grain were replaced with snaplage (SN) in a replicated 3 × 3 Latin square design. While dry matter and starch intake were unaffected, feeding SN resulted in greater ( P = 0.02) ruminal but not total tract starch digestibility than BG. Ruminal pH did not differ between HC and BG, but SN reduced ( P = 0.02) minimum ruminal pH relative to BG. Feeding BG increased ( P = 0.04) ruminal ammonia concentrations over HC. In conclusion, high-moisture shelled corn can partially replace barley grain with minimal impact on nutrient digestibility or ruminal fermentation, but replacement of barley silage and some barley grain with snaplage may increase the risk of ruminal acidosis.

Nutrient utilization and ingestive behavior by lambs fed a partial mixed ration consisting of different carbohydrate sources combined with fresh alfalfa

The objective of the current study was to evaluate the nutrient utilization by lambs fed partial mixed ration (PMR) containing either cereal grain or fibrous by-products as an energy source complemented with fresh alfalfa. Eighteen male Corriedale × Ile-de France lambs (32.2 ± 1.82 kg body weight and 4 months old) fitted with permanent rumen catheters were individually housed in metabolism cages and randomly assigned to the treatments (diets): FF, fresh alfalfa ad libitum; PMR-C, PMR containing cereal grains plus fresh alfalfa or PMR-F, PMR containing fibrous by-products plus fresh alfalfa. The amount of PMR offered corresponded to 75% of the potential total dry matter intake of lambs, in two equal meals daily (i.e. morning and afternoon) whereas fresh alfalfa was offered ad libitum from 10:00 to 18:00 h The inclusion of PMR, independently of the energy source, increased the nutrient intake and digestibility of lambs and reduced daily eating time. The ruminal fluid of lambs fed either PMR showed lower pH, higher propionate and butyrate concentration, and lower NH3 concentration compared to lambs fed only alfalfa (P < 0.01). Lambs fed PMR-F showed lower digestibility of N compounds and ruminal ammonia concentration compared to lambs fed PMR-C (P < 0.01). We concluded that offering PMR combined with fresh alfalfa to lambs had positive effects on nutrient intake, regardless of whether the energy source in PMR was starch or fibers.

Effect of replacing cottonseed meal with canola meal on growth performance, blood metabolites, thyroid function, and ruminal parameters of growing lambs

The objective was to clarify the impact of replacing cottonseed meal with canola meal (CM) on growth performance, blood metabolites, thyroxin function, and ruminal parameters of growing lambs. Twenty-four growing Barki male lambs (4–5 months of age) were assigned randomly into four equal groups (6 lambs each). Four dietary treatments were the control group with 0% CM (CON) and three experimental groups where CM replaced 25% (CN1), 50% (CN2), and 75% (CN3) of cottonseed meal. There were no dietary effects (P > 0.05) on the lambs’ feed intake, average daily gain, and feed conversion ratio of the lambs. The dietary CM linearly decreased the concentrations of serum total proteins (P = 0.003), albumin (P = 0.010), globulin (P = 0.011), AST (P = 0.041), and urea (P = 0.001) in growing lambs. The levels of ALT and creatinine, however, were not significantly affected by dietary treatments (P > 0.05). Furthermore, serum triiodothyronine, thyroxine, and electrolyte concentrations were similar (P > 0.05) in different dietary groups. Dietary treatments significantly affected the values of ruminal pH and ammonia at 0 h (P = 0.003 and 0.048, respectively) and 3 h (P = 0.033 and P = 0.006, respectively) postfeeding. The CN3 group showed significantly higher concentrations of ruminal ammonia at 0 and 3 h postfeeding. Furthermore, dietary CM (CN3) significantly reduced the ruminal pH values at 0 and 3 h postfeeding. Meanwhile, dietary treatments did not affect the concentration of total VFAs in the ruminal fluid. In conclusion, CM can replace the cottonseed meal (up to 75%) in lamb diets without compromising their growth performance, thyroid function, and ruminal fermentation parameters.

Utilization of tannin from chestnut as a protective agent in slow release urea: An in vitro rumen fermentation study

Urea has been utilized as a non-protein nitrogen supplement for ruminants due to its affordable price, abundantly available, easy to use, and positively affect microbial protein synthesis in the rumen. However, urea have a weakness since it is rapidly converted into ammonia in the rumen and may lead to nitrogen loss and even ammonia toxicity. Development of a slow release urea (SRU) is therefore important in order to overcome such potential negative impacts. This experiment was conducted to evaluate the effects of SRU, made by complexing the urea with tannin from chestnut, on in vitro rumen fermentation parameters. The treatments were the addition of different forms and levels of urea into a basal diet, i.e., 1% conventional urea (T0), 1% SRU (T1), 2% SRU (T2), and 3% SRU (T3). Data were analyzed by using analysis of variance and continued with a post-hoc test namely the Tukey’s test. Results revealed that the SRU treatments (T1-T3) reduced (P<0.05) ruminal ammonia concentration at various time point intervals than that of the conventional urea (T0). However, the SRU did not alter microbial protein synthesis and nutrient digestibility. In conclusion, SRU made from tannin is an effective supplement for enhancing nitrogen utilization in the rumen.

Supplementation of graded levels of rumen-protected choline to a pelleted total mixed ration did not improve the growth and slaughter performance of fattening lambs.

Choline is an essential nutrient in ruminant diets, which contributes to the fundamental biological functions of the animal. However, choline is easily degraded in the rumen before it can be absorbed. Rumen-protected choline (RPC) supplementation might support the fast growth of ruminants. This study aimed to investigate the effects of supplementing graded levels of RPC in a pelleted total mixed ration for fattening lambs. Sixty three-month-old male Small Tail Han and northeast fine wool sheep hybrid lambs with a liveweight of 15.3 ± 1.8 kg (mean ± SD) were fed designated diets and randomly assigned into five treatment groups (n = 12 per group). The five treatments were the rate of RPC supplementation at 0, 1.25, 2.50, 3.75, and 5.00 g (equivalent to 0, 0.31, 0.63, 0.94, and 1.25 g of choline chloride, respectively)/kg basal diet and the RPC-supplemented feed was offered for 112 days after 12 days of adaptation. Average daily gain, dry matter intake, and nutrient digestibility were similar across treatments. The rumen pH was quadratically significant among treatments, with the lowest and highest pH observed from the 2.5 and 5 g/kg RPC supplement groups, respectively (P = 0.02). After feeding, the ruminal ammonia concentrations among treatments were different (P < 0.05), with the highest value observed from the 5 g/kg RPC supplement group. Microbial crude protein level was different, with the highest value recorded from the 0 g/kg RPC supplement group (P = 0.028). A linear effect (P < 0.05) was observed from short-chain fatty acid values among treatments before and after feeding. Serum albumin (P = 0.003) and albumin/globulin ratio (P = 0.002) had a quadratic effect, with the highest value found in the 0 g/kg RPC supplement group. Abdominal fat was higher in RPC-supplemented groups (P < 0.05) compared to the control group. Drip loss was 65% higher in RPC-supplemented groups compared to the control group (P = 0.012). Overall, the study results showed an effect of RPC on ruminal parameters, but the supplementation of low-level RPC did not improve the growth and slaughter performance of fattening lambs.

Association of virginiamycin and multiple supplement for cattle fed a high-quality tropical forage

The aim of this study was to evaluate the effect of adding virginiamycin to either mineral mixture or multiple supplement on intake, digestion, ruminal fermentation profile, rumen microbial production, blood metabolites, and liver metabolism of zebu heifers fed a high-quality tropical forage. Eight Brahman heifers were assigned to a replicated 4 × 4 Latin Square design. The treatments were: mineral mixture, mineral mixture with virginiamycin, multiple supplement, and multiple supplement with virginiamycin. The basal diet consisted of a high-quality Tifton 85 hay (Cynodom sp.) chopped at 10-cm particle size and fed twice daily. The mineral mixture was provided daily at 120 g/animal. The multiple supplement was formulated to provide 300 g of crude protein (CP)/kg as fed, contained mineral mixture, corn grain, and urea: ammonium sulfate, and was daily provided at 200 g/animal. The mineral mixture and multiple supplement provided the same daily amount of minerals. The amount of supplemental virginiamycin was based on a maximum theoretical response on animal performance (50 mg/100 kg body weight) and daily mixed to the supplements types. The treatments were compared according to a 2 × 2 factorial arrangement (mineral mixture and multiple supplement, with or without virginiamycin). The virginiamycin supplementation did not alter either voluntary intake or digestibility (P≥0.44). Using the multiple supplement decreased forage (P&amp;lt;0.05) and digested organic matter (DOM, P&amp;lt;0.10) intake, but increased dietary CP : DOM ratio (P&amp;lt;0.01). The multiple supplement increased the ruminal ammonia concentration (P&amp;lt;0.04) and the acetate-to-propionate ratio (P&amp;lt;0.06). Virginiamycin increased urinary nitrogen (N) when provided along with multiple supplement (P&amp;lt;0.05). Fecal N was decreased by multiple supplement (P&amp;lt;0.06). Despite these effects, no effect was verified on either body N accretion (P≥0.48) or microbial N production in the rumen (P≥0.27). Virginiamycin decreased the blood IGF-1 (P&amp;lt;0.07). The hepatic gene expression for propionyl-CoA carboxylase was increased by virginiamycin (P&amp;lt;0.01). Virginiamycin increased the hepatic gene expression of both citrate synthase and pyrivate carboxylase when mineral mixture was provided (P&amp;lt;0.01), but decreased it when animals were fed multiple supplement (P&amp;lt;0.04). Using a low-intake multiple supplement with a high CP content for cattle fed high-quality forage causes a substitutive effect on forage intake, but keeps nitrogen accretion unchanged. That pattern indicates an improvement in feed efficiency. On the other hand, virginiamycin supplementation seems to cause some post-prandial influences, which may vary according to the type of supplement. Those influences apparently improve animal efficiency.

Nutrient digestibility, rumen parameters, and (cannabinoid) residues in sheep fed a pelleted diet containing green hemp (Cannabis sativa L.) biomass.

The feeding value for ruminants of green hemp biomass, from the low Δ9-tetrahydrocannabinol (Δ9-THC) variety of Cannabis sativa L., is unknown. Twelve Merino ewes were individually penned and randomly allocated on a stratified liveweight basis to one of two pelleted dietary treatments, control (0% hemp, n = 6) or hemp (42% green hemp biomass, n = 6) that delivered a diet meeting the nutrient requirements of the animals. The experimental period consisted of 17 d dietary and housing adaptation, followed by 7 d total urine and feces collection for determination of apparent nutrient digestibility. A ruminal fluid sample was collected on day 27 and assessed for pH, ammonia, volatile fatty acid (VFA), and cannabinoid concentrations. A blood sample from the jugular vein and incisional subcutaneous fat biopsy from an area around the base of the tail were collected on day 28 with additional fat biopsies taken 35 d and 140 d post-feeding to measure cannabinoids. The dry matter (DM), organic matter (OM), and crude protein (CP) digestibilities, along with total VFA concentration did not differ (P = 0.713) between the two diets; however, acid detergent fiber (ADF) and neutral detergent fiber (NDF) digestibilities (P < 0.001), water intake (P = 0.023), and fecal water output (P < 0.001) were significantly lower for the sheep-fed Hemp. Rumen pH did not vary (P = 0.256) between diets, but ruminal ammonia concentration was significantly lower (P = 0.024) for sheep consuming Hemp. Sheep-fed Hemp had significantly greater molar proportions of butyric (P = 0.039) and hexanoic (P = 0.012) acids and lower molar proportions of propionic acid (P = 0.003). There were no differences between diets for N intake (P = 0.175), fecal N output (P = 0.253), and N balance (P = 0.695), with all sheep in positive N balance; however, there was significantly lower (P = 0.001) urinary N output for sheep-fed Hemp. Cannabidiolic acid (CBDA) and tetrahydrocannabinolic acid (THCA) were detected in plasma of all sheep-fed Hemp. ∆9-tetrahydrocannabinol was present in the subcutaneous fat of four of the six sheep on the final day of being fed Hemp, and in all (six) sheep 35 d post-feeding and one sheep 140 d post-feeding Hemp. No cannabinoids were detected in the corresponding samples taken from the sheep-fed Control. Thus, despite green hemp biomass being nutritionally a suitable feed for ruminants, under current Food Standards in Australia, the presence of these cannabinoid residues restricts its use in ruminant diets.

Effect of live yeast supplementation on energy partitioning and ruminal fermentation characteristics of steers fed a grower-type diet in heat-stress conditions.

The objective of this trial was to determine the influence of live yeast supplementation (LY), environmental condition (ENV), and their interaction (TRT) on energy partitioning, nitrogen metabolism, and ruminal fermentation dynamics of steers receiving a grower-type diet. The effects of LY and ENV were investigated using a 2 × 2 crossover design that spanned five periods. Eight Angus-crossbred steers were randomly split into pairs and housed in four outdoor pens outfitted with an individualized feeding system. Animals were limit-fed a grower diet (DIET) at 1.2% shrunk body weight (SBW) with no live yeast supplementation (NOY) or a grower diet top-dressed with 10 g LY/d for 14 d (1.2 × 1012 CFU/d). On days 13 and 14, animals were subjected to one of two ENV conditions, thermoneutral (TN; 18.4 ± 1.1 °C, 57.6 ± 2.8% relative humidity [RH]) or heat stress (HS; 33.8 ± 0.6 °C, 55.7 ± 2.7% RH), in two side-by-side, single-stall open-circuit, indirect respiration calorimetry chambers. Data were analyzed using a random coefficients model. Carryover effects were examined and removed from the model if not significant. Gross (GE), digestible, metabolizable, heat, and retained energies were not influenced by DIET, ENV, or TRT (P ≥ 0.202). Gaseous energy, as a percentage of GE, tended to increase during HS (P = 0.097). The only carryover effect in the study was for oxygen consumption (P = 0.031), which could be attributed to the tendency of NOY (P = 0.068) to have greater oxygen consumption. DIET, ENV, or TRT (P ≥ 0.154) had no effects on total animal methane or carbon dioxide emissions. Similarly, DIET, ENV, or TRT (P ≥ 0.157) did not affect ruminal pH, redox, protozoa enumeration, ruminal ammonia concentrations, and acetate-to-propionate ratio. Propionate concentrations were the greatest in animals in TN conditions receiving LY (P = 0.034) compared to the other TRT. This effect is mirrored by TN-LY tending to have greater acetate concentrations (P = 0.076) and total VFA concentrations (P = 0.065). Butyrate concentrations tended to be greater for animals fed LY (P = 0.09). There was a tendency for LY to have elevated numbers of Fusobacterium necrophorum (P = 0.053). Although this study lacked effects of LY on energy partitioning, nitrogen metabolism, and some ruminal parameters during HS, further research should be completed to understand if LY is a plausible mitigation technique to enhance beef animals' performance in tropical and sub-tropical regions of the world.

345 Evaluation of the Effects of Hempseed Cake on Ruminal Fermentation Parameters, Nutrient Digestibility, Nutrient Flow, and Nitrogen Balance in Finishing Steers

Abstract There is interest in feeding industrial hemp production byproducts to livestock, but little is known about the digestibility and ruminal fermentation parameters associated with this feedstuff. A nutrient balance experiment using crossbred steers (n = 5; initial BW = 542 kg, SD = 40 kg) in a Youden square design was conducted to evaluate the effects of feeding hempseed cake (HEMP) or dried corn distillers grains plus solubles [DDGS; each included at 20% of diet dry matter (DM) in respective treatments] in comparison with a dry-rolled corn-based negative control treatment (CON) on ruminal fermentation parameters, nutrient digestibility, nutrient flow and nitrogen (N) balance. Organic matter (OM) tended (P = 0.07) to increase and OM total tract apparent digestibility decreased (P = 0.03) in steers fed the HEMP diet compared with steers fed the DDGS and CON diets. Total tract apparent N digestibility was greatest (P &amp;lt; 0.01) in steers fed the HEMP diet, while total tract apparent digestibility in all other nutrients was not influenced (P ≥ 0.13) by treatment. Furthermore, apparent ruminal digestibility of OM was greatest (P &amp;lt; 0.01) in steers fed the HEMP or CON diets, and neutral detergent fiber, acid detergent fiber (ADF), and true ruminal digestibility of N was greatest (P ≤ 0.04) in steers fed the HEMP diet. Ruminal total amino acid degradation and total ruminal VFA concentration was greatest (P &amp;lt; 0.01) in steers fed the HEMP diet. A treatment by hour interaction (P = 0.01) was observed for ruminal ammonia concentration. Nitrogen retention was greatest (P &amp;lt; 0.01) in steers fed the HEMP diet, suggesting that feeding hempseed cake improved utilization of N. These results suggest that although ruminal digestibility of all nutrients is greater in steers fed the HEMP diet, greater ADF concentration in hempseed cake negatively influences total tract apparent OM digestibility when fed to finishing steers.

Intake, digestibility, and rumen fermentation by lactating beef cows offered bermudagrass hay with different sources of dried distillers grains

Supplements of protein co-products, such as dried distillers grains with solubles (DDGS), are often offered to lactating beef cattle consuming bermudagrass [ Cynodon dactylon (L.) Pers.]. The quality of DDGS can vary greatly by source, including levels of ADIN, which could influence hay intake and digestibility. The aim of the experiment was to evaluate bermudagrass hay intake, digestibility, and in situ forage disappearance for lactating beef cows consuming DDGS from different sources and ADIN levels. Four 8-yr-old multiparous, ruminally cannulated lactating beef cows (535 ± 6.3 kg) were offered each of 4 diets during 1 of the 4 periods in a 4 × 4 Latin square design. Diets consisted of bermudagrass hay (17.7% CP) without supplement (CON) or with supplementation with 0.45% of BW (DM basis) from either DDGS source 1 (DG1; 29.7% ADIN), DDGS source 2 (DG2; 31.2% ADIN), or DG2 that was heated (HDG2; 41.3% ADIN). Hay and NDF intake (g/kg of BW) were greater ( P = 0.04) from CON compared with DG1 and DG2; HDG2 did not differ from any treatment. Ruminal ammonia concentrations were greater ( P = 0.05) from DG1 and DG2 compared with the CON, and DG1 was greater than HDG2. However, HDG2 did not differ from DG2 or CON. Ruminal acetate ( P = 0.03) and butyrate ( P = 0.01) had diet-by-time interactions, and propionate was less ( P < 0.05) in CON compared with the other diets. The water-soluble fraction for bermudagrass hay was greater ( P = 0.05) from cows offered DG1 compared with DG2 and HDG2 but not different from that of CON cows. Different DDGS sources and ADIN of 41.3% of N did not affect total intake or digestibility of bermudagrass for lactating beef cows.

Effect of Supplementing Grass Silage-Based Diets with Concentrate Carbohydrate Sources with Different Fermentation Profiles on N Metabolism of Beef Heifers Fed to Maintenance

The synchronous supply of energy and nitrogen (N) substrates to the rumen microbes on grass silage (GS)-based diets can potentially lead to reduced levels of N excreted in the urine. The objective of this study was to evaluate the effect of supplementing GS-based diet with carbohydrate sources differing in rumen fermentation profile on N metabolism of beef heifers. Six Belgian Blue × Holstein Friesian cross beef heifers (487 ± 29 kg BW) were used in a 3 × 3 Latin Square design (n = 6). Dietary treatments were: (RB) GS supplemented with rolled barley; (MM) GS supplemented with maize meal and; (SH) GS supplemented with soya hulls offered at 40:60 forage to concentrate ratio on a dry matter (DM) basis, at maintenance feeding (40 g DM/kg BW0.75). Carbohydrate source had no effect on DM, organic matter, or N intake or total N excretion and the amount of N excreted in the urine (p &gt; 0.05). Animals offered MM excreted a higher percentage of N in the faeces and a lower percentage of N in the urine compared to animals offered RB (p &lt; 0.05). There was a time by interaction for ruminal ammonia (NH3) concentrations (p &lt; 0.01). Ruminal NH3 concentrations peaked at 2 h post-feeding for all treatments. At 3 h post-feeding, ruminal NH3 concentrations for the RB treatment remained higher compared to MM and SH treatments. Molar proportions and total ruminal volatile fatty acids were similar among dietary treatments (p &gt; 0.05). Supplementing GS-based diets with different carbohydrate sources had no impact on the total level of N excreted or the amount of N excreted in the urine. However, there was a higher percentage of N excreted in the faeces and a lower percentage of N excreted in the urine when animals were offered MM compared to those offered RB (p &lt; 0.05).

Replacing concentrates with a high-quality hay in the starter feed of dairy calves: II. Effects on the development of chewing and gut fermentation, and selected systemic health variables

Early development of the rumen, rumination, and fermentation is highly important in dairy calves. Yet, common rearing practices with feeding of concentrate-rich starters may jeopardize them because of lacking physically effective fiber (peNDF). The main objective of this study was to establish the influence of the composition of the calf starter feed (only forage with 2 different qualities or concentrate-rich starter diet) on chewing behavior, rumen development, rumen and hindgut fermentation, and selected systemic health and stress variables of dairy calves. The experiment was carried out with 40 newborn Holstein-Friesian calves, randomly assigned to 4 different solid feed treatments: MQH = 100% medium-quality hay (9.4 MJ metabolizable energy, 149 g of crude protein, and 522 g of neutral detergent fiber/kg of dry matter); HQH = 100% high-quality hay (11.2 MJ of metabolizable energy, 210 g of crude protein, 455 g of neutral detergent fiber/kg of dry matter); MQH+C = 30% MQH + 70% starter concentrate; HQH+C = 30% HQH + 70% starter concentrate). All calves were up to 14 wk in the trial and received acidified whole milk ad libitum in the first 4 wk of life, thereafter in reduced quantity until weaning on 12 wk of age. Water and the solid feed treatments were available ad libitum throughout the trial. Chewing activity was measured in wk 4, 6, 10, and 12 using RumiWatch halters. Until wk 3, rumen fluid, feces and blood were sampled weekly, thereafter every 2 wk. Rumen mucosal thickness (RMT) was measured on the same days with rumen fluid samples. Data showed that calves fed the HQH diet consumed more peNDF and this was associated with longer rumination time (591 min/d) and more ruminating boli (709 boli/d) than calves fed concentrate-rich diets (MQH+C: 430 min/d, 518 boli/d; HQH+C: 430 min/d, 541 boli/d), whereas the MQH group was intermediate (539 min/d, 644 boli/d). Ruminal and fecal pH were higher in calves fed only hay (especially MQH) compared with calves with concentrate supplementation. In both hay-fed groups, ruminal and fecal short-chain fatty acids were shifted toward acetate, whereas only the HQH diet increased the butyrate proportion in the ruminal short-chain fatty acids profile. Ruminal ammonia concentration was at a high level only in the first 3 wk and decreased thereafter. Feeding HQH tended to increase ruminal ammonia, likely because of its high crude protein content and ruminal degradability as well as lower assimilation from rumen microbes. The RMT similarly, though nonlinearly, increased in all groups over the course of the experiment. When using RMT as an indicator of rumen development in dairy calves in the practice, our data suggest an RMT of 1.7mm and >2mm at wk 5 and 10 of life, respectively. Feeding did not affect the blood levels of aspartate aminotransferase, gamma glutamyl transferase, glutamate dehydrogenase, and cortisol. In conclusion, feeding high-quality hay, instead of concentrate-rich starter feeds, resulted in improved rumination and ruminal fermentation profile, without affecting ruminal pH and systemic and stress health variables.

Syngenta Enogen Corn Fed as Corn Grain and Corn Silage in Diets Containing Corn Coproducts Did Not Enhance Diet Digestibility in Growing Heifers

Objective: Evaluate the effect of feeding corn grain and corn silage from Enogen corn (EC; Syngenta Seeds, LLC., Downers Grove, IL) or conventional corn (CON) in diets containing either wet distillers grain (WDG; ICM Biofuels, St. Joseph, MO) or Sweet Bran [proprietary wet corn gluten feed (WCGF); Cargill Animal Nutrition, Blair, NE] on intake and digestibility in growing cattle. Study Description: Eight ruminally cannulated crossbred heifers (initial body weight = 816 ± 94 lb) were used in an intake and digestibility study designed as a replicated 4 × 4 Latin square. Four consecutive, 15-day periods consisted of 10 days for diet adaptation, 4 days of fecal sampling, and 1 day of ruminal sampling. Heifers were fed once daily at 10:00 a.m. Chromic oxide (Cr2O3) was used as an external digestion marker to calculate apparent total-tract diet digestibility. Results: Heifers eating EC tended to have greater starch digestibility (P = 0.07) than heifers eating CON. No differences (P > 0.34) in dry matter or fiber digestibilities were observed between corn sources. There were coproduct × hour interactions for concentration of ruminal ammonia (P < 0.01) and two branched chain fatty acids, isobutyrate (P < 0.01) and isovalerate (P < 0.01). In heifers fed WCGF, isobutyrate and isovalerate concentrations reached a peak at 2 hours after feeding, then declined between 2 and 24 hours after feeding. Heifers fed WDG isobutyrate and isovalerate concentrations were greatest at 0 hours after feeding. Differences between concentrations of isobutyrate and isovalerate can be explained by differences in protein digestibility of WCGF and WDG. The Bottom Line: Enogen corn hybrids fed as dry rolled corn and corn silage in diets containing corn coproducts did not result in better diet digestibility compared to conventional corn hybrids, but diets containing WDG may offer better growth performance (Scilacci et al., 2022) for growing cattle due to more ruminally undegradable protein compared to diets containing WCGF.