Influence of BOVAMINE DEFEND Plus on growth performance, carcass characteristics, estimated dry matter digestibility, rumen fermentation characteristics, and immune function in finishing beef steers

One hundred and eighty crossbred beef steers (406.0 ± 2.2 kg) were used to determine the impact of a novel direct-fed microbial (DFM) on growth performance, carcass characteristics, rumen fermentation characteristics, and immune response in finishing beef cattle. Steers were blocked by body weight (BW) and randomly assigned, within block, to 1 of 2 treatments (3 replicates/treatment: 30 steers/replicate). Treatments included: (1) no DFM (control) and (2) DFM supplementation at 50 mg ∙ animal-1 ∙ d-1 (BOVAMINE DEFEND Plus). All steers were fed a high-concentrate finishing diet and individual feed intake was recorded daily via the GrowSafe system. BWs were collected every 28 d. On day 55, 10 steers per pen were injected with ovalbumin (OVA). Jugular blood samples were collected from each steer on days 0, 7, 14, and 21 post injection. On day 112, the same steers were injected again with OVA and intramuscularly with a pig red blood cell solution. Jugular blood samples were collected from each steer on days 0, 7, 14, and 21 post injection. On day 124, rumen fluid was collected from 3 steers per treatment and used to estimate in vitro rumen fermentation characteristics. Equal numbers of steers per treatment were transported to a commercial abattoir on days 145, 167, and 185 of the experiment, harvested, and carcass data were collected. Initial BW was similar across treatments. On days 28 and 55, steers receiving DFM had heavier BW (P < 0.01) compared to controls. The average daily gain was greater in DFM-supplemented steers from days 0 to 28 (P < 0.01) and days 0 to 55 (P < 0.01) of the experiment compared to controls. Overall dry matter intake (DMI) was greater (P < 0.04) and overall feed efficiency was similar in DFM-supplemented steers compared to controls. Dressing percentage (P < 0.02) was greater in steers receiving DFM compared to controls. Antibody titers to injected antigens were similar across treatments. However, red blood cell superoxide dismutase activity was greater (P < 0.05) in DFM-supplemented steers compared to controls. In vitro molar proportions of isobutyric and butyric acid were greater (P < 0.01) and dry matter (DM) digestibility tended (P < 0.07) to be greater in rumen fluid obtained from steers supplemented with DFM. These data suggest that BOVAMINE DEFEND Plus supplementation improves growth performance during the initial period of the finishing phase, increases overall DMI and dressing percentage, and may impact antioxidant status in beef cattle.

The Effects of Long-term Molybdenum Exposure in Drinking Water on Molybdenum Metabolism and Production Performance of Beef Cattle Consuming a High Forage Diet

Fifty-four multiparous beef cows with calves were used to evaluate the effects of Mo source (feed or water) on reproduction, mineral status, and performance over two cow-calf production cycles (553 days). Cows were stratified by age, body weight, liver Cu, and Mo status and were then randomly assigned to one of six treatment groups. Treatments were (1) negative control (NC; basal diet with no supplemental Mo or Cu), (2) positive control (NC + Cu; 3 mg of supplemental Cu/kg DM), (3) NC + 500 µg Mo/L from Na2MoO4·2H2O supplied in drinking water, (4) NC + 1000 µg Mo/L of Na2MoO4·2H2O supplied in drinking water, (5) NC + Mo 1000-water + 3 mg of supplemental Cu/kg DM, and (6) NC + 3.0 mg of supplemental Mo/kg diet DM from Na2MoO4·2H2O. Animals were allowed ad libitum access to both harvested grass hay (DM basis: 6.6% crude protein; 0.15% S, 6.7 mg Cu/kg, 2.4 mg Mo/kg) and water throughout the experiment. Calves were weaned at approximately 6 months of age each year. Dietary Cu concentration below 10.0 mg Cu/kg DM total diet reduced liver and plasma Cu concentrations to values indicative of a marginal Cu deficiency in beef cows. However, no production parameters measured in this experiment were affected by treatment. Results suggest that Mo supplemented in water or feed at the concentrations used in this experiment had minimal impact on Cu status and overall performance.

The effect of breed, sex and oral meloxicam administration on pain biomarkers following hot-iron branding in Hereford and Angus calves

Hot-iron branding uses thermal injury to permanently identify cattle causing painful tissue damage. The primary objective was to examine the physiological and behavioral effects of oral meloxicam (MEL), compared to a control, administered at the time of hot-iron branding in Angus and Hereford steers and heifers. The secondary objectives were to investigate breed and sex effects on pain biomarkers. A total of 70 yearlings, consisting of 35 heifers and 35 steers (Angus, Hereford, or Angus × Hereford), were enrolled in the study. Animals were blocked by sex, randomized across weight, and assigned to receive MEL (1 mg/kg) or a placebo (CON). Biomarkers were assessed for 48 h after branding and included infrared thermography (IRT), mechanical nociceptive threshold (MNT), accelerometry and a visual analog scale (VAS), and serum cortisol and prostaglandin E₂ metabolites (PGEM). Wound healing was assessed for 12 wk. Hair samples to quantify cortisol levels were taken prior to and 30 d post-branding. Responses were analyzed using repeated measures with calf nested in treatment as a random effect, and treatment, time, treatment by time interaction, breed, and sex as fixed effects. There was a treatment by time interaction for PGEM (P < 0.01) with MEL having lower values than CON at 6, 24, and 48 h (MEL: 18.34 ± 3.52, 19.61 ± 3.48, and 22.24 ± 3.48 pg/mL, respectively; CON: 32.57 ± 3.58, 37.00 ± 3.52, and 33.07 ± 3.48 pg/mL; P < 0.01). MEL showed less of a difference in maximum IRT values between the branded (2.27 ± 0.29 °C) and control site (3.15 ± 0.29 °C; P < 0.01). MEL took fewer lying bouts at 0–12 h (4.91 bouts ± 0.56) compared with CON (6.87 bouts ± 0.55; P < 0.01). Compared with Hereford calves, Angus calves exhibited greater serum but lower hair cortisol, greater PGEM, more lying bouts, and less healed wound scores at 3, 4, and 5 wk. Compared with heifers, steers exhibited lower PGEM, lower branding site and ocular IRT, higher MNT, and lower plasma meloxicam levels. Steers spent more time lying, took more lying bouts and had greater VAS pain, and more healed wound scores at 5 wk than heifers. Meloxicam administration at branding reduced branding and control site temperature differences and reduced lying bouts for the first 12 h. Breed and sex effects were observed across many biomarkers. Changes from baseline values for IRT, MNT, lying time, step count, VAS pain, and wound scoring all support that branding cattle is painful.

Hot-iron branding uses thermal injury to permanently identify cattle causing painful tissue damage. The primary objective was to examine the effects of oral meloxicam (MEL), compared with a control, administered at the time of hot-iron branding in Angus and Hereford steers and heifers. The secondary objectives were to investigate breed and sex effects on pain biomarkers. A total of 70 yearlings, consisting of 35 heifers and 35 steers (Angus, Hereford, or Angus × Hereford), were enrolled. Animals were assigned to receive MEL or a placebo. Changes from baseline values for infrared thermography (IRT), mechanical nociceptive threshold, lying time, step count, visual analog scale score, and wound scoring all support that hot-iron branding cattle is painful and investigation into analgesic strategies is needed. MEL administration reduced IRT differences from the branding and control site and reduced lying bouts. Breed and sex effects were observed across a wide range of biomarkers and should be considered in future pain studies. The practicality of administering a nonsteroidal anti-inflammatory drug once at the time of branding is attractive. However, a multimodal approach using a combination of analgesics or longer acting analgesic option warrants further investigation to alleviate pain and discomfort caused by hot-iron branding.

PSIII-14 The influence of dietary barley supplementation on American Wagyu feedlot performance

Eighty-nine American Wagyu steers were used to evaluate the effects of dietary barley supplementation on feedlot performance. We hypothesized that barley supplementation would increase ADG compared to non-supplemented control animals. The experimental design was a randomized complete block design. Steers were blocked by initial body weight (BW) and randomly assigned within block to one of two treatments. Treatments consisted of 1) Control (no supplemental barley) and 2) Control diet + 0.9 kg∙animal-1∙d-1 of supplemental barley. Steers were housed in feedlot pens (all pens contained n = 4 steers/pen with the exception of one Control pen that contained n=5 steers; 11 replicates/treatment; experimental unit = pen) and fed a traditional American Wagyu finishing diet (DM basis: 68.42% DM, 14.33% CP; TDN: 74.76%, NEg: 1.16 Mcal/kg, 5.25% EE) for 270d. The basal diet consisted of grass hay, corn silage, cracked corn grain, soybean meal, corn distillers grain, white salt, ground limestone, and olive byproduct. Diets were fed once daily in the morning and barely was top dressed to the appropriate pens, immediately after the basal diet was delivered. Steers were individually weighed on d -1 and 0, and approximately every 28 days throughout the 270d experiment. Data were analyzed using a mixed effects model (PROC MIXED, SAS) for a completely randomized block design. Initial pen BW was used as a covariate in the statistical analysis of all performance data and significance was determined at P ≤ 0.05. Initial and final BW, ADG, DMI, and feed:gain were similar across treatments. Therefore, under the conditions of this experiment, these data suggest that barley supplementation for 270d to American Wagyu cattle did not impact overall animal performance.

PSXVI-22 The influence of Propionibacteria on in vivo rumen fermentation characteristics and in vitro lactic acid clearance rate in fistulated steers fed moderately high concentrate diets

Six steers fitted with ruminal cannulae were used in a crossover design to examine the impact of direct fed microbial (DFM) supplementation on in vivo rumen fermentation characteristics and in vitro lactic acid clearance. Steers were fed a moderately high concentrate -1∙day-1 of 4.45x 1010 CFU/g of Propionibacteria acidipropionici). Treatments were administered daily, directly into the rumen via the cannula as a single bolus dose at the time of feeding. Rumen contents were sampled two h post-feeding daily and analyzed for short chain fatty acids (SCFA). On d 7 and 14, rumen fluid was collected from all steers and subjected to an in vitro lactic acid clearance challenge. Lactic acid and SCFA concentrations were determined at 3, 6 and 9 h post incubation. After d 14, all cattle received the basal diet for 21 d. On d 22, treatment crossover was implemented and the experiment repeated. Animal was considered the experimental unit and data were analyzed as a crossover design using Proc Mixed in SAS. In vivo propionic acid concentrations were greater (P &lt; 0.05) and total SCFA tended (P &lt; 0.06) to be greater in rumen fluid from steers receiving DFM. D- and total lactic acid concentrations were lesser (P &lt; 0.05) at 3 h post in vitro incubation for steers receiving DFM. D-, L+, and total lactic acid concentrations were similar between treatments at all other timepoints. In vitro propionic acid and total SCFA concentrations were greater (P &lt; 0.05) and acetic acid concentrations lesser (P &lt; 0.05) in steers receiving DFM. These data indicate that the DFM Propionibacteria acidipropionici, alters in vivo and in vitro rumen fermentation characteristics.

PSIV-10 Effects of chronic molybdenum exposure in drinking water or feed on molybdenum and copper status and production performance of gestating and lactating beef cattle consuming a low-quality forage diet

The objective of this experiment was to evaluate the effects of Mo source (feed or water) on performance and mineral status of cows and calves fed a forage-based diet for two years (DM basis: 6.6% CP; 0.14% S, 6.7 mg Cu/kg, 2.4 mg Mo/kg). Fifty-four cow-calf pairs were stratified by cow age, BW, and liver Cu and Mo status, and randomly assigned to one of six treatments. Treatments consisted of: 1) Negative control (NC; no supplemental Mo or Cu); 2) Positive control [PC: NC + Cu (3 mg Cu/kg diet DM from CuSO4·5H2O)]; 3) NC + 500 µg Mo/L from MoNa2O4·2H2O in drinking water (Mo 500-water); 4) NC + 1000 µg Mo/L of MoNa2O4·2H2O in drinking water (Mo 1000-water); 5) Mo 1000-water + 3 mg Cu/kg diet DM from CuSO4·5H2O (Mo 1000-water+Cu); and 6) NC + 3 mg Mo/kg diet DM from MoNa2O4·2H2O (3.0 Mo-diet). Cattle were allowed ad-libitum access to feed, water, and a protein supplement throughout the experiment. During the winter months animals were housed in three replicate pens per treatment and during the summer months animals were housed in separate pastures by treatment where cow and calf feed and water intake could be measured separately. Data were analyzed as a completely randomized block design. Throughout the experiment no signs of molybdenosis were observed. There was a treatment x time (P &lt; 0.01) interaction for cow liver Cu concentrations. Cows not receiving supplemental Cu had lower (P &lt; 0.01) liver Cu concentrations than cows receiving supplemental Cu. Cow and calf performance, calf mineral status, cow liver Mo, and plasma and milk Mo and Cu concentrations were similar across treatments. These data indicate that Mo supplemented in water or feed at concentrations used in this experiment had minimal impact on Cu status and overall animal performance.

PSX-A-12 Late-Breaking: Effects of Renergy™ on ruminal fermentation in steers fed a high-grain diet

Renergy™ is a proprietary blend of organic acids with a proposed mode of action of increasing ruminal propionate production. Little is known about the efficacy of Renergy™ supplementation in modifying ruminal fermentation in beef cattle consuming high-grain diets. Therefore, eight Angus steers (BW 531.7 ± 20.4 kg) fitted with ruminal cannulae were used to determine the effects of Renergy™ on ruminal fermentation characteristics. Steers were fed a high concentrate diet (DM basis: 13.6% CP, 1.38 Mcal/kg NEg, and 2.02 Mcal/kg NEm) with no monensin sodium or tylosin phosphate added to the diet for 30 d prior to the initiation of the experiment. Treatments consisted of control (CON; no supplemental Renergy™) and Renergy (REN) fed at 27.6 g.animal-1.d-1 (n = 4 steers/treatment; experimental unit = animal). Following the 30 d diet adaptation period, dietary treatments were initiated for 28-d. On day 28, rumen fluid was collected at 3 h post feeding and analyzed for VFA, pH, and NH3. Ruminal pH (P = 0.62) and NH3 (P = 0.56) were unaffected by treatment. However, total VFA (P = 0.05) and propionate (P = 0.03) production were increased by Renergy, 13.3% and 25.7% respectively. There was a tendency (P = 0.14) for acetate production to be increased 10.9% in steers supplemented with Renergy™. Butyrate was unaffected (P = 0.51) by treatment. However, isobutyrate production was lower (P &lt; 0.01) in steers receiving Renergy™. Feeding Renergy™ also resulted in 25% less (P = 0.07) L-lactate production. Under conditions of this experiment, results indicate that supplementing Renergy™ for 28d to beef cattle consuming high concentrate diets impacts ruminal fermentation 3 h post feeding.

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PSXVI-23 The influence of trace mineral source on digestion, ruminal fermentation characteristics, and mineral solubility in beef cattle fed a high concentrate feedlot diet

Twelve Angus steers (BW 530.9 ± 22.7kg) fitted with ruminal cannulae were used to determine the impact of trace mineral (TM) source on digestibility and ruminal VFA and soluble concentrations of Cu, Mn, and Zn. Steers were fed a high concentrate diet balanced to meet the requirement of finishing feedlot steers for 21d. Treatments consisted of Cu, Mn, and Zn supplemented at 18, 40, and 90 mg/kg DM, respectively, from either sulfate (STM) or hydroxy trace mineral (HTM) sources (n = 6 steers/treatment; experimental unit = steer). Following a 21-d adaptation period total fecal output was collected for 5 d. Trace mineral sources had no impact on nutrient digestibility. On d 6, rumen fluid was collected at 0, 2, and 4 h post-feeding for VFA analysis. There were no treatment x time interactions for any VFA measured. However, HTM steers had greater (P &lt; 0.05) ruminal molar proportions of propionate and tended (P &lt; 0.07) to have greater molar proportions of valerate compared to STM steers. Steers fed STM had greater (P &lt; 0.05) molar proportions of butyrate compared to HTM steers. Steers were then fed the same high concentrate diet without supplemental Cu, Zn, or Mn for 14 d. On d 15 steers received a pulse dose (via rumen cannula) from either STM or HTM. Ruminal samples were obtained at 2 h intervals starting at -4 and ending at 24 h relative to dosing. There was a treatment x time interaction (P &lt; 0.05) for ruminal soluble Cu concentrations. Ruminal soluble mineral concentrations were greater (P &lt; 0.05) for Cu at 4, 6, 8, and 16 h post-dosing in STM compared to HTM supplemented steers. Results indicate that ruminal solubility of Cu differs between STM and HTM sources and may impact rumen fermentation characteristics.

Trace mineral source impacts rumen trace mineral metabolism and fiber digestion in steers fed a medium-quality grass hay diet

Twelve Angus steers (BW 452.8 ± 6.1 kg) fitted with ruminal cannulae were used to determine the impact of trace mineral (TM) source on digestibility, ruminal volatile fatty acid (VFA) composition, ruminal soluble concentrations of Cu, Zn, and Mn, and relative binding strength of trace minerals located in the rumen insoluble digesta fraction. Steers were fed a medium-quality grass hay diet (DM basis: 10.8% CP, 63.1% neutral detergent fiber [NDF], 6.9 mg Cu/kg, 65.5 mg Mn/kg, and 39.4 mg Zn/kg) supplemented with protein for 21 d. Treatments consisted of either sulfate (STM) or hydroxy (HTM) sources (n = 6 steers/treatment) to provide 20, 40, and 60 mg supplemental Cu, Mn, and Zn/kg DM, respectively. Following a 21-d adaptation period, total fecal output was collected for 5 d. Dry matter (P < 0.07) and CP (P < 0.06) digestibility tended to be reduced, and NDF (P < 0.04) and acid detergent fiber (ADF) (P < 0.05) digestibility were reduced in STM- vs. HTM-supplemented steers. On day 6, ruminal fluid was collected at 0, 2, and 4 h post-feeding and analyzed for VFA. There were no treatment x time interactions for VFA. Steers receiving HTM had less (P < 0.02) molar proportions of butyric acid and greater (P < 0.05) total VFA concentrations than STM-supplemented steers. Steers were then fed the same diet without supplemental Cu, Zn, or Mn for 14 d. On day 15 steers received a pulse dose of 20 mg Cu, 40 mg Mn, and 60 mg Zn/kg DM from either STM or HTM (n = 6 steers/treatment). Ruminal samples were obtained at 2-h intervals starting at -4 and ending at 24 h relative to dosing. There was a treatment x time interaction (P < 0.03) for ruminal soluble Cu, Mn, and Zn concentrations. Ruminal soluble mineral concentrations were greater (P < 0.05) for Cu at 4, 6, 8, 10, 12, and 14 h; for Mn at 4 and 6 h; and for Zn at 4, 6, and 8 h post-dosing in STM compared with HTM-supplemented steers. Copper concentrations were greater (P < 0.05) at 12 and 24 h and Zn concentrations in ruminal solid digesta were greater at 24 h in HTM-supplemented steers. Upon dialysis against Tris-EDTA, the percent Zn released from digesta was greater (P < 0.05) at 12 h (P < 0.03) and 24 h (P < 0.05), and the percent Cu released was greater (P < 0.02) at 24 h post-dosing in HTM steers when compared with STM-supplemented steers. Results indicate that Cu and Zn from HTM have low solubility in the rumen and appear to be less tightly bound to ruminal solid digesta than Cu and Zn from STM. The lower ruminal soluble concentrations of Cu and Zn in steers given HTM were associated with greater fiber digestibility.

Molybdenum Exposure in Drinking Water Vs Feed Impacts Apparent Absorption of Copper Differently in Beef Cattle Consuming a High-Forage Diet

Twelve Angus steers were utilized to investigate the influence of molybdenum (Mo) in drinking water or feed on apparent absorption and retention of copper (Cu) and Mo. Steers were fed a low-quality grass hay diet for 14 days. Steers were then housed in individual metabolism stalls and blocked by body weight and dry matter intake (DMI) and randomly assigned within block to one of three treatments. Treatments consisted of (1) control (no supplemental Mo), (2) 5.0 mg Mo/kg DM from sodium molybdate dihydrate (Mo-diet), and (3) 1.5 mg Mo/L from sodium molybdate dihydrate delivered in the drinking water (Mo-water). Total fecal and urine output were then collected for 5 days. Dry matter, Cu and water intake, and DM digestibility were similar across treatments. Molybdenum intake was greater (P < 0.05) in Mo-water and Mo-diet steers when compared to controls but similar between Mo-water and Mo-diet steers. Apparent absorption and retention of Cu were greater (P < 0.05) in controls when compared to Mo-diet supplemented steers. Apparent absorption and retention of Cu in steers in the Mo-water treatment did not differ from controls or those receiving the Mo-diet. Molybdenum-diet and Mo-water supplemented steers had similar apparent absorption and retention of Cu. Apparent absorption and retention of Mo (% of Mo intake) was greater in controls when compared to Mo-supplemented steers. These data indicate that Mo consumed in water may impact Cu absorption and retention to a lesser extent than Mo supplemented in the diet.

PSVI-12 Effects of polyphenols (mixed tannins) and saponin (Yucca schidigera), with or without a direct fed microbial (DFM) on in vitro rumen fermentation

Rumen fluid from fistulated steers receiving a high concentrate diet was utilized to examine the impact of polyphenols and saponin with or without a direct fed microbial (DFM) on in vitro fermentation characteristics. Treatments consisted of: Control (no polyphenols, saponin or DFM); 2) Polyphenols (Mixed Tannins = 15 g/hd/d); 3) Saponin (Y. schidigera = 2 g/hd/d); 4) Polyphenols + DFM (DFM = 1E+7 Lactobacillus animalis + 1E+8 Propionibacteria acidilactici cfu/hd/d); and 5) Saponin + DFM. Rumen fluid was collected and combined in equal amounts from 3 rumen fistulated steers and mixed at a 1:1 ratio of artificial saliva to rumen fluid. Fermentation substrate consisted of 0.5 g of the high concentrate diet. Fermentation bottles were capped with an air-tight rubber stopper and incubated in a water bath for 12 and 18h (7 replicates/treatment/time point). After incubation, the total volume of gas produced was measured and a subsample analyzed for N, CH4 and CO2 concentrations. After gas sampling, pH, VFA concentrations, and DMD were determined. In vitro fermentation parameters were analyzed using a mixed effects model repeated measures analysis for a completely randomized block design. Acetic acid was decreased while valeric acid was increased (P &lt; 0.05) by the Saponin + DFM treatment vs. Control. At 12h DMD was greater in Saponin, Saponin + DFM and Polyphenols + DFM (P &lt; 0.001) treatments compared to Control or Polyphenols alone. Polyphenols produced greater amounts of CH4 /DMD than all other treatments (P &lt; 0.01). Microbial protein production and efficiency were greater (P &lt; 0.001), Saponin + DFM compared to other treatments. Other fermentation parameters measured were not impacted by treatments. Under the conditions of this experiment these data suggest combining DFM with Saponin or Polyphenols produces different ruminal effects from when they are fed alone.

PSXII-14 The influence of trace minerals source on copper, manganese, and zinc binding strength to rumen digesta in cattle fed a corn silage-based diet

Twelve crossbred steers fitted with rumen cannulae were used to determine the influence of trace mineral (TM) source on relative binding strength of minerals in the ruminal insoluble digesta fraction (IDF). Steers (n = 4/treatment) were fed a corn silage-based diet containing no supplemental Cu, Mn, and Zn for 7d. On d 8, steers received a bolus dose (2 x NRC requirement) of the respective TM from sulfate (STM), organic (ORG; provided as Zn methionine, Mn methionine, and Cu lysine), or hydroxy TM (HTM; Micronutrients USA LLC) sources. Ruminal samples were obtained at 2 h intervals starting at -4 and ending at 24 h post dosing. Ruminal samples were centrifuged and supernatant and the IDF were collected and frozen separately. Binding strength of Cu, Mn, and Zn to the IDF was estimated at 0, 12, and 24 h using dialysis against 0.05 M Tris-EDTA. At 0 h pre-dosing, IDF concentrations of Cu, Mn, and Zn were similar across treatments. At 12 h post dosing Cu and Zn IDF concentrations were greater (P &lt; 0.05) in HTM vs. STM and ORG supplemented steers, and Mn concentrations were greater (P &lt; 0.05) in HTM and ORG vs. STM supplemented steers. At 24 h post dosing, IDF Zn concentrations were greater (P &lt; 0.05) in HTM vs STM and ORG supplemented steers and Cu and Mn concentrations were similar across treatments. At 12 and 24 h post dosing the percent Cu and Zn released following dialysis was greater (P &lt; 0.05) in HTM vs STM and ORG supplemented steers. The percent released of Cu, Mn, and Zn at 0 h, and Mn at 12 and 24 h were similar across treatments. Data indicate that a greater concentration of Cu and Zn from HTM is loosely bound to the ruminal IDF.

PSXII-13 The influence of trace mineral source on copper, manganese, and zinc binding strength to rumen digesta in cattle fed a high forage-based diet

Twelve crossbred Angus steers fitted with rumen cannulae were used to determine the influence of trace mineral source on ruminal soluble mineral concentrations and relative binding strength of trace minerals in the ruminal insoluble digesta fraction. Steers were adjusted to a low-quality hay (chopped) diet balanced to meet the nutrient requirements for growing steers. For 7 d prior to initiation of the study, steers were fed the diet without supplemental Cu, Mn, and Zn. On day 8 steers received a pulse dose (2 x NRC requirement) of Cu, Mn, and, Zn from sulfate (STM) or hydroxy trace minerals (HTM; Micronutrients LLC, USA). Ruminal samples were obtained at 2 h intervals until 24 h post-dosing for soluble (fraction obtained after centrifugation) Cu, Mn, and Zn concentrations. Binding strength of Cu, Mn, and Zn to ruminal solid digesta (post centrifugation) was estimated at 0, 12, and 24h post-dosing using dialysis against 0.05 M Tris-EDTA. Ruminal soluble mineral concentrations were greater (P &lt; 0.05) for Cu at 4, 6, 8, 10, 12, and 16 h; for Mn at 4 and 6 h; and for Zn at 4, 6, and 8 h post dosing in STM compared to HTM steers. Concentration of Cu, Mn, and Zn remaining in the insoluble fraction were greater (P &lt; 0.05) at 12 h post dosing in HTM vs STM supplemented steers. At 24 h post dosing, Mn concentrations were lesser (P &lt; 0.03) and Zn concentrations were greater (P &lt; 0.001) in HTM vs STM supplemented steers. Following dialysis, the % Cu, and Zn released from the insoluble fraction was greater (P &lt; 0.001) at 12 h and 24h in HTM vs. STM supplemented steers. Results indicate that a greater proportion of Cu and Zn HTM remained loosely bound to the insoluble fraction within the rumen.

PSXII-12 The influence of long-term molybdenum supplementation (in drinking water or feed) on beef calf performance through weaning

Fifty-four multiparous beef cows were used to examine the effect of molybdenum (Mo) supplemented in drinking water or feed on offspring performance. Cows were blocked by body weight (BW) and age into one of 6 groups. Group were then randomly assigned to treatment. Treatments consisted of: 1) Control (no supplemental Mo or Cu), 2) Control+Cu (3 mg Cu/kg DM from CuSO4·5H2O added to the basal diet), 3) Control + 500 µg Mo/L from MoNa2O4·2H2O in drinking water (Mo 500-water), 4) Control + 1000 µg Mo/L of MoNa2O4·2H2O in drinking water (Mo 1000-water), 5) Mo 1000-water plus 3 mg Cu/kg DM from CuSO4·5H2O added to the basal diet (Mo 1000-water+Cu, and 6) Control plus 3 mg Mo/kg DM from MoNa2O4·2H2O added to the basal diet (3.0 Mo-diet). Cows were housed in dry lot pens (n = 3 cows/pen; 3 pens/treatment) and fed a low-quality grass hay diet (DM basis: 6.6% CP; 0.14% S, 6.2 mg Cu/kg, 2.3 mg Mo/kg) and a protein supplement (30% CP). Cows received their respective treatments beginning 60 d prior to breeding and remained on treatments until all calves were weaned at approximately 7 mo. of age. Calf birth weights were collected on the day of birth and all calves were weaned on the same day. Data were analyzed using a mixed effects model for a completely randomized block design. Birthweight, ADG, and 205d adjusted weaning weights were similar (P &gt; 0.05) across treatments. These data indicate that Mo supplemented in the drinking water or the diet regardless of the inclusion of additional Cu did not impact calf performance through weaning.

226 Influence of trace mineral source on digestion, ruminal volatile fatty acid and soluble mineral on steers fed a dairy type diet balanced to meet requirements for a high producing lactating dairy cow

Twelve Angus steers (BW 530.9 ± 22.7kg) fitted with ruminal cannulae were used to determine the impact of trace mineral source on digestibility, ruminal VFA, and soluble concentrations of Cu, Zn, and Mn. Steers were fed a dairy type diet balanced to meet requirements for a high producing lactating dairy cow (DM basis: 16.8% CP, 29.2 Mcal NEm, 30.3 Mcal NEl, 33.6% NDF) for 21 d. Treatments consisted of 10 mg Cu, 40 mg Mn, and 60 mg Zn/kg DM from either sulfate (STM), hydroxy (HTM; IntelliBond) or organic (ORG; metal specific amino acid complexes) sources (n=4 steers/treatment). Following a 21-d adaptation period, total fecal output was collected for 5 d. On d 6, rumen fluid was collected at 0, 2, and 4 h post feeding and analyzed for VFA. Steers were then fed the same diet without supplemental Cu, Zn, or Mn for 14 d. On d 15 steers received a pulse dose (cannulae) of 100 mg Cu, 400 mg Mn, and 60 mg Zn from either STM, HTM, or ORG. Ruminal samples were obtained at 2-h intervals starting at -4 and ending at 24 h post dosing and analyzed for soluble Cu, Mn, and Zn. Digestibility of NDF and ADF were lesser (P &lt; 0.05) in STM vs. HTM and ORG supplemented steers. Steers receiving HTM and ORG had greater (P &lt; 0.05) total VFA concentrations than STM supplemented steers at 2 and 4h post feeding. Ruminal soluble Cu and Zn concentrations were greater (P &lt; 0.001) post dosing in STM and ORG supplemented steers at 2, 4, and 6 h for Cu and 4, 6, 8, 10 and 12 h for Zn when compared to HTM supplemented steers. Results indicate that ruminal solubility of Cu and Zn differs between STM, HTM and ORG sources and trace mineral source impacts fiber digestion and ruminal VFA concentrations.

414 The influence of trace mineral source on fiber digestion, rumen fermentation characteristics, and mineral solubility in beef cattle fed a low-quality forage diet

Twelve Angus steers (BW 452.8 ±21.8 kg) fitted with ruminal cannulae were used to determine the impact of trace mineral source on neutral detergent fiber (NDF) digestibility, short chain fatty acid (SCFA) production, and ruminal solubility of Cu, Mn, and Zn. Steers were fed a low-quality grass hay diet (10.8% CP, 63.1% NDF, 6.9 mg Cu/kg, 65.5 mg Mn/kg, and 39.4 mg Zn/kg) supplemented with protein for 21 d. Treatments consisted of 20, 40, and 60 mg supplemental Cu, Mn, and Zn/kg DM, respectively from either sulfate (STM) or hydroxy (HTM) sources (n = 6 steers/treatment). Following a 21-d adaptation period total fecal output was collected for 5 d. Dry matter digestibility tended (P &lt; 0.07) to be reduced (51.9 vs. 53.4 ±0.52%) and NDF digestibility was reduced (P &lt; 0.04; 40.4 vs. 42.7 ±0.67%) in STM vs. HTM steers. On d 6, rumen fluid was collected at 0, 2, and 4h post feeding. Steers receiving HTM had lesser (P &lt; 0.02) butyric acid and greater (P &lt; 0.05) total SCFA than STM steers. Steers were then fed the same grass hay diet without supplemental Cu, Zn, or Mn for 14 d. On d 15 steers received a pulse dose of 20, 40, and 60 mg Cu, Mn, and Zn/kg DM, respectively from either STM or HTM. Ruminal samples were obtained at 2h intervals starting at -4 and ending at 24h relative to dosing. Ruminal soluble mineral concentrations were greater (P &lt; 0.05) for Cu at 4, 6, 8, 10, 12, and 14h; for Mn at 4 and 6h; and for Zn at 4, 6, and 8h post dosing in STM compared to HTM steers. Results indicate that ruminal solubility of Cu, Mn, and Zn differs between STM and HTM sources and rumen Cu, Mn, and Zn solubility may impact ruminal fermentation.