Feeding Monensin Research Articles

105 Effects of Monensin on Intake, Growth Performance, and Health of Newly-Received Feedlot Calves

Abstract Monensin is an ionophore commonly fed to feedlot cattle to increase feed efficiency (gain:feed ratio; G:F) typically by decreasing dry matter intake (DMI) when fed at the commonly adopted dose of 33 mg∙kg DM-1. During the receiving period when intake is often suppressed due to management stressors, feeding monensin to light-weight feedlot calves may be detrimental to DMI and consequently to growth performance. The objective of this experiment was to evaluate the effects of feeding sodium monensin to newly-received feedlot calves. A total of 380 crossbred beef steers [initial body weight (BW) = 231 ± 25 kg and approximately 8 months of age] were sourced from local auctions in Delhi, LA and transported approximately 16 h to Clayton, NM. Upon arrival, steers were processed, blocked by off-truck shrunk BW, randomly assigned to 20 pens (19 animal∙pen-1), and pens were then randomly assigned to one of two dietary treatments (n = 10 pens/treatment): control (CON; no feed additive) or sodium monensin at 170 mg∙animal-1∙day-1 (MON; Rumensin 90; Elanco Animal Health, Greenfield, IN). The basal diet consisted of a complete starter feed composed predominantly of wet corn gluten feed (RAMP; Cargill Sweet Bran, Dalhart, TX). The experiment was 56 days in length. The amount of feed offered to each pen was adjusted based on the DMI of the previous day and bunks were managed to contain trace amounts of feed at 0600 h. Body weight was recorded on days 0, 14, 28, and 56 for average daily gain (ADG) and G:F calculation. Dietary net energy for maintenance (NEm) and gain (NEg) were estimated based on observed growth performance. Daily animal health evaluations were performed using a 4-point scale method based on depression, appetite, respiration, and temperature throughout the experiment. All data were analyzed as a randomized complete block design using SAS with pen serving as the experimental unit. Feeding MON did not affect feed intake (P = 0.58) compared with CON, yet ADG was increased (P < 0.01) by 12.5% in steers fed MON compared with CON. Thus, there was a 10.7% increase (P < 0.01) in G:F for MON, which corresponds with a greater (P = 0.02) observed NEm and NEg for MON compared with CON. Feeding MON tended (P = 0.07) to elicit a 2.9% increase in final BW compared with CON. Additionally, there was no treatment effect (P ≥ 0.57) on morbidity based on the number of therapeutic treatments among calves which were treated for indications of bovine respiratory disease. Moreover, treatments did not affect mortality rate. In summary, feeding monensin at 170 mg∙animal-1∙d-1 (26 mg∙kg DM-1) increases growth performance of light-weight, newly-received feedlot cattle without influencing DMI or animal health.

25 Effect of Cyclic Monensin Feeding onin Situ Degradability of Low-Quality Forage Fed to Ruminally Cannulated Beef Steers

Abstract Effects of cyclic monensin feeding on in situ disappearance kinetics of low-quality forage (LQF; 4.9% CP) were evaluated. Ruminally cannulated steers (n = 12; Bos taurus; 260 kg BW) consuming LQF were randomly assigned to of 3 treatments in a completely randomized design: CON (0 mg∙animal-1∙day-1 monensin; Rumensin 90, Elanco Animal Health, Greenfield, IN), 2) MON (200 mg∙animal-1∙day-1 monensin), or 3) CYC (200 mg∙animal-1∙day-1 monensin for 4 d and 0 mg∙animal-1∙day-1 monensin for subsequent 4 d). Steers were fed dried distillers’ grains with solubles (1 kg∙animal-1∙day-1) for monensin inclusion. Four 28-d replicated cycles were used allowing 9 days for treatment adaptation, 4 days for sampling, and 4 days for withdrawal of monensin within the CYC treatment group. Low-quality forage samples were weighed into 0 × 20 cm polyester bags in replicates of four for each sampling hour. On d 0, all replicates were placed into the ventral area of the rumen and replicates were removed 0, 4, 8,6, 24, 48, and 72 hours post feeding. Upon removal, bags were rinsed in ice water, and frozen until final replicates were removed. Subsequently, bags were washed utilizing a commercial washing machine, dried at 55°C to a constant weight and dried residues were analyzed for DM. Ruminal in situ DM degradation data over time were fitted to the first-order exponential model with discrete lag using the NLIN procedure of SAS 9.4, then model parameters were compared with PROC GLIMMIX model to compare dietary treatments with period included as a random variable. There was no effect of treatment (P ≥ 0.22) on potentially degradable DM, rate of DM degradation, DM residue, DM lag, or wash loss of DM. Results are consistent with findings in the concurrent in vivo study conducted by Hook et al. (2022). Further evaluation of NDF degradability is required to determine a clear effect of cyclic monensin feeding on steers consuming an LQF.

Ruminal fermentation pattern of acidosis-induced cows fed either monensin or polyclonal antibodies preparation against several ruminal bacteria.

This study was designed to evaluate a spray-dried multivalent polyclonal antibody preparation (PAP) against lactate-producing bacteria as an alternative to monensin (MON) to control ruminal acidification. Holstein cows (677 ± 98 kg) fitted with ruminal cannulas were allocated in an incomplete Latin square design with two 20 days period. Cows were randomly assigned to control (CTL), PAP, or MON treatments. For each period, cows were fed a forage diet in the first 5 days (d-5 to d-1), composed of sugarcane, urea and a mineral supplement, followed by a 74% concentrate diet for 15 days (d 0 to d 14). There were no treatment main effects (P > 0.05) on dry matter intake (DMI) and microbial protein synthesis. However, there was a large peak (P < 0.01) of intake on d 0 (18.29 kg), followed by a large decline on d 1 (3.67 kg). From d2, DMI showed an increasing pattern (8.34 kg) and stabilized around d 8 (12.96 kg). Higher mean pH was measured (P < 0.01) in cattle-fed MON (6.06 vs. PAP = 5.89 and CTL = 5.91). The ruminal NH3-N concentration of CTL-fed cows was lower (P < 0.01) compared to those fed MON or PAP. The molar concentration of acetate and lactate was not affected (P > 0.23) by treatments, but feeding MON increased (P = 0.01) propionate during the first 4 days after the challenge. Feeding MON and PAP reduced (P = 0.01) the molar proportion of butyrate. MON was effective in controlling pH and improved ruminal fermentation of acidosis-induced cows. However, PAP was not effective in controlling acidosis. The acidosis induced by the challenge was caused by the accumulation of SCFAs. Therefore, the real conditions for evaluation of this feed additive were not reached in this experiment, since this PAP was proposed to work against lactate-producing bacteria.

Simultaneous determination of some antibiotics with coccidiosis effect in feed by LCMS/MS

Liquid chromatography tandem mass spectrophotometry (LC-MS/MS) has been&amp;nbsp;developed for simultaneous determination of four antibiotics which have coccidiicidal&amp;nbsp;effects including monensin, dimetridazole, sulfadimethoxin, and sulfadimidine in feed&amp;nbsp;samples. The research conducted by using mobile phase A (0.1% formic acid solution; 10 mM&amp;nbsp;ammonium formate) and phase B (MeOH; 0.1% formic acid; 10 mM ammonium formate)&amp;nbsp;with C18 reversed-phase chromatography column (2.1 &amp;times; 1.5 mm, ID 3.5 &amp;mu;m)&amp;nbsp;simultaneously and successfully identified these four antibiotics in a short time about 10&amp;nbsp;minutes. The method detection limits and quantification limits for all analytes were 15.0&amp;nbsp;and 45.0 &amp;micro;g/kg, respectively. The calibration curve of the method was in the range of 45 -&amp;nbsp;1,500 &amp;micro;g/L. The method was validated for high accuracy, efficiency and applied to analyze&amp;nbsp;the feed samples on the Hanoi market.

Combined use of monensin and virginiamycin to improve rumen and liver health and performance of feedlot-finished steers.

Monensin and virginiamycin are included in beef cattle finishing diets as prophylaxis to minimize the incidence of ruminal acidosis and liver abscesses. Due to different and probably complementary modes of action, this study aimed to determine the effects of a combination of monensin and virginiamycin, both included in the diet at recommended doses, on ruminal health, the occurrence of liver abscesses, and growth performance of feedlot-finished cattle. One hundred and forty-four steers (6 animals/pen) were fed 1 of 3 corn-based finishing diets containing 30 mg of monensin (MN), 25 mg of virginiamycin (VM), or 30 and 25 mg of monensin and virginiamycin (MN + VM), respectively, per kilogram of dry matter. Ruminal pH probes were inserted into two animals per pen and set to record pH every 10 min. On d 100, animals were slaughtered, and rumens and livers were recovered, on which occurrence and degree of ruminal damage, prevalence and number of liver abscesses, and liver scores (A-: livers with no more than two small abscesses; A+: livers with at least one large abscess or more than four medium abscesses; A: any other abscessed liver) were determined. Simultaneous inclusion of monensin and virginiamycin resulted in a 4.3% decrease (P < 0.04) in dry matter intake (DMI; 8.8, 9.2, and 9.2 ± 0.19 kg/d for MN + VM, MN, and VM-fed animals, respectively) and similar (P > 0.13) average daily body weight gain (ADG; 1.49 ± 0.021 kg/d) and hot carcass weight (HCW; 269 ± 1.7 kg), compared with feeding diets containing one additive or the other. Therefore, in terms of ADG, a 9.4% improvement (P < 0.01) in feed efficiency was observed in MN + VM-fed animals. Backfat thickness (5.6 ± 0.08 mm) and ribeye area (69.9 ± 0.53 cm2) remained unaffected (P ≥ 0.74), as well as the minimum (4.98 ± 0.047), mean (6.11 ± 0.037), and maximum ruminal pH (7.23 ± 0.033) values and the time (125 ± 22.3 min/d), area (57.67 ± 12.383 pH × h), and episodes (22 ± 3.8 bouts) of pH below 5.6 (P ≥ 0.12). Overall, prevalence (24 ± 3.4%) and the number of liver abscesses (1.6 ± 0.14 abscesses/abscessed liver), liver scores (20 ± 3.1% of A- and 4 ± 1.8% of A livers), and prevalence (67 ± 3.5%) and degree of damage to the ruminal epithelium (2.5 ± 0.22% affected surface) were similar (P ≥ 0.18) across treatments; however, the occurrence of ruminal lesions tended (P ≤ 0.07) to be associated with that of liver abscesses and reduced ADG when feeding monensin alone.

Saponin-Rich Plant Premixture Supplementation Is as Efficient as Ionophore Monensin Supplementation Under Experimental Eimeria spp Challenge in Broiler Chicken.

For decades avian coccidiosis prevention was based on the use of synthetic coccidiostats. However, their intensive use led to the development of resistance phenomena. In addition, societal demand is increasing for antibiotic-free animal products. Thus, there is a need for a natural and efficient solution for coccidiosis management. Saponin-rich plants, like Yucca schidigera and Trigonella foenum-graecum, are promising tools for coccidiosis management. This study assessed the effects of supplementing broiler chickens with a commercial blend of these two plants (NorponinXO2) under an experimental Eimeria challenge and compared their effects to monensin supplementation. Three trials were performed. For each trial, chickens were divided into 4 groups, untreated uninfested control (UUC), infested untreated control (IUC), infested supplemented with 120 ppm of Monensin in feed (PM), and infested supplemented with 250 ppm of Norponin XO2 in the feed (PX). Chickens were raised in cages; experimental infestation was performed on d14. On d21, intestinal lesions (ILs) scores and growth performances were recorded. A statistical study was carried out on each trial, as well as data from the 3 trials. Experimental infestation reduced in a significant way final body weight in IUC broilers compared to UUC broilers. This loss was numerically compensated by PM and PX treatment. As expected, intestinal lesions were almost absent in the UUC group; however, broilers from the IUC group showed a higher intestinal lesion occurrence. Supplementations with Monensin and NPXO were able to reduce intestinal lesions occurrence. These results suggest that NPXO supplementation is as efficient as Monensin in managing coccidiosis.

Effects of residual monensin in livestock manure on nitrogen transformation and microbial community during “crop straw feeding-substrate fermentation-mushroom cultivation” recycling system

Although crop-livestock integration recycling systems improve nitrogen (N) utilization in agroecosystems, there are limited studies regarding impacts of residual antibiotics in livestock manure on N transformation in entire recycling system. The objective was to evaluate effects of feeding monensin on N recycling during “straw feeding-substrate fermentation-mushroom cultivation”. This experiment contained 3 steps. During straw feeding, beef cattle were allocated into 2 groups and fed diets with or without monensin, respectively. During fermentation, beef cattle manure (with or without monensin) and straw (corn or wheat) and were co-fermented for 35 d to produce substrates. During cultivation, Agaricus bisporus was cultivated on 4 substrates to recycle N in the form of mushrooms. Rates of N retention during fermentation were significant higher for monensin and corn straw treatments and there was an significant interaction between straw and antibiotic on N retention rate during cultivation. However, residual monensin significantly reduced amount of recycled N during entire recycling system, due to changes in N transformation-associated enzyme activity, ammonification and denitrification plus microbial community structure and succession. Specifically, residual monensin inhibited growth of dominant bacterial phylum Bacteroidetes and fungal phylum Neocallimastigomycota, and increased bacterial phylla Actinobacteriota and Firmicutes. These alterations in functional microbes increased N retention rates but reduced mushroom yields in antibiotic treatments during cultivation. In conclusion, monensin decreased the N recycling rate in recycling system, but also reduced N losses during fermentation by inhibiting ammonification and denitrification, so, avoiding antibiotics usage is an effective strategy to improve the efficiency of recycling systems.

Effects of cyclic monensin feeding on ruminal function in cannulated beef steers consuming low-quality forage

The aim of this research was to evaluate the effects of cyclically feeding monensin (Rumensin 90, Elanco Animal Health) to ruminally cannulated steers (12 Bos taurus; 260 kg of BW) consuming low-quality forage (4.9% CP) on measures of intake, digestion, and ruminal function. Twelve steers were randomly assigned to 1 of 3 treatments in a completely randomized design: (1) no monensin (CON); (2) 200 mg·head−1·d−1 monensin (MON); or (3) 200 mg·head−1·d−1 monensin for 14 d and 0 mg·head−1·d−1 monensin for the subsequent 14 d (CYC; recurrent cycle). Hay and ort samples were collected d 10 through 13 for intake determination during each of the four 28-d replicated cycles. Rumen fluid was collected with a suction strainer 0, 2, 4, 8, and 12 h after feeding on d 14 for pH and VFA analysis. Data were analyzed using the MIXED procedure of SAS 9.4 (SAS Institute Inc.). Treatment × cycle interactions or treatment effects were not observed for any measure of intake (OM intake, NDF intake; P ≥ 0.17) or pH (P = 0.13). A tendency for a treatment × cycle interaction was observed (P = 0.08) for OM digestion but not for NDF digestion (P = 0.37). Treatment × cycle interactions were observed (P < 0.01) for molar proportions of acetate, propionate, and acetate:propionate ratio. Because these treatment × cycle interactions occurred, treatment × hour interactions, treatment effects, and hour effects were evaluated within cycles for these parameters. Treatment × hour interactions (P ≤ 0.02) occurred for molar proportion of propionate in cycle 1 and propionate and acetate:propionate ratio in cycle 3, and there was a tendency (P = 0.09) for a treatment × hour interaction for acetate:propionate in cycle 4. Although treatment effects were observed for molar proportions of acetate, propionate, and acetate:propionate ratio in cycle 1 (P ≤ 0.01), these effects had diminished by cycle 4 (P ≥ 0.39). An effect of hour after feeding was observed (P ≤ 0.02) in all 4 cycles for acetate, propionate, acetate:propionate, and ruminal pH. Further evaluation of monensin feeding methods that vary duration of feeding and withdrawal periods may be warranted. Additionally, further study concerning differences in the effect of these methods on a diet bases on concentrate versus low-quality forage warrant investigation.

Effect of Level of Concentrate Feeding and Addition of Monensin on Blood Parameters of Awassi Lambs

This study was conducted to investigate the effect of level of concentrate feeding and addition of monensin on blood parameters. Sixteen Awassi lambs were used at 4-6 months of age and mean initial weight of 21.27 kg. Concentrate diet was offered at two levels (2.5 and 3% of body weight, BW) with or without the addition of monensin at a rate of 30 mg/kg DM. Ground wheat straw was offered adlibitum. Results showed that increasing level of concentrate significantly increased (P<0.01) blood concentration of total protein (BTP) from 6.94 to 8.84 g.100 ml-1, urea nitrogen (BUN), and triglyceride (TG) from 15.54 to 18.23 and 22.66 to 25.12 mg.100 ml-1 respectively. The addition of monensin significantly increased (P<0.05) TP concentration from 7.61 to 8.17 g.100 ml-1, whereas, BUN concentration was decreased (P<0.01) from 18.15 to 15.62 mg.100 ml-1. All blood parameters were also affected (P<0.05) by the interaction between the level of concentrate and the addition of monensin. In the study of diurnal changes, blood parameters showed an expected response to the time of withdrawing blood samples from lambs.

PSXIII-6 Effects of cyclic monensin feeding on ruminally cannulated beef steers consuming low-quality forage

Abstract The loss of monensin efficacy when fed continuously requires further study for development of novel feeding strategies that may prolong its effectiveness. In the present study, effects of cyclic monensin feeding on utilization of low-quality forage (LQF; 4.9%CP) were evaluated using ruminally cannulated steers (12 Bos taurus; 260 kg BW). Steers were randomly assigned to one of three treatments: 1) CON (0 mg∙hd-1∙d-1 monensin; Rumensin® 90, Elanco Animal Health, Greenfield, IN), 2) MON (200 mg∙hd-1∙d-1 monensin) or 3) CYC (200 mg∙hd-1∙d-1 monensin for 14 d and 0 mg∙hd-1∙d-1 monensin for subsequent 14 d). Dried distillers grains (1 kg∙hd-1∙d-1) were fed for monensin inclusion. Each of four periods were 28 days in length. Hay, ort, and fecal samples were collected d 10–14 of each period for measures of digestion. Rumen fluid was collected with a suction strainer 0, 2, 4, 8, and 12 h after feeding on d 14 for VFA analysis. Data were analyzed using the MIXED procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC). A period × treatment interaction was not observed for any measure of digestion (DMD, OMD, NDFD; P ≥ 0.39). A period × treatment interaction (P &amp;lt; 0.01) was observed for acetate, propionate, and A:P. An hour effect was observed for all ruminal fermentation parameters (acetate, propionate, A:P ratio, total VFA; P ≤ 0.01). No treatment effects or interactions were observed for any ruminal fermentation parameters by period 4 (P ≥ 0.15), but an hour effect was observed for all parameters (P ≤ 0.03) in period 4. Exploration of novel feeding strategies results in knowledge beef cattle producers can apply in their operations. This data is particularly relevant in cow-calf operations where LQF is often consumed. Although cyclically feeding monensin was similar to continuous feeding, this research furthers our knowledge and understanding of monensin.

Nutrient digestibility, blood metabolites, and production performance of peripartal ewes fed dietary plant extract and monensin

The influences of a blend of plant extracts (PE; broadleaf plantain and peppermint) and monensin (MON) on metabolite status, digestibility and performance of ewes during periparturient period were investigated. Thirty-two estrus-synchronized multiparous Afshari ewes (90 ± 3.1 kg body weight (BW); 3.0 ± 0.15 body condition score (BCS); mean ± standard deviation) were used in a completely randomized design with a 2 × 2 factorial arrangement and assigned to one of four dietary treatments with supplementation of 1) no additive (control, CON-PE), 2) 2 g/d of a commercial blend of PE (CON + PE), 3) 30 mg/d of MON (MON-PE) or 4) combination of 2 g/d of PE along with 30 mg/d of monensin (MON + PE). Ewes were individually fed to diets containing hay at 650 g/kg from −21 d relative to lambing and 600 g/kg until 21 d after lambing. Blood was collected weekly and at +1 day relative to lambing 3 h of morning feeding. The overall dry matter intake (DMI) was increased (P = 0.004) by PE and MON+PE inclusion. Although dietary additives did not influence BCS, BW and subcutaneous fat thickness (SFT) in pre- and postpartum, the MON+PE diet tended to increase BCS (P = 0.092), BW (P = 0.076) and SFT (P = 0.077) on d 21 postpartum. Plasma concentration of cholesterol and albumin was not significantly affected by dietary additives, whereas plasma glucose concentration was increased by feeding MON alone or MON+PE (P = 0.002). Apparent digestibility of dry matter and organic matter was similar among the treatments. Production of colostrum (P = 0.002) and milk (P = 0.01) increased when diets were supplemented with MON+PE. The MON-PE diet decreased milk fat content. Addition of PE alone increased milk fat (P = 0.001) and protein (P < 0.001) percentages. In conclusion, feeding PE and (or) MON+PE increased DMI and colostrum, milk and protein yield. Therefore, supplementation of MON+PE may be beneficial for improving production performance in transition ewes.

Effects of grain adaptation programs and antimicrobial feed additives on performance and nutrient digestibility of Bos indicus cattle fed whole shelled corn.

Two experiments were conducted to evaluate the effects of feed additives [monensin (MON); 30 mg/kg of dry matter (DM), and virginiamycin (VM); 25 mg/kg DM] and grain adaptation programs [adding roughage (ROU; sugarcane bagasse) or not (NO-ROU) during the 20-d adaptation period] on performance, carcass characteristics, and nutrient digestibility of Bos indicus cattle fed finishing diets containing 85% whole shelled corn and 15% of a pelleted protein-mineral-vitamin supplement. In Exp.1, 105 Nellore bulls [initial body weight (BW) = 368 ± 25 kg] were used in a complete randomized block design with a 2 × 2 factorial arrangement of treatments, consisting of two feed additives (MON and VM) associated with two adaptation programs (ROU or NO-ROU during the 20-d adaptation period). Effects of feed additives × adaptation programs were not detected (P ≥ 0.13). Feed additives did not affect dry matter intake (DMI), average daily gain (ADG), and feed efficiency (G:F) during the 20-d adaptation period (P ≥ 0.35). During the total feeding period (105 d), feeding MON decreased DMI (P ≤ 0.03) compared to VM. Adding sugarcane bagasse to finishing diets during the 20-d adaptation period (ROU) increased ADG (P = 0.05) and G:F (P = 0.03), and tended to increase BW (P = 0.09) compared to NO-ROU. In Exp. 2, 10 ruminally cannulated Nellore steers (BW = 268 ± 38 kg) were used in a completely randomized design to evaluate the effects of the two feed additives used in the Exp. 1 (MON and VM; 5 steers/treatment) on DMI, total apparent digestibility of nutrients, and ruminal fermentation characteristics. No differences in DMI, total tract apparent digestibility of nutrients, and ruminal fermentation characteristics were observed between MON and VM (P ≥ 0.32). An effect of sampling day (P < 0.001) was observed for ruminal pH, which was greater on day 0 compared to day 7, 14, and 21 of the experimental period (P ≤ 0.05). In summary, supplementing monensin and virginiamycin for finishing Nellore bulls fed whole shelled corn diets, resulted in similar growth performance and carcass characteristics. Including sugarcane bagasse to adapt finishing bulls to no-roughage diets containing whole shelled corn is an alternative to increase growth performance.

Influence of monensin on intake of some anti-nutritive components in diets fed to West African dwarf (WAD) goats

Sixteen (16) West African dwarf goats weighing an average of 73 kg +1.2 were used in a completely randomized experimental design to determine the influence of feeding monensin on intake of some anti-nutritive components contained in the diet. Results showed that animals placed on monensin supplemented diets at levels of 15, 30 and 45 mg/kg DM had significantly (P&lt;0.05) reduced intakes of tannin, oxalate, saponin and nitrate compared to those placed on the control diet (0 mg monensin/ kg DM). No significant difference (P&gt;0.05) occurred amongst the monensin-supplemented groups. Fecal concentrations of tannin, oxalate, saponin and nitrate were similarly observed to reduced (P&lt;0.05) with monensin inclusion. However, the percentage disappearance of each of the anti nutritive components was not altered (P&gt;0.05). Reductions in total dry matter intake were observed in response to monensin supplementation at 15, 30 and 45 mg/kg DM relative to the control but dry matter digestibility and weight gain in animals were not altered. The reductions in the intake of dry matter with monensin feeding were assumed to have consequently caused the reductions in the intake of anti-nutritive components from the diet. This reduction caused by monensin would be of benefit, in a bid to lessen some of the nutritional problems usually encountered when animals consume large quantities of these components in the diet. Monensin inclusion at levels between 15 and 45mg/kg DM could therefore be recommended to alleviate toxicity problems commonly associated with intake of anti-nutritive substances in feed.

198 Ruminal pH of Angus and Nellore steers during adaptation to high-energy diets with different nutritional strategies

Abstract The objective of this study was to evaluate the effect of adding monensin into high-concentrate diets based on either finely-ground or high-moisture corn during the transition from adaptation to finishing diets on ruminal pH of cannulated Angus and Nellore steers. Four 30-mo-old Nellore and four 30-mo-old Angus steers were divided (± 550 kg) into two 4 x 4 Latin squares, where each square was composed by animals from same breed, and randomly submitted to a 2 x 2 factorial arrangement of treatments as follows: T1) Finely-ground corn + monensin; T2) Finely-ground corn; T3) High moisture corn + monensin; T4) High-moisture corn. Periods were divided as follows: 14 days of adaptation diets and 18 days of finishing diet (80% concentrate). The study lasted 149 days, including three 7-d washout intervals. The rumen pH was assessed continuously via data loggers on days 4, 8, 12, 16, 20, 24 and 28. Interactions between breed and days were observed for DMI (P = 0.02) and pH duration below 5.6 (P = 0.01), where Angus steers had greater DMI and spent a longer time below 5.6 than Nellore animals on days 12, 16, 20, 24 and 28. The addition of monensin decreased (P = 0.01) DMI on days 16, 20, 24 and 28. Regarding pH duration and area below 5.6, an interaction between breed and corn was observed (P = 0.001), in which Angus steers fed finely-ground corn spent a longer time (416 min/day) and had a larger area (224.6 min x pH units/day) below 5.6 than animals from other treatments. For mean pH, steers consuming high-moisture corn had higher pH (6.45 vs. 6.29); and an interaction was observed (P = 0.03) between breed and monensin, where monensin addition decreased pH for Angus (5.96 vs. 6.18), but not for Nellore steers (6.68 vs. 6.63). The feeding of monensin and finely-ground corn did not positively impact rumen pH of Angus steers.

203 Feeding a calf starter containing monensin alone or in combination with a blend of essential oils and a proprietary cobalt source to Holstein calves

Abstract Gut health is critical for neonatal calves, and nutritional technologies are needed for disease and stress prevention. Previous work feeding Monensin (MON) in combination with a blend of essential oils and a proprietary cobalt source (EOC) blend had demonstrated improved calf gut health and growth performance. The objective was to evaluate MON and EOC alone or in combination on calf growth performance. Eighty (80) new born Holstein calves were randomly assigned to one of four treatments arranged in a 2 x 2 factorial (MON and EOC). Treatments were: 1) Control without MON or EOC added to the calf starter (CS); 2) MON: 50.8 mg/kg CS (Norvikon Biotechnology Co., Hunan, China); 3) EOC: 44.1 mg/kg CS (Rum-A-Fresh, Ralco Inc. Marshall, MN); 4) MON+EOC: MON and EOC added to CS. Calves were fed colostrum followed by whole milk through weaning at 42 d, while CS was fed ad libitum through the 70-d experimental period. The MON by EOC interaction was found to be nonsignificant (P &amp;gt; 0.41) for growth performance. Calves fed without or with MON demonstrated similar (P &amp;gt; 0.70) body weight (BW; 68.7 and 68.9 kg without and with MON, respectively), while calves fed EOC demonstrated greater (P &amp;lt; 0.01) BW (67.3 and 70.4 kg without and with EOC, respectively) compared with calves fed without EOC. Calves fed a CS containing MON were similar (P &amp;gt; 0.47) in ADG (0.88 and 0.91 kg/d) compared with calves fed without MON; however, calves fed a CS with EOC increased (P &amp;lt; 0.01) ADG (0.84 and 0.95 kg/d) 13% through the 70 d experimental period compared with calves not fed EOC. These data demonstrate that EOC and MON fed in combination was not beneficial for enhancing growth performance, but that calf growth performance can be improved with EOC compared to MON.

Effects of intake of monensin during the stocker phase and subsequent finishing phase on performance and carcass characteristics of finishing beef steers

Use of monensin during the stocker phase of production has been suggested as a possible cause of reduced response to monensin during finishing. Experiments were conducted to determine the carryover effects of monensin supplementation during the stocker phase and effects of feeding monensin during the finishing phase on performance and efficiency of beef steers. Steers were fed hay or grazed cool-season annuals or bermudagrass in Arkansas before finishing in Canyon, Texas (blocks 1 and 2) or Stillwater, Oklahoma (block 3). Treatments were arranged as a 3 × 2 factorial with 3 monensin doses during the stocker phase (0, 882, or 1,764 g/t offered in a free-choice mineral) and 2 levels during finishing (0 or 37.5 mg/kg of diet DM). There were no block × treatment interactions ( P ≥ 0.19) for performance or carcass measurements; therefore, data were pooled across blocks and finishing locations. Stocker × finishing treatment interactions were not observed for finishing performance and efficiency data ( P ≥ 0.50). There was no carryover effect on overall finishing performance or efficiency. Cattle consuming monensin during the finishing phase had decreased ( P < 0.01) DMI during finishing and increased ( P < 0.01) G:F and ( P = 0.03) fat thickness compared with those not fed monensin during the finishing phase. Supplementation of monensin to stocker cattle before finishing did not affect subsequent finishing efficiency response to monensin during finishing. Providing monensin in finishing diets still decreases DMI and improves feed efficiency of finishing cattle.

Impacts of feeding monensin sodium on production and the efficiency of milk production in dairy cows fed total mixed rations: evaluation of a confounded literature

The amount of milk Canadian dairy farmers produce is limited to a production quota expressed in milk fat. Because milk economic value is primarily based on fat and protein, it can be advantageous to decrease the milk fat to protein ratio. Monensin sodium has been suggested to reduce milk fat proportion and outputs, but not milk protein. Publications using lactating dairy cows were utilized to assess predictability of production responses to monensin feeding based upon their base production characteristics and diet composition. Predicted animal output changes due to monensin had poor fits with low r2 (0.31–0.44) and unevenly distributed residuals. Further assessment revealed that cow characteristics, and diets, were not independent of monensin feeding level. Thus, the 43 comparisons were clustered into levels of 10–12, 14–18, or 20–24 mg kg−1 of diet dry matter (DM). Milk fat yield reductions due to monensin differed (P &lt; 0.05; 10–12 and 14–18 mg kg−1 DM), or tended to differ (P = 0.057; 20–24 mg kg−1 DM), from zero (i.e., no change). Monensin addition to total mixed rations of lactating dairy cows negatively impacted milk fat yield to a greater extent than milk protein.

A rapid and convenient screening method for detection of restricted monensin, decoquinate, and lasalocid in animal feed by applying SERS and chemometrics

The surface-enhanced activities of size- and shape-controlled gold nanoparticles (AuNPs) with superior chemical stability were investigated to explore a possible development of a simple and non-destructive spectroscopic method to help the regulatory agency's analytical services for rapid detection and characterization of selected antimicrobials in animal feeds. Feed samples spiked at different concentration ranges of antimicrobials were evaluated using AuNPs as a surface-enhanced Raman spectroscopy (SERS) agent. The collected SERS spectra were mathematically preprocessed for further analysis. The classification models obtained 100% predictive accuracy with zero or little misclassification. The first two canonical variables (p = 0.001) could explain >95% of the variability in preprocessed spectral data. Most chemometric models for predicting MON, DEC, and LAS concentrations showed a high predictive accuracy (r2 > 0.90), lower predictive error (<20 mg/kg), and satisfactory regression quality (slope close to 1.0). The statistical results showed no statistically significant difference between the reference and SERS predicted values (p > 0.05). The findings and implications from the study indicate that SERS would be a powerful and efficient technique possessing a great potential serving as an excellent monitoring and screening tool for antimicrobial contaminated samples in the on-site analysis.

Dietary supplementation with oregano essential oil and monensin in combination is antagonistic to growth performance of yearling Holstein bulls

Our previous work indicated that feeding oregano essential oil (OEO) in combination with monensin (MON) may not be mutually beneficial to dairy calf growth performance. To evaluate this observation further, a 240-d long-term growth experiment was conducted using 12 young growing Holstein bulls using a 2 × 2 factorial treatment arrangement. Main factors were OEO and MON arranged in 4 individual treatments: (1) ration fed without OEO or MON (control), (2) OEO fed at 26 mg/kg of dry matter (DM), (3) MON fed at 25 mg/kg of DM, and (4) OEO and MON fed in combination (OEO+MON). Holstein bulls were 70 d of age and similar in body weight (BW; 93.3 ± 4.54 kg) and individually fed for 240 d. The targeted feeding rates of OEO and MON were blended into 200 g of concentrate and top dressed each morning to a corn stalklage-based ration. Body weights, frame measurements, and blood samples were collected monthly. Interactions of OEO by MON were detected for BW, BW gain, average daily gain, and a trend for feed conversion. Bulls fed OEO or MON demonstrated greater final BW (368, 385, 381, and 358 kg for control, OEO, MON, and OEO+MON, respectively), and BW gains (278, 292, 285, and 265 kg) and average daily gain (1.16, 1.22, 1.19, 1.11 kg/d) were greatest for bulls fed OEO or MON compared with bulls fed OEO+MON; bulls fed the control were intermediate and similar to bulls fed MON. Intake of DM was greater for bulls fed OEO (6.55, 6.99, 6.60, and 6.42 kg/d) compared with bulls fed remaining treatments. Frame growth gain measurements for heart girth, abdominal girth, withers height, body length, and cannon bone circumference were similar for bulls fed all treatments. Serum triglyceride (0.23, 0.25, 0.28, and 0.24 mmol/L) concentrations were greater for bulls fed MON compared with bulls fed the control and OEO+MON, and bulls fed OEO were intermediate and similar. Cholesterol (2.06, 2.29, 2.20, and 2.07 mmol/L) concentrations were greater for bulls fed OEO compared with bulls fed the control and OEO+MON, and bulls fed MON were intermediate and similar. Serum antioxidant measurements were similar for bulls fed all treatments. Serum IgA, IgG, and IgM concentrations were similar for bulls fed all treatments. Feeding OEO or MON separately can improve growth performance of growing Holstein bulls. We do not know why the combination of OEO and MON is antagonistic to growth performance of Holstein bulls. However, these technologies should not be fed in combination to growing dairy cattle.

Feeding a calf starter containing monensin alone or in combination with an oregano, and cobalt blend to Holstein calves.

Gut health is critically important for growing neonatal calves, and nutritional technologies are needed to prevent disease and stress challenges. Previous work feeding monensin (MON) in combination with an oregano, prebiotic, and cobalt-lactate (EOC) blend had demonstrated improved calf gut health and growth performance. The objective of this study was to evaluate the growth performance of calves fed MON and EOC alone or in combination. Eighty (80) newborn Holstein (37) female and (43) male calves were randomly assigned to one of four treatments arranged in a 2 × 2 factorial (MON and EOC). Treatments were: 1) Control: without MON or EOC added to the calf starter (CS); 2) MON: 50.8 mg/kg CS (Elanco, Greenfield, IN); 3) EOC: 44.1 mg/kg CS (Rum-A-Fresh, Ralco Inc. Marshall, MN); 4) MON + EOC: MON and EOC added to CS. Calves were fed colostrum followed by whole milk through weaning at 42 d, while CS was fed ad libitum through the 70-d experimental period. The MON by EOC interaction was found to be nonsignificant (P > 0.41) for growth performance. Calves fed without or with MON demonstrated similar (P > 0.70) body weight (BW; 68.7 and 68.9 kg without and with MON, respectively), while calves fed EOC demonstrated greater (P < 0.01) BW (67.3 and 70.4 kg without and with EOC, respectively) compared with calves fed without EOC. Calves fed a CS containing MON were similar (P > 0.47) in average daily gain (ADG; 0.88 and 0.91 kg/d) compared with calves fed without MON; however, feeding calves a CS with EOC increased (P < 0.01) ADG (0.84 and 0.95 kg/d) by 13% through the 70-d experimental period compared with calves not fed EOC. Frame measurements indicated that the greater ADG was due to increased (P < 0.10) frame growth for calves fed essential oils (EO) compared with calves fed without EO. A MON by EOC interaction (P < 0.01) for serum propionate concentration demonstrated calves fed MON + EOC and EOC were greater (P < 0.05) compared with calves fed Control, while calves fed MON were intermediate and different (P < 0.05). Feeding calves a CS with EOC increased (P < 0.04) immunoglobulin A, immunoglobulin G, and immunoglobulin M concentrations compared with calves fed without EOC. A MON by EOC interaction was detected (P < 0.01) for total tract starch digestibility for calves fed EOC or MON + EOC demonstrating greater (P < 0.05) starch digestibilities than Control-fed calves. These data demonstrate that EOC and MON fed in combination was not beneficial for enhancing the growth performance, but that calf growth performance can be improved with EOC compared with MON.