Stocking rate and monensin supplemental level effects on growth performance of beef cattle consuming warm-season grasses

The Impact of Mineral and Energy Supplementation and Phytogenic Compounds on Rumen Microbial Diversity and Nitrogen Utilization in Grazing Beef Cattle

The objective of this study was to evaluate the effect of the addition of a phytogenic compound blend (PHA) containing hydrolyzable tannins, carvacrol, and cinnamaldehyde oil to mineral salt or energy supplementation on the rumen microbiota and nitrogen metabolism of grazing Nellore cattle. Eight castrated Nellore steers were distributed in a double-Latin-square 4 × 4 design, with a 2 × 2 factorial arrangement (two types of supplements with or without the addition of the PHA), as follows: energy supplement without the PHA addition (EW); energy supplement with the PHA addition (EPHA); mineral supplement without the addition of the PHA (MW); mineral supplement with the PHA addition (MPHA). Steers that received supplements with the PHA have a lower ruminal proportion of valerate (with the PHA, 1.06%; without the PHA, 1.15%), a lower ruminal abundance of Verrucomicrobia, and a tendency for lower DM digestibility (with the PHA, 62.8%; without the PHA, 64.8%). Energy supplements allowed for higher ammonia concentrations (+2.28 mg of NH₃-N/dL), increased the propionate proportion (+0.29% of total VFA), and had a higher ruminal abundance of Proteobacteria and Spirochaetae phyla in the rumen. The PHA addition in the supplement did not improve nitrogen retention, reduced the ruminal proportion of valerate, and had a negative impact on both the total dry-matter digestibility and the abundance of several ruminal bacterial groups belonging to the Firmicutes and Verrucomicrobia phyla.

Monensin supplementation during late gestation of beef cows alters maternal plasma concentrations of insulin-like growth factors 1 and 2 and enhances offspring preweaning growth

This study evaluated the effects of maternal prepartum supplementation of dried distillers grains (DDG), with or without monensin addition, on maternal performance and physiology and offspring preweaning growth. On day 0 (approximately 197 ± 4 d prepartum), 150 multiparous, Brangus crossbred beef cows were ranked by their initial body weight (BW; 524 ± 51 kg) and body condition score (BCS; 5.0 ± 0.63), and then randomly assigned into one of 15 bahiagrass (Paspalum notatum) pastures (10 cows and 8.1 ha/pasture). Maternal treatments were randomly assigned to pastures (5 pastures/treatment) and consisted of no prepartum supplementation of DDG (NOSUP) or supplementation of DDG at 1 kg/cow/d (dry matter basis; DM) added with 0 mg (SUP) or 200 mg/d of monensin (SUPMO) from days 0 to 77. Effects of maternal treatment and maternal treatment × day of the study were not detected (P ≥ 0.63) for any forage data. Cow BCS on day 35 and near calving (day 77) did not differ (P ≥ 0.19) between SUP and SUPMO cows but both groups had greater (P ≤ 0.001) BCS compared with NOSUP cows. Cow BCS at the start of the breeding season (day 142) and on day 168 were the greatest (P < 0.0001) for SUPMO cows, least for NOSUP cows, and intermediate (P ≤ 0.02) for SUP cows. Maternal plasma concentrations of glucose did not differ (P ≥ 0.25) among treatments. Plasma concentrations of insulin-like growth factor 1 (IGF-1) on day 77 were the least for NOSUP cows (P ≤ 0.05) and did not differ (P = 0.66) between SUP and SUPMO cows, whereas plasma concentrations of IGF-2 on days 35 and 77 were greatest (P ≤ 0.05) for SUPMO cows and did not differ (P ≥ 0.60) between NOSUP and SUP cows. Birth BW of first offspring did not differ (P = 0.77) between SUP and SUPMO calves but NOSUP calves were lighter at birth (P ≤ 0.05) compared with SUP and SUPMO calves. Percentage of cows pregnant with a second offspring did not differ (P = 0.72) between SUP and SUPMO cows and were the least for NOSUP cows (P ≤ 0.05). First offspring BW at weaning (day 325) was greatest (P ≤ 0.05) for SUPMO calves, least for NOSUP calves, and intermediate for SUP calves. Therefore, adding monensin into prepartum DDG supplements for Bos indicus-influenced beef cows did not increase cow prepartum BCS but led to greatest offspring preweaning growth, likely by modulating maternal plasma concentrations of IGF-1 and IGF-2 during gestation.

Growth, physiology, and coccidiosis infestation of suckling beef calves grazing warm-season grasses and offered creep-feeding supplementation with or without monensin

This study evaluated the growth, physiology, and coccidiosis infestation of suckling beef calves provided monensin and grazing limpograss (Exp. 1) or bahiagrass (Exp. 2) pastures. Treatments were randomly assigned to pastures (4 pastures/treatment; 3 cow-calf pairs/pasture in Exp. 1; 4 pastures/treatment; 10 cow-calf pairs/pair of pastures in Exp. 2) and comprised of supplementation of 0.40 kg/d of soybean meal added or not with monensin (20 mg/kg of total DM intake) for 112 and 78 days before weaning in Exp. 1 and 2, respectively. In Exp. 1, supplement DM disappearance tended (P = 0.10) to be less for calves supplemented with vs. without monensin, but treatment × day and treatment effects were not observed (P ≥ 0.18) for herbage mass (HM), herbage allowance (HA), cow body condition score (BCS), calf average daily gain (ADG), calf plasma data, and fecal coccidia egg count. In Exp. 2, forage nutritive value, HM and HA, and cow BCS did not differ (P ≥ 0.43) between treatments. Supplemental monensin did not impact (P ≥ 0.78) plasma concentrations of insulin-like growth factor 1 but increased (P ≤ 0.05) calf overall ADG and plasma concentrations on day 78 and reduced plasma concentrations of urea nitrogen (PUN) on day 78 and fecal coccidia egg count on day 78 compared to calves provided no monensin supplementation. Hence, monensin supplementation successfully improved growth performance of creep-fed suckling beef calves, when herbage mass was not a limiting factor and coccidiosis infestation occurred.

Effects of supplementation with corn distillers' dried grains on animal performance, nitrogen balance, and enteric CH4 emissions of young Nellore bulls fed a high-tropical forage diet

The inclusion of corn-dried distillers' grains (DDG) could be an alternative supplement to increase animal performance, nitrogen efficiency usage (NEU), and decrease enteric methane (CH₄) emissions. Our goal was to determine whether DDG could replace a traditional supplement (cottonseed meal) without affecting animal performance, N balance, and CH₄ emissions. The experiment was conducted during the forage growing season (December to April), with 15 d adaptation, and a 112 d experimental period. The experimental design was completely randomized with four treatments: a mineral supplement (MS), cottonseed meal supplement (CS), 50% replacement of CS by DDG (50DDG), and 100% replacement of CS by DDG (100DDG). Cottonseed meal and DDG were used as protein supplement. A total of 12 paddocks, 3 per treatment, were used to measure forage mass: morphological and chemical composition of forage, forage allowance, and animal performance. Six animals per treatment were used to evaluate DM intake, digestibility, CH₄ emissions, microbial protein production (MCP), and NEU of each treatment. Eighty-one Young Nellore bulls (48 testers, 12 per treatments and 33 adjusters) with initial BW of 255 ± 5 kg (10-12 months old) were supplemented with each supplement type at a level of 0.3% of BW. Pasture management was continuous stocking with a variable stocking rate (put-and-take). Enteric CH₄ was measured using the gas tracer technique. The MCP was quantified using purine derivatives and the NEU mass balance. No differences were found in nutrient intake (P > 0.228). Individual animal performance and gain per area were higher in the treatments with concentrates compared with that of MS; however, there was no difference among treatments CS, 50DDG, and 100DDG. The ADG was 0.83 for MS and 1.08 kg/animal/d when supplemented (P < 0.05). Gain per hectare was 709 kg/ha for MS and 915 kg/ha when supplemented with concentrates (P < 0.05). There was no difference in CH₄ production among treatments that average 180 g/animal/d; however, CH₄ per kg of gain was reduced with CS. The CH₄ conversion factor averaged 5.91%. There was no difference in the synthesis of MCP and NEU. Corn DDG can replace 100% of cottonseed meal as a protein source for supplementation of young Nellore bulls grazing in tropical pastures without affecting animal performance, NEU, MCP, and CH₄ emissions.

Strategic supplementation of growing cattle on tropical pastures improves nutrient use and animal performance, with fewer days required on the finishing phase

Context Cattle grazing tropical forages usually perform below genetic potential due to limited nutrient intake. Aims Four experiments were conducted to evaluate supplementation strategies on performance and metabolism of cattle grazing intensively managed marandu palisade grass (Urochloa brizantha). Methods Experiment 1 evaluated the average daily gain (ADG) of 72 young bulls (222 ± 25 kg bodyweight, BW) grazing palisade grass and supplemented (22% crude protein, CP) at 0.0%, 0.3%, 0.6% and 0.9% BW, and their ADG during the feedlot finishing phase. Experiment 2 evaluated the ADG of 80 bulls (240 ± 18 kg BW) grazing palisade grass and supplemented with energy (11.3% CP) or three protein sources (≈20.5% CP) at 0.6% BW. Experiment 3 investigated intake, rumen parameters and digestibility of nutrients in fistulated steers (410 ± 8.6 kg BW) fed an energy supplement, that is, ground corn, at 0.0%, 0.3%, 0.6% and 0.9% BW, with a parallel in vitro study of fermentation kinetics (Experiment 4). Key results Increased levels of supplementation resulted in linear increases (P &lt; 0.05) in ADG, stocking rate (SR) and in BW gain per area. There were no differences (P &gt; 0.05) in ADG, SR and BW gain per area among supplemental sources of protein or the energy supplement. Increasing energy levels caused a linear decrease (P &lt; 0.05) in forage intake and grazing time and a linear increase (P &lt; 0.05) in total dry matter and digestible-nutrient intakes, but did not affect (P &gt; 0.05) fibre degradability. Corn supplementation also caused a linear decrease (P &lt; 0.05) in acetate:propionate ratio, in ruminal ammonia-N and in N excretion, and a linear increase (P &lt; 0.05) in rumen propionate concentration, in microbial synthesis and in N retention. The supplementation increased BW at the start of the feedlot phase, resulting in similar hot carcass weights with fewer days on feed and no effects on meat quality. Conclusions Overall, despite the source utilised, supplementation increased ADG, SR and BW gain per area, with fewer days being required on the finishing period. Implications Having adequate supplementation strategies in place will help producers increase the efficiency of their systems.

Supplementation frequency and amount modulate postweaning growth and reproductive performance of Bos indicus-influenced beef heifers

This 2-yr study evaluated the growth and puberty attainment of Bos indicus-influenced beef heifers offered 2 different postweaning concentrate supplementation amounts and delivery frequencies. On day 0 of each year, 64 Brangus crossbred heifers were stratified by initial body weight (BW) and age (mean = 244 ± 22 kg; 314 ± 17 d) and assigned into 1 of 16 bahiagrass pastures (4 heifers/pasture/yr). Treatments were randomly assigned to pastures in a 2 × 2 factorial design (4 pastures/treatment/yr) and consisted of concentrate dry matter (DM) supplementation at 1.25% or 1.75% of BW which were offered either daily (7×) or 3 times weekly (3×) for 168 d. On day 56 of each year, heifers were assigned to an estrus synchronization protocol consisting of intravaginal controlled internal drug release (CIDR) insertion on day 56, CIDR removal on day 70, i.m. injection of 25 mg of prostaglandin F2α (PGF2α) on day 86, and i.m. injection of 100 µg of gonadotropin-releasing hormone and timed-AI at 66 h after PGF2α injection (day 89). Heifers were exposed to Angus bulls from day 89 to 168 (1 bull/pasture). Pregnancy diagnosis was assessed on day 213 of each year. Supplementation amount × frequency effects were not detected (P ≥ 0.12) for any variable, except for plasma concentrations of glucose (P = 0.10) and urea nitrogen (PUN; P = 0.01). Herbage mass, herbage allowance, and nutritive value did not differ (P ≥ 0.12) among treatments. Increasing supplementation DM amount from 1.25% to 1.75% of BW increased (P ≤ 0.05) plasma concentrations of insulin-like growth factor 1 (IGF-1), overall average daily gain (ADG), final BW, percentage of pubertal heifers on day 89, pregnancy and calving percentages, and percentage of heifers calving within the first 21 d of the calving season. However, reducing the supplementation frequency from daily to 3× weekly, regardless of supplementation amount, did not impact overall pregnancy and calving percentages (P ≥ 0.42), but caused (P ≤ 0.05) fluctuations in plasma concentrations of insulin and IGF-1 and decreased (P ≤ 0.03) overall ADG, final BW, puberty attainment on days 56, 89, and 168, and percentage of heifers calving during the first 21 d of the calving season. Hence, increasing the supplement DM amount did not prevent the negative effects of reducing the frequency of supplementation (3× vs. 7× weekly) on growth and reproduction of replacement Bos indicus-influenced beef heifers.

Virginiamycin and sodium monensin supplementation for beef cattle on pasture

ABSTRACT The aim of this paper was to evaluate the effects of including virginiamycin (VM), sodium monensin (MON) or the association (VM+MON) in the energetic mineral supplement, on the intake and performance of beef cattle on pasture. Forty Nellore heifers with 24 months of age and initial body weight (BW) of 251.5±16.6kg, were distributed in four treatments in a randomized block design. Treatments consisted of adding VM, MON or VM+MON to the supplement (CONT). Additive concentrations were defined to reach a dose of 40 to 45mg/100kg BW. The herbage allowance was not a limiting factor for the animals’ intake. Supplement intake was lower than expected, with 33.0, 18.8 and 26.3mg per 100kg BW for VM, MON and VM+MON, respectively. Dry matter intake (DMI, mean=2.65% BW) and animal performance were not affected by the inclusion of additives. The average daily gain (ADG) was 0.561kg/animal day-1. The inclusion of additives in energetic mineral supplement does not affect the DMI and the ADG of grazing animals. The variability in supplement intake and daily dose intake of additives may have influenced the performance of the animals. Monensin inclusion presented the less expensive supplementation cost, due to reduction in supplement intake without changing weight gain.

Effects of monensin feeding on performance, nutrient utilisation and enteric methane production in growing buffalo heifers

Murrah buffalo heifers (live weight 135 ± 17 kg) were fed a total mixed ration without supplementation (CON), or supplemented with sodium monensin (MON; Rumensin® 200, Elanco Animal Health, Brazil) @ 0.6 mg/kg of body weight for 90 days. Nutrient digestibility and nitrogen retention were estimated during the mid-experiment, and enteric methane production was measured by sulphur hexafluoride tracer technique for consecutive-5 days after the digestion trial. The dry matter (DM) and nutrient intake were not affected but DM intake expressed as percent of body weight was decreased by monensin supplementation (3 vs 2.7% for CON and MON, respectively). The crude protein digestibility was higher for MON whereas, digestibility of other nutrients was not affected. Nitrogen retention (+ 4.59 g/day) and daily body weight gain (+ 56 g/day) were greater for MON-fed heifers without any significant effect on nitrogen intake and nitrogen excretion through faeces and urine. Daily enteric methane production was reduced by 12.61% but the treatments did not differ significantly. Methane emission expressed as gram per unit of DM, organic matter and digestible DM intake was lower for MON than CON and methane conversion rate (Ym) % of GE and ME intake was also decreased by 8-9%. On day 60, blood glucose level was increased and urea nitrogen was decreased in MON-fed heifers. This study indicated that monensin supplementation at 0.6 mg/kg body weight in growing heifers improved daily gain and feed efficiency while it reduced enteric methane production which can reduce feedlot time and consequent life time CH4 production.

Effects of monensin inclusion into increasing amount of concentrate on growth and physiological parameters of early-weaned beef calves consuming warm-season grasses

Two experiments evaluated the effects of concentrate amount and monensin inclusion on growth and physiological parameters of early-weaned beef calves consuming warm-season grasses in drylot (Exp. 1) and pastures (Exp. 2). In both experiments, treatments consisted of two concentrate DM amounts (1 or 2% of BW) and two inclusion rates of monensin (0 or 20 mg of monensin/kg of total DM intake). In Exp. 1, 48 Angus × Brahman crossbred early-weaned (EW) beef calves (initial age = 90 ± 13 d; initial BW = 83 ± 12 kg) were distributed in 12 drylot pens (four calves per pen; three pens per treatment) and provided stargrass (Cynodon nlemfuensis) hay (9% CP and 52% IVDOM) at amounts to ensure 10% DM refusals for 56 d. In Exp. 2, 36 Angus × Brahman crossbred EW heifer calves (initial BW = 171 ± 15 kg) were randomly allocated into one of 12 bahiagrass (Paspalum notatum) pastures on a continuous and fixed stocking rate (1 ha and three heifers per pasture; three pastures per treatment) and received daily supplementation of their respective treatments for 84 d. In both experiments, effects of monensin inclusion × concentrate amount were not detected for any variable (P ≥ 0.14), but overall ADG and plasma IGF-1 concentrations were greater (P ≤ 0.05), whereas fecal coccidia egg counts tended (P = 0.09; Exp. 1) or were less (P = 0.05; Exp. 2) for calves offered concentrate with vs. without monensin inclusion. Calves offered concentrate at 2% of BW had greater (P ≤ 0.05) overall ADG (Exps. 1 and 2), herbage mass (Exp. 2 only), in vivo apparent digestibility, total DMI and plasma concentrations of glucose and IGF-1 (Exp. 1 only), less forage DM intake (Exp. 1 only), and no effects on fecal coccidia egg counts (Exps. 1 and 2) compared to calves offered concentrate at 1% of BW. Increasing concentrate amount is an effective management practice to increase ADG and decrease forage DMI in early-weaned calves consuming warm-season grasses, whereas the decrease in fecal coccidia egg count and additional ADG provide evidence that monensin should be supplied to early-weaned calves grazing warm-season pastures and receiving concentrate at 1% of BW or above.

Effects of monensin on growth performance of beef heifers consuming warm-season perennial grass and supplemented with sugarcane molasses

The objective of this study was to evaluate the effects of monensin on performance of beef heifers fed warm-season forages. Brangus heifers (n = 24) were stratified by BW and BCS, and randomly assigned into 1 of 12 bahiagrass pastures (1.2 ha and 2 heifers/pasture). Heifers were offered 14 kg of sugarcane molasses and 3.5 kg of cottonseed meal weekly from day 0 to 84. Treatments were randomly assigned to pastures (6 pastures/treatment) and consisted of heifers supplemented with or without 200 mg/day of monensin. On d 85, heifers were allocated to individual drylot pens, provided free choice access to bermudagrass hay, and received their respective treatment for 10 d of adaptation and 11 d of data collection. Monensin did not impact (P ≥ 0.13) heifer BW, BCS, overall ADG, bahiagrass IVDOM, CP, herbage mass, and allowance. Supplement disappearance after 10 and 34 h of supplementation was greater for control vs. monensin heifers (P = 0.04) and tended to be greater for control vs. monensin heifers 24 h post-supplementation (P = 0.07). Plasma concentrations of glucose, IGF-1, and BUN (P ≥ 0.24) did not differ between treatments. From d 85 to 106, forage and total DM intake, in vivo DM digestibility, and heifer growth performance did not differ between treatments (P ≥ 0.12). Therefore, adding monensin to sugarcane molasses-based supplements decreased supplement consumption rate, but did not impact growth and blood parameters of heifers grazing warm-season grasses with limited nutritive value.

Dynamics of methanogenesis, ruminal fermentation, and alfalfa degradation during adaptation to monensin supplementation in goats

This study aimed to examine the temporal (hourly within a day and daily over the long term) effects of monensin on CH₄ emissions, ruminal fermentation, and in situ alfalfa degradation in dairy goats during dietary monensin supplementation by controlling the confounding effects of feed intake and ambient temperature. Six ruminally cannulated dairy goats were used, and they were housed in environmental chambers and fed a restricted amount of ration throughout the experiment. The experiment included a baseline period of 20 d followed by a treatment period of 55 d with 32 mg of monensin/d. During the whole experiment, CH₄ production was measured every 5 d, whereas fermentation characteristics and in situ alfalfa degradation were analyzed every 10 d. The CH₄-depressing effect of monensin was time dependent on the duration of treatment, highly effective at d 5 but thereafter decreased gradually until d 55 even though CH₄-suppressing effect still remained significant. The decreasing effects of monensin on ruminal acetate proportion and acetate to propionate ratio also faded over days of treatment, and the acetate proportion returned up to the pre-supplementation level on d 50. Monensin supplementation elevated ruminal propionate proportion and decreased the effective ruminal degradability of alfalfa NDF, but both measurements tended to recover over time. The postprandial increase rate of hourly CH₄ emissions was reduced, whereas that of propionate proportion was enhanced by monensin supplementation. However, the postprandial responses to monensin in CH₄ emission rates, ruminal VFA profiles, and in situ degradation kinetics declined with both hours after feeding and days of treatment. Our results suggest that the CH₄-suppressing effect of monensin supplementation in goats was attributed to reductions in both ruminal feed degradation and acetate to propionate ratio, but those reductions faded with time, hours after feeding, and days of treatment.

Degradabilidade de gramíneas, fermentação e protozoários no rúmen de bovinos em dietas com diferentes aditivos

RESUMO Quatro bovinos, com fistulas ruminais, foram alimentados em Quadrado Latino com os tratamentos compreendendo a adição diária no rúmen de: levedura (5g), monensina(200mg), Fator P (3g) e controle. Foram determinadas a Degradabilidade in situ de três capins tropicais (Tifton-85, Brachiaria e Mombaça e silagem de Mombaça), o pH ruminal, produção de ácidos graxos voláteis, N-amoniacal e população de protozoários. Não foi observada interação significativa entre tratamentos e capins e diferenças significativas entre os tratamentos, exceto na fração b da Brachiaria e silagem de Mombaça. O Mombaça apresentou alta solubilidade da MS e da FDN em relação aos demais capins e a Brachiaria maior solubilidade da PB. O processamento do Mombaça na forma de silagem promoveu redução fração solúvel e degradabilidades potencial (DE) e efetiva (DE) da MS e FDN e aumento da fração solúvel e DE da PB. A monensina promoveu menor produção de ácido acético, maior de propiônico e menor acético:propiônico em relação a controle. A levedura e Fator P apresentaram maior concentração total de AGCC que a monensina e controle. A monensina promoveu aumento de protozoários Diplodiniinae em relação à dieta controle, mas não houve diferença na contagem de Entodinium e de total de ciliados entre os tratamentos. Capins tropicais na forma de feno e de silagem apresentam diferentes degradabilidade ruminal não sendo influenciados por aditivos na dieta, com exceção da monensina no capim Brachiaria e silagem de Mombaça, mas estes afetam a fermentação e a população de protozoários no rúmen.

Effects of supplements containing different additives on nutritional and productive performance of beef cattle grazing tropical grass

A grazing trial was carried out to evaluate the inclusion of three feed additives in supplements (crude protein, CP 230 g/kg dry matter, DM) on the performance, voluntary intake, and digestibility of beef heifers grazing Brachiaria decumbens (CP 81 and neutral detergent fiber, NDF 615 g/kg DM). Thirty-five Nellore heifers (21 months of age and 383 ± 6.29 kg of body weight, BW) were used in a completely randomized design. The treatments were as follows: no supplement (control); supplement fed at 1 kg/animal/day without additives (S); supplement with monensin (S + M); supplement with yeast culture (S + YC); and supplement with enzyme complex (S + EC). All of the supplemented heifers had greater (P < 0.1) average daily gain (∼0.186 kg/day) compared to the control treatment (0.014 kg/day). Average daily gain and final BW were similar (P > 0.1) among supplemented heifers. Monensin inclusion in the supplement decreased (P < 0.1) forage DM (expressed as g/kg BW) and NDF intake (expressed as kg/day and as g/kg BW). All of the feed additive inclusions decreased (P < 0.1) NDF digestibility. In conclusion, the heifers' performance was improved by concentrate supplementation. However, the inclusion of additives did not enhance this effect.