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This study evaluated the effect of feeding ergot contaminated grain continuously or intermittently through backgrounding (BG) and finishing (FN) in a mash or pelleted supplement on the growth performance, health and welfare parameters, and carcass characteristics of feedlot beef steers. Sixty black Angus steers (300 ± 29.4 kg BW) were used in a complete randomized 238-d study. Steers were stratified by weight and randomly assigned to four different diets (15 steers/treatment) and individually housed. Treatments included: (1) control [CON; no added ergot alkaloids (EA)], (2) continuous ergot mash (CEM; fed continuously at 2 mg total EA/kg of DM), (3) intermittent ergot mash (IEM; fed at 2 mg total EA/kg of DM, during the first week of each 21-d period and CON for the remaining 2 wk, this feeding pattern was repeated in each period), and (4) intermittent ergot pellet (IEP; fed at 2 mg of total EA/kg of DM as a pellet during the first week of each 21-d period and CON for the remaining 2 wk as described for IEM). Steers were fed barley based BG diets containing 40% concentrate:60% silage (DM basis) for 84 d (four 21-d periods), transitioned over 28 d (no ergot fed) to an FN diet (90% concentrate:10% silage DM basis) and fed for 126 d (six 21-d periods) before slaughter. In the BG phase, steer DMI (P< 0.01, 7.45 vs. 8.05 kg/d) and ADG (P< 0.01) were reduced for all EA diets compared to CON. The CEM fed steers had lower ADG (P< 0.01, 0.735 vs. 0.980 kg) and shrunk final BW (P< 0.01, 350 vs. 366 kg) than CON. CEM had lower gain:feed (P< 0.07, 0.130 vs. 0.142) than CON. In the FN phase, steer DMI (P< 0.01, 9.95 vs. 11.05 kg/d) and ADG (P= 0.04) were also decreased for all EA fed steers compared to CON. Total shrunk BW gain (P = 0.03, 202.5 vs. 225.2 kg), final BW (P= 0.03, 617.9 vs. 662.2 kg), and carcass weight (P= 0.06) decreased for all EA fed steers compared to CON. The percentage of AAA carcasses decreased for all EA fed steers (P< 0.01, 46.7 vs. 93.3%) compared to CON. EA fed steers had increased rectal temperatures (P< 0.01, 39.8 vs. 39.4 °C) compared to CON. Pelleting ergot contaminated grain did not reduce the impact of ergot alkaloids on any of the measured parameters during BG or FN. Continuously or intermittently feeding ergot contaminated diets (2 mg total EA/kg of DM) significantly reduced intake, growth performance, and carcass weight, with minimal impact on blood parameters in feedlot steers. Pelleting was not an effective method of reducing ergot toxicity.This study evaluated the effect of continuous or intermittent feeding EA in a mash or pelleted form on growth performance, health and welfare parameters, and carcass characteristics of feedlot beef steers. Continuously or intermittently feeding an ergot contaminated diet (2 ppm EA) both reduced intake, growth performance, and carcass weight, but pelleting did not reduce the toxicities of EA.Produced by the fungus Claviceps purpurea, ergot alkaloids (EA) are toxic to beef cattle when consumed and can lead to reduction in feed intake and growth performance, vasoconstriction of the blood vessels, hyperthermia, damage to extremities (ears, tails, and hooves) and in severe cases, death. Grain is often cleaned to meet quality standards, and the resulting screenings are often utilized for feeding livestock and can have high concentrations of EA. The application of heat during pelleting of EA contaminated grain has been suggested to reduce its toxicity. Backgrounding and finishing beef cattle feeding experiments were conducted to assess the effect of continuously or intermittently feeding EA contaminated grain (2 mg/kg of diet DM) either as a pellet or as mash on growth performance, health, and animal welfare. Feeding EA grain continuously or intermittently either as a mash or pellet drastically reduced growth performance of steers, with no difference between treatments.

The rumen simulation technique (RUSITEC) was used to investigate the effect of ergot alkaloids (EA) and a mycotoxin deactivating product (Biomin AA; MDP) on nutrient digestion, ruminal fermentation parameters, total gas, methane, and microbial nitrogen production. Ruminal fermentation vessels received a feedlot finishing diet of 90:10 concentrate:barley silage (DM basis). Using a randomized complete block design, treatments were assigned (n= 4 vessels/treatment) within two RUSITEC apparatuses in a 2 × 2 factorial arrangement. Treatments included: (1) control (CON) diet (no EA and no MDP); (2) CON diet + 1 g/d MDP; (3) CON diet + 20 mg/kg EA; and (4) CON diet + 20 mg/kg EA + 1 g/d MDP. The study was conducted over 14 d with 7 d of adaptation and 7 d of sample collection. Data were analyzed in SAS using PROC MIXED including fixed effects of EA, MDP, and the EA×MDP interaction. Random effects included RUSITEC apparatus and cow rumen inoculum (n= 4). Ergot alkaloids decreased dry matter (DMD) (P= 0.01; 87.9 vs. 87.2%) and organic matter disappearance (OMD) (P= 0.02; 88.8 vs. 88.4%). Inclusion of MDP increased OMD (P= 0.01; 88.3 vs. 88.9%). Neutral detergent fiber disappearance (NDFD) was improved with MDP; however, an EA×MDP interaction was observed with MDP increasing (P< 0.001) NDFD more with EA diet compared to CON. Acetate proportion decreased (P= 0.01) and isovalerate increased (P= 0.03) with EA. Consequently, acetate:propionate was reduced (P= 0.03) with EA. Inclusion of MDP increased total volatile fatty acid (VFA) production (P< 0.001), and proportions of acetate (P= 0.03) and propionate (P= 0.03), and decreased valerate (P< 0.001), isovalerate (P= 0.04), and caproate (P= 0.002). Treatments did not affect (P≥ 0.17) ammonia, total gas, or methane production (mg/d or mg/g of organic matter fermented). The inclusion of MDP reduced (P< 0.001) microbial nitrogen (MN) production in the effluent and increased (P= 0.01) feed particle-bound MN. Consequently, total MN decreased (P= 0.001) with MDP. In all treatments, the dominant microbial phyla were Firmicutes, Bacteroidota, and Proteobacteria, and the major microbial genus was Prevotella. Inclusion of MDP further increased the abundance of Bacteroidota (P= 0.04) as it increased both Prevotella(P= 0.04) and Prevotellaceae_UCG-003 (P= 0.001). In conclusion, EA reduced OMD and acetate production due to impaired rumen function, these responses were successfully reversed by the addition of MDP.Ergot alkaloids can affect ruminal metabolism of cattle, which can have large impacts on production, welfare, and health. Mycotoxin deactivators can alleviate some of the negative impacts that dietary ergot has on cattle.Ergot formed from a parasitic fungus (Claviceps purpurea) affects various types of grains (rye, wheat, or oats) and may contain several toxic ergot alkaloids (EA). Individual EA may impact the rumen microorganisms, and cattle feed intake, digestibility, health, and overall performance. A common method to alleviate toxicity in mycotoxin-contaminated feed is through the addition of mycotoxin binders (MDP); however, their efficacy against EA is unknown. To better understand the effect of EA in cattle, we performed an in vitroexperiment to examine the impact of EA on the ruminal microbial populations and fermentation of a finishing feedlot diet using an artificial rumen (RUSITEC). Additionally, an MDP was added to test if it could reduce the detrimental effects of EA on rumen fermentation. MDP increased total volatile fatty acids (VFA) and reduced total microbial protein synthesis. Furthermore, EA reduced microbial diversity and the acetate:propionate ratio. Although EA reduced organic matter digestibility and acetate production, these negative effects were reversed by the addition of the MDP.