Probabilistic Risk Assessment of Polioencephalomalacia from Texas Beef Consuming Rations Containing Multiple Sources of Dietary Sulfur

The purpose of this probabilistic assessment was to estimate the risk of sulfur-induced polioencephalomalacia (S-PEM) for beef raised across Texas, from a dietary perspective. Ruminant nutritionists in Amarillo, TX, formulated two typical nutritional regimens based on cattle production stages, each containing six feed ingredients and well water. The Office of the Texas State Chemist (OTSC), National Research Council (NRC), and the published literature provided S data for feed ingredients. The Texas Water Development Board provided data for S content in Texas well water, categorized into twelve districts established by the Texas A&M AgriLife Research Extension Service. The S-PEM risk was estimated at five different eNDF levels ranging from 0% to 8% in 2% increments, using rumen degradable S (RDS) as an input value. Findings identified cattle raised in the South Plains district as the most susceptible population to S toxicity, with beef in the finishing production stage experiencing increased sensitivity. The most potential (MP) risk scenario suggested that the S-PEM risk could reach 28.5% for growers and 100% for finishers. Results further revealed that when S concentrations in well water exceeded 14.5 mg/L, water became the greatest contributor to RDS content for Texas beef, suggesting that high S content in well water is the most prominent concern for Texas beef.

Ruminal effects of excessive dietary sulphur in feedlot cattle

Sulphur (S) dietary excess can limit productive performance and increase polioencephalomalacia (PEM) incidence in feedlot cattle (FC). Sulphur excess ingested is transformed to hydrogen sulphide (H₂ S) by sulfo-reducing ruminal bacteria (SRB), being high ruminal H₂ S concentration responsible for aforementioned damages. As the ruminal mechanisms involved in H₂ S concentrations increase have not been elucidated, this study aimed to evaluate the ruminal environment, and the association between ruminal H₂ S and dissimilatory SRB (DSRB) concentration in FC experimentally subjected to S dietary excess. Twelve crossbred steers were randomly assigned to one of two dietary S levels (6 animals per treatment): low (LS, 0.19% S) and high (HS, 0.39% S obtained by sodium sulfate inclusion at 0.86%). The study lasted 38 days, and on days 0, 22 and 38, ruminal gas samples were taken to quantify H₂ S concentration, and ruminal fluid to determine total bacteria, DSRB, protozoa, volatile fatty acid and ammonia nitrogen concentration. For ruminal H₂ S concentration, S dietary × sampling day interaction was significant (p < 0.001), so that the greater concentration was observed on days 22 and 38 with the HS diet. The remaining ruminal parameters were not affected by dietary S level, and no significant correlation between H₂ S and DSRB concentrations was observed. The ruminal adaptation that maximizes H₂ S production in FC consuming S excess does not seem to be associated with biological or biochemical alterations, nor DSRB concentration changes. The microbial diversity and ruminal environment were resilient to the S excess evaluated, suggesting that 0.39% of dietary S achieved by 0.86% sodium sulfate addition, could be used without disturbances on digestion nor health of FC.

Dual-purpose crops: the potential to increase cattle liveweight gains in winter across southern Australia

Context Dual-purpose wheat (Triticum aestivum L.) and canola (Brassica napus L.) crops have been extensively researched for grazing in Australian farming systems, with a focus on grazing by sheep. In some regions, dual-purpose crops have been grazed by cattle, but there have been reports of animal health problems. Aims This paper sought to collate all known experiments conducted throughout Australia of cattle grazing dual-purpose crops, in order to evaluate grazing management options for cattle on dual-purpose crops that result in high growth rates and good animal health outcomes. Methods There were six experiments. In Expts 1–3, cattle were grazed on wheat crops with and without available mineral supplementation of NaCl and MgO in a 1:1 ratio. In Expt 3, lime was also added to the mineral mix. In Expts 4 and 5, dual-purpose crops were grazed in combination with annual pastures to determine whether strategic use of dual-purpose crops could increase whole farm livestock productivity. In Expt 6, cattle were introduced to dual-purpose canola with different periods of adaptation (0, 4 and 7 days). Liveweight gain was monitored regularly to assess differences between adaptation treatments. Key results Liveweight gain was increased by 0–27% when cattle grazing high quality, dual-purpose wheat were provided with mineral supplement. Cattle had an initial lag in growth rate when introduced to dual-purpose canola for grazing and this was not affected by the adaptation strategy used. Cattle that experienced a shorter adaptation period achieved higher weight gains more quickly. After the lag phase, average daily gain (ADG) was ≥2 kg/head.day, with an ADG over the entire grazing period for all treatments of 1.75 kg/head.day. The effect on the farm system was determined by extending the length of the grazing period on the dual-purpose crops. Grazing periods of shorter duration did not increase overall liveweight gains compared with grazing only pasture, whereas extending the period of dual-purpose crop grazing resulted in increased cattle weights. Conclusions Cattle benefit from the addition of mineral supplements when grazing a dual-purpose wheat crop, with a response similar to that previously demonstrated in sheep. Cattle can safely graze dual-purpose canola and achieve high ADG. Inclusion of dual-purpose crops can improve overall cattle performance in the farming system. Implications The potential area for production of dual-purpose crops within the Australian mixed farming zone is large and there may be insufficient livestock numbers within the zone to utilise the potential forage production. Cattle from other regions could be introduced during autumn and winter to realise this large forage potential during a period that is commonly a feed deficit on grazing-only properties. Estimates suggest that up to two million young cattle could be supported for 60 days, increasing liveweight by 90 kg/head.

Biofuels Co-Products Tolerance and Toxicology for Ruminants: An Update

Corn co-products are a co-product of the dry and wet corn-milling ethanol manufacturing industry. The dry mill corn co-product is distiller's grains. Distillers grain can be further categorized into dry distillers grains (DDG), DDG with solubles, wet distillers grains with solubles (WDGS), modified WDGS, and corn syrup (solubles). Wet mill ethanol production produces 2 main feed stuffs: corn gluten (wet and dry) and heavy steep water.

Effects of Sulfur Levels in Fermented Total Mixed Ration Containing Fresh Cassava Root on Feed Utilization, Rumen Characteristics, Microbial Protein Synthesis, and Blood Metabolites in Thai Native Beef Cattle

Simple Summary

Feeding of fresh cassava root to animals is restricted because it contains hydrocyanic acid at a high level, which is the origin for poisoning. High levels of hydrocyanic acid from fresh cassava root could be detoxified by sulfur addition to become nontoxic to cattle. The addition of 2% sulfur in a fermented total mixed ration containing fresh cassava root and ensiling for 7 days could improve dry matter digestibility, efficiency of microbial protein synthesis, and concentrations of total volatile fatty acid, propionic acid, and blood thiocyanate.

Abstract

The influence of sulfur included in fermented total mixed ration (FTMR) containing fresh cassava root on rumen characteristics, microbial protein synthesis, and blood metabolites in cattle was evaluated. Four Thai native beef cattle were randomly assigned according to a 2 × 2 factorial in a 4 × 4 Latin square design, and dietary treatments were as follows: factor A included a level of sulfur at 1% and 2% in total mixed ration, and factor B featured ensiling times at zero and 7 days. Digestibility of dry matter was increased when FTMR was supplemented with 2% sulfur. Blood thiocyanate increased by 69.5% when ensiling time was 7 days compared to no ensiling (p < 0.01). Bacterial populations were significantly different in the FTMR containing sulfur at 2% and 7 days of ensiling. Furthermore, microbial crude protein and efficiency of microbial protein synthesis were higher in the FTMR containing 2% sulfur and 7 days of ensiling (p < 0.01). Thus, high levels of hydrocyanic acid from fresh cassava root could be detoxified by a sulfur addition with an ensiling process to become nontoxic to cattle.