No abstract

Background Total fresh cassava root (FCR) production was 275 million tonnes in 2018 which equals 61.1 % of the total production, and Thailand produced 10.7 % FCR of the total production. FCR is one of the main energy source for ruminant. The limitation of FCR utilization is due to the presence of hydrogen cyanide (HCN). The study aimed to evaluate the effect of sulfur, urea and FCR at various levels on in vitro gas production, ruminal fermentation and in vitro degradability. The study hypothesized that: (1) sulfur, urea and FCR have no interaction effect and (2) effect of FCR and urea is related to sulfur addition. Results The study aimed to elucidate the optimum level of elemental sulfur, fresh cassava root (FCR) and urea and their effect on in vitro gas production, ruminal fermentation, thiocyanate concentration, and in vitro degradability. A 3 × 2 × 4 in a completely randomized design were conducted. Factor A was level of sulfur at 0 %, 1 and 2 % of concentrate dry matter (DM), factor B was level of urea at 2 and 4 % of concentrate DM, and factor C was level of the FCR at 0, 200, 300 and 400 mg DM of the total substrate. The study found that elemental sulfur, urea and FCR had no interaction effect on the kinetics of in vitro gas, ruminal fermentation, HCN and in vitro degradability. Elemental sulfur supplementation (P < 0.05) significantly increased the in vitro gas produced from an insoluble fraction (b), in vitro DM degradability and either neutral detergent fiber (NDF) or acid detergent fiber (ADF) degradability and propionate (C3) concentration while decreased the ruminal HCN concentration. Urea levels showed a (P < 0.05) significant increase of the potential extent of in vitro gas production, ruminal ammonia nitrogen (NH3-N) and total volatile fatty acid (TVFA). Fresh cassava root supplementation (P < 0.05) significantly increased the in vitro gas produced from an immediate soluble fraction (a), in vitro gas produced from insoluble fraction, in vitro gas production rate constant, total VFA, C3 concentration and HCN while decreased ruminal pH, acetate and butyrate concentration. It could be concluded that 2 % elemental sulfur, 4 % urea and 300 mg FCR showed a greater effect on in vitro gas production, ruminal fermentation and HCN reduction. Conclusions The study found that elemental sulfur, urea, and FCR had no interaction effect on the kinetics of in vitro gas, total in vitro gas, ruminal fermentation, and HCN concentration. It could be concluded that 2 % elemental sulfur, 4 % urea, and 300 mg FCR showed a greater effect on in vitro gas production, ruminal fermentation, and HCN reduction.

Fresh cassava roots that contain hydrocyanic acid (HCN) can be hazardous to animals when consumed. Prior literature has shown that adding sulfur may eliminate HCN without harming the health of animals. Additionally, adding urea is advised if sulfur was utilized since it helps with microbial protein synthesis. We thus proposed that supplementing the fresh cassava root diet with a high sulfur and urea in concentrate diet would be advantageous for rumen fermentation and milk production in animals. The purpose of this study was to see how high sulfur and urea levels in concentrate combinations affected feed utilization, rumen fermentation, and milk production in dairy cows fed diets including fresh cassava root. Four Holstein Friesian cows with 480 ± 50.0 kg BW, 10 ± 2 kg/head/day of milk yield, and 90 days in milk (DIM) were assigned at random in a 4 × 4 Latin square design with a 2 × 2 factorial design. Factor A was the concentration of sulfur in the concentrate diet at 10 g/kg and 20 g/kg dry matter (DM), while factor B was the concentration of urea in the concentrate diet at 10 g/kg and 20 g/kg DM. Fresh cassava root was given to each cow on a daily basis at a rate of 15 g DM/kg of BW. According to the findings, sulfur and urea had no interaction impact on feed intake, rumen fermentation, or milk production. Sulfur supplementation at 20 g/kg DM improved sulfur intake and digestibility of DM and organic matter much more than 10 g/kg sulfur. Additionally, sulfur supplementation at a dose of 20 g/kg DM in concentrate markedly increased blood and milk thiocyanate concentrations while lowering the somatic cell count. When compared to 10 g/kg DM urea, 20 g/kg DM urea significantly enhanced crude protein digestibility, ammonia-nitrogen concentration, blood urea nitrogen, and total volatile fatty acid concentration. Sulfur might detoxify hydrogen cyanide toxicity and be added at 20 g/kg DM in concentrate without harming the animals, whereas urea at 20 g/kg DM could increase feed digestion and rumen fermentation.

The study aimed to elucidate the optimum level of elemental sulfur, fresh cassava root (FCR), and urea and their effect on gas production, ruminal fermentation, thiocyanate concentration, and in vitro degradability. A 3&times;2&times;4 in a completely randomized design were conducted. Factor A was level of sulfur at 0%, 1%, and 2% of concentrate dry matter (DM), factor B was level of urea at 2% and 4% of concentrate DM, and factor C was level of the FCR at 0, 200, 300, and 400 mg of the total substrate. The study found that elemental sulfur, urea, and FCR had no interaction effect on the kinetics of gas, ruminal fermentation, hydrogen cyanide (HCN), and in vitro degradability. Elemental sulfur supplementation (P&lt;0.05) significantly increased the gas produced from an insoluble fraction (b), in vitro DM degradability and either neutral detergent fiber or acid detergent fiber degradability, and propionate (C3) concentration while decreased the ruminal HCN concentration. Urea levels showed a (P&lt;0.05) significant increase of the potential extent of gas production, ruminal NH3-N, and total volatile fatty acid (VFA). FCR supplementation (P&lt;0.05) significantly increased the gas produced from an immediate soluble fraction (a), gas produced from insoluble fraction, gas production rate constant, total VFA, C3 concentration, and HCN while decreased ruminal pH, acetate, and butyrate concentration. It could be concluded that 2% elemental sulfur, 4% urea, and 300 mg FCR showed a greater effect on gas production, ruminal fermentation, and HCN reduction.

This study aimed to study the effect of excessive elemental sulfur addition on intake, digestibility, rumen characteristics, blood metabolites and nitrogen balance in Thai native beef cattle fed diets containing high fresh cassava root (FCR) supplementation. Four Thai native beef cattle with an initial body weight (BW) of 100 ± 10.0 kg were used and randomly assigned to a 2 × 2 factorial in a 4 × 4 Latin square design. Two levels of FCR supplementation at 15 (FCR‐1.5) and 20 g/kg of BW (FCR‐2) and two levels of sulfur supplementation in concentrate at 10 (Sulfur‐1) and 20 g/kg dry matter concentrate (Sulfur‐2) were evaluated. This study showed that sulfur and FCR in combination (p < 0.05) increased dry matter and organic matter digestibility and bacterial population. Sulfur‐2 resulted in higher (p < 0.05) sulfur intake and serum thiocyanate concentration than Sulfur‐1. FCR‐2 had a greater (p < 0.05) FCR intake, total volatile fatty acids and propionate concentration than FCR‐1.5. In conclusion, excessive elemental sulfur addition with high FCR supplementation showed no negative effect in Thai native beef cattle.