Background and Aim: Hydrolyzable tannins are an important group of secondary plant metabolites, which are known for antimicrobial activity. This study aimed to assess the efficiency with which a hydrolyzable tannin extract from sweet chestnut wood (Castanea sativa Mill.) could inhibit mastitis-causing bacteria in vitro. Materials and Methods: The negative control used was sterile water, and the positive controls were penicillin and gentamicin. The treatments included five concentrations of hydrolyzable tannins (63, 190, 313, 630, and 940 mg/mL). In cows with subclinical mastitis, the bacteria causing the disease were isolated and identified. Then, the antibacterial activity of the hydrolyzable tannin extract was assessed by the disk diffusion method, by determining the minimum inhibitory concentration (MIC) and by determining the minimum bactericidal concentration (MBC). Results: Penicillin inhibited (p0.05) the growth of Streptococcus agalactiae, Escherichia coli, and Klebsiella pneumoniae. However, gentamicin and hydrolyzable tannins could inhibit (p<0.01) all isolated bacteria. Increasing the concentration of hydrolyzable tannin extract resulted in a quadratic increase in the inhibition zone diameter of S. aureus and S. agalactiae and a linear increase in the inhibition zone diameter of E. coli, K. pneumoniae, and P. aeruginosa. In addition, 630 and 940 mg/mL of hydrolyzable tannin extract showed the highest antibacterial activity against S. agalactiae and E. coli (p<0.01), while 940 mg/mL concentration had the highest antibacterial activity against K. pneumoniae (p<0.01). The MIC and MBC of the extract were 27.3-190 mg/mL and 58.8-235 mg/mL, respectively, with the MBC: MIC ratio being 2:1. Conclusion: The antimicrobial activity of the hydrolyzable tannin extract against subclinical mastitis bacteria was comparable to the antibiotics (positive controls) at concentrations over 630 mg/mL. Although these in vitro findings are promising, further research is needed to determine whether hydrolyzable tannins could be used to control or prevent subclinical mastitis in dairy cows.

The objective of this study was to evaluate the effects of supplementation with a feed additive containing a combination of betaine, biotin, and chromium (BBC) and concentrate-to-roughage ratio (C:R ratio) on nutrient digestibility, blood metabolites, ruminal fermentation, nitrogen balance, and energy utilization in Thai native beef cattle. Five Thai feedlot native beef bulls at one year old of age and 87.6 ± 15.7 kg of body weight were assigned in a (2 × 2) + 1 augmented factorial experiment according to a 5 × 5 Latin square design with five periods of 21 days. The two levels of BBC were 3 g/kg DM and 6 g/kg DM, and the two ratios of C:R were 60C:40R and 70C:30R. A C:R ratio of 70C:30R without BBC supplementation was used as a negative control. The cattle were offered feed at 3% BW, which provides sufficient energy and protein to support a weight gain of 500 g/day. The results showed that dry matter intake (DMI) and organic matter intake (OMI) were not different (p > 0.05), but the intake of crude protein (CP) and ether extract (EE) was higher (p < 0.05), whereas neutral detergent fiber (NDF) and acid detergent fiber (ADF) were lower (p < 0.05) in the 70C:30R ratio diets compared to the 60:40R ratio diets. Energy balance and nitrogen balance were not influenced (p > 0.05) by the C:R ratio or the addition of BBC. Rumen pH and ammonia-nitrogen (NH₃-N) did not differ (p > 0.05) among treatments groups. Total volatile fatty acid (VFA) production was higher (p < 0.05) in bulls fed with the 70C:30R ratio diet. The addition of BBC resulted in a lower (p < 0.01) glucose-to-insulin ratio compared to cattle fed with the control diet. Energy and protein utilization efficiency did not differ (p > 0.05) among the experimental treatment groups, which were higher (p > 0.05) than the control group. In conclusion, BBC supplementation showed greater growth performance of cattle compared to the control. BBC supplementation appeared to improve glucose uptake and insulin sensitivity and energy and protein utilization efficiency. Whether BBC supplementation increases glucose production in the liver remains to be determined in future studies.

Effects of feeding modified cassava chip and corn seed as energy source inclusion in diet were investigated on growth performance, rumen fermentation, and blood metabolites in early fattening bulls. Thirty-six 1-year-old Charolais crossbred bulls with initial weight 270 ± 50 kg were randomly assigned into 6 groups with different experimental rations as cassava-based concentrates including non-modified cassava chip (Cass-Con), with 15 % of alkaline-treated cassava chip (Cass-Alkaline), with 15 % of steam-treated cassava chip (Cass-Steam) and corn-based concentrates including non-modified corn seed (Corn-Con), with 15 % of alkaline-treated corn seed (Corn-Alkaline), and with 15 % of steam-treated corn seed (Corn-Steam), according to completely randomized design (CRD). Results showed that feed intake and digestibility were not significantly different among treatments, while digestible dry matter and organic matter intake of Cass-Steam and Corn-Alkaline were higher than those of the other diets (P < 0.05). Ruminal pH post-feeding was highest in Corn-Alkaline and lowest in Cass-Con (P < 0.05). Blood glucose was similar among treatments. However, blood insulin at 4 h post-feeding was higher in Cass-Steam, Corn-Alkaline, and Corn-Steam than in the others. Blood insulin in bulls fed corn-based concentrate was higher than in bulls fed cassava-based concentrate (P < 0.01). Body weight gain and average daily gain were significantly higher (P < 0.05), while feed conversion ratio was lower in Cass-Steam, Corn-Alkaline, and Corn-Steam as compared with in Cass-Con, Cass-Alkaline and Corn-Con. Results indicated that using a modified energy source can improve growth performance in early fattening beef bulls. An appropriate method to modify cassava chip was steam method, while alkaline method for corn seed was superior.

Eighteen Wagyu crossbred steers (average initial body weight: 596.9 ± 46.4 kg; average age: 36 ± 2.7 months) were subjected to three levels of betaine–biotin–chromium (BBC) supplementation for 98 days before slaughter. Animals were fed a basal diet and BBC supplemented at 0, 3 or 6 g/kg of dry matter (DM). The experimental design was a randomized complete block design by a group of animals with six replicates. The intake and digestibility among treatments were not different (p > 0.05). The average daily gain (ADG) of steers that received BBC at 6 g/kg of DM (0.79 kg/day) tended to be higher (p = 0.07) than that of those receiving BBC at 0 and 3 g/kg/day (0.52 and 0.63 kg/day, respectively). Blood metabolites were not different (p > 0.05) among treatments. Carcass characteristic traits included chilled carcass dressing percentage and loin eye area, while meat quality included drip loss, cooking loss, and Warner-Bratzler shear force were not different (p > 0.05). Back fat thickness tended to be higher (p = 0.07) in steers fed BBC at 6 g/kg. The marbling score did not differ (p > 0.05) among treatments; however, the intramuscular fat content of the longissimus dorsi (LD) on a DM basis was significantly higher (p < 0.05) in steers fed BBC at 6 g/kg (39.8% DM) than in those fed BBC at 0 g/kg (28.2% DM) and at 3 g/kg (29.1% DM). Based on the findings, BBC supplementation had no effect on growth performance and carcass characteristics; however, BBC at 6 g/kg DM increased fat content in LD muscle of finishing Wagyu crossbred steers.

Objective: This study aimed to evaluate the effects of incorporating unqualified cacao pod powder into beef cattle diets on nutrient digestibility, rumen fermentation, greenhouse gas emissions, and blood metabolites.Methods: A 4×4 Latin square design was used with four of Brahman×Thai native crossbred steers (207.1±45.1 kg body weight). Treatments included; T1: a control (no supplement), T2: supplemented with 50 g/d of cacao powder, T3: supplemented with mineral block containing cacao powder and T4: both supplemented with 50 g/d of cacao powder and mineral block containing cacao powder.Results: Results showed no significant effect on feed intake, but polyphenol and tannin intake increased (p<0.01). Apparent digestibility of dry matter, organic matter, protein, and both detergent fibers increased with cacao supplementation (p<0.01). Rumen pH, total volatile fatty acid, and acetate concentrations increased, while methane and carbon dioxide emissions were reduced (p<0.01). Blood urea nitrogen levels decreased (p<0.05), while concentrations of white blood cells, red blood cells, hemoglobin, and lymphocyte percentage remained unchanged. The neutrophil percentage tended to decrease, as same as, the neutrophil to lymphocyte ratio in the supplemented groups (p = 0.06 and p = 0.08, respectively).Conclusion: These findings suggest that unqualified cacao pods can enhance nutrient utilization and mitigate enteric methane emissions, offering a sustainable strategy for valorizing cacao byproducts in ruminant production.