The effect of feeding a mix of condensed and hydrolyzable tannins to heifers on rumen fermentation patterns, blood urea nitrogen, and amino acid profile

Impact of growth implants and low-level tannin supplementation on enteric emissions and nitrogen excretion in grazing steers

The primary objective of this experiment was to evaluate the effects of a growth-hormone implant (Revalor-G, Merck Animal Health., Rahway, NJ, USA) and tannin supplementation (Silvafeed BX, Silva Team, San Michele Mondovi CN, Italy) on enteric methane (CH4) emissions and estimated nitrogen (N) excretion in grazing steers. Steers (n = 20; initial body weight [IBW] = 343 ± 14 kg) were acclimated to use a portable automated head-chamber system (AHCS) to measure CH4 and a SmartFeed Pro automated feeder for dietary supplementation (C-Lock Inc., Rapid City, SD, USA). After the training period, steers were randomly assigned to a 2 × 2 factorial arrangements of treatments, with 2 levels of growth-hormone implants, no-implant (NO-IMP) or implanted (IMP), and 2 levels of tannin supplementation, no tannin supplementation (NO-TAN) or tannin supplementation (TAN). This created 4 treatment groups: (1) NO-TAN and NO-IMP, (2) TAN and NO-IMP, (3) IMP and NO-TAN, and (4) TAN and IMP. Tannin was offered daily at 0.30% dry matter intake (DMI) through 0.5 kg/hd/d sweetfeed supplement (Sweetfeed Mix, AgFinity., Eaton, CO, USA) with a targeted tannin intake at 48 g/hd/d. No (P ≥ 0.05) implant × tannin interaction was detected for any dependent variable, so only the main effects of implant (NO-IMP vs. IMP) and tannin supplementation (NO-TAN vs. TAN) are discussed. Implant status did not affect (P ≥ 0.56) final body weight (FBW) or average daily gain (ADG) during the 90 d grazing period. There was no effect (P ≥ 0.15) of growth implant on CH4 production or emission intensity (EI; g CH4/kg gain). Additionally, IMP steers tended (P ≤ 0.08) to have less CH4 yield (MY; g CH4/g DMI) and higher blood urea nitrogen (BUN) than NO-IMP steers. Tannin supplementation did not impact (P ≥ 0.26) FBW or ADG. However, NO-TAN steers tended (P = 0.06) to have a greater total DMI than steers supplemented with tannin. No effect (P ≥ 0.22) of tannin supplementation was observed for CH4 production and EI. Nitrogen utilization as measured through BUN, urine N, fecal N, or fecal P was similar (P ≥ 0.12) between TAN and NO-TAN animals. The findings indicate that low-level dietary supplementation to reduce enteric emissions is difficult in grazing systems due to inconsistent animal intake and that growth implants could be used as a strategy to improve growth performance and reduce EI of steers grazing improved pasture.

Mitragyna speciosa Korth Leaf Pellet Supplementation on Feed Intake, Nutrient Digestibility, Rumen Fermentation, Microbial Protein Synthesis and Protozoal Population in Thai Native Beef Cattle

This experiment evaluated the use of Mitragyna speciosa Korth leaf pellets (MSLP) on feed intake and nutrient digestibility in Thai native beef cattle. Four Thai native beef cattle steers were randomly assigned according to a 4 × 4 Latin square design to receive four dietary treatments. The treatments were as follows: control (no supplementation), MSLP supplement at 10 g/hd/d, MSLP supplement at 20 g/hd/d and MSLP supplement at 30 g/hd/d, respectively. All animals were fed a concentrate mixture at 0.5% body weight, while urea lime-treated rice straws were fed ad libitum. Findings revealed that feed intakes were increased by MSLP, which also significantly increased the digestibility of dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF). Ruminal total volatile fatty acid (TVFA) concentration and propionate (C3) proportion were increased (p < 0.05) with MSLP supplementation, whereas ruminal ammonia-N (NH3-N), plasma urea nitrogen (PUN), acetate (C2), C2:C3 ratio and estimated methane (CH4) production decreased (p < 0.05). Total bacterial, Fibrobacter succinogenes and Ruminococus flavefaciens populations increased (p < 0.05) at high levels of MSLP supplementation, while protozoal populations and methanogenic archaea reduced (p < 0.05). Supplementation of MSLP also increased the efficiency of microbial nitrogen protein synthesis. Supplementing beef cattle with MSLP 10−30 g/hd/d significantly increased rumen fermentation end products and nutrient digestibility by mitigating protozoal populations and estimated CH4 production.