Improving the nutrition of livestock is an important aspect of global food production sustainability. This study verified whether lactic acid bacteria (LAB) inoculant could promote ensiling characteristics, nutritive value, and in vitro enteric methane (CH₄) mitigation of forage sorghum (FS) mixture silage in attacking malnutrition in Zebu beef cattle. The FS at the soft dough stage, Cavalcade hay (CH), and cassava chip (CC) were obtained. The treatments were designed as a 4 × 2 factorial arrangement in a completely randomized design. Factor A was FS prepared without or with CH, CC, and CH + CC. Factor B was untreated or treated with Lactobacillus casei TH14. The results showed that all FS mixture silages preserved well with lower pH values below 4.0 and higher lactic acid contents above 56.4 g/kg dry matter (DM). Adding LAB boosted the lactic acid content of silages. After 24 h and 48 h of in vitro rumen incubation, the CC-treated silage increased in vitro DM digestibility (IVDMD) with increased total gas production and CH₄ production. The LAB-treated silage increased IVDMD but decreased CH₄ production. Thus, the addition of L. casei TH14 inoculant could improve lactic acid fermentation, in vitro digestibility, and CH₄ mitigation in the FS mixture silages.

The enteric methane conversion factor (Y_m) is an important country‐specific value for the provision of precise enteric methane emissions inventory reports. The objectives of this meta‐analysis were to develop and evaluate the empirical Y_m models for the national level and the farm level for tropical developing countries according to the IPCC's categorization. We used datasets derived from 18 in vivo feeding experiments from 1999 to 2015 of Zebu beef cattle breeds fed low‐quality crop residues and by‐products. We found that the observed Y_m value was 8.2% gross energy (GE) intake (~120 g methane emission head⁻¹ day⁻¹) and ranged from 4.8% to 13.7% GE intake. The IPCC default model (tier 2, Y_m = 6.5% ± 1.0% GE intake) underestimated the Y_m values by up to 26.1% compared with its refinement of 8.4% ± 0.4% GE intake for the national‐level estimate. Both the IPCC default model and the refined model performed worse in predicting Y_m trends at the farm level (root mean square prediction error [MSPE] = 15.1%–23.1%, concordance correlation coefficient [CCC] = 0.16–0.18, R² = .32). Seven of the extant Y_m models based on a linear regression approach also showed inaccurately estimated Y_m values (root MSPE = 16.2%–36.0%, CCC = 0.02–0.27, R² < .37). However, one of the developed models, which related to the complexity of the energy use efficiencies of the diet consumed to Y_m, showed adequate accuracy at the farm level (root MSPE = 9.1%, CCC = 0.75, R² = .67). Our results thus suggest a new Y_m model and future challenges for estimating Zebu beef cattle production in tropical developing countries.

Napier cultivars are widespread in the tropics. To effectively prepare two Napier grasses at the late maturity stageas silage for ruminant feedstock, the silage fermentation characteristics, aerobic stability, in vitro digestibility, and gas kinetics were studied. Napier Pakchong grass (NP) and sweet grass (SG) were harvested at 120 dof regrowth and untreated (control) or treated with normal or a double dose of cellulase, urea, and formic acid. After 30 d of ensiling, the pH values of silages (ranging from 3.91 to 7.79) were affected (p < 0.05) by additives and lower in control and cellulase-treated silages than in urea- and formic acid-treated silages. Adding cellulase resulted in greater lactic acid concentrations in SG silage. Adding urea boosted acetic acid, propionic acid, butyric acid, and ammonia nitrogen levels of silages. Adding formic acid spoiled silages and shortened the aerobic stability of NP silage. Compared with the control, the addition of cellulase at a double dose enhanced in vitrodry matter digestibility, and the gas production kinetics parameters of silages. Taking silage fermentation quality and in vitro dry matter digestibility into consideration, adding cellulase (0.2 g/kg fresh matter) to Napier grasses at the late maturity stage could be a better option compared with the other additives.

Improving the productive performance of agricultural residue silage has practical relevance to sustaining livestock production. Sweet corn stover (SCS) and cassava pulp (CSVP) are widespread in the tropics as low-cost feed resources. To efficiently prepare SCS and CSVP silage, the impact of adding Acremonium cellulase (AC), Lactobacillus casei strain TH14 inoculant (TH14), and their combination (AC+TH14) on ensiling characteristics, microbial population, chemical compositions, and in vitro digestibility were tested in comparison to control (no additive). After 60 d of ensiling, the pH value and ammonia nitrogen content of silage were lower (p < 0.05) when AC was used as the additive. Compared with other treatments, TH14 provided abundant lactic acid fermentation in silage. All tested additives increased the crude protein (CP) content and decreased the neutral detergent fiber (NDF) content of SCS silage. In CSVP silage, only AC and AC+TH14 altered the CP and NDF content. In addition, AC and AC+TH14 provided greater in vitro dry matter digestibility and a lower in vitro fiber digestibility. Overall, optimized either AC or TH14 can be recommended as an attractive additive to improve the ensiling characteristics of SCS and CSVP silage. AC significantly modifies the in vitro digestibility of silage.

Yeast (Saccharomyces cerevisiae) has been used to improve the nutritive value of feedstuffs, especially rubber seed kernel. In the current study, rubber seed kernel was grated and subjected to solid-state fermentation with yeast to enhance the nutritive value. The yeast-fermented rubber seed kernel (YERSEK) was substituted for soybean meal in ruminant diets to evaluate the effect of YERSEK on feed intake, digestibility, rumen fermentation and microbial protein synthesis in dairy heifers. Five Holstein Friesian crossbred heifers with an initial body weight (BW) of 215 ± 20 kg were used in this research. The experimental design was a 5 × 5 Latin squared design and the dietary treatments were five levels of YERSEK at 0, 100, 150, 200 and 250 g/kg dry matter in concentrate at 1% of BW, with rice straw fed ad libitum. The supplementation with YERSEK reduced rice straw and total DM intake linearly (p < 0.05). The intake of neutral detergent fiber and acid detergent fiber decreased linearly (p < 0.05), while ether extract intake increased linearly (p < 0.01) with YERSEK supplementation. The ether extract digestibility tended to be high (p < 0.01) with increasing levels of YERSEK. Supplementation with the YERSEK did not change (p > 0.05) ruminal pH and blood urea nitrogen in this study, but ruminal ammonia nitrogen was increased (p < 0.01) in the heifers receiving YERSEK. Increasing the YERSEK levels did not adversely affect the proportion of volatile fatty acids (VFA), which included acetate, propionate and butyrate and the microbial population (p > 0.05). Microbial protein synthesis was similar among the treatments (p > 0.05). The inclusion of YERSEK at 250 g/kg DM in concentrate feed had no effect on the utilization of feed, rumen fermentation characteristics and microbial protein synthesis. The YERSEK could be used as a protein replacement for up to 86% of the soybean meal in feed concentrate for dairy heifers.

This experiment was conducted to assess the effect of hydrolyzed yeast (HY) on growth performance, nutrient digestibility, rumen fermentation, and hematology in growing crossbred Bos indicus cattle. Twenty crossbred beef cattle with an initial body weight (BW) of 142 ± 12 kg were randomly assigned to one of four treatments for 90 d in a randomized complete block design (RCBD) having five blocks based on a homogenous subpopulation of sex and BW. Cattle were fed with a total mixed ration (TMR) and supplemented with HY at 0, 1, 2, and 3 g/kg dry matter (DM), respectively. Supplementation with the HY did not change average daily gain (ADG), dry matter intake (DMI), and gain to feed ratio (G:F) (p ≥ 0.06). The addition of HY did not adversely affect nutrient intake (p ≥ 0.48), while the digestibility of crude protein (CP) increased quadratically (p= 0.03) in the cattle receiving HY. The addition of HY did not affect rumen pH, but NH₃-N concentration increased linearly (p = 0.02) in the cattle. The total volatile fatty acid (total VFA) increased quadratically (p= 0.03) when cattle were fed with HY supplementation. The proportion of acetate decreased cubically (p= 0.03) while propionate increased cubically (p= 0.01), resulting in a decrease in the acetate to propionate ratio (p= 0.01) when cattle were fed with HY supplementation. In addition, acetate was the lowest, but total VFA and propionate were the highest in cattle fed the HY at 2 g/kg DM. Butyrate increased cubically (p = 0.02) with the addition of HY. The protozoal and fungal populations were similar among treatments (p ≥ 0.11), but the bacterial population increased linearly (p < 0.01) with the addition of HY. Supplementation of HY did not influence blood urea nitrogen (BUN), red blood cells (RBC), hemoglobin, hematocrit, white blood cells (WBC), lymphocytes, or eosinophils (p≥ 0.10). However, monocytes and neutrophils increased linearly (p = 0.04 and p = 0.01, respectively) by HY supplementation. In conclusion, supplementation of HY at 2 g/kg DM promotes CP digestibility, rumen fermentation efficiency, and hematology but does not affect the growth performance of growing beef cattle.