Relationship between the structure and composition of rumen microorganisms and the digestibility of neutral detergent fibre in goats

Kaizhen Liu,Lizhi Wang,Tianhai Yan,Zhisheng Wang,Bai Xue,Quanhui Peng 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.1

Objective: This experiment was conducted to compare the structure and composition of ruminal microorganisms in goats with high and low neutral detergent fibre (NDF) digestibility. Methods: Nineteen crossbred goats were used as experimental animals and fed the same total mixed rations during the 30-day pre-treatment and 6-day digestion trialperiods. All faeces were collected during the digestion period for measuring the NDF digestibility. Then, high and the low NDF digestibility individuals were chosen for the high NDF digestibility group (HFD) and low NDF digestibility group (LFD), respectively. Rumen contents were collected for total microbial DNA extraction. The V4 region of the bacterial 16S rRNA gene was amplified using universal primers of bacteria and sequenced using high-throughput sequencer. The sequences were mainly analysed by QIIME 1.8.0. Results: A total of 18,694 operational taxonomic units were obtained, within 81.98% belonged to bacteria, 6.64% belonged to archaea and 11.38% was unassigned microorganisms. Bacteroidetes, Firmicutes, and Proteobacteria were the predominant microbial phyla in both groups. At the genus level, the relative abundance of fifteen microorganisms were significantly higher (p<0.05) and six microorganisms were extremely significantly higher (p<0.01) in LFD than HFD. Overall, 176 core shared genera were identified in the two groups. The relative abundance of 2 phyla, 5 classes, 10 orders, 13 families and 15 genera had a negative correlation with NDF digestibility, but only the relative abundance of Pyramidobacter had a positive correlation with NDF digestibility. Conclusion: There were substantial differences in NDF digestibility among the individual goats, and the NDF digestibility had significant correlation with the relative abundance of some ruminal microorganisms.

Assessment of cutting time on nutrient values, in vitro fermentation and methane production among three ryegrass cultivars

Wang Chunmei,Hou Fujiang,Wanapat Metha,Yan Tianhai,김은중,Scollan Nigel David 아세아·태평양축산학회 2020 Animal Bioscience Vol.33 No.8

Objective: The 3×3 factorial arrangement was used to investigate if either high water-soluble carbohydrates (WSC) cultivars or suitable time of day that the grass cut could improve nutrient values and in vitro fermentation characteristics. Methods: The 3 cultivars were mowed at 3 diurnal time points and included a benchmark WSC ryegrass cultivar ‘Premium’, and 2 high WSC cultivars AberAvon and AberMagic, which contained, on average, 157, 173, and 193 g/kg dry matter (DM) of WSC, and 36.0, 36.5, and 34.1 g/kg DM of N during 7th regrowth stage, respectively. The fermentation jars were run at 39°C with gas production recorded and sampled at 2, 5, 8, 11, 14, 17, 22, 28, 36, and 48 h. The rumen liquid was collected from 3 rumen fistulated cows grazing on ryegrass pasture. Results: High WSC cultivars had significantly greater WSC content, in vitro DM digestibility (IVDMD) and total gas production (TGP), and lower lag time than Premium cultivar. Methane production for AberMagic cultivar containing lower N concentration was marginally lower than that for AberAvon and Premium cultivars. Grass cut at Noon or PM contained greater WSC concentration, IVDMD and TGP, and lower N and neutral detergent fiber (NDF) contents, but CH4 production was also increased, compared to grass cut in AM. Meanwhile, the effects of diurnal cutting time were influenced by cultivars, such as in vitro CH4 production for AberMagic was not affected by cutting time. The IVDMD and gas production per unit of DM incubated were positively related to WSC concentration, WSC/N and WSC/NDF, respectively, and negatively related to N and NDF concentrations. Conclusion: These results imply either grass cut in Noon or PM or high WSC cultivars could improve nutrient values, IVDMD and in vitro TGP, and that AberMagic cultivar has a slightly lower CH4 production compared to AberAvon and Premium. Further study is necessary to determine whether the increase of CH4 production response incurred by shifting from AM cutting to Noon and/or PM cutting could be compensated for by high daily gain from increased WSC concentration and DM digestibility.

Laser methane detector-based quantification of methane emissions from indoor-fed Fogera dairy cows

Kobayashi, Nobuyuki,Hou, Fujiang,Tsunekawa, Atsushi,Yan, Tianhai,Tegegne, Firew,Tassew, Asaminew,Mekuriaw, Yeshambel,Mekuriaw, Shigdaf,Hunegnaw, Beyadglign,Mekonnen, Wondimeneh,Ichinohe, Toshiyoshi Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.8

Objective: Portable laser methane detectors (LMDs) may be an economical means of estimating CH₄ emissions from ruminants. We validated an LMD-based approach and then used that approach to evaluate CH₄ emissions from indigenous dairy cows in a dryland area of Ethiopia. Methods: First, we validated our LMD-based approach in Simmental crossbred beef cattle (n = 2) housed in respiration chambers and fed either a high- or low-concentrate diet. From the results of the validation, we constructed an estimation equation to determine CH₄ emissions from LMD CH₄ concentrations. Next, we used our validated LMD approach to examine CH₄ emissions in Fogera dairy cows grazed for 8 h/d (GG, n = 4), fed indoors on natural-grassland hay (CG1, n = 4), or fed indoors on Napier-grass (Pennisetum purpureum) hay (CG2, n = 4). All the cows were supplemented with concentrate feed. Results: The exhaled CH₄ concentrations measured by LMD were linearly correlated with the CH₄ emissions determined by infrared-absorption-based gas analyzer (r² = 0.55). The estimation equation used to determine CH₄ emissions (y, mg/min) from LMD CH₄ concentrations (x, ppm m) was y = 0.4259x+38.61. Daily CH₄ emissions of Fogera cows estimated by using the equation did not differ among the three groups; however, a numerically greater milk yield was obtained from the CG2 cows than from the GG cows, suggesting that Napier-grass hay might be better than natural-grassland hay for indoor feeding. The CG1 cows had higher CH₄ emissions per feed intake than the other groups, without significant increases in milk yield and body-weight gain, suggesting that natural-grassland hay cannot be recommended for indoor-fed cows. Conclusion: These findings demonstrate the potential of using LMDs to valuate feeding regimens rapidly and economically for dairy cows in areas under financial constraint, while taking CH₄ emissions into consideration.

Appropriate level of alfalfa hay in diets for rearing Simmental crossbred calves in dryland China

Nobuyuki Kobayashi,Fujiang Hou,Ausushi Tsunekawa,Xianjiang Chen,Tianhai Yan,Toshiyoshi Ichinohe 아세아·태평양축산학회 2018 Animal Bioscience Vol.31 No.12

Objective: In dryland areas of China, alfalfa hay (AH) is a possible substitute for concentrate feed for beef cattle. To evaluate the potential benefits of this substitution, we studied the effect of the ratio of AH intake to total dry matter (DM) intake on average daily body-weight gain (ADG), dietary energy utilization status, and economic benefit in Gansu province. Methods: In each of two feeding trials in 2016 (trial 1 [T1], July 3 to 17; trial 2 [T2], August 15 to September 23), crossbred male Simmental calves were allocated to low AH (LA), medium AH (MA), and high AH (HA) feeding groups (n = 4 per group). The target ADG was set as 1 kg for both trials. In a one-way-layout design based on conventional feeding practices in the province, calves received diets containing the different AH amounts, with a constant ratio of corn stover:total DM and decreasing rations of concentrate feed proportional to the increase in AH. Calves in T1 received AH at 15% (T1-LA), 23% (T1-MA), or 31% (T1-HA) of their dietary DM allowances; those in T2 received 9% (T2-LA), 24% (T2-MA), or 34% (T2-HA) AH. Results: Among the T1 groups, both ADG and economic benefit were highest in T1-LA; whereas in T2, they were higher in the T2-LA and T2-MA groups than in T2-HA. Energy digestibility did not significantly differ among the groups in either trial. The dietary AH inclusion ratios of 14% in the warm season and 8% to 21% in the cool season appeared to yield optimal ADG, metabolizable energy intake, and economic benefit. Conclusion: Low-level inclusion of AH, ranging from 8% to 21%, is a practical approach for beef cattle feeding. This modified feeding regimen likely will promote increased growth performance during the fattening stage of beef steers in dryland areas of Gansu province, China.