A relatively stable microbial ecological balance system in the rumen plays an important role in rumen environment stability and ruminant health maintenance. No studies have reported how rumen fluid transplantation (RFT) affects the composition of rumen microorganisms and yak growth performance. In this experiment, we transplanted fresh rumen fluid adapted to house-feeding yaks to yaks transitioned from natural pastures to house-feeding periods to investigate the effects of rumen fluid transplantation on rumen microbial community regulation and production performance. Twenty yaks were randomly divided into the control group (CON; n = 10) and the rumen fluid transplantation group (RT; n = 10). Ten yaks that had been adapted to stall fattening feed in one month were selected as the rumen fluid donor group to provide fresh rumen fluid. Ruminal fluid transplantation trials were conducted on the 1st, 3rd, and 5th. Overall, 1 L of ruminal fluid was transplanted to each yak in the RT and CON group. The formal trial then began with both groups fed the same diet. After this, growth performance was measured, rumen fluid was collected, and rumen microbial composition was compared using 16s rRNA sequencing data. The results showed that rumen fluid transplantation had no significant effect on yak total weight gain or daily weight gain (p > 0.05), and feed efficiency was higher in the RT group than in the CON group at 3 months (treatment × month: p < 0.01). Ruminal fluid transplantation significantly affected rumen alpha diversity (p < 0.05). Up to day 60, the RT group had significantly higher OTU numbers, Shannon diversity, and Simpson homogeneity than the CON group. Principal coordinate analysis showed that the rumen microbiota differed significantly on days 4 and 7 (p < 0.05). Bacteroidota, Firmicutes, Proteobacteria, and Spirochaetes were the most abundant phyla in the rumen. The relative abundances of Bacteroidota, Proteobacteria, and Spirochaetes were lower in the RT group than in the CON group, with a decrease observed in Bacteroidota in the RT group on days 7 and 28 after rumen fluid transplantation (p = 0.013), while Proteobacteria showed a decreasing trend in the CON group and an increasing trend in RT; however, this was only at day 4 (p = 0.019). The relative abundance of Firmicutes was significantly higher in the RT group than in the CON group on days 4, 7, and 28 (p = 0.001). Prevotella and Rikenellaceae_RC9_gut_group were the predominant genera. In conclusion, our findings suggest that rumen fluid transplantation improves yak growth performance and rumen microbial reshaping. The findings of this study provide new insights into yak microbial community transplantation and a reference for improving feed efficiency in the yak industry.

A triple cropping system, combining spring maize, pearl millet, and twice-cut blast disease resistant Italian ryegrass, was examined for the 2016–2017 and 2017–2018 growing seasons to achieve quality herbage production in Miyazaki, southern Kyushu, Japan. The growth of the three crops reached to harvest, even though typhoon and heavy rainfall occurred. Annual dry matter (DM) yield of the triple crops was 4098 g m⁻² and 4349 g m⁻² in the first and second cropping seasons, respectively. The observed total digestible nutrients (TDN) were higher in spring maize (up to 68.2% and 76.8%), pearl millet (up to 60.0% and 67.9%), and Italian ryegrass (up to 71.6% and 68.6%), during the first and second season, respectively, leading to an annual TDN yield of 2357 g m⁻² and 2938 g m⁻². The results suggest that the present established triple cropping system is feasible for obtaining high yields with more digestible nutrients in the forages.

This study investigates the effect of altitude on the fatty acid composition of pasture grass, yak milk, and yak ghee on the Qinghai–Tibet Plateau, aiming to understand how environmental factors influence the nutritional quality of these products. Samples were collected from four different altitudes and analyzed for fatty acid profiles using gas chromatography. The analysis reveals that higher altitudes are associated with an increased prevalence of beneficial unsaturated fatty acids, such as oleic acid (C18:1) and linoleic acid (C18:2n6c). These findings highlight the significant influence of altitude on yak lipid metabolism, ultimately enhancing the nutritional value of dairy products. This adaptation not only supports the health and resilience of yaks, but also provides vital nutritional benefits to residents in high-altitude regions. The research underscores the importance of further investigations to optimize dairy production practices, ensuring improved food security and health outcomes for residents of the plateau.

(1) Background: This study aimed to investigate the effects of different dietary concentrate to roughage ratios on growth performance and fecal microbiota composition of yaks by 16S rRNA gene sequencing. (2) Methods: In the present study, three diets with different dietary forage-to-concentrate ratios (50:50, 65:35, and 80:20) were fed to 36 housed male yaks. (3) Results: The result shows that Final BW, TWG, and ADG were higher in the C65 group than in the C50 and C80 groups, but the difference was not significant (p > 0.05). DMI in the C65 group was significantly higher than in the other two groups (p < 0.05). The DMI/ADG of the C65 group was lower than that of the other two groups, but the difference was insignificant (p > 0.05). At the phylum level, Firmicutes were the most abundant in the C65 group, and the relative abundance of Bacteroidetes was lower in the C65 group than in the other two groups. At the genus level, the relative abundances of Ruminococcaceae_UCG_005, Romboutsia, and Christensenellaceae_R-7 were higher in the C56 group than in the C50 and C80 groups. The relative abundance of Lachnospiraceae_NK3A20 and Rikenellaceaewas_RC9_gut is lower in the C65 group, but the difference was insignificant (p > 0.05). At KEGG level 2, the relative abundance of lipid metabolism and energy metabolism were lowest in the C50 group, and both showed higher relative abundance in the C65 group. (4) Conclusions: In conclusion, the structure of fecal microbiota was affected by different concentrate-to-forage ratios. We found that feeding diets with a concentrate-to-forage ratio of 65:35 improved yaks’ growth and energy metabolism.

Yaks are important for the ecology and economy of the Qinghai-Tibetan Plateau. The growth of the yak industry depends on sustainable and accelerated growth of calves, sustaining herd reproduction and production systems. Yak calves born in the summer months of June and July are faced with a heightened risk of winter mortality. Exclusive traditional, natural feeding prolongs the suckling period, and this leads to a series of problems due to the harsh high-altitude environment, such as inadequate nutrition leading to retarded growth and an imbalanced herd structure. To enhance growth performance and breeding efficiency, 12 male calves of similar weights (68.53 ± 6.41 kg) were randomly assigned to a control group (suckle the dam (SU)) or an experimental group (early weaning with full feeding, concentrate and oat hay at a 7:3 ratio (CO)). The results showed that compared with suckling, early weaning with full feeding significantly improved the growth performance, volatile fatty acids and digestive enzyme activity. The abundance of the Firmicutes was reduced, but there was an increased abundance of Bacteroidetes, which affected the rumen metabolome. In conclusion, early weaning with full feeding improves growth performance, promotes rumen fermentation and carbohydrate degradation, reduces the diversity and richness of rumen microbial flora and alters the content and pathways of metabolites in yak calves. These factors contribute to the growth and market readiness of yak calves born in June and July, accelerate herd turnover and enhance the production efficiency of grazing yaks.

The large lakes and reservoirs of the northeastern Tibetan Plateau play a key role in regional water resources, yet their influence on terrestrial water storage (TWS) changes at different spatial scales remains unclear. This study employed the constrained forward modeling (CFM) method to correct leakage errors in level-2 spherical harmonic (SH) coefficients from the Gravity Recovery and Climate Experiment and its follow-on missions (GRACE/GRACE-FO) at three spatial scales: two circular regions covering 90,000 km² and 200,000 km², respectively, and a 220,000 km² region based on the shape of mass concentration (Mascon). TWS changes derived from SH solutions after leakage correction through CFM were compared with level-3 Mascon solutions. Individual water storage components, including lake and reservoir water storage (LRWS), groundwater storage (GWS), and soil moisture storage (SMS), were quantified, and their relationships with precipitation were assessed. From 2003 to 2022, the CFM method effectively mitigated signal leakage, revealing an overall upward trend in TWS at all spatial scales. Signals from Qinghai Lake and Longyangxia Reservoir dominated the long-term trend and amplitude variations of LRWS, respectively. LRWS explained more than 47% of the TWS changes, and together with GWS, accounted for over 85% of the changes. Both CFM-based and Mascon-based TWS changes indicated a consistent upward trend from January 2003 to September 2012, followed by declines from November 2012 to May 2017 and October 2018 to December 2022. During the decline phases, GWS contributions increased, while LRWS contributions and component exchange intensity decreased. LRWS, SMS, and TWS changes were significantly correlated with precipitation, with varying time lags. These findings underscore the value of GRACE/GRACE-FO data for monitoring multiscale TWS dynamics and their climatic drivers in lake- and reservoir-dominated regions.