The gastrointestinal microbiota greatly affects the health status and production performance of bovines. Presently, many studies have used high-throughput sequencing methods to investigate the gastrointestinal microbiome in bovines. However, the microbiome profile of crossbred cattle across the whole gastrointestinal tract (GIT) has not been thoroughly reported. In this study, the digesta at ten regions (including the rumen, reticulum, omasum, abomasum, duodenum, jejunum, ileum, cecum, colon, and rectum) of the GIT were collected in three Simmental × Holstein crossbred heifers aged 17 months, and microbial DNA was extracted and amplified for sequencing of the V3–V4 regions of the 16S rRNA gene. Functional orthologs of the microbiota genome were predicted and analyzed. We found that samples were categorized into three groups (the stomach, small intestine, and large intestine) by principal coordinate analysis (PCoA) based on Bray–Curtis dissimilarity in both the bacterial composition and functional profile. Samples from small intestine had the lowest alpha diversity of bacteria composition and highest alpha diversity of the functional composition. Three groups of GIT regions were characterized by several microbiome features. The stomach was characterized by Bacteroidetes and Fibrobacteres at the phylum level, and KEGG pathways related to the metabolism of cofactors and vitamins, glycan biosynthesis, and metabolism were enriched in the stomach. The small intestine was characterized by Actinobacteria and Patescibacteria at the phylum level, and KEGG pathways related to xenobiotics biodegradation and metabolism were enriched in the small intestine. The large intestine featured Ruminococcaceae, Rikenellaceae, and Bacteroidacea at the family level, and KEGG pathways, including steroid hormone biosynthesis, linoleic acid metabolism, and cysteine and methionine metabolism were enriched in the large intestine. The results of the current study revealed the spatial heterogeneity of microbiota across the GIT in Simmental × Holstein crossbreeds and identified microbial biomarkers of different regions. The results can provide useful information for the study of the gastrointestinal microbiome in bovines.

The gastrointestinal bacterial microbiota is essential for maintaining the health of dairy cows and ensuring their production potential, and it may also help explain the breed-related phenotypic differences. Therefore, investigating the differences in gastrointestinal bacterial microbiota between breeds is critical for deciphering the mechanisms behind these differences and exploring the potential for improving milk production by regulating the gastrointestinal bacterial microbiota. This study holistically examined the differences between rumen and hindgut bacterial microbiota in a large cohort of two breeds of dairy cows, comprising 184 Jersey cows and 165 Holstein cows. Significant distinctions were identified between the rumen and hindgut bacterial microbiota of dairy cows, with these differences being consistent across breeds. A total of 20 breed-differentiated microorganisms, comprising 14 rumen microorganisms and 6 hindgut microorganisms, were screened, which may be the primary drivers of the observed differences in lactation performance between Jersey and Holstein cows. The present study revealed the spatial heterogeneity of the gastrointestinal bacterial microbiota of Jersey and Holstein cows and identified microbial biomarkers of different breeds. These findings enhance our understanding of the differences in the gastrointestinal bacterial microbiota between Jersey and Holstein cows and may provide useful information for optimizing the composition of the intestinal bacterial microbiota of the two breeds of dairy cows.

Agricultural activities are a significant contributor to global greenhouse gas emissions, accounting for 14.5% of total anthropogenic emissions. Specifically, greenhouse gas emissions from beef cattle and dairy cattle constitute 35% and 30% of total global livestock emissions, respectively. This study focuses on dairy cattle, exploring the complex relationships between rumen microbiota and methane emission. The methane emissions of 968 lactating Holstein cows were measured using a laser methane detector (LMD, Shanghai Hesai Technology Co., Ltd., Shanghai, China). Among the measured cows, 107 individuals were further selected into high (HME) and low methane-emitting (LME) groups, including 50 cows in the HME group and 57 in the LME group. This study analyzed differences in rumen microbiota and microbial functions between cows with varying levels of methane emissions. The results showed significant differences in the Simpson and Pielou indices of rumen bacterial communities between the HME and LME groups. Beta diversity analysis revealed significant differences in microbial community structure between the two groups. It was found that the abundance of Bacteroidales and Prevotellaceae in the rumen of cows in the HME group cows was significantly higher than that of cows in the LME group (LDA > 3, p < 0.05). Additionally, bacterial functions related to biosynthesis and carbohydrate metabolism were more active in the HME group. This study revealed distinct differences in the rumen bacterial communities between HME and LME cow in Chinese Holstein cattle, and identified specific bacteria and their functional differences in the HME group. The microbial characteristics and metabolic pathways provide new insights for developing strategies to reduce methane emissions, supporting the sustainable development of the dairy industry.

The bovine tongue is a complex and very important muscular and gustatory organ, yet a comprehensive understanding of its gustatory apparatus across diverse genetic resources remains elusive. In this study, we conducted a multidimensional analysis of the lingual morphology and taste bud (TB) distribution in 40 specimens from 12 representative bovine breeds and species across China, encompassing Bos taurus taurus (Taurine cattle), Bos taurus indicus (Zebu cattle), Bubalus bubalis (water buffalo), and Bos grunniens (domestic yak). Morphometric measurements and histological quantifications were integrated to evaluate the influence of species, sex, age, and geographical factors. Given the relatively limited sample size per breed, these findings are presented as exploratory research. Our results revealed that yak and water buffalo showed the most distinct morphological patterns of mechanical papillae compared to the other populations. Taurine and Zebu cattle displayed more similar lingual morphology traits. Although high phenotypic correlations were observed between lingual morphometric parameters and quantitative papillae indicators, factors such as age, altitude, and feeding methods showed minimal influence on lingual phenotypic variation within this cohort (p > 0.05). Furthermore, we constructed a topological atlas of TB distribution, revealing that TB distribution patterns are decoupled from macro-anatomical dimensions, highlighting the complexity of the bovine gustatory system. These findings provide a quantitative baseline for ruminant comparative anatomy and offer structural insights into the evolutionary adaptation and nutrient regulation mechanisms of diverse bovine species in varying environments.

Calves derived from in vitro embryo production (IVP) often have higher birth weights than those produced by artificial insemination or in vitro embryo tran