Dairy cow longevity is an essential economic trait that can supplement the breeding value of production traits, which is related to the herd time and lifetime milk yield of dairy cows. However, longevity is a relatively difficult trait to select for dairy cow breeding due to low heritability and numerous influence factors of the longevity in dairy cows. Longevity trait has been used as an important breeding target of a comprehensive selection index in many dairy developed countries; however, it has not been included in performance index in many developing countries. At present, cows in these countries are still in the primary stage of “large quantity, low quality, high cost, and low yield.” The average parity of dairy cows is less than 2.7, which is difficult to maintain the production efficiency to meet the demands of the dairy industry. Therefore, there is an urgent need to select and breed for the longevity of dairy cows. The various definitions and models (including linear, threshold, random regression, sire, and survival analysis) of longevity were reviewed and standardized. Survival analysis is the optimal model to evaluate longevity, and the longevity heritability is 0.01–0.30 by using different definitions and models. Additionally, the relationship between longevity and other traits was summarized, and found that longevity was regulated by multiple factors, and there were low or medium genetic correlations between them. Conformation traits, milk production traits, reproductive traits, and health traits may be used as indicators to select and breed the longevity of dairy cows. The genetic assessment methods, heritability, influencing factors, importance, breeding, and genetics of longevity were reviewed in the manuscript, which could provide a valuable reference for the selective breeding to extend the productive life of Holstein cattle.

Background: In China, although buffaloes are abundant, beef is mainly obtained from cattle, and this preference is mainly attributed to the low intramuscular fat (IMF) content of buffalo. Genetic factors are an important driver that affects IMF deposition. Results: To reveal the intrinsic factors responsible for the low IMF content of buffalo, mRNA expression patterns in muscle and adipose tissue between buffalo and cattle were characterized by RNA sequencing analysis. The IMF content in Nanyang cattle was higher than that in Xinyang buffalo. A total of 1566 mRNAs expressed in adipose tissue showed differential expression between the longissimus dorsi muscles of buffalo and cattle. Functional annotation suggested a difference in the glycolysis/gluconeogenesis pathway between the two species. The results of RT-qPCR analysis and gain-of-function experiments confirmed the positive association between the IMF content and phosphoenolpyruvate carboxykinase 1 (PCK1) expression in buffalo. In both mouse C2C12 cells and cultured bovine myocytes, the activity of the PCK1 promoter in buffalo is lower than that in cattle. However, in mouse 3T3-L1 adipocytes and cultured bovine adipocytes, the activity of PCK1 in buffalo promoter is higher than that in cattle. Conclusions: These results indicate the important role of PCK1 in buffalo IMF deposition and illustrate the differences between buffalo and cattle promoter activity that drive PCK1 expression. This research helps to establish a foundation for further studies investigating IMF deposition in buffalo.

The objective of this study was to explore the genetic parameters of conformation traits and milk production traits in Chinese Holstein cattle and to provide a reference for dairy cattle breeding. We collected the phenotypic data of 23 conformation traits and five milk production traits of Chinese Holsteins and used animal models to estimate the genetic parameters of conformation traits and milk production traits. The estimated heritability of conformation traits ranged from 0.11 (angularity) to 0.37 (heel depth) and the genetic correlation between conformation traits ranged from −0.73 (bone quality and rear leg-rear view) to 0.76 (chest width and loin strength). The heritability of milk production traits ranged from 0.23 (somatic cell score) to 0.50 (305-d milk yield). The estimated values of genetic correlation between conformation traits and milk production traits ranged from −0.56 (heel depth and 305-d milk yield) to 0.57 (udder texture and milk fat percentage). There was a positive genetic correlation between most conformation traits and milk fat percentage, but a weak negative genetic correlation with milk yield. Strengthening the moderately and highly heritable milk production and conformation traits, especially the selection of rear udder traits and body shape total score, will be beneficial in improving the performance of dairy cows.

Background: Fat is a tissue that not just stores energy and plays a protective role; it is also a vital endocrine organ that generates and integrates signals to influence metabolism. Meanwhile, the excessive accumulation of lipids in adipose tissue can lead to metabolic disturbance and diseases. To date, the complicated molecular mechanisms of bovine adipose tissue are still unknown. This study aimed to identify key genes and functionally enriched pathways in various adipose tissue types.Results: The RNAseq data of 264 samples were downloaded from Gene Expression Omnibus (GEO) and analyzed by weighted gene co-expression network analysis (WGCNA). We identified 19 modules that significantly associated with at least one adipose tissue type. The brown module from GSE39618 was most closely associated with intramuscular fat tissue, which contained 550 genes. These genes were significantly enriched in pathways that related to inflammation and disease, such as TNF signaling pathway, IL-17 signaling pathway, and NF-kappa B signaling pathway. The pink module (GSE39618) that contained 58 genes was most closely associated with omental fat tissue. The turquoise (GSE39618), blue (GSE116775), and yellow (GSE65125) module were most closely associated with subcutaneous fat tissue. Genes in these modules were significantly enriched in pathways related to fat metabolism, such as the PPAR signaling pathway, fatty acid metabolism and PI3K-Akt signaling pathway. At last, key genes for intramuscular fat (PTGS2 and IL6), omental fat (ARHGEF5 and WT1), and subcutaneous fat (KIT, QR6Q1, PKD2L1, etc.) were obtained and verified. In addition, it was found that IL10 and VCAM1 might be potential genes to distinguish adipose and muscle.Conclusion: The study applied WGCNA to generate a landscape of adipose tissue and provide a basis for identifying potential pathways and hub genes of different adipose tissue types.

Circular RNAs (circRNAs) have been identified as a novel type of regulators involved in multiple biological processes. However, circRNAs with a potential function in fat deposition in buffalo are poorly understood. In this study, six RNA libraries of adipose tissue were constructed for three young and three adult Chinese buffaloes with paired-ends RNA sequencing using the Illumina HiSeq 3000 platform. A total of 5141 circRNAs were computationally identified. Among them, 252 circRNAs were differentially expressed (DE) between the young and adult buffaloes. Of these, 54 were upregulated and 198 were downregulated in the adult group. Eight DE circRNAs were further identified by quantitative real-time-PCR (qRT-PCR) and Sanger sequencing. Co-expression analysis revealed that 34 circRNAs demonstrated a strong correlation with fat deposition-associated genes (|r| > 0.980). Among these, expressional correlation between two circRNAs (19:45387150|45389986 and 21:6969877|69753491) and PR/SET domain 16 was further verified using qRT-PCR, and a strong correlation was revealed (1 > |r| > 0.8). These results strongly suggest that circRNAs 19:45387150|45389986 and 21:6969877|69753491 are potential regulators of buffalo fat deposition. In summary, this study characterized the circRNA profiles of adipose tissues at different stages for the first time and revealed two circRNAs strongly correlated with fat deposition-associated genes, which provided new candidate regulators for fat deposition in buffalo.