Exogenous Vitamin D3 Modulates Response of Bovine Macrophages to Mycobacterium avium subsp. paratuberculosis Infection and Is Dependent Upon Stage of Johne’s Disease

Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of ruminant enteritis, targets intestinal macrophages. During infection, macrophages contribute to mucosal inflammation and development of granulomas in the small intestine which worsens as disease progression occurs. Vitamin D3 is an immunomodulatory steroid hormone with beneficial roles in host-pathogen interactions. Few studies have investigated immunologic roles of 25-hydroxyvitamin D3 (25(OH)D3) and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in cattle, particularly cattle infected with MAP. This study examined the effects of exogenous vitamin D3 on immune responses of monocyte derived macrophages (MDMs) isolated from dairy cattle naturally infected with MAP. MDMs were pre-treated with ± 100 ng/ml 25(OH)D3 or ± 4 ng/ml 1,25(OH)2D3, then incubated 24 hrs with live MAP in the presence of their respective pre-treatment concentrations. Following treatment with either vitamin D3 analog, phagocytosis of MAP by MDMs was significantly greater in clinically infected animals, with a greater amount of live and dead bacteria. Clinical cows had significantly less CD40 surface expression on MDMs compared to subclinical cows and noninfected controls. 1,25(OH)2D3 also significantly increased nitrite production in MAP infected cows. 1,25(OH)2D3 treatment played a key role in upregulating secretion of pro-inflammatory cytokines IL-1β and IL-12 while downregulating IL-10, IL-6, and IFN-γ. 1,25(OH)2D3 also negatively regulated transcripts of CYP24A1, CYP27B1, DEFB7, NOS2, and IL10. Results from this study demonstrate that vitamin D3 compounds, but mainly 1,25(OH)2D3, modulate both pro- and anti-inflammatory immune responses in dairy cattle infected with MAP, impacting the bacterial viability within the macrophage.

Phenotypic Selection of Dairy Cattle Infected with Bovine Leukemia Virus Demonstrates Immunogenetic Resilience through NGS-Based Genotyping of BoLA MHC Class II Genes

Characterization of the bovine leukocyte antigen (BoLA) DRB3 gene has shown that specific alleles associate with susceptibility or resilience to the progression of bovine leukemia virus (BLV), measured by proviral load (PVL). Through surveillance of multi-farm BLV eradication field trials, we observed differential phenotypes within seropositive cows that persist from months to years. We sought to develop a multiplex next-generation sequencing workflow (NGS-SBT) capable of genotyping 384 samples per run to assess the relationship between BLV phenotype and two BoLA genes. We utilized longitudinal results from milk ELISA screening and subsequent blood collections on seropositive cows for PVL determination using a novel BLV proviral load multiplex qPCR assay to phenotype the cows. Repeated diagnostic observations defined two distinct phenotypes in our study population, ELISA-positive cows that do not harbor detectable levels of provirus and those who do have persistent proviral loads. In total, 565 cows from nine Midwest dairy farms were selected for NGS-SBT, with 558 cows: 168 BLV susceptible (ELISA-positive/PVL-positive) and 390 BLV resilient (ELISA-positive/PVL-negative) successfully genotyped. Three BoLA-DRB3 alleles, including one novel allele, were shown to associate with disease resilience, *009:02, *044:01, and *048:02 were found at rates of 97.5%, 86.5%, and 90.3%, respectively, within the phenotypically resilient population. Alternatively, DRB3*015:01 and *027:03, both known to associate with disease progression, were found at rates of 81.1% and 92.3%, respectively, within the susceptible population. This study helps solidify the immunogenetic relationship between BoLA-DRB3 alleles and BLV infection status of these two phenotypic groupings of US dairy cattle.

Genetic Diversity in the Italian Holstein Dairy Cattle Based on Pedigree and SNP Data Prior and After Genomic Selection

Genetic diversity has become an urgent matter not only in small local breeds but also in more specialized ones. While the use of genomic data in livestock breeding programs increased genetic gain, there is increasing evidence that this benefit may be counterbalanced by the potential loss of genetic variability. Thus, in this study, we aimed to investigate the genetic diversity in the Italian Holstein dairy cattle using pedigree and genomic data from cows born between 2002 and 2020. We estimated variation in inbreeding, effective population size, and generation interval and compared those aspects prior to and after the introduction of genomic selection in the breed. The dataset contained 84,443 single-nucleotide polymorphisms (SNPs), and 74,485 cows were analyzed. Pedigree depth based on complete generation equivalent was equal to 10.67. A run of homozygosity (ROH) analysis was adopted to estimate SNP-based inbreeding (FROH). The average pedigree inbreeding was 0.07, while the average FROH was more than double, being equal to 0.17. The pattern of the effective population size based on pedigree and SNP data was similar although different in scale, with a constant decrease within the last five generations. The overall inbreeding rate (ΔF) per year was equal to +0.27% and +0.44% for Fped and FROH throughout the studied period, which corresponded to about +1.35% and +2.2% per generation, respectively. A significant increase in the ΔF was found since the introduction of genomic selection in the breed. This study in the Italian Holstein dairy cattle showed the importance of controlling the loss of genetic diversity to ensure the long-term sustainability of this breed, as well as to guarantee future market demands.

Economic Analysis of Smallholder Dairy Cattle Enterprises In Senegal

Smallholder dairy production in Senegal is important to both livelihoods and food and nutrition security. Here we examine the economic performance of smallholder dairy cattle enterprises in Senegal, using data from longitudinal monitoring of 113 households. The mean (and standard deviation) of the net returns (NR) per cow per annum (pcpa) was 21.7 (202.9) USD, whilst the NR per household herd per annum (phpa) was 106.1 (1740.3) USD. Only about half (52.2 %) of the dairy cattle enterprise had a positive NR. The most significant income components were milk sale followed by animal sale, whilst the most significant cost components were animal feed followed by animal purchase. When households were grouped by ranking on NRpcpa an interesting trend was observed: whilst the mean NRpcpa showed a fairly linear increase from the lowest to highest NR groups, income and cost did not. Income and costs were both higher for the lowest and highest NR groups, in comparison to the intermediate NR groups. The mean NRs of households grouped by the main breed-type they kept were not significantly different from each other, due to large variances within the breed groups. However, the mean total income and costs were significantly higher for households mainly keeping improved dairy breeds (Bos taurus or Zebu x Bos taurus crosses) in comparison to those keeping indigenous Zebu or Zebu by Guzerat crosses. This study highlights the highly variable (and often low) profitability of smallholder dairy cattle enterprise in Senegal. Further actions to address this are strongly recommended.

Validation of somatic cell score-associated SNPs from Holstein cattle in Sudanese Butana and Butana × Holstein crossbred cattle

The Bos indicus zebu cattle Butana is the most commonly used indigenous dairy cattle breed in Sudan. In the last years, high-yielding Holstein dairy cattle were introgressed into Butana cattle to improve their milk yield and simultaneously keep their good adaption to extreme environmental conditions. With the focus on the improvement of milk production, other problems arose such as an increased susceptibility to mastitis. Thus, genetic selection for mastitis resistance should be considered to maintain healthy and productive cows. In this study, we tested 10 single nucleotide polymorphisms (SNPs) which had been associated with somatic cell score (SCS) in Holstein cattle for association with SCS in 37 purebred Butana and 203 Butana × Holstein crossbred cattle from Sudan. Animals were genotyped by competitive allele-specific PCR assays and association analysis was performed using a linear mixed model. All 10 SNPs were segregating in the crossbred Butana × Holstein populations, but only 8 SNPs in Sudanese purebred Butana cattle. The SNP on chromosome 13 was suggestively associated with SCS in the Butana × Holstein crossbred population (rs109441194, 13:79,365,467, PBF = 0.054) and the SNP on chromosome 19 was significantly associated with SCS in both populations (rs41257403, 19:50,027,458, Butana: PBF = 0.003, Butana × Holstein: PBF = 6.2 × 10−16). The minor allele of both SNPs showed an increase in SCS. Therefore, selection against the disadvantageous minor allele could be used for genetic improvement of mastitis resistance in the studied populations. However, investigations in a bigger population and across the whole genome are needed to identify additional genomic loci.

Deltamethrin Application on Pre-Weaned Calves Improves Feed Consumption, Stress and Fatigue Status under Heat Stress Conditions

Fly infestation remains a universal problem for dairy cattle herds, affecting the animals’ health and welfare status. Pre-weaned dairy calves are significantly challenged by the direct and indirect consequences of severe fly infestation, heat-stress and their interaction, which contribute to a stressful and fatiguing environment. Among several physiological, behavioral, clinical and biochemical traits, serum cortisol (SC) and creatine kinase (CK) levels, as well as feed consumption can be used as valid indicators of potential stressful and fatiguing conditions and, therefore, can be efficiently used for stress analysis studies. Hence, the objective of the study was to assess the fly-repellency effect of deltamethrin on pre-weaned dairy calves exposed to heat stress conditions, as well as its association with SC, CK concentrations and feed consumption. Two commercial dairy cattle herds of the Holstein breed in Central Macedonia (Greece) were involved in the study during summer months and under heat stress conditions. Deltamethrin administration resulted in (i) a decreased fly population (100% Musca domestica) landing on pre-weaned dairy calves, (ii) a reduced SC (stress indicator) and CK (fatigue indicator) concentration, and (iii) an increased consumption of feedstuff in deltamethrin treated animals compared to the untreated ones.

Multi-Omics Integration and Network Analysis Reveal Potential Hub Genes and Genetic Mechanisms Regulating Bovine Mastitis

Mastitis, inflammation of the mammary gland, is the most prevalent disease in dairy cattle that has a potential impact on profitability and animal welfare. Specifically designed multi-omics studies can be used to prioritize candidate genes and identify biomarkers and the molecular mechanisms underlying mastitis in dairy cattle. Hence, the present study aimed to explore the genetic basis of bovine mastitis by integrating microarray and RNA-Seq data containing healthy and mastitic samples in comparative transcriptome analysis with the results of published genome-wide association studies (GWAS) using a literature mining approach. The integration of different information sources resulted in the identification of 33 common and relevant genes associated with bovine mastitis. Among these, seven genes—CXCR1, HCK, IL1RN, MMP9, S100A9, GRO1, and SOCS3—were identified as the hub genes (highly connected genes) for mastitis susceptibility and resistance, and were subjected to protein-protein interaction (PPI) network and gene regulatory network construction. Gene ontology annotation and enrichment analysis revealed 23, 7, and 4 GO terms related to mastitis in the biological process, molecular function, and cellular component categories, respectively. Moreover, the main metabolic-signalling pathways responsible for the regulation of immune or inflammatory responses were significantly enriched in cytokine–cytokine-receptor interaction, the IL-17 signaling pathway, viral protein interaction with cytokines and cytokine receptors, and the chemokine signaling pathway. Consequently, the identification of these genes, pathways, and their respective functions could contribute to a better understanding of the genetics and mechanisms regulating mastitis and can be considered a starting point for future studies on bovine mastitis.

Growing of replacement young cattle in ООО «PskovAgroInvest»

ООО «PskovAgroInvest» pays great attention to the rearing of replacement young animals. The rate of increase in the intensity of raising heifers on the farm meets the standards and requirements of pedigree dairy cattle breeding. The farm uses stage-bystage rearing of replacement young stock, taking into account its age. A group approach to rearing young animals. Replacement heifers use natural and cultivated pastures in the summer. In recent years, the age of replacement heifers at the first insemination has noticeably decreased and approached the norm. At the same time, the live weight of animals at the first insemination increased, which in 2020 amounted to 460 kg, which opens up prospects for a further decrease in the age of the first insemination. This became possible due to an increase in the average daily growth in cultivation, which regularly increases every year and amounts to 756 g in 2020, which is 98 g, or 14.9%, more than in 2016. From table 2 it follows that in recent years, at all age periods, replacement heifers had a live weight exceeding the breed standard, which is 250 kg at 10-month-old, 290 kg at 12-month-old and 390 kg at 18-month-old age. At the same time, an increase in the average live weight of the replacement livestock is observed every year. So, in 2020, the value of the indicator was 278 kg at the age of 10 months, 331 kg at the age of 12 months, 463 kg at the age of 18 months, which is 16 kg, 54 kg and 75 kg, or 6.1%, 19, 5% and 19.3%, more than in 2016, respectively. Thus, the analyzed period allows us to conclude about the effectiveness of zootechnical work to improve the rearing of replacement heifers on the farm, but it must be continued in order to reduce the age of first insemination to 15–17 months with the optimal live weight of the livestock.

Genome-wide association studies for immunoglobulin concentrations in colostrum and serum in Chinese Holstein

Background The early death and health problems of calves caused substantial economic losses in the dairy industry. As the immune system of neonates has not been fully developed, the absorption of maternal immunoglobulin (Ig) from colostrum is essential in protecting newborn calves against common disease organisms in their early life. The overwhelming majority of Ig in bovine whey is transported from the serum. Therefore, Ig concentration in the colostrum and serum of dairy cows are critical traits when estimating the potential disease resistance of its offspring. Results Colostrum, blood, and hair follicle samples were collected from 588 Chinese Holstein cows within 24 h after calving. The concentration of total IgG, IgG1, IgG2, IgA and IgM in both colostrum and serum were detected via ELISA methods. With GCTA software, genome-wide association studies (GWASs) were performed with 91,620 SNPs genotyped by GeneSeek 150 K (140,668 SNPs) chips. As a result, 1, 5, 1 and 29 significant SNPs were detected associated with the concentrations of colostrum IgG1, IgG2, IgA IgM, and serum IgG2 at the genome-wide level (P < 3.08E–6); 11, 2, 13, 2, 12, 8, 2, 27, 1 and 4 SNPs were found significantly associated with total IgG, IgG1, IgG2, IgA and IgM in colostrum and serum at the suggestive level (P < 6.15E–5). Such SNPs located in or proximate to (±1 Mb) 423 genes, which were functionally implicated in biological processes and pathways, such as immune response, B cell activation, inflammatory response and NF-kappaB signaling pathways. By combining the biological functions and the known QTL data for immune traits in bovine, 14 promising candidate functional genes were identified for immunoglobulin concentrations in colostrum and serum in dairy cattle, they were FGFR4, FGFR2, NCF1, IKBKG, SORBS3, IGHV1S18, KIT, PTGS2, BAX, GRB2, TAOK1, ICAM1, TGFB1 and RAC3. Conclusions In this study, we identified 14 candidate genes related to concentrations of immunoglobulins in colostrum and serum in dairy cattle by performing GWASs. Our findings provide a groundwork for unraveling the key genes and causal mutations affecting immunoglobulin concentrations in colostrum and important information for genetic improvement of such traits in dairy cattle.