Browsing by Author "Van Campen, Hana, committee member"
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Item Open Access Genetics of bovine respiratory disease in feedlot cattle(Colorado State University. Libraries, 2010) McAllister, Chase, author; Enns, Richard Mark, advisor; Crews, Denny H., 1967-, advisor; Van Campen, Hana, committee memberBovine respiratory disease (BRD) is one of the most prevalent and economically limiting diseases facing the United States beef industry today. Therefore, the objectives of this study were to (1) characterize the occurrence and prevalence of BRD in feedlot steers utilizing three disease classifications; treatment records (Trt), lung lesions present at harvest, and total BRD (treatment or lung lesion or both), (2) to examine the effects of Trt, number of treatments (NumTrt), mean lung score, lesions present, and total BRD on economically relevant carcass traits, and(3) to estimate heritabilities for BRD classifications and associated genetic and environmental correlations with economically relevant carcass traits. Data included health and carcass records on 2,870 crossbred steers managed in a commercial feedlot in Southeast Colorado over a two year period. Disease prevalence varied from 45% (n = 698) to 7% (n = 94) in years one and two, respectively. Averaged across the two year period, 27.6% of the steers exhibited clinical signs and were treated for BRD. Lung lesions were collected on 1,226 and 1,261 steers in year one and year two, respectively. Lesions were present in 71% in of steers year one and 47% in year two, and were present in 59% (n=1,461) of the steers over the two year period. Incidence for total BRD, was 76%, 59%, and 64% for years one, two, and overall, respectively. A subset of data (n = 1,260) of animals with birth information was used to evaluated the effect of age (P > 0.05) and BRD classification on carcass traits. Similarly, two models were fitted to the complete data to test the effect of receiving BW as an approximation for age. Evaluation of the models indicated receiving weight to be a significant fixed effect for prediction of carcass merit (P < 0.001). Incidence of BRD in the feedlot had a negative impact on both marbling score (MS) and subcutaneous backfat thickness (Fat) (P < 0.001), while accounting for minimal variation (P > 0.05) in HCW and LM area after adjusting for fixed contemporary group effects and receiving BW. However, animals that were chronically infected (at least 3 treatments) had reduced HCW (-16.5 ± 4.5 kg) and LM area (4.9 ± 1.25) (P < 0.05) compared to steers that were never treated. Lesions present at harvest did not have a significant effect (P > 0.05) on any evaluated traits. Animals that were categorized as suffering from BRD by the definition of total BRD had reduced MS (6.1 ± 2.8) and Fat (0.39 ± 0.18) (P < 0.05) when compared to healthy steers. Heritability estimates of BRD susceptibility were 0.15 ± 0.06, 0.04 ± 0.03, 0.0 ± 0.0, 0.04 ± 0.06, and 0.07 ± 0.06 for Trt, NumTrt, mean lung score, lesions present, and total BRD, respectively. Genetic correlations were not estimated for mean lung score due to the lack of genetic variability. Genetic correlations of Trt with carcass traits were unfavorable (0.19 ± 0.30) for HCW and LM area (0.03 ± 0.25), and favorable for MS (-0.30 ± 0.21) and Fat (-0.004 ± .26). Genetic correlations for NumTrt were similar at 0.23 ± 0.42, -0.05 ± 0.35, -0.29 ± 0.29, and -0.06 ± 0.35, between HCW, LM area, MS, and Fat, respectively. Estimates of genetic correlations for presence of lesions were zero for all traits. Estimates for total BRD were opposite when compared to Trt, and NumTrt at -0.03 ± 0.4, -0.35 ± 0.36, 0.28 ±0.30, and 0.12 ± 0.35 between HCW, LM area, MS, and Fat, respectively. Results indicate that with selection genetic improvement can be made over time by utilizing feedlot health records. Genetic correlations between treatments records and carcass traits were in general favorable and would increase profitability when incorporated into selection programs.Item Open Access Management strategies to improve beef feedlot performance and assessment of nutrient composition of beef retail cuts(Colorado State University. Libraries, 2011) Schutz, Jennifer Sue, author; Engle, Terry, advisor; Belk, Keith, committee member; Archibeque, Shawn, committee member; Van Campen, Hana, committee memberTo view the abstract, please see the full text of the document.Item Embargo Mechanisms and associated biomarkers of early embryo mortality in Holstein-Friesian cows(Colorado State University. Libraries, 2022) González-Berríos, Carolina L., author; Hansen, Thomas R., advisor; Thomas, Milton G., advisor; Schountz, Tony, committee member; Van Campen, Hana, committee memberIntensive genetic selection for milk yield has declined fertility trait levels that has led to infertility for over 50 years in Holstein-Friesian cows. A substantial contributor to infertility is embryo mortality, but the exact mechanism of how a pregnancy is poorly understood. Recent use of candidate single nucleotide polymorphisms (SNPs) in genetic panels has shown to improve genomic estimates of predicted transmitting abilities for fertility traits that are known to be of low heritability. The objectives of this dissertation were then divided into two chapters. The first chapter had as an objective to elucidate the transcriptomic responses of reproductive tissues (endometrium, peripheral blood mononuclear cells [PBMC] and corpus luteum [CL]) in normal compared to pregnancies with embryo mortality in lactating Holstein- Friesian cows based upon two follow up experiments (E1 and E2). At day 16, after artificial insemination (pregnant group) or of estrous cycle (non-pregnant group), reproductive tissues (endometrium, PBMC and CL [only for E2]), serum (E1) or plasma (E2) and uterine flushings were collected. Cows from pregnant group were re-classified based on embryo morphology and appearance [embryo mortality (EM) pregnancies had pink, red, restricted in elongation and (or) opaque conceptuses or normal (N) pregnancies had translucent and elongated conceptuses]. The main findings for this chapter were that: N conceptuses were longer compared to EM conceptuses. Interferon-tau (IFNT) protein concentrations in uterine flushings were greater in N compared to EM and NP in E1 but not for E2. Western blot analyses for interferon stimulated genes (ISG) 15 protein in endometrium from N cows were greater (E1 and E2) than EM and NP and EM tended to be greater than non-pregnant in E2. The RTqPCR for ISG15 mRNA levels in N endometrium were greater (E1 and E2) when compared to EM and NP endometrium but only tended to be greater in EM compared to NP endometrium in E2. Concentrations of progesterone in the radioimmunoassay were only significant on days 7 and 16 in E2. In RNA sequencing, IFNT mRNA were greater (E1 and E2) in N conceptuses compared to EM conceptuses. For E1 and E2, IPA revealed for EM compared to N conceptuses the key canonical pathways of T helper 1 (Th1) and Th2 to be up-regulated and are adaptive immune response that activated pro-inflammatory cytokines. Within EM compared to N endometrium, E1 had Th1 and Th2 pathways up-regulated while E2 identified differentially expressed genes (DEGs) that were up-regulated and associated with estradiol-mediated luteolytic action. Comparison of EM compared to N in PBMC were only significantly in E1 and had down-regulated DEGs associated with tissue growth, remodeling and/or development, cell cycle, conceptus implantation, essential mineral transporters, innate immune system and Th1 activation. The CL of E2 for embryo mortality compared to normal exhibited up-regulation of DEGs associated with inflammation, calcium sequestration/delivery, glucose- and estradiol-metabolism that may be involved in the luteolysis pathway. The second chapter focused on the identification and validation of candidate SNPs within pregnancies with early embryo mortality that were associated with inferior fertility traits. The RNA sequencing of conceptuses (normal and embryo mortality) in Holstein-Friesian (n=15) cows from the first chapter were used to conduct the SNP discovery phase. Validation of candidate SNPs and genotype to phenotype analysis were conducted in a different cohort of Holstein-Friesian cows (n=500) by collecting blood samples to be genotyped via a genotyping assay panel and collecting cow farms records. Further filtering of candidate SNPs involved removing those that were monomorphic and not in minor allele frequency and a quality control pipeline via pLink software. The main findings for this chapter were: a total of sixty-nine candidate SNPs were initially discovered but only twenty-three passed the quality control pipeline in pLink software. All candidate SNPs were found explain a higher amount of the R2 variation of each of the models and were in close proximity to SNP that were associated with quantitative trait loci of fertility traits. Out of the twenty-three candidate SNPs, seven (DSC2: age of cows at 1st calving were older with A allele; SREBF1 and UBD: cows took longer to conceive with T or G allele, respectively; UMPS and SREBF1: required longer time to their 1st artificial insemination with C allele; DECR1 and FASN: cows were less likely to become pregnant at 1st artificial insemination with C allele; SREBF1 and BOLA-DMB: cows were less likely to become pregnant at 150 days in milk with T allele) were significantly associated to fertility traits. It was also found that two candidate SNPs (DSC2 gene: 4 SNPs and 2 SNPs] were considered as TAG SNPs. Only two of the seven candidate SNPs had significant allele substitution effects where DSC2 in cows with G allele decreased in the age at 1st calving by 10 days and SREBF1 [rs41912290] in cows with the C allele decreased days to 1st artificial insemination by 5 days and more probability of becoming pregnant at 150 days in milk by 6%. In summary, the data and results described in this thesis describe mechanisms of why most pregnancies fail, while others succeed in purebred Holstein-Friesian cows. The EM embryos undergo a massive T helper response either as part of or a consequence of dying. These studies may lead to the development of future technologies to improve reproductive efficiency. In addition, the identified candidate SNPs could then be used to genetically screen young heifers to identify the most fertile females while also making progress in milk production. These genetic tools will aid farmers in making decisions of culling reproductively inefficient heifers and cows within a herd.Item Open Access Molecular consequences of fetal BVDV persistent infection: tales from the placenta and spleen(Colorado State University. Libraries, 2021) Georges, Hanah Michale, author; Hansen, Thomas R., advisor; Van Campen, Hana, committee member; Bielefeldt-Ohmann, Helle, committee member; Hess, Ann M., committee memberTo view the abstract, please see the full text of the document.Item Open Access Noncytopathic type 2 bovine viral diarrhea virus 96B2222 induces upregulation of type-I interferon and chemokine receptor 4 expression in bovine peripheral blood mononuclear cells during in vitro infection(Colorado State University. Libraries, 2010) Weiner, Cristina M., author; Vandewoude, Sue, advisor; Hansen, Thomas R., advisor; Van Campen, Hana, committee memberBovine viral diarrhea virus (BVDV) infection leads to monetary losses in cattle operations due to morbidity and impaired growth. IT is not currently possible to identify pregnant cattle carrying fetuses persistently infected (PI) with BVDV. We previously described a type-I interferon (IFN-I) response to acute non-cytopathic (ncp) BVDV infection in PI fetuses. It was hypothesized that infection of peripheral blood mononuclear cells (PBMC) with ncp-2 96b2222 BVDV would: (1) up-regulate IFN-stimulated genes (IFN-(3, ISG 15), antiviral molecules (retinoic acid inducible gene I, RIG- 1) and chemokine receptor four (CXCR4); (2) viral entry would be mediated through CXCR4; and (3) differentially affect immune cell populations and expression of CXCR4. After optimization of in vitro conditions, PBMCs isolated from a BVDV-naive steer were infected with ncp-2 96b2222 BVDV and treated with AMD3100 and/or CXCR4's ligand, chemokine ligand 12 (CXCL12). Cells were collected and processed for RT-PCR and flow cytometry staining post-infection. At 32 hours post-infection (hpi), mRNA expression of IFN-I pathway genes (IFN-(3, ISG-15), antiviral molecules (RIG-I), CXCR4, CXCLJ 2 and CD8 increased (P < 0.05). Treatment of PBMCs with AMD3100 prior to BVDV infection did not affect BVDV mRNA replication but caused a decrease in CXCR4 mRNA and cell surface expression. CXCL12 treatment increased the concentration of BVDV, CXCR4, IFN- ß, ISG15, and RIG-I transcription. Blocking CXCR4 with AMD3100 and/or CXCL12 did not prevent viral entry and/or replication, but abrogated a BVDV-induced increase in CXCR4 mRNA expression while CXCL12 modulated infection. During PBMC infection in vitro, BVDV may induce release of IFN- ß which then activates ISGs to increase CXCR4 mRNA and protein. Flow cytometry data suggest trends in immune cell populations during ncp-2 96b2222 BVDV infection.Item Open Access Persistent bovine viral diarrhea virus infection in the bovine fetus: morphogenesis of skeletal lesions and innate immune response(Colorado State University. Libraries, 2012) Webb, Brett Thomas, author; Hansen, Thomas R., advisor; Norrdin, Robert W., advisor; Mason, Gary L., committee member; Smirnova, Natalia P., committee member; Van Campen, Hana, committee memberTo view the abstract, please see the full text of the document.Item Open Access Resin-based method for concentration of enteric viruses and F-RNA coliphages from water samples(Colorado State University. Libraries, 2014) Perez-Méndez, Alma Topiltzin, author; Goodridge, Lawrence, advisor; Marshall, Douglas, committee member; Nightingale, Kendra, committee member; Van Campen, Hana, committee memberFecal contamination of source and recreational waters represents a public health concern due to potential content of human pathogens, and the variety of sources from which an individual may be exposed to such contamination. Enteric viruses such as noroviruses, rotaviruses, adenoviruses and hepatitis viruses are dispersed by fecal contamination and are a major cause of waterborne diseases in the US and worldwide. Given the variety of viral enteric pathogens and their particular growth requirements, their detection is technically difficult and time consuming. An alternative to determine the risk of enteric virus contamination in water is to detect viral indicators of fecal contamination. F-RNA coliphages are recognized as enteric virus surrogates, fecal indicators useful for source tracking. Enteric viruses and F-RNA coliphages are often present at low concentrations in contaminated waters; therefore rapid, sensitive and cost effective viral concentration methods applicable to different environmental water samples are needed for an accurate assessment of water microbiological safety. Here, a resin-based virus concentration method was developed and tested. The method is based on adsorption of the viruses to an anion exchange resin dispersed in the water sample, followed by direct isolation of nucleic acids from the resin to provide a small volume final sample. In order to test the method with a wide variety of viral structures and characteristics, three enteric viruses (hepatitis A virus, adenovirus and rotavirus) and four F-RNA coliphages were used. Additionally, tap water and a variety of environmental samples were tested. After virus concentration, detection was performed through real time RT-PCR, a sensitive molecular technique widely use for detection of these viruses. In tap water containing 105 pfu/ml of F-RNA coliphages, the anion exchange resin adsorbed over 96% of the coliphage present, allowing for detection of between 100 to 10-1 pfu/ml of F-RNA coliphages in 50 ml samples. Similarly, experiments with large volumes of tap water showed that the resin-based method was capable of detection limits as low as 10 TCID50 of enteric viruses in tap water. Finally, the evaluation of the method with different samples of environmental water showed that the resin was useful for concentration of F-RNA coliphages in most of the samples, despite the presence of PCR inhibitors in the water. Limitations of the method included incomplete recovery of nucleic acids from the resin and concentration of PCR inhibitors from the samples. Given the simplicity of the method and the promising results obtained in this work, studies focused in increasing the yield of nucleic acids and decreasing the concentration of environmental inhibitors in the concentrated sample is warranted.Item Open Access Selection for fertility in lactating dairy cows: implications of conceptus-derived signals(Colorado State University. Libraries, 2016) Liebig, Bethany Ellen, author; Hansen, Thomas R., advisor; Thomas, Milton G., committee member; Van Campen, Hana, committee member; McConnel, Craig S., committee memberInfertility is a source of major economic loss in the dairy industry. Selection for fertility in dairy cows is difficult because fertility traits based on a genetic evaluation, such as daughter pregnancy rate (DPR), are lowly heritable (h2 ≤ 0.04), influenced by on-farm events, such as services per conception (SPC), and influenced by complex mechanisms that cause embryo mortality (EM). Embryo survival depends on robust interferon tau (IFNT) production and release from the trophectoderm, induction of IFN stimulated genes (ISG) in the endometrium to block the luteolytic, pulsatile release of prostaglandin F2α (PGF), and continued progesterone production by the corpus luteum throughout maternal recognition of pregnancy. Genes negatively affecting IFNT and ISG expression may increase the occurrence of EM. We hypothesized that selection for high direct genomic value for DPR (DGV-DPR) and low on-farm SPC records would be associated with increased: 1) IFNT production by the conceptus, 2) ISG expression in endometrium and peripheral blood mononuclear cells (PBMC), and 3) embryo survival. Freshening dairy cows (n=86) were sorted by DGV-DPR (determined by Clarifide®, Zoetis) and SPC into high fertile (HF; -1.3 DGV-DPR; 1.4 SPC) nonpregnant (NP) or pregnant (HP), and low fertile (LF; -2.3 DGV-DPR; 3.7 SPC) pregnant (LP) groups (n = 7 each). After the voluntary wait period, cows were estrous synchronized and time-artificially inseminated to a HF bull (+1.8 DPR). NP cows were not inseminated. On day 16 following onset of estrus, embryos were flushed from the uterus and typed as viable or EM based on morphology and length. The DGV-DPR was negatively correlated (r = -0.57; P < 0.05) with SPC. Days in milk and number of lactations were not different between groups. Serum progesterone tended (P < 0.10) to be lower in the cows carrying EM embryos than NP cows. Two of 7 embryos from HP cows and 3/6 embryos from LP cows were classified as EM. Viable embryos were significantly (P < 0.05) longer than EM embryos when fertility group was not considered. Viable HP embryos tended to be longer (P < 0.10) than LP embryos. Interferon tau concentrations in uterine flushing (UF) were: 1) greater in HP compared to LP and NP cows (P < 0.05), 2) positively correlated with DPR (r = 0.68; P < 0.05) and 3) negatively correlated with SPC (r = -0.59; P < 0.05). Interferon stimulated gene 15 mRNA concentrations were significantly: 1) upregulated in endometrium from HP viable compared to LP viable and NP cattle (P < 0.05), and 2) upregulated in peripheral blood mononuclear cells from HP compared to LP and NP cows (P < 0.05). Furthermore, ISG15 protein concentrations in endometrial tissue were significantly upregulated in HP compared to LP and NP cattle (P < 0.05). In conclusion, selection of dairy cows combining DPR and SPC may improve fertility through increased production and action of IFNT.