VTechWorks Archives

Permanent URI for this community

https://hdl.handle.net/10919/25799

Browse

Now showing 1 - 20 of 134

Acute heat stress activated inflammatory signaling in porcine oxidative skeletal muscle
Ganesan, Shanthi; Volodina, Olga; Pearce, Sarah C.; Gabler, Nicholas K.; Baumgard, Lance H.; Rhoads, Robert P.; Selsby, Joshua T. (2017-08)
Despite well-studied clinical manifestations, intracellular mechanisms of prolonged hyperthermic injury remain unclear, especially in skeletal muscle. Given muscle's large potential to impact systemic inflammation and metabolism, the response of muscle cells to heat-mediated injury warrants further investigation. We have previously reported increased activation of NF-κB signaling and increased NF-κB and AP-1-driven transcripts in oxidative skeletal muscle following 12 h of heat stress. The purpose of this investigation was to examine early heat stress-induced inflammatory signaling in skeletal muscle. We hypothesized that heat stress would increase NF-κB and AP-1 signaling in oxidative skeletal muscle. To address this hypothesis, 32 gilts were randomly assigned to one of four treatment groups (n = 8/group): control (0 h: 21°C) or exposed to heat stress conditions (37°C) for 2 h (n = 8), 4 h (n = 8), or 6 h (n = 8). Immediately following environmental exposure pigs were euthanized and the red portion of the semitendinosus muscle (STR) was harvested. We found evidence of NF-κB pathway activation as indicated by increased protein abundance of NF-κB activator IKK-α following 4 h and increased total NF-κB protein abundance following 6 h of heat stress. Heat stress also stimulated AP-1 signaling as AP-1 protein abundance was increased in nuclear fractions following 4 h of heat stress. Interleukin-6 protein abundance and activation of the JAK/STAT pathway were decreased in heat stressed muscle. These data indicate that heat stress activated inflammatory signaling in the porcine STR muscle via the AP-1 pathway and early activation of the NF-κB pathway.
Additional Molecular Evidence that The Royal Palm is Probably a Turkey Breed
Smith, Edward J.; Xu, Jun; Adikari, J. (2019-07-09)
In earlier investigations, we reported the uniqueness of Royal Palm from other commonly raise heritage turkeys. Here, we provide evidence from screening using primers specific for the Melanocortin 1 (MC1R) Receptor gene (located on turkey chromosome 13, accession number NC_015023). Five heritage strains, including Broad Breasted Bronze (48), Blue Slate (40), Midget White (40), Royal Palm (45), and Spanish Black (48) were included in the analyses of approximately 3300 base pairs of the MC1R gene. Seven SNPs were identified and validated. Among the haplotypes identified, only Royal Palm had unique haplotypes. When combined with previous investigations, we believe that the Royal Palm may be a breed and not a strain. It may therefore be the most viable resource for introgression with a goal of genetic improvement.
Advancing livestock genomics education and research in developing countries using strategies from the Virginia Tech PREP and IMSD training programs
Smith, Edward J. (2019-07-11)
Our unique and impactful research and education program plan includes distinct activities that target three overlapping phases of each trainee’s tenure, which we define as the “moving in,” “moving through,” and “moving out” phases. During the “moving in” phase, 8 trainees “who need a PREP” will be recruited and assigned to mentors using our proven strategy that is “scholar-driven” and combines mentor qualities such as prior experience, which has resulted in a 98% retention for each of our 3 funding cycles. $409,537 annually or ~2.1 Million for five years. our successful interdisciplinary Initiative for Maximizing Student Development (IMSD) program for pre-doctoral (graduate) and pre-baccalaureate (undergraduate) students from groups underrepresented in careers in the biomedical and behavioral sciences. Our training program is a partnership with departments and interdisciplinary graduate programs which takes advantage of Virginia Tech’s (VT) history of excellence in Engineering and the Behavioral and Life Sciences. With lessons learned in the last eight years, we will continue to recruit across disciplines and from diverse geographic areas and institutions. From the first cycle, 2007-12, a total of 23 pre-doctoral students participated in the VT IMSD program. A total of 16 (or 69.5%) have completed and received the PhD degree; Total Year 1: $467,489.
Ag Commodities - VCE Showcasing Scholarship Poster
Arnold, Sandy; Baker, Karen (2017-02-22)
Youth are our future. Agriculture is our lifeline. Extension merges these two vital topics together through the 4-H Agriculture Commodities Tour, bringing awareness of the necessity for both to meet on an intimate real-life, out-of-classroom experience. Despite the continual and increasing demand for educated agriculturalists, interest and enrollment in agricultural fields of study has stagnated or declined. Lack of exposure, experience and familiarity with agricultural opportunities is likely a large contributor to this problem. By connecting across the state with Extension Agriculture State Specialists and Agents at the ARECs as part of the 2016 tour, 28 inner-city youth had the opportunity of a lifetime to explore agricultural lifestyles and potential careers. Providing more than basic agricultural information books can ever provide, these youths explored the importance of sustainability and stewardship across the state through talks, demonstrations and experiential hands-on learning opportunities. In addition, while learning how agriculture relates to their lives, this also gave them an awareness of career opportunities in agriculture that interest them. Studies demonstrate these interventions yield positive in attracting youth considering agricultural fields as viable career options (McCallister, Lee, & Mason, 2005; Shivy & Koehly, 2002; Esters, 2007; Ladany, Melincoff, Constantine, & Love, 1997). Although measuring the outcome of our youth and their future is beyond the scope of this initial investment, it is hoped that this tour has made a significant impact on the youth’s perception of agriculture outside of the classroom, and encourages them to seek further into this new world of possibilities.
Altered phosphorylation, electrophysiology, and behavior on attenuation of PDE4B action in hippocampus
Campbell, Susan L.; van Groen, Thomas; Kadish, Inga; Smoot, Lisa High Mitchell; Bolger, Graeme B. (BMC, 2017)
Background: PDE4 cyclic nucleotide phosphodiesterases regulate 3′, 5′ cAMP abundance in the CNS and thereby regulate PKA activity and phosphorylation of CREB, which has been implicated in learning and memory, depression and other functions. The PDE4 isoform PDE4B1 also interacts with the DISC1 protein, implicated in neural development and behavioral disorders. The cellular functions of PDE4B1 have been investigated extensively, but its function(s) in the intact organism remained unexplored. Results: To specifically disrupt PDE4B1, we developed mice that express a PDE4B1-D564A transgene in the hippocampus and forebrain. The transgenic mice showed enhanced phosphorylation of CREB and ERK1/2 in hippocampus. Hippocampal neurogenesis was increased in the transgenic mice. Hippocampal electrophysiological studies showed increased baseline synaptic transmission and enhanced LTP in male transgenic mice. Behaviorally, male transgenic mice showed increased activity in prolonged open field testing, but neither male nor female transgenic mice showed detectable anxiety-like behavior or antidepressant effects in the elevated plus-maze, tail-suspension or forced-swim tests. Neither sex showed any significant differences in associative fear conditioning or showed any demonstrable abnormalities in pre-pulse inhibition. Conclusions: These data support the use of an isoform-selective approach to the study of PDE4B1 function in the CNS and suggest a probable role of PDE4B1 in synaptic plasticity and behavior. They also provide additional rationale and a refined approach to the development of small-molecule PDE4B1-selective inhibitors, which have potential functions in disorders of cognition, memory, mood and affect.
Animal welfare considerations for on-farm slaughter of poultry
Jacobs, Leonie (2018)
Association of Polymorphisms in the Period3 (turPer3) Gene with Growth and Reproductive Traits in Turkeys (Meleagris gallopavo)
Smith, E.; Adikari, A. M.; Xu, J. (2018)
Background and objective: Biological clock controls behavioral, physiological and biochemical circadian rhythms of animals. Circadian clock genes including period3 are involved in the circadian clock mechanism. The present study was conducted to test the hypothesis that differences in DNA sequence variations of the turkey period3 (turPer3) gene may be associated with performance traits including growth and reproduction. Methodology: The turPer3 gene was screened for DNA sequence variations and evaluated the relationships among haplogroups with performance traits. The DNA sequences of turPer3 (16.6 kb) gene were screened using 290 turkey birds by re-sequencing the individual amplicons. Results: Seven SNPs, including one each in exon 18 and intron 5, two SNPs in exon 19 and three SNPs in intron 6, were detected. The SNPs detected in the exon 19 were non-synonymous, which changed the amino acids from methionine to threonine and serine to phenylalanine at 953rd and 955th positions, respectively. Linkage disequilibrium (Dʼ) among SNPs ranged from 0.03-1.00. Pairwise FST ranged from 0.01-0.43. Haplogroup frequencies of the turPer3 ranged from 0.02-1.00, were significantly associated with body weight (BW) at 231 days of age, average daily gain (ADG) for the period of 160-231 d of age, FCR for the periods of 69-159 d and 160-231 d, egg production and semen quality traits (p#0.05). Conclusion: The DNA sequence variations of turPer3 gene are significantly associated with BW, ADG, FCR, egg production, egg weight and semen quality traits. turPer3 gene may seem to have some regulatory role in the molecular mechanism of the circadian clock. Genomic reagents reported in the present study would be valuable for future genotype: phenotype evaluation studies in the turkey using a candidate gene approach.
Attracting and Retaining Minorities in the Biomedical Sciences Including Genomics: a Community-based Approach
Smith, Edward J. (2014-08-21)
B-Lymphocytes Expressing an Ig Specificity Recognizing the Pancreatic beta-Cell Autoantigen Peripherin Are Potent Contributors to Type 1 Diabetes Development in NOD Mice
Leeth, Caroline M.; Racine, Jeremy; Chapman, Harold D.; Arpa, Berta; Carrillo, Jorge; Carrascal, Jorge; Wang, Qiming; Ratiu, Jeremy; Egia-Mendikute, Leire; Rosell-Mases, Estela; Stratmann, Thomas; Verdaguer, Joan; Serreze, David V. (American Diabetes Association, 2016-07-01)
Although the autoimmune destruction of pancreatic b-cells underlying type 1 diabetes (T1D) development is ultimately mediated by T cells in NOD mice and also likely in humans, B cells play an additional key pathogenic role. It appears that the expression of plasma membrane–bound Ig molecules that efficiently capture b-cell antigens allows autoreactive B cells that bypass normal tolerance induction processes to be the subset of antigen-presenting cells most efficiently activating diabetogenic T cells. NOD mice transgenically expressing Ig molecules recognizing antigens that are (insulin) or are not (hen egg lysozyme [HEL]) expressed by b-cells have proven useful in dissecting the developmental basis of diabetogenic B cells. However, these transgenic Ig specificities were originally selected for their ability to recognize insulin or HEL as foreign, rather than autoantigens. Thus, we generated and characterized NOD mice transgenically expressing an Ig molecule representative of a large proportion of naturally occurring islet-infiltrating B cells in NOD mice recognizing the neuronal antigen peripherin. Transgenic peripherin-autoreactive B cells infiltrate NOD pancreatic islets, acquire an activated proliferative phenotype, and potently support accelerated T1D development. These results support the concept of neuronal autoimmunity as a pathogenic feature of T1D, and targeting such responses could ultimately provide an effective disease intervention approach.
Beef heifer fertility: importance of management practices and technological advancements
Moorey, Sarah E.; Biase, Fernando H. (2020-10-01)
The development of replacement heifers is at the core of cow-calf beef production systems. In 2020, the USDA, National Agricultural Statistics Service reported 5.771 million beef heifers, 500 pounds and over, are under development for cow replacement. A compilation of data from several studies indicate that between 85% and 95% of these heifers will become pregnant in their first breeding season. Several thousands of heifers being raised for replacement may not deliver a calf on their first breeding season and result in economic losses to cow-calf producers. Many management procedures have been developed to maximize the reproductive potential of beef heifers. Such approaches include, but are not limited to the following: nutritional management for controlled weight gain, identification of reproductive maturity by physiological and morphological indicators, and the implementation of an estrous synchronization program. The implementation of management strategies has important positive impact(s) on the reproductive efficiency of heifers. There are limitations, however, because some heifers deemed ready to enter their first breeding season do not become pregnant. In parallel, genetic selection for fertility-related traits in beef heifers have not promoted major genetic gains on this particular area, most likely due to low heritability of female fertility traits in cattle. Technologies such as antral follicle counting, DNA genotyping and RNA profiling are being investigated as a means to aid in the identification of heifers of low fertility potential. To date, many polymorphisms have been associated with heifer fertility, but no DNA markers have been identified across herds. Antral follicle count is an indication of the ovarian reserve and is an indicator of the reproductive health of a heifer. We have been working on the identification of transcriptome profiles in heifers associated with pregnancy outcome. Our current investigations integrating protein-coding transcript abundance and artificial intelligence have identified the potential for bloodborne transcript abundance to be used as indicators of fertility potential in beef heifers. In summary, there is an ongoing pressure for reducing costs and increasing efficiency in cow-calf production systems, and new technologies can help reduce the long-standing limitations in beef heifer fertility.
Biallelic modification of IL2RG leads to severe combined immunodeficiency in pigs
Clark-Deener, Sherrie; Kang, Jung-Taek; Cho, Bumrae; Ryu, Junghyun; Ray, Caitlin; Lee, Eun-Jin; Ahn, SunMi; Lee, JinSeok; Ji, Dal-Young; Jue, Nathaniel; Lee, Kiho; Park, Kwang-Wook (2016-11-03)
Background: Pigs with SCID can be a useful model in regenerative medicine, xenotransplantation, and cancer cell transplantation studies. Utilizing genome editing technologies such as CRISPR/Cas9 system allows us to generate genetically engineered pigs at a higher efficiency. In this study, we report generation and phenotypic characterization of IL2RG knockout female pigs produced through combination of CRISPR/Cas9 system and SCNT. As expected, pigs lacking IL2RG presented SCID phenotype. Methods: First, specific CRISPR/Cas9 systems targeting IL2RG were introduced into developing pig embryos then the embryos were transferred into surrogates. A total of six fetuses were obtained from the embryo transfer and fetal fibroblast cell lines were established. Then IL2RG knockout female cells carrying biallelic genetic modification were used as donor cells for SCNT, followed by embryo transfer. Results: Three live cloned female piglets carrying biallelic mutations in IL2RG were produced. All cloned piglets completely lacked thymus and they had a significantly reduced level of mature T, B and NK cells in their blood and spleen. Conclusions: Here, we generated IL2RG knockout female pigs showing phenotypic characterization of SCID. This IL2RG knockout female pigs will be a promising model for biomedical and translational research.
Can Dogs Learn Concepts the Same Way We Do? Concept Formation in a German Shepherd
Feuerbacher, Erica N.; Rosales-Ruiz, Jesus (International Society For Comparative Psychology, 2017-01-01)
Growing evidence shows that dogs can complete complex behavioral tasks, such as learning labels for hundreds of objects, readily learning the name of a novel object, and responding differentially to objects by category (e.g., “toy,” “ball,” “Frisbee”). We expand here on the evidence for complex behavioral abilities in dogs by demonstrating that they are capable of concept formation by strict criteria. A German shepherd responded differentially to two sets of objects (“toys” and “non-toys”) in Experiment 1. Additionally, the dog’s differential responding in Experiment 1 occurred from the first trial, indicating that he entered the experiment with this stimulus class already differentiated from his day-to-day exposure to contingencies. In Experiment 2 we used a common response (tug-of-war) with three objects that were not retrieved in Experiment 1 to attempt to add these objects to the stimulus class. After repeated sessions of tug-of-war, the dog began retrieving all three objects in the retrieval test, although the rates of retrieval varied between objects. Finally, in Experiment 3, we conducted a transfer of function test in which the dog emitted a new response to untrained exemplars suggesting that his differential responding in Experiment 1 was indicative of a concept by the strictest criteria. Additionally, the reliably emitted the new response in the transfer test to one of the three new objects from Experiment 2, suggesting this object had been reliably added to the conceptual class.
Central administration of dipeptides, beta-alanyl-BCAAs, induces hyperactivity in chicks
Tsuneyoshi, Yousuke; Tomonaga, Shozo; Asechi, Mari; Morishita, Koji; Denbow, D. Michael; Furuse, Mitsuhiro (2007-05-31)
Background Carnosine (β-alanyl-L-histidine) is a putative neurotransmitter and has a possible role in neuron-glia cell interactions. Previously, we reported that carnosine induced hyperactivity in chicks when intracerebroventricularly (i.c.v.) administered. In the present study, we focused on other β-alanyl dipeptides to determine if they have novel functions. Results In Experiment 1, i.c.v. injection of β-alanyl-L-leucine, but not β-alanyl-glycine, induced hyperactivity behavior as observed with carnosine. Both carnosine and β-alanyl-L-leucine stimulated corticosterone release. Thus, dipeptides of β-alanyl-branched chain amino acids were compared in Experiment 2. The i.c.v. injection of β-alanyl-L-isoleucine caused a similar response as β-alanyl-L-leucine, but β-alanyl-L-valine was somewhat less effective than the other two dipeptides. β-Alanyl-L-leucine strongly stimulated, and the other two dipeptides tended to stimulate, corticosterone release. Conclusion These results suggest that central β-alanyl-branched chain amino acid stimulates activity in chicks through the hypothalamus-pituitary-adrenal axis. We named β-alanyl-L-leucine, β-alanyl-L-isoleucine and β-alanyl-L-valine as Excitin-1, Excitin-2 and Excitin-3, respectively.
Changes with age in density of goblet cells in the small intestine of broiler chicks
Reynolds, K. L.; Cloft, Sara E.; Wong, Eric A. (Elsevier, 2020-05-01)
Goblet cells secrete mucin 2 (Muc2), which is a major component of the mucus that lines the intestinal tract and creates a protective barrier between pathogens and the intestinal epithelial cells and thus are important for chick health. The objectives of this study were to determine the age-specific and intestinal segment–specific expression of Muc2 mRNA and changes in the number of goblet cells from late embryogenesis to early after hatch. Small intestinal samples from the duodenum, jejunum, and ileum were collected from Cobb 500 broilers at embryonic day 19 (e19), day of hatch (doh), and day 2 and 4 after hatch. Cells expressing Muc2 mRNA and mucin glycoprotein were detected by in situ hybridization or alcian blue and periodic acid–Schiff staining, respectively. Along the villi, there were many more cells expressing Muc2 mRNA than those stained for mucin glycoprotein. In the crypt, cells expressing Muc2 mRNA did not stain for mucin glycoprotein. There was an increase in the density of goblet cells in the villi and Muc2 mRNA expressing cells in the crypts of the jejunum and ileum from e19 to doh and day 2 to day 4, with no change between doh and day 2. In contrast, in the duodenum, the density of goblet cells in the villi and Muc2 mRNA expressing cells in the crypts remained constant from e19 to day 4. At day 4, the villi in the ileum had a greater density of goblet cells than the duodenum. In the crypt, the ileum had a greater density of Muc2 mRNA expressing cells than the duodenum at doh, and the ileum and jejunum both had greater densities of Muc2 mRNA expressing cells than the duodenum at day 4. These results indicate that the population of goblet cells has reached a steady state by doh in the duodenum, whereas in the jejunum and ileum, a steady-state population was not reached until after hatch.
Characterization of Expressed Sequence Tags From a Gallus gallus Pineal Gland cDNA Library
Hartman, Stefanie; Touchton, Greg; Wynn, Jessica; Geng, Tuoyu; Chong, Nelson W.; Smith, Edward J. (Hindawi, 2005-01-01)
The pineal gland is the circadian oscillator in the chicken, regulating diversefunctions ranging from egg laying to feeding. Here, we describe the isolation andcharacterization of expressed sequence tags (ESTs) isolated from a chicken pinealgland cDNA library. A total of 192 unique sequences were analysed and submittedto GenBank; 6% of the ESTs matched neither GenBank cDNA sequences nor thenewly assembled chicken genomic DNA sequence, three ESTs aligned with sequencesdesignated to be on the Z_random, while one matched a W chromosome sequence andcould be useful in cataloguing functionally important genes on this sex chromosome.Additionally, single nucleotide polymorphisms (SNPs) were identified and validatedin 10 ESTs that showed 98% or higher sequence similarity to known chicken genes.Here, we have described resources that may be useful in comparative and functionalgenomic analysis of genes expressed in an important organ, the pineal gland, in amodel and agriculturally important organism.
Characterization of the endogenous retrovirus insertion in CYP19A1 associated with henny feathering in chicken
Li, Jingyi; Davis, Brian W.; Jern, Patric; Dorshorst, Benjamin J.; Siegel, Paul B.; Andersson, Leif (2019-08-28)
Background Henny feathering in chickens is determined by a dominant mutation that transforms male-specific plumage to female-like plumage. Previous studies indicated that this phenotype is caused by ectopic expression in skin of CYP19A1 encoding aromatase that converts androgens to estrogen and thereby inhibits the development of male-specific plumage. A long terminal repeat (LTR) from an uncharacterized endogenous retrovirus (ERV) insertion was found in an isoform of the CYP19A1 transcript from henny feathering chicken. However, the complete sequence and the genomic position of the insertion were not determined. Results We used publicly available whole genome sequence data to determine the flanking sequences of the ERV, and then PCR amplified the entire insertion and sequenced it using Nanopore long reads and Sanger sequencing. The 7524 bp insertion contains an intact endogenous retrovirus that was not found in chickens representing 31 different breeds not showing henny feathering or in samples of the ancestral red junglefowl. The sequence shows over 99% sequence identity to the avian leukosis virus ev-1 and ev-21 strains, suggesting a recent integration. The ERV 3’LTR, containing a powerful transcriptional enhancer and core promoter with TATA box together with binding sites for EFIII and Ig/EBP inside the CYP19A1 5′ untranslated region, was detected partially in an aromatase transcript, which present a plausible explanation for ectopic expression of aromatase in non-ovarian tissues underlying the henny feathering phenotype. Conclusions We demonstrate that the henny feathering allele harbors an insertion of an intact avian leukosis virus at the 5’end of CYP19A1. The presence of this ERV showed complete concordance with the henny feathering phenotype both within a pedigree segregating for this phenotype and across breeds.
Cloverbuds in Equine 4-H Programs
Ransdell, Leona P. (2016-01-16)
Presentation about how to engage and retain cloverbud members in an equine 4-H program
Combination of probiotics and coccidiosis vaccine enhances protection against an Eimeria challenge
Ritzi, Miranda M.; Abdelrahman, Wael; van-Heerden, Kobus; Mohnl, Michaela; Barrett, Nathaniel W.; Dalloul, Rami A. (BMC, 2016-11-08)
Coccidiosis is endemic in the commercial broiler industry capable of inflicting devastating economic losses to poultry operations. Vaccines are relatively effective in controlling the disease; their efficacy could potentially be improved with concurrent use of probiotics as evaluated in this study using an Eimeria challenge. Day of hatch 400 Cobb-500 male broilers were assigned to one of four treatment groups including control (CON), vaccine-only gel application (VNC), probiotic-only gel application (NPC), and vaccine-plus-probiotic gel application (VPC). Birds were placed in floor pens (6 replicate pens/treatment, 16–17 birds/pen). NPC and VPC birds received the probiotics in the water on days 2–4, 8, 14–20, 22, 29, and 34–36. On day 15, birds were mildly challenged with 0.5 mL of a mixed oral inoculum of Eimeria sp. prepared with the coccidiosis vaccine at 10× the vaccination dose. Performance measurements were recorded on first day and weekly afterwards, and lesion scores were evaluated 6 days post-challenge. Overall, the probiotics and coccidiosis vaccine resulted in an enhanced protective effect against the challenge, with VPC birds exhibiting lower lesion scores in the duodenum than VNC or NPC birds. Birds in the VPC treatment also demonstrated higher weight gains during days 1–15, days 7–15, and days 21–28 when compared to the VNC birds. These results suggest that the combination of probiotics and coccidiosis vaccines could enhance performance and provide an additional protective effect against a mixed Eimeria challenge.
Commercial Hy-Line W-36 pullet and laying hen venous blood gas and chemistry profiles utilizing the portable i-STAT (R) 1 analyzer
Schaal, T. P.; Arango, J.; Wolc, A.; Brady, J. V.; Fulton, J. E.; Rubinoff, I.; Ehr, I. J.; Persia, Michael E.; O'Sullivan, Neil P. (Oxford University Press, 2016-02-01)
Venous blood gas and chemistry reference ranges were determined for commercial Hy-Line W-36 pullets and laying hens utilizing the portable i-STAT 1 analyzer and CG8+ cartridges. A total of 632 samples were analyzed from birds between 4 and 110 wk of age. Reference ranges were established for pullets (4 to 15 wk), first cycle laying hens (20 to 68 wk), and second cycle (post molt) laying hens (70 to 110 wk) for the following traits: sodium (Na mmol/L), potassium (K mmol/L), ionized calcium (iCa mmol/L), glucose (Glu mg/dl), hematocrit (Hct% Packed Cell Volume [PCV]), pH, partial pressure carbon dioxide (PCO2 mm Hg), partial pressure oxygen (PO2 mm Hg), total concentration carbon dioxide (TCO2 mmol/L), bicarbonate (HCO3 mmol/L), base excess (BE mmol/L), oxygen saturation (sO2%), and hemoglobin (Hb g/dl). Data were analyzed using ANOVA to investigate the effect of production status as categorized by bird age. Trait relationships were evaluated by linear correlation and their spectral decomposition. All traits differed significantly among pullets and mature laying hens in both first and second lay cycles. Levels for K, iCa, Hct, pH, TCO2, HCO3, BE, sO2 , and Hb differed significantly between first cycle and second cycle laying hens. Many venous blood gas and chemistry parameters were significantly correlated. The first 3 eigenvalues explained ∼2/3 of total variation. The first 2 principal components (PC) explained 51% of the total variation and indicated acid-balance and relationship between blood O2 and CO2. The third PC explained 16% of variation and seems to be related to blood iCa. Establishing reference ranges for pullet and laying hen blood gas and chemistry with the i-STAT 1 handheld unit provides a mechanism to further investigate pullet and layer physiology, evaluate metabolic disturbances, and may potentially serve as a means to select breeder candidates with optimal blood gas or chemistry levels on-farm.
Comparison of reproductive performance of AI- and natural service-sired beef females under commercial management
Marrella, Mackenzie A.; White, Robin R.; Dias, Nicholas W.; Timlin, Claire; Pancini, Stefania; Currin, John F.; Clark, Sherrie G.; Stewart, Jamie L.; Mercadante, Vitor R. G.; Bradford, Heather L. (Oxford University Press, 2021-07)
The objective of this study was to assess differences in reproductive performance of natural service and artificial insemination (AI) sired beef females based on pregnancy outcomes, age at first calving, and calving interval. Data were sourced from 8,938 cows sired by AI bulls and 3,320 cows sired by natural service bulls between 2010 and 2017. All cows were in a commercial Angus herd with 17 management units located throughout Virginia and represented spring and fall calving seasons. All calves were born to dams managed with estrus synchronization. Pregnancy was analyzed with generalized linear mixed models and other reproductive measures with linear mixed models in R. Six models were evaluated with the dependent variables of pregnancy status at the first diagnosis, pregnancy status at the second diagnosis, pregnancy type (AI or natural service) at the first diagnosis, pregnancy type at the second diagnosis, calving interval, and age at first calving. Independent variables differed by model but included sire type of the female (AI or natural service), prebreeding measures of age, weight, and body condition score, postpartum interval, sex of the calf nursing the cow, and management group. No differences were observed between AI- and natural service-sired females based on pregnancy status at first and second pregnancy diagnosis (P > 0.05). Sire type was only found to be significant for age at first calving (P < 0.05) with AI-sired females being 26.6 ± 1.6 d older at their first calving, which was expected because AI-sired females were born early in the calving season making them older at breeding. Surprisingly, age and body condition score were not significant predictors of pregnancy (P > 0.05). Body weight at breeding was not significant for pregnancy (P > 0.05) but was significant for age at first calving (P < 0.05). These data suggested that lighter heifers calved earlier which contradicts our original hypothesis. Overall, commercial Angus females sired by AI or natural service bulls had similar reproductive performance. Factors that were commonly associated with reproductive success were not significant in this commercial Angus herd managed with estrus synchronization. Given the size of these data, the importance of body condition, age, and weight should be reassessed in modern genetics and management practices.

Browse

Browsing VTechWorks Archives by Department "Animal and Poultry Sciences"

Results Per Page

Sort Options