Publications by authors named "Jay S Johnson"

Article Synopsis
  • Climate change is increasingly threatening the livestock industry by affecting animal productivity, welfare, and management, prompting a focus on enhancing livestock's climatic resilience (CR).
  • A study performed genome-wide association studies on lactating sows under heat stress, identifying 31 significant single nucleotide polymorphisms (SNPs) linked to nine CR indicators and revealing that CR is a polygenic trait with small effect sizes across various chromosomes.
  • Key candidate genes related to heat stress response and various physiological processes were identified, along with relevant pathways indicating links to stress, immune responses, and various traits like health and production quality in livestock.
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The desire to reach ever-diminishing lower limits of quantification (LLOQ) to probe changes in low abundance protein targets has led to enormous progress in sample preparation and liquid chromatography-tandem mass spectrometry (LC-MS/MS) instrumentation. To maximize signal and reduce noise, many approaches have been employed, including specific immunoaffinity (IA) enrichment and reducing the LC flow to the nanoflow (nLC) level; however, additional sensitivity gains may still be required. Recently, a technique termed "echo summing" has been described for small-molecular-weight analytes on a triple quadrupole (QqQ) MS where multiple iterations of the same, single selected reaction monitoring (SRM) transition are collected, summed, and integrated, yielding significant analyte dependent signal-to-noise (S/N) improvements.

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The study objective was to investigate the effect of repeated hypothalamic-pituitary-adrenal (HPA) axis stimulation using synthetic adrenocorticotropic hormone (ACTH) intramuscular injections on hair cortisol concentration, growth, and behavior in preweaned dairy calves. Twenty-seven Holstein calves were assigned to nine triads (based on sex and birth order) and randomly assigned to 1 of 3 treatments: 1) control (CON; 2 mL saline weekly); 2) moderate (MOD; alternating Cosyntropin [2 mcg/kg body weight (BW)] and saline weekly); or 3) frequent (FREQ; Cosyntropin [2 mcg/kg BW] weekly). Calves received their first injection on study day 0 (7 ± 1 d of age).

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Article Synopsis
  • Researchers analyzed vaginal temperature data from lactating sows to create 15 new indicators of climatic resilience (CR) to improve pig breeding, particularly during heat stress periods.
  • Heritability estimates for CR traits varied, with some traits showing moderate to high genetic correlations with key reproductive traits and indicators of heat stress.
  • Sows with higher genomic estimated breeding values (GEBV), indicating they are more sensitive to climate conditions, tended to have higher skin temperature and respiration rates, but lower body condition scores compared to those with lower GEBV, suggesting differences in resilience.
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Background: Heat stress (HS) poses significant threats to the sustainability of livestock production. Genetically improving heat tolerance could enhance animal welfare and minimize production losses during HS events. Measuring phenotypic indicators of HS response and understanding their genetic background are crucial steps to optimize breeding schemes for improved climatic resilience.

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Background: Automatic and continuous recording of vaginal temperature (T) using wearable sensors causes minimal disruptions to animal behavior and can generate data that enable the evaluation of temporal body temperature variation under heat stress (HS) conditions. However, the genetic basis of T in lactating sows from a longitudinal perspective is still unknown. The objectives of this study were to define statistical models and estimate genetic parameters for T in lactating sows using random regression models, and identify genomic regions and candidate genes associated with HS indicators derived from automatically-recorded T.

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Article Synopsis
  • Non-additive genetic effects, though often overlooked, could enhance genomic breeding value accuracy and influence traits like heat tolerance and heterosis in livestock.
  • Including these effects in performance models for purebred pigs didn't significantly alter residual variance, but it did lead to lower estimates of additive genetic variance and some animal re-ranking across models.
  • For heat tolerance in crossbred sows, while most traits had minor non-additive variance, significant epistatic variances were found in panting scores and hair density, indicating their importance in total genetic variance.
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Article Synopsis
  • Genetic improvement of livestock, particularly Large White pigs, has led to increased metabolic heat production and a higher risk of heat stress, but genetic selection for heat tolerance is feasible.
  • The study aimed to evaluate genomic breeding values for heat tolerance using routinely recorded traits and to explore the genetic factors influencing heat tolerance in relation to key economic traits.
  • By analyzing data from over 265,000 pigs and using genomic predictions, the study compared breeding values across different temperature conditions to determine the effectiveness of temperature-specific data for improving heat tolerance assessment.
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The study objective was to evaluate the interaction between corticotrophin releasing factor () receptor signaling and prophylactic antibiotic administration on intestinal physiology in newly weaned and transported pigs. Pigs (n = 56; 5.70 ± 1.

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Background: Genetic selection based on direct indicators of heat stress could capture additional mechanisms that are involved in heat stress response and enable more accurate selection for more heat-tolerant individuals. Therefore, the main objectives of this study were to estimate genetic parameters for various heat stress indicators in a commercial population of Landrace × Large White lactating sows measured under heat stress conditions. The main indicators evaluated were: skin surface temperatures (SST), automatically-recorded vaginal temperature (T), respiration rate (RR), panting score (PS), body condition score (BCS), hair density (HD), body size (BS), ear size, and respiration efficiency (R).

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l-Glutamine supplementation improves gastrointestinal and immune function in dairy calves during controlled immune and stress challenges. However, it is unknown whether supplementing milk replacer (MR) with l-glutamine improves preweaning dairy calf health and welfare under production conditions. Therefore, the study objective was to evaluate the effects of supplementing MR with l-glutamine on gastrointestinal permeability, immune function, growth performance, postabsorptive metabolic biomarkers, and physiological stress response in preweaning dairy calves.

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  • Heat stress negatively affects cows' welfare and productivity, prompting the need for a deeper understanding of their physiological responses across different parities for improved management strategies.
  • First-parity cows showed significant increases in rectal temperature and respiration rate during summer, along with reduced milk yield and lactose percentage compared to spring, while second-parity cows exhibited similar but less pronounced trends.
  • Metabolite analysis revealed distinct biological responses between first and second-parity cows, with specific biomarkers identified for differentiating their responses to heat stress across seasons, highlighting varying effects on metabolism and gut health.
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Domesticated sows are motivated to perform nesting behavior prior to farrowing, and nesting material can reduce piglet cold stress. However, nesting material may not be practical in most production systems due to the potential for clogging slurry systems. Therefore, the study objectives were to assess an alternative nesting material provided prior to farrowing on sow welfare and piglet survival, and to investigate the effect of the entire nesting environment on piglet survival and growth performance.

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An accurate understanding of boar temperature preferences may allow the swine industry to design and utilize environmental control systems in boar facilities more precisely. Therefore, the study objective was to determine the temperature preferences of sexually mature Duroc, Landrace, and Yorkshire boars. Eighteen, 8.

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Article Synopsis
  • * The study was conducted at a commercial farm in North Carolina, involving measurements of temperature and humidity in both naturally and mechanically ventilated barns, and included monitoring various thermoregulatory measures in sows over a period of weeks.
  • * Data were analyzed using advanced statistical methods to determine the relationship between thermoregulatory responses and phenotype characteristics, with findings suggesting that both ventilation types showed similar temperature response patterns amidst varying HS conditions.
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Background: Although thermal indices have been proposed for swine, none to our knowledge differentiate by reproductive stage or predict thermal comfort using behavioral and physiological data. The study objective was to develop a behavior and physiology-based decision support tool to predict thermal comfort and stress in multiparous (3.28 ± 0.

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  • Quantitative modeling plays a key role in drug discovery, helping to determine target selection, compound properties, and dosing decisions.
  • The manuscript introduces a site-of-action modeling framework specifically for monoclonal antibodies aimed at soluble targets.
  • It details the construction and parameterization of the model, provides examples of its application, and discusses both the benefits and limitations of this method.
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Article Synopsis
  • The colon has a diverse microbial community crucial for metabolism, nutrition, and immune function, and changes in this microbiota can lead to metabolic diseases like obesity and colorectal cancer.
  • Existing methods to study microbiota-diet interactions are often invasive or limited to fecal samples, making it difficult to get accurate spatial information.
  • A new electronic-free smart capsule has been developed to allow targeted sampling of gut microbiota in the proximal colon, using a special pH-sensitive coating to ensure it only collects data from that specific region.
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Oral administration of indigestible markers and subsequent urine collection is a useful method to determine in vivo gastrointestinal tract (GIT) permeability in cattle for research purposes. However, urine sampling techniques often rely on total waste collection, which reduces the ability to perform more frequent sampling and obtain accurate volumes and sterile samples. An alternative is urethral catheterization, though the feasibility of this technique has not been thoroughly tested in preweaned Holstein heifer calves.

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This study aimed to determine what effects in utero heat stress (IUHS) in pigs may have on quality of processed pork products. In two experiments, patties and emulsion sausages were prepared from lean and fat from pigs subjected to IUHS or in utero thermoneutral (IUTN) conditions. Patties formulated to contain 25% added fat had altered textural properties compared to those without additional fat, as shown by lower hardness, cohesiveness, springiness, and chewiness values (p < 0.

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Characterizing the sow physiological response to an increased heat load is essential for effective heat stress mitigation. The study objective was to characterize the effects of a 400-min heating episode on sow heart rate variability (HRV) at different reproductive stages. HRV is a commonly used noninvasive proxy measure of autonomic function.

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Heat stress (HS) decreases lactation output in sows due to an attempt to reduce metabolic heat production. However, this negatively affects litter growth performance. Therefore, the study objective was to determine whether electronically controlled cooling pads (ECP) would improve indirect measures of lactation output (e.

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Although serum and fecal biomarkers (, lactoferrin, and calprotectin) have been used in management and distinction between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), none are proven to be a differential diagnostic tool between Crohn's disease (CD) and ulcerative colitis (UC). The main challenge with laboratory-based biomarkers in the stool test is the inability to indicate the location of the disease/inflammation in the gastrointestinal (GI) tract due to the homogenous nature of the collected fecal sample. For the first time, we have designed and developed a battery-free smart capsule that will allow targeted sampling of inflammatory biomarkers inside the gut lumen of the small intestine.

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In utero heat stress alters postnatal physiological and behavioral stress responses in pigs. However, the mechanisms underlying these alterations have not been determined. The study objective was to characterize the postnatal hypothalamic-pituitary-adrenal axis response of in utero heat-stressed pigs.

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The metabolic heat production of modern pigs has increased by an average of 16%, compared with sows of 30 years ago. Therefore, it is likely that temperature recommendations require updating to meet the needs of modern pigs. The objective of this study was to evaluate whether different reproductive stages of sows altered thermal preference and if current recommendations required updating.

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