Evaluation of Precision Livestock Technology and Human Scoring of Nursery Pigs in a Controlled Immune Challenge Experiment

The objectives were to determine the sensitivity, specificity, and cutoff values of a visual-based precision livestock technology (NUtrack), and determine the sensitivity and specificity of sickness score data collected with the live observation by trained human observers. At weaning, pigs (n = 192; gilts and barrows) were randomly assigned to one of twelve pens (16/pen) and treatments were randomly assigned to pens. Sham-pen pigs all received subcutaneous saline (3 mL). For LPS-pen pigs, all pigs received subcutaneous lipopolysaccharide (LPS; 300 µg/kg BW; E. coli O111:B4; in 3 mL of saline). For the last treatment, eight pigs were randomly assigned to receive LPS, and the other eight were sham (same methods as above; half-and-half pens). Human data from the day of the challenge presented high true positive and low false positive rates (88.5% sensitivity; 85.4% specificity; 0.871 Area Under Curve, AUC), however, these values declined when half-and-half pigs were scored (75% sensitivity; 65.5% specificity; 0.703 AUC). Precision technology measures had excellent AUC, sensitivity, and specificity for the first 72 h after treatment and AUC values were \u3e0.970, regardless of pen treatment. These results indicate that precision technology has a greater potential for identifying pigs during a natural infectious disease event than trained professionals using timepoint sampling

Low-stress sampling and cortisol measurements in periparturient sows

The most common method of cortisol sample collection for sows is jugular venipuncture, which requires restraint via snaring. Snaring can be an added stressor to sows, especially during the periparturient phase, when cortisol concentrations are already elevated and variable responses are expected. Therefore, the objectives of this study were to determine the variation of stress-responses to farrowing using less-invasive sample collection methods (saliva vs. low-volume ear vein blood). Samples were collected from 10 multiparous sows (DNA Genetics; K-State Swine Research Center) at -1 and +1 d relative to farrowing. Sows were offered a 51 cm cotton-rope to chew on and 300 uL of blood was drawn after ear venipuncture using a 26 gauge needle and syringe treated with heparin. After centrifugation, saliva and plasma were harvested from solid-particles and blood cells then immediately frozen at -20°C until cortisol concentration analysis using a commercially available ELISA kit (Detect X Cortisol Assay; Arbor Assays, Anne Arbor, MI). Sows tended, (P = 0.06) to have less ear-vein plasma cortisol concentrations at -1 than +1 d relative to parturition but differences in cortisol concentrations were not detected from saliva samples (P = 0.67). The range of cortisol concentration was greater in the plasma-samples than the salivary samples (19.17 to 55.50 vs. 0.69 to 6.14 ng/mL, respectively). Nonetheless, CV% was lower among plasma than salivary samples (24.8 vs. 67.3%). If a treatment is expected to cause a 25% change in cortisol secretion, then only 21 sows will be needed per treatment if plasma is measured, whereas 152 pigs will be needed if saliva is measured. Therefore, the preferred sample collection method for future experiments involving periparturient sows will be ear-venipuncture, rather than salivary collection

Image Classification and Automated Machine Learning to Classify Lung Pathologies in Deceased Feedlot Cattle

Bovine respiratory disease (BRD) and acute interstitial pneumonia (AIP) are the main reported respiratory syndromes (RSs) causing significant morbidity and mortality in feedlot cattle. Recently, bronchopneumonia with an interstitial pattern (BIP) was described as a concerning emerging feedlot lung disease. Necropsies are imperative to assist lung disease diagnosis and pinpoint feedlot management sectors that require improvement. However, necropsies can be logistically challenging due to location and veterinarians’ time constraints. Technology advances allow image collection for veterinarians’ asynchronous evaluation, thereby reducing challenges. This study’s goal was to develop image classification models using machine learning to determine RS diagnostic accuracy in right lateral necropsied feedlot cattle lungs. Unaltered and cropped lung images were labeled using gross and histopathology diagnoses generating four datasets: unaltered lung images labeled with gross diagnoses, unaltered lung images labeled with histopathological diagnoses, cropped images labeled with gross diagnoses, and cropped images labeled with histopathological diagnoses. Datasets were exported to create image classification models, and a best trial was selected for each model based on accuracy. Gross diagnoses accuracies ranged from 39 to 41% for unaltered and cropped images. Labeling images with histopathology diagnoses did not improve average accuracies; 34–38% for unaltered and cropped images. Moderately high sensitivities were attained for BIP (60–100%) and BRD (20–69%) compared to AIP (0–23%). The models developed still require fine-tuning; however, they are the first step towards assisting veterinarians’ lung diseases diagnostics in field necropsies

Epidemiological Factors Associated with Gross Diagnosis of Pulmonary Pathology in Feedyard Mortalities

Respiratory disease continues to be the major cause of mortality in feedyard cattle, with bronchopneumonia (BP) and acute interstitial pneumonia (AIP) as the two most common syndromes. Recent studies described a combination of these pathological lesions with the presence of AIP in the caudodorsal lungs and BP in the cranioventral lungs of necropsied cattle. This pulmonary pathology has been described as bronchopneumonia with an interstitial pneumonia (BIP). The epidemiological characteristics of BIP in U.S. feedyard cattle are yet to be described. This study’s objectives were to describe the agreement between feedyard clinical and necropsy gross diagnosis and to characterize epidemiological factors associated with four gross pulmonary diagnoses (AIP, BIP, BP, and Normal pulmonary tissue) observed during feedyard cattle necropsies. Systemic necropsies were performed at six feedyards in U.S. high plains region, and gross pulmonary diagnoses were established. Historical data were added to the dataset, including sex, days on feed at death (DOFDEATH), arrival weight, treatment count, and feedyard diagnosis. Generalized linear models were used to evaluate epidemiological factors associated with the probability of each pulmonary pathology. Comparing feedyard clinical diagnosis with gross pathological diagnosis revealed relatively low agreement and the frequency of agreement varied by diagnosis. The likelihood of AIP at necropsy was higher for heifers than steers and in the 100–150 DOFDEATH category compared with the 0–50 DOFDEATH (p = 0.05). The likelihood of BIP increased after the first treatment, whereas the DOFDEATH 0–50 category had a lower likelihood compared with the 150–200 category (p = 0.05). These findings highlight the importance of necropsy for final diagnosis and can aid the development of future diagnosis and therapeutic protocols for pulmonary diseases

Side-bias and time-of-day influenced cognition after minipigs were conditioned using a novel tactile stimulation device

Agricultural and clinical research communities seek objective tools to detect and track prepathological states for prevention, disease-treatment, and therapeutics. We propose a novel, quantitative approach to test the functional state of the somatosensory system and detect aberrations in neurophysiology associated with prepathological injury or sickness. Leveraging the evolutionarily preserved concepts of lateral inhibition and parallel processing, the human version of this approach can detect the slightest changes in brain health. However, an animal model is needed to benefit and translate results to both agriculture and clinical researchers. The objective of this study was to refine methodologies for the use of tactile stimulation (TS; vibration at 75 Hz for 1 s; Porcine Brain Gauge; Cortical Metrics, North Carolina) to condition and test a pigs ability to associate right-TS with a right-ball and left-TS with a left-toy during 12 tests (right and left tested every test). Minipigs (n = 8; boars = 7 gilt = 1; NSRRC, Columbia, MO) were used to determine the effects of: 1) placement of two TS-devices (sides or behind ears); 2) right- or left-bowl bias, time (1000 h or 0300 h) and; 3) day (6 test consecutive days). Pig with ear-placement spent more time at the correct bowl than pigs with side-placement (P = 0.05). All pigs spent more time (P = 0.02) in the correct-bowl area and tended to have a greater correct-index (P = 0.09) if the first test administered was on the right than when the test started on the left. Pigs tended (P = 0.06) to spend less time making a decision and spent more time at the correct bowl (P < 0.01) in the morning tests than evening tests. In addition, all pigs spent less time at the correct bowl and decreased correct frequency after each day (P < 0.05). Future studies will be designed to repeat tests for side-bias and take place in the mornings, after feeding. The effects of day suggest that pigs became bored over time, therefore, future experiments will include more operant-conditioned tasks to test motivation, and physical barriers to restrict movement after the subject enters the right- or left-bowl area

Association of plasma haptoglobin concentration and other biomarkers with bovine respiratory disease status in pre-weaned dairy calves.

We conducted a nested, case-control study of pre-weaned dairy calves ( n = 477; 4 California dairy farms) to assess the association between bovine respiratory disease (BRD) and hematologic biomarkers, including plasma haptoglobin (Hp) and plasma bactericide (PB). At each location, heifer or bull dairy calves were observed 2-4 times per week until confirmed as BRD-positive using parallel interpretation of thoracic ultrasound examination and auscultation. In addition, control calves were enrolled after being confirmed as BRD-negative using ultrasound and auscultation. Complete blood counts (CBC), PB, and Hp concentrations were measured. Hp values were higher in calves with confirmed BRD than in controls ( p &lt; 0.01). The area under the curve (AUC) for the various biomarkers was obtained from the corresponding receiver operating characteristic curves. The AUC for Hp was 0.68, a value greater than those for PB or the remaining CBC parameters, indicating that Hp may be the most useful biomarker of BRD in pre-weaned dairy calves. The cutoff value for Hp was 0.195 g/L

Evaluation of Precision Livestock Technology and Human Scoring of Nursery Pigs in a Controlled Immune Challenge Experiment

The objectives were to determine the sensitivity, specificity, and cutoff values of a visual-based precision livestock technology (NUtrack), and determine the sensitivity and specificity of sickness score data collected with the live observation by trained human observers. At weaning, pigs (n = 192; gilts and barrows) were randomly assigned to one of twelve pens (16/pen) and treatments were randomly assigned to pens. Sham-pen pigs all received subcutaneous saline (3 mL). For LPS-pen pigs, all pigs received subcutaneous lipopolysaccharide (LPS; 300 μg/kg BW; E. coli O111:B4; in 3 mL of saline). For the last treatment, eight pigs were randomly assigned to receive LPS, and the other eight were sham (same methods as above; half-and-half pens). Human data from the day of the challenge presented high true positive and low false positive rates (88.5% sensitivity; 85.4% specificity; 0.871 Area Under Curve, AUC), however, these values declined when half-and-half pigs were scored (75% sensitivity; 65.5% specificity; 0.703 AUC). Precision technology measures had excellent AUC, sensitivity, and specificity for the first 72 h after treatment and AUC values were >0.970, regardless of pen treatment. These results indicate that precision technology has a greater potential for identifying pigs during a natural infectious disease event than trained professionals using timepoint sampling

Resumos concluídos - Neurociências

Resumos concluídos -  Neurociência