David R. Smith

Non-contact temperature assessment is highly valuable for screening animal populations, but its performance can be influenced by various external and biological variables. This study aimed to quantify the association between eye temperature (ET) and rectal temperature (RT) in dogs, and to identify physiological and environmental factors associated with these readings. Field study: ET was obtained with a thermal camera up to 3 times per visit (~10-min intervals), followed by RT measurement. Eye temperature was defined as the highest temperature recorded from either eye. A linear mixed-effects model evaluated ET in relation to capture time (1–3), RT, age, sex, body size, coat length, ambient temperature, and relative humidity. Device temporal stability assessment: To account for potential camera drift observed in our previous research, temperature at a fixed target inside an insulated box was recorded every 5 min for 1 h and analyzed with repeated-measures mixed model regression. Results. We analyzed 129 observations from 78 dogs. In the final ET model, both RT ( β = 0.77 °C; 95% C.I. 0.512–1.019 °C) and humidity ( β = 0.01 °C; 95% C.I. 0.002–0.013 °C) were positively and significantly associated with ET. The device stability assessment demonstrated no significant time-related measurement drift. Overall, ET was associated with RT but was not interchangeable and ET was slightly affected by environmental humidity. These results support further investigation of using ET as a rapid, noncontact temperature monitoring procedure.

Non-invasive thermal monitoring, such as infrared thermography (IRT), offers a potential alternative to traditional thermometry in veterinary settings. This study aimed to characterize the relationship between maximum eye temperature (ET) and rectal temperature (RT) in dogs. Our field study included 97 observations from 57 shelter dogs whose ET was measured using IRT on 4 separate days. For each observation, 3 consecutive ET measurements were obtained at 10-min intervals, followed by a RT measurement. Device temporal stability was evaluated measurement drift using an insulated box as a controlled environment; the temperature of a fixed point on the inner wall was recorded at 5-min intervals for 1 h using the same thermal camera. Data from both studies were analyzed using repeated-measures linear mixed-effects regression models. In field study, RT, age group, and repetition number were significantly associated with ET. For every 1 °C increase in RT, ET increased by an estimated 0.6 °C (95% CI, 0.3 to 0.9). On average, compared with puppies, adults had lower ET ( β = −0.4 °C; 95% CI, −0. 6 to −0.1), and ET decreased with repeated measurements. Device Stability assessment demonstrated a consistent drop in temperature readings, suggesting information bias related to the camera. Eye temperature measured by IRT was positively associated with RT, and age-related differences were observed. Repeated measurements showed a progressive decline in ET, consistent with device-related measurement drift rather than physiologic change. These findings underscore the importance of accounting for equipment performance characteristics when considering application of IRT. Eye thermography may serve as a noninvasive adjunct for assessing body temperature in dogs; however, device-related behavior should be validated and considered when interpreting readings.

A recently developed Tritrichomonas foetus RT-rtPCR reports higher sensitivity and specificity, and lower limit of detection (LOD) than other diagnostic modalities at approximately 1 organism/100 μL. Clinical interpretation of cycle threshold (Ct) results could have major implications on beef cattle herd level decisions. The objective of this study was to develop likelihood ratios for T. foetus RT-rtPCR Ct results near the LOD. Six hundred samples inoculated with T. foetus at approximately LOD, and 600 samples left uninoculated, were submit­ted to a diagnostic laboratory for T. foetus RT-rtPCR. Category specific likelihood ratios (LRcat) were calculated to compare Ct results ≤ 35.00, 35.01-39.99 and 40.00+. The median Ct of inoculated samples was 32.93 (min = 22.39, max = 40.00), and of uninoculated samples was 40.00 (min = 32.81, max = 40.00). For Ct ≤ 35.00, LRcat = 432 (95% CI: 60.91-3063.85); Ct = 35.01-39.99, LRcat = 149 (95% CI: 20.92-1061.3); and Ct = 40.00+, LRcat = 0.03 (95% CI: 0.02-0.05). The high LR for categories Ct ≤ 35.00 and Ct = 35.01-39.99 show that those values were more likely to occur in samples that were inoculated than in sam­ples uninoculated. This suggests that any amplification could be indicative of a true positive, and results in the Ct = 35.01-39.99 category should be considered for retest­ing. The LR for category Ct = 40.00+ demonstrates that truly inoculated samples were less likely to have that result. Using LR to estimate post-test prob­ability could aid clinical interpretation of results and more accurate bull culling decisions.

The objective of this study was to estimate the sensitivity and specificity of the semen morphology portion of the bull breeding soundness evaluation (BSE) for classifying Bos taurus bulls as sub-fertile. Semen, collected during BSE from bulls at the U.S. Meat Animal Research Center in Clay Center, Nebraska was evaluated using eosin-nigrosin stained slides at 1000X magnification by an experienced technician (Evaluator A) and an experienced veterinarian (Evaluator B). Slides with <70% morphologically normal sperm were classified as sub-fertile. Inter-evaluator agreement was assessed using Cohen’s kappa coefficient. Sensitivity, specificity, and true prevalence were estimated using Bayesian latent class analysis. Sensitivity was defined as the probability of correctly identifying a bull as sub-fertile, and specificity as the probability of correctly identifying a bull as satisfactory. Of 478 bulls, 68 (14%) were classified as sub-fertile by Evaluator A and 96 (20%) were classified as sub-fertile by Evaluator B; the kappa coefficient was 0.5. The estimated true prevalence of sub-fertile bulls was 16% (95%C.I. 6-32%). The estimated sensitivity and specificity for Evaluator A were 52% (95%C.I. 22-84%) and 93% (95%C.I. 86-99%) respectively, and for Evaluator B were 62% (95%C.I. 31-89%) and 88% (95%C.I. 80-97%). Test diagnostic performance was similar between the two evaluators. Diagnostic value of the morphologic examination was slightly greater than knowledge of bull fertility status prior to testing. Given a practitioner’s pre-test assessment of the probability of a bull’s subfertility, these diagnostic parameters can be used to predict the probability that the morphology portion of the BSE accurately predicts subfertility.

"Enhancing the health of animals through antimicrobial stewardship research" published on 01 May 2024 by American Veterinary Medical Association.

Reproductive efficiency is a major driver of profitability in cow-calf herds, yet many beef producers do not hire veterinar­ians to perform services intended to improve reproductive ef­ficiency such as bull breeding soundness evaluation (BSE) or pregnancy diagnosis. The objective of this study was to deter­mine reasons Mississippi cow-calf producers do or do not hire veterinarians to perform these services. Anonymous surveys were mailed to 1,500 randomly selected members of the Missis­sippi Cattlemen’s Association. Multivariable logistic regression was used to test respondent characteristics for association with outcome variables (e.g., respondents hire a veterinarian for BSEs and/or pregnancy diagnosis). Of 414 returned surveys, 397 (96%) qualified for analysis for an overall response rate of 26%. Of respondents that answered the respective ques­tions, 155/386 (40%) hire a veterinarian for BSEs, and 103/392 (26%) hire a veterinarian for pregnancy diagnosis. Of 396 re­spondents, 229 (58%) indicated they had some form of a defined breeding season. The most common reasons for not hiring a veterinarian were lack of time/help (82/202, 41%) for BSEs and cost (91/248, 37%) for pregnancy diagnosis. On in­ferential analysis, the factors positively associated with hiring a veterinarian for BSEs were having a defined breeding season (OR = 6.8, 95% C.I. = 4.1-11.1) and raising seedstock cattle (OR = 1.7, 95%C.I. = 1.0-13.3). The only factor positively associ­ated with hiring a veterinarian for pregnancy diagnosis was having a defined breeding season (OR = 4.2, 95%C.I. = 2.5-7.3). Management style and operation type influenced producers hiring a veterinarian for BSEs and pregnancy diagnosis.

The purpose of this survey was to describe veterinarians’ methods for performing bull breeding soundness evaluations (BSEs). Veterinarians in Mississippi, Louisiana and Arkansas were emailed a survey regarding their experience, demo­graphics, opinions and perceptions of client pref­erences regarding BSEs. Logistic regression was used to test respondent characteristics for associations with dichotomous outcomes including evaluating semen morphology as part of every BSE and detecting the diadem defect. Of 3,757 veterinar­ians solicited, 204 (5%) responded and 83 (2%) qualified for analysis. Of these, 10/73 (14%) indicated they do not evaluate morphology during every BSE. When shown an image of the diadem defect, 18/73 (25%) indicated seeing it often or some­times, and 55/73 (75%) indicated rarely or never. The only fac­tor associated with evaluating morphology as part of every BSE, was indicating belief that morphology was most predic­tive of bull fertility vs. believing motility was most predictive, or being unsure (OR = 11.2, 95% C.I. = 1.3-94.1). Respondents who always evaluate morphology with bright field microscopy at 1,000X (OR = 4.1, 95% C.I. = 1.2-13.3) or with phase contrast microscopy at ≥ 400X (OR = 5.4, 95% C.I. = 1.1-27.7) had higher odds of indicat­ing they detect the diadem defect sometimes/often. There was an interaction between always using 1000X magnification, or not, and always using 400X, or not, on the reported detection of the diadem defect. Veterinarians’ perceptions of which as­pects of the BSE are most predictive of fertility influence their methods for performing BSEs, and influence the frequency of detecting diadem defects.

To establish and compare the precision of serum total protein (STP) measured by an optical refractometer to the precision of IgG concentrations measured using radial immunodiffusion (RID), the reference test for quantifying IgG in neonatal calves. 6 sera with previously measured IgG concentration using RID from neonatal beef calves were selected from 3 stratum: low-serum IgG stratum between >5.0 and P = .39). The average CV for STP was 4.2%, 10.1% for the low IgG stratum, and 15.5% for the moderate/high IgG stratum. Variance differed in serum IgG concentration (P < .0001). Serum with higher IgG concentrations had more variance. Simulated CV for STP and IgG had homogeneity of variance for only 1 sera (P = .31). STP had a smaller CV compared to IgG for every serum (P < .0001). Estimating IgG concentration directly by RID or indirectly by STP lacks the precision that might affect diagnostic interpretation regarding a calf’s absorption of maternal antibodies. To establish and compare the precision of serum total protein (STP) measured by an optical refractometer to the precision of IgG concentrations measured using radial immunodiffusion (RID), the reference test for quantifying IgG in neonatal calves. 6 sera with previously measured IgG concentration using RID from neonatal beef calves were selected from 3 stratum: low-serum IgG stratum between >5.0 and P = .39). The average CV for STP was 4.2%, 10.1% for the low IgG stratum, and 15.5% for the moderate/high IgG stratum. Variance differed in serum IgG concentration (P < .0001). Serum with higher IgG concentrations had more variance. Simulated CV for STP and IgG had homogeneity of variance for only 1 sera (P = .31). STP had a smaller CV compared to IgG for every serum (P < .0001). Estimating IgG concentration directly by RID or indirectly by STP lacks the precision that might affect diagnostic interpretation regarding a calf’s absorption of maternal antibodies.

"Mississippi State College of Veterinary Medicine research prepares one-health scientists" published on 12 Apr 2023 by American Veterinary Medical Association.

The objective of this study was to identify factors associated with veterinary involvement in cattle health and production record (CHPR) management on U.S. cow-calf operations. We anonymously surveyed 14,294 cow-calf producers across the U.S. Multivariable logistic regression by manual forward variable selection was used to test demographic factors for association with veterinary involvement in CHPR management outcomes. A total of 3,741 (26%) responses were received, with 3,641 (97%) actively involved in cow-calf production. Of these, 2,216 of 3,486 (64%) said local veterinarians were their primary source of cattle health, treatment, and vaccination information. If available, 1,067 of 3,382 (32%) respondents would pay a veterinarian to analyze CHPR and provide management advice based on that information. Factors associated with willingness to pay a veterinarian for CHPR-keeping services include region (midwest: OR = 1.5; mountain: OR = 1.3; northeast: OR = 1.4; northern plains: OR = 1.8; southern plains: OR = 1.7; southeast: OR = 1.9; compared to west), cow-calf operation is not respondent’s primary income source (OR = 1.4; compared to being respondent’s primary income source), respondent records antibiotic treatments (OR = 1.4; compared to not recording antibiotic treatments), respondent education level (post-graduate or professional degree: OR = 1.4; some college up to completed Bachelor’s degree: OR = 1.1; compared to high-school diploma or less). A meaningful number of respondents were willing to pay a veterinarian for CHPR management services depending on region, income source, antibiotic record use and education level.