Effect of extended heat stress in dairy cows on productive and behavioral traits.

This study evaluates the response of dairy cows to short and extended heat stressing conditions (from 1 to 28 days), as expressed in changes in their behavior. Due to climate change, heat stress and strong heat waves are frequently affecting the productivity and behavior of dairy cows. In the five years under study from 2018 to 2022, two were characterized by extremely strong heat waves occurring in the region analyzed in this study (Northern Italy). The dairy cattle farm involved in this study is located in Northern Italy and includes about 1 600 Holstein Friesian lactating dairy cows. Phenotypic data were provided by the Afimilk system and compromised behavioral and productive traits. Behavioral traits analyzed were activity, rest time, rest bouts, rest ratio, rest per bout and restlessness. Production traits were daily milk yield, average milking time, somatic cell count, fat percentage, protein percentage and lactose percentage. Climate data came from the National Aeronautics and Space Administration/Prediction of Worldwide Energy Resources database. Heat stress was analyzed considering Temperature-Humidity Index (THI) averaged over 28 different time windows of continuous heat stress. Results showed that rest time and milk yield were the two traits most affected by the increased THI. Rest time was immediately affected by high THI, showing a marked decrease already from 1d window and maintaining this all over the other windows. Furthermore, results show that rest time and rest ratio were only slightly negatively correlated with milk yield (-0.14 and -0.15). In addition, heat stress has a different effect depending on parity and lactation stages on the studied traits. In conclusion, the results indicate that heat stress increases activity and compromises milk production, rest time and milk quality traits. Results further suggest that rest time can be a better parameter than activity to describe the effects of heat stress on dairy cattle. The novel approach used in this study is based on the use of different time windows (up to 28 days) before the emergence of undesired THI and allows to identify the traits that are immediately influenced by the undesirable THI values and those that are influenced only after a prolonged heat stress period.

Monitoring ventral tail base surface temperature for fever detection in calves.

In this study, we investigated whether monitoring the ventral tail base surface temperature (ST) using a wearable wireless sensor could be effective for fever detection in calves with experimentally induced pneumonia after inoculation with Histophilus somni strain 2336. We found a significant difference in the changes in ST values between the control and H. somni-inoculated groups after 24 h of inoculation and detected fever; however, the rectal temperature showed a significant difference between the groups after 12 h of inoculation. When a significant difference in the ST between the two groups was observed, serum haptoglobin concentration and exacerbation of clinical score increased in the H. somni-inoculated group compared with those in the control group. Pneumonia was observed in the H. somni-inoculated group at necropsy, indicating that the changes in ST may reflect fever with inflammation caused by H. somni infection. Our results demonstrated that monitoring ST using a sensor attached to the ventral tail base can detect fever in calves and may be a useful and labor-saving tool for the health management of calves.

Clinical diagnosis and outcome of cervicofacial cellulitis in pyrexic rabbits: six cases (2014-2021).

OBJECTIVES: To assess the signalment, history, exam findings, diagnostics, treatment and outcome of rabbits diagnosed with pyrexia and concurrent cervicofacial cellulitis. MATERIALS AND METHODS: Retrospective evaluation of medical records of rabbits diagnosed with cervicofacial cellulitis and pyrexia based on physical exam, contrast-enhanced CT, clinicopathology and microbiology findings. RESULTS: Six out of 1588 rabbits met the study inclusion criteria. Rabbits presented with a median age of 6 years (range, 8 months to 8 years) with a presenting complaint of anorexia or hyporexia. All rabbits had a rectal temperature >40.2°C (104.4°F). Physical exam and contrast-enhanced CT revealed unilateral submandibular and ipsilateral cervical diffuse soft tissue swelling in five of six rabbits. No antemortem evidence of periodontal or dental disease was found on physical exam or CT. Leucopenia was present in five of six rabbits. A left shift with marked toxic changes was present in all four rabbits, for which blood smears were reviewed. Bacterial cultures of the aspirated subcutaneous soft tissue swelling cultured Escherichia coli, Pasteurella multocida, Granulicatella adiacens, Streptococcus species, Haemophilus species and Bacteroides species. Treatment was pursued in five rabbits, where all rabbits received supportive care and four of five rabbits received systemic antibiotics. One rabbit was euthanased following a diagnosis of cervicofacial cellulitis. Three out of five rabbits continued to decline clinically despite medical management, and thus, euthanasia was pursued within 24 hours of starting treatment. Two rabbits responded to initial treatment and developed subsequent multi-focal abscessation. One rabbit was euthanased due to client cost constraints, and one rabbit died shortly after achieving clinical resolution of cervicofacial cellulitis. CLINICAL SIGNIFICANCE: Cervicofacial cellulitis should be considered a differential diagnosis in pyrexic rabbits with facial or cervical swelling with medical and surgical management pursued for therapy.

Listeria monocytogenes cholangiohepatitis in a lactating Holstein cow.

OBJECTIVE: To describe a unique presentation of systemic Listeria monocytogenes infection in a lactating adult Holstein cow. ANIMAL: 3-year-old second-parity female Holstein, 200 days in milk. CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES: A 3-year-old Holstein dairy cow was presented for decreased appetite, decreased milk production, and pyrexia. Blood work displayed marked abnormalities in liver-associated parameters. A diagnosis of L monocytogenes cholangiohepatitis was made following liver biopsy, histopathology, and bacterial culture. TREATMENT AND OUTCOME: The cow was treated with systemic antimicrobial and antipyretic therapy. The cow was discharged to continue treatment on farm, and at time of last communication with the owner, the cow was doing very well, with full resolution of clinical signs. CLINICAL RELEVANCE: This case report describes a novel presentation of L monocytogenes infection in an adult bovine. L monocytogenes cholangiohepatitis should be considered a rare differential diagnosis in cattle presenting with evidence of pyrexia and liver disease.

Metritis and clinical mastitis events in lactating dairy cows were associated with altered patterns of rumination, physical activity, and lying behavior monitored by an ear-attached sensor.

Understanding changes in parameters recorded by automated health monitoring systems based on ear-attached sensors on the days immediately before and after diagnosis of metritis and clinical mastitis can help develop dairy cow health monitoring strategies. The objective of this observational cohort study was to characterize rumination time, physical activity, and lying time monitored by an ear-attached sensor before, during, and after clinical diagnosis (CD) of metritis and clinical mastitis. Lactating Holsteins monitored daily for 21 d in milk for detection of health disorders were retrospectively included in the no clinical health disorder group (NCHD; n = 616) if no disorders were diagnosed. Cows were included in the metritis (MET; n = 69) or clinical mastitis (MAST; n = 36) group if diagnosed only with nonsevere metritis (watery, reddish, and fetid uterine discharge with or without pyrexia) or nonsevere clinical mastitis (visibly abnormal milk secretion with or without signs of udder inflammation, with no pyrexia and no systemic signs of disease), respectively. Cows diagnosed with severe metritis (signs of metritis plus systemic signs of disease) or severe clinical mastitis (signs of mastitis plus pyrexia and systemic signs of disease), and cows diagnosed with nonsevere metritis or clinical mastitis plus another disorder within -7 to +7 d of CD of metritis or clinical mastitis diagnosis, were included in the metritis plus (MET+; n = 25) or the clinical mastitis plus (MAST+; n = 15) group, respectively. Cows were fitted with an ear-attached accelerometer to measure rumination time, physical activity, and lying time. Mean daily values, mean value absolute change, and relative change for the mean daily value from 3 or 5 d before CD to the nadir for cows with metritis and clinical mastitis, respectively, were analyzed with linear mixed models with or without repeated measures. Rumination time and physical activity were lesser, and lying time was greater for the MET and MET+ groups than for the NCHD group for most days from -4 to +7 d of CD of metritis. Generally, daily rumination time, physical activity, and lying time differences were greater and more prolonged between the MET+ and NCHD than between the MET and NCHD groups. Similarly, cows in the MAST and MAST+ groups had lesser rumination time and physical activity than cows in the NCHD group for several days before diagnosis. Lying time was greater for the MAST+ than the NCHD group on d -1 and 0 relative to CD. Absolute values and relative changes from 3 d before CD to the day of the nadir for rumination time and physical activity, or peak for lying time, were different for cows in the MET and MET+ groups than for the NCHD group. Similar results were observed for the MAST and MAST+ groups compared with the NCHD group. For cows with metritis, either an increase in rumination time and physical activity or a decrease in lying time was observed from the day of CD to resolution of clinical signs, but no changes were observed for the NCHD. Cows with clinical mastitis and the NCHD group had different rumination times, physical activity, and lying times on the day of CD and resolution of clinical signs, but cows with clinical mastitis had no significant changes from the day of CD to resolution of clinical signs. We conclude that cows affected by metritis and clinical mastitis presented substantial alterations of the patterns of rumination time, physical activity, and lying time captured by an ear-attached sensor. Thus, automated health monitoring systems based on ear-attached sensors might be used as an aid for identifying cows with metritis and clinical mastitis. Moreover, behavioral parameter changes after CD might be good indicators of resolution of clinical signs of metritis but not mastitis.

Review: Reproductive consequences of whole-body adaptations of dairy cattle to heat stress.

Heat stress has far-reaching ramifications for agricultural production and the severity of its impact has increased alongside the growing threats of global warming. Climate change is exacerbating the already-severe consequences of seasonal heat stress and is predicted to cause additional losses in reproductive performance, milk production and overall productivity. Estimated and predicted losses are staggering, and without advancement in production practices during heat stress, these projected losses will threaten the human food supply. This is particularly concerning as the worldwide population and, thus, demand for animal products grows. As such, there is an urgent need for the development of technologies and management strategies capable of improving animal production capacity and efficiency during periods of heat stress. Reproduction is a major component of animal productivity, and subfertility during thermal stress is ultimately the result of both reproductive and whole-body physiological responses to heat stress. Improving reproductive performance during seasonal heat stress requires a thorough understanding of its effects on the reproductive system as well as other physiological systems involved in the whole-body response to elevated ambient temperature. To that end, this review will explore the reproductive repercussions of whole-body consequences of heat stress, including elevated body temperature, altered metabolism and circulating lipopolysaccharide. A comprehensive understanding of the physiological responses to heat stress is a prerequisite for improving fertility, and thus, the overall productivity of dairy cattle experiencing heat stress.

Listeriosis in a goat herd.

Two 3-week-old goat kids from a herd of ~50 to 60 goats were examined by a veterinarian. The goats were in lateral recumbency with an inability to rise. Unilateral cranial nerve deficiencies included cervical rotation, nystagmus, ptosis, facial paralysis, and absence of palpebral reflex. One of the 2 kids had a fever. The kids died and necropsy examinations were performed. Histopathology findings were highly suggestive of Listeria monocytogenes infection, which was confirmed by bacterial culture. This case suggests that listeriosis should be included in the differential diagnosis for goats with neurological signs even if they are not fed silage or haylage and are kept in a clean barn.

Listériose dans un troupeau de chèvres. Deux chevreaux de 3 semaines d'un troupeau d'environ 50 à 60 chèvres ont été examinés par un vétérinaire. Les chèvres étaient en décubitus latéral avec une incapacité à se lever. Les déficiences unilatérales des nerfs crâniens comprenaient une rotation cervicale, du nystagmus, une ptose, une paralysie faciale et l'absence de réflexe palpébral. Un des 2 chevreaux avait de la fièvre. Les chevreaux sont morts et des nécropsies ont été effectués. Les résultats de l'histopathologie étaient très évocateurs d'une infection à Listeria monocytogenes, qui a été confirmée par culture bactérienne. Ce cas suggère que la listériose devrait être incluse dans le diagnostic différentiel pour les chèvres présentant des signes neurologiques même si elles ne sont pas nourries avec de l'ensilage ou de l'ensilage préfané et sont gardées dans une étable propre.(Traduit par Dr Serge Messier).

[Body temperature measurement in pigs: Are infrared thermometers a non-invasive alternative?] / Messung der Körpertemperatur beim Schwein: Können Infrarotthermometer eine Alternative sein?

OBJECTIVE: Internal body temperature is an essential parameter in evaluation an animal's general health status. The rectal temperature as 'gold standard' requires restraining of the animal which may cause stress especially when not accustomed to handling procedures. Stress on the other hand should whenever possible be avoided as it negatively affects animal welfare and may increase body temperature. The present study evaluated whether measuring the body surface temperature with an infrared thermometer (IRT) may represent a stressless alternative method to rectal body temperature measurements. MATERIAL AND METHODS: Twelve male fattening pigs were included in the study. Body temperature was measured once a week for 11 weeks. Body surface temperature measurements were performed in the areas of the forehead, caudal base of the ear and anus using two infrared thermometers (IRT1 and IRT2) each. RESULTS: Throughout the study, all pigs were clinically healthy. Best repeatability was found for the rectal thermometer and IRT1 in the anus region. Homogeneity of variance was not found for the measurements of the three thermometers. Mean values of body temperature were significantly different (p<0,05) between thermometers and measurement points. Thereby, the type of thermometer and measurement point possessed a moderate to strong effect. The Bland-Altman plot shows that differences in the values of the thermometers and measurement points are within the acceptable range of variation (95% interval). However, the range of variation is too substantial for clinical assessment of the body temperature. CONCLUSION: The repeatability of temperature data measured with IRT on the body surface of pigs is acceptable. For this procedure, restraining the animals is not necessary, therefore reducing the animal's stress level during the clinical examination. However, the correlation to the rectal body temperature is weak to moderate. CLINICAL RELEVANCE: In order to use IRT for health monitoring in animals, reference values for respective IRT and measurement points need to be established. In the current study no case of hyper- or hypothermia occurred. Further research is warrented to evaluate whether IRT reliably detect fever.

Ingesta-associated choledocholithiasis in horses: 2 cases and literature review.

Equine ingesta-associated choledocholithiasis is a rare cause of morbidity and mortality. We describe here the clinical, gross, histologic, and microbiologic features of this condition in 2 horses and compare the features to 2 previous cases. Case 1 was a 4-y-old Thoroughbred mare with colic. Case 2 was an 18-y-old American Paint Horse mare with colic, chronic weight loss, and inappropriate mentation. Both had elevated biochemical markers of hepatocellular injury and cholestasis and were euthanized given a poor prognosis. Case 1 had a well-formed 5-cm choledocholith surrounding a piece of hay, and had chronic neutrophilic cholangiohepatitis, bridging fibrosis, and extrahepatic obstruction. Case 2 had an ill-formed choledocholith with occasional hay fragments, wood stick, and twigs, and had regionally extensive hepatocellular necrosis with mild neutrophilic cholangiohepatitis and bridging fibrosis. Enterococcus casseliflavus and Escherichia coli were isolated in both cases; Clostridium spp. were also isolated from case 2. All 4 reported cases had increased activity of cholestatic enzymes, hyperbilirubinemia, portal inflammation, and bridging fibrosis. Colic, pyrexia, leukocytosis with neutrophilia, and elevated hepatocellular enzyme activity were documented in 3 cases. Foreign material in all 4 cases was plant origin (choledochophytolithiasis), including hay (n = 2), sticks/twigs (n = 2), and grass awns (n = 1). Ingesta-associated choledocholithiasis may be considered as a cause of colic, pyrexia, and elevated cholestatic biomarkers in horses.

Use of thermography and physiological rate to assess heat tolerance in cattle breeds.

Thermography has grown in use in recent years. It is a valuable tool for measuring animal heat tolerance under heat stress conditions since it is a non-invasive, safe and practical methodology. Physiological variables such as respiration rate and eye temperature, and environmental variables such as air temperature and wet bulb temperature were analysed in animals from nine cattle breeds (Angus, Braford, Brangus, Canchim, Charolais, Hereford, Nelore, Simmental and Santa Gertrudis) and one bubaline (Mediterranean) at Rio Grande do Sul, Brazil. Positive correlations were observed between air temperature and respiration rate and eye temperature. Furthermore, the breed strongly influenced the eye temperature and respiration rate of the animals. Eye temperature showed strong correlation with air temperature and wet bulb temperature. Simmental and Nelore animals presented higher eye temperature values. Simmental presented alteration in respiratory rate before the other breeds and Nelore was the last breed to present this alteration. The inflection points in the broken line analysis indicated the environmental temperature limits at which breeds begin to change their respiration to compensate for environmental variation. The use of thermography has proven to be a technique with possible application to evaluate the temperature of animals. Logistic regression analysis allows us to observe how each breed behaves with the temperature change. Using respiration rates and eye temperatures it was possible to identify physiological limits for comfort in different breeds of bovine. In the future it would be interesting to conduct additional studies using other physiological variables and also other indices of climatic conditions.

Current perceptions and use of paracetamol in dogs among veterinary surgeons working in the United Kingdom.

BACKGROUND: Paracetamol (acetaminophen) is recommended as a first-line drug in the management of pain and pyrexia in humans due to its minor gastrointestinal, renal and vascular side effects. OBJECTIVES: To explore the perceptions and use of paracetamol in dogs by UK veterinarians. METHODS: Veterinarians were invited to complete an online survey. Questions addressed career history, previous use, and personal perceptions of the use of paracetamol in dogs. RESULTS: A total of 450 veterinarians were included in the survey; 96% (n = 431) of whom worked in small animal practice only. The majority reported a frequency of use of 1-3 times a week (n = 197), with oral dosing being the most common route of administration (n = 440). Only 8 had never prescribed paracetamol. Paracetamol was more commonly used to provide analgesia (n = 431) than for the treatment of pyrexia (n = 292) and was predominantly used as an alternative to NSAIDs (n = 408) or as part of multimodal analgesia (n = 406). Hepatotoxic (n = 311) and gastrointestinal (n = 120) side effects were a common concern, although the majority perceived a low risk of side effects and felt they were likely to be mild if they did occur (n = 279). Only 5% (n = 24) of respondents reported having experienced side effects, with gastrointestinal signs (n = 14) and hepatotoxicity (n = 6) being the most common. CONCLUSIONS: Paracetamol is widely used by veterinarians working in the UK. Most veterinarians have changed their perception on the use of paracetamol over the last decade and consider it to be associated with fewer side effects and with more effective analgesic and antipyretic effects than they had previously believed.

Non-surgical correction of nephrosplenic entrapment and colitis in a Quarter Horse.

A 16-year-old Quarter Horse was examined and observed to have acute signs of colic, pyrexia, and diarrhea. A nephrosplenic entrapment was detected via rectal palpation and confirmed with abdominal ultrasound. The nephrosplenic entrapment was resolved non-surgically with jogging and anti-inflammatory medication. Concurrent colitis, toxic laminitis, and inappetence were managed and the horse made a full recovery.

Correction non chirurgicale d'emprisonnement néphro-splénique et de la colite chez un Quarter Horse. Un Quarter Horse âgé de 16 ans a été examiné et on a observé des signes aigus de coliques, de pyrexie et de diarrhée. Un piégeage néphro-splénique a été détecté par palpation rectale et confirmé par échographie abdominale. L'emprisonnement néphro-splénique a été résolu de manière non chirurgicale avec du jogging et des médicaments anti-inflammatoires. La colite concomitante, la fourbure toxique et l'inappétence ont été gérées et le cheval s'est complètement rétabli.(Traduit par Dr Serge Messier).

Diagnosis and Analysis of Clinical Characteristics of Chlamydia psittaci Pneumonia.

Objective: We assessed the clinical characteristics of three patients with Chlamydia psittaci-associated pneumonia. Methods: Clinical data for three patients with C. psittaci-associated pneumonia admitted to our hospital from June 2020 to December 2020 were retrospectively analyzed, and the diagnosis, clinical features, and treatment of the disease are summarized. Results: Fever, headache, and fatigue were the main symptoms in all three patients, whereas local respiratory symptoms such as cough and expectoration were not obvious. Not all patients had a definite contact history with poultry and birds. Chest computed tomography (CT) showed inflammatory exudation, consolidation, and bronchial inflation signs on one side of the lungs, which progressed rapidly. Treatment with beta-amides did not result in positive clinical responses. Combined with clinical manifestations, the disease was confirmed by detection of C. psittaci nucleic acid sequences in alveolar lavage fluid and blood by metagenomic second-generation sequencing technology. Fever and malaise were rapidly relieved after the administration of moxifloxacin-based regimens and levels of infectious blood markers decreased; and the consolidation shadow on chest CT was gradually absorbed. Conclusion: Early application of metagenomic second-generation sequencing in patients with community-acquired pneumonia due to rare and complex pathogens that cannot be diagnosed by conventional tests and for whom empirical anti-infective therapy is ineffective is important for definitive diagnosis and selection of appropriate antibacterial drugs.

Effect of calving season on metritis incidence and bacterial content of the vagina in dairy cows.

Heat stress and uterine diseases, including metritis and endometritis, both reduce milk yields and reduce reproductive performance. Bacterial growth is promoted by elevated temperature while heat stress reduces host immune cell function, but it is not known whether increased environmental temperature promotes uterine disease by altering host immunity or bacterial growth. We hypothesize that seasonal variations in environmental temperature influence metritis incidence in the dairy cow independent of bacterial prevalence in the reproductive tract. To investigate how environmental temperature may impact metritis incidence, records of 3507 calvings in Florida over a 5-year period were evaluated. The incidence of metritis increased from 21.1% in the cool season (October through March) to 24.2% during the warm season (April through September, P < 0.05). To elucidate a link between environmental temperature and uterine disease, 102 cows were enrolled during the warm season (September 2017; n = 51) and cool season (February-March 2018; n = 51). Cows were maintained on pasture during the dry period and moved to free stall barns with fans and water soakers immediately prior to calving and remained in that environment after calving. Vaginal mucus was collected and scored on days 7 (to evaluate metritis) and 21 (to evaluate endometritis) postpartum to evaluate the incidence of uterine disease and quantify bacterial content and species using qPCR. Daily milk yield for the first 60 DIM was reduced during the warm season compared with the cool season (32.6 ± 1.62 vs 37.23 ± 1.60 kg, P < 0.05) consistent with effects of prepartum heat stress. Interestingly, more cows had persistent uterine disease on both d 7 and d 21 in the warm season compared with the cool season (58.0 vs 29.4%, P < 0.05). Regardless of calving season the total bacterial content in the vagina was greater on d 7 compared to d 21. While metritis incidence was increased in the warm season, the vaginal content of total bacteria, Escherichia coli, Trueperella pyogenes, Fusobacterium necrophorum and Prevotella melaninogenica were similar during the cool season and the warm season. Our data suggests that prepartum heat stress related to season of calving increased the incidence of metritis and persistence of uterine disease in the dairy cow independent of vaginal bacteria content. The possibility that prepartum heat stress perturbs host immune function and increases the risk of metritis when cows are exposed to an equivalent number of pathogenic bacteria requires further investigation.

Viral dynamics and immune responses to foot-and-mouth disease virus in African buffalo (Syncerus caffer).

Foot-and-mouth disease (FMD) is one of the most important livestock diseases restricting international trade. While African buffalo (Syncerus caffer) act as the main wildlife reservoir, viral and immune response dynamics during FMD virus acute infection have not been described before in this species. We used experimental needle inoculation and contact infections with three Southern African Territories serotypes to assess clinical, virological and immunological dynamics for thirty days post infection. Clinical FMD in the needle inoculated buffalo was mild and characterised by pyrexia. Despite the absence of generalised vesicles, all contact animals were readily infected with their respective serotypes within the first two to nine days after being mixed with needle challenged buffalo. Irrespective of the route of infection or serotype, there were positive associations between the viral loads in blood and the induction of host innate pro-inflammatory cytokines and acute phase proteins. Viral loads in blood and tonsil swabs were tightly correlated during the acute phase of the infection, however, viraemia significantly declined after a peak at four days post-infection (dpi), which correlated with the presence of detectable neutralising antibodies. In contrast, infectious virus was isolated in the tonsil swabs until the last sampling point (30 dpi) in most animals. The pattern of virus detection in serum and tonsil swabs was similar for all three serotypes in the direct challenged and contact challenged animals. We have demonstrated for the first time that African buffalo are indeed systemically affected by FMD virus and clinical FMD in buffalo is characterized by a transient pyrexia. Despite the lack of FMD lesions, infection of African buffalo was characterised by high viral loads in blood and oropharynx, rapid and strong host innate and adaptive immune responses and high transmissibility.

The use of percutaneous thermal sensing microchips for non-invasive measurement of body temperature in foals during summer seasons in a subtropical region.

Continuous accurate attainment of the body temperature of foals is important to detect early stages of severe heat stress or fever due to a systemic illness. Among a number of methods to measure body temperature, measuring rectal temperature with a digital thermometer is most frequently used due to being relatively fast and simple method. It is also comparatively accurate and correlates well with the core body temperature. However, this method requires restraining the foal for a few seconds to obtain the temperature, and it can be dangerous for the handling person. Percutaneous thermal sensing microchips (PTSMs) are a means of monitoring the body temperature of horses, which offers a non-invasive, hygienic, quick, and accurate way to measure body temperature and provide an identification number for each individual, once it is implanted. This study tested the hypothesis that PTSM has a strong relationship with a conventional body temperature measurement, i.e., measuring rectal temperature with a digital thermometer of foals during summer seasons. Thirty-two foals in three consecutive foaling seasons (2018, 2019, and 2020 season) were implanted a PTSM into the right pectoral muscle, the right splenius muscle, the right gluteal muscle, and the nuchal ligament as early as two weeks after birth. The four PTSM temperatures, rectal temperature, and climate conditions (air temperature, relative humidity, and wet-bulb globe temperature) were obtained simultaneously during the three summer seasons and paired for comparison analysis. Among the PTSM temperatures, the pectoral muscle had the highest correlation and the least differences with rectal temperature. Using PTSM was safe, easy, and reliable for attaining body temperature in foals.