Infrared thermography and ultrasonography to indirectly monitor the influence of liner type and overmilking on teat tissue recovery

Correlation of udder thermogram and somatic cell counts as a tool for detection of subclinical mastitis in buffaloes

This study aimed to monitor the mammary health of 37 multiparous Murrah buffaloes through infrared thermography (IRT). Based on the California Mastitis Test (CMT) and milk somatic cell counts (SCC), buffaloes were grouped into healthy (H, n = 16), subclinical mastitis (SCM, n = 10), and clinical mastitis (CM, n = 11). Buffaloes were milked twice daily in the morning (5:00-6:00 AM) and evening (5:00-6:00 PM). Rectal temperature and respiratory rates were recorded, CMT was performed and thermal images of the mammary gland of all the buffaloes were taken before and after each milking. Milk samples were analysed after each milking for SCC, fat, Solids-Not-Fat (SNF), density, protein, lactose, salts, conductivity, and pH immediately in the laboratory from fresh milk samples. The surface temperature of the periocular region of both the eyes, muzzle, flank, and vagina were also taken. Thermal images were used to assess the surface temperature of the udder (USST), teat apex (TAT), teat barrel (TB1T), teat base (TB2T), and teat skin surface (TSST). Eye and USST showed significantly higher temperatures (p < 0.05), whereas skin surface temperatures (SST) of different body parts were non-significant in both SCM and CM animals than buffaloes in the H group. Milk SCC showed a positive correlation with conductivity (r > 0.7), salts, and pH (r < 0.6) and a negative correlation with fat, SNF, density, protein, and lactose. TAT, TB1T, TB2T, TSST, and USST were positively correlated with milk SCC. Receiver Operating Characteristic (ROC) analysis of H and SCM groups showed that USST before milking had optimum sensitivity (Se = 0.80) and specificity (Sp = 0.906) among the various skin temperatures recorded. Thermal images captured during the morning showed higher sensitivity compared to images taken in the evening. Results indicate IRT can be used to monitor the mammary health of buffaloes but using IRT in conjunction with milk SCC can help in the accurate prediction of SCM in dairy buffaloes.

Seasonal assessment of mastitis using thermogram analysis in murrah buffaloes

Mastitis is a global threat that challenges dairy farmers' economies worldwide. Sub-clinical mastitis (SCM) beholds the lion's share in it, as its visible clinical signs are not evident and are challenging to diagnose. The treatment of intramammary infection (IMI) demands antimicrobial therapy and subsequent milk withdrawal for a week or two. This context requires a non-invasive diagnostic tool like infrared thermography (IRT) to identify mastitis. It can form the basis of precision dairy farming. Therefore, the present study focuses on thermal imaging of the udder and teat quarters of Murrah buffaloes during different seasons to identify SCM and clinical mastitis (CM) cases using the Darvi DTL007 camera. A total of 30-45 lactating Murrah buffalo cows were screened out using IRT regularly throughout the year 2021-22. The IMI was further screened using the California mastitis test. The thermogram analysis revealed a significant difference (p < 0.01) in the mean values of the udder and teat skin surface temperature of Murrah buffaloes between healthy, SCM, and CM during different seasons. The mean values of udder skin surface temperature (USST) during different seasons ranged between 30.28 and 36.81 °C, 32.54 to 38.61 °C, and 34.32 to 40.02 °C among healthy, SCM, and CM-affected quarters. Correspondingly, the mean values of teat skin surface temperature (TSST) were 30.52 to 35.96 °C, 32.92 to 37.55 °C, and 34.51 to 39.05 °C, respectively. Further results revealed an increase (p < 0.01) in the mean values of USST during winter, summer, rainy, and autumn as 2.26, 4.04; 2.19, 3.35; 1.80, 3.21; and 1.45, 2.64 °C and TSST as 2.40, 3.99; 2.28, 3.26; 1.59, 3.09; and 1.68, 2.92 °C of SCM, CM-affected quarters to healthy quarters, respectively. The highest incidence of SCM was observed during autumn and CM during winter. Henceforth, irrespective of the seasons studied in the present study, IRT is an efficient, supportive tool for the early identification of SCM.

Applicability of thermography as a potential non-invasive technique to assess the body-thermal status of heat-stressed and water-deprived goats (Capra hircus)

To evaluate the use of infrared thermography to assess the thermal status of heat-stressed and water-deprived Capra hircus, full-body surface temperature (TS) and six other body-thermal variables [core, rectal (TR), and skin (TSK) temperatures, respiratory and heart rates, and total body-thermal gradient (core-to-ambient, BTG)] were measured after three days of euhydration (EU), dehydration (DE), and rehydration (RE). Results revealed that the combined effect of heat stress and water deprivation had affected all tested variables including the TS, and once these animals gained access to water in the RE stage variables returned to their EU levels. Moreover, there were positive correlations between TS and all variables with the exception of BTG. From these six variables, only three variables (i.e. the TR, TSK, and BTG) during the DE stage and two variables (i.e. the TSK and BTG) throughout the experimental stages showed higher constancy (R2 ≥ 0 75, P < 0 001; agreement intervals ±1 96 95 % CI) with TS. However, BTG appeared more closely correlated with TS, representing the body-thermal status more realistically than other variables. In effect, the mean and thresholds of the BTG were predicted using the recorded TS and were within 0.02 °C of original estimates. Collectively, these findings show that infrared thermography is appropriate for assessing body-thermal status, and thus the welfare, of these animals under the three conditions studied, and conclude that full-body TS can be a surrogate proxy for BTG in these animals. Further experiments are needed to adequately examine the reproducibility of these results under biometeorologically-simulated environments and natural habitats.

Seasonal assessment of mastitis using thermogram analysis in Sahiwal cows

"India is the world's leading producer of milk" and demands a non-invasive diagnostic tool like infrared thermography (IRT) to identify the costliest production disease, mastitis. It can form the basis of precision dairy farming. Therefore, the present study focuses on thermal imaging of the udder and teat quarters of Sahiwal cows during different seasons to identify subclinical (SCM) and clinical mastitis (CM) cases using the Darvi DTL007 camera. A total of 24-69 lactating Sahiwal cows were screened out using IRT regularly throughout the year. The intramammary infection status was further assessed using the CMT. The receiver operating characteristic analysis was carried out to develop the current study's cut-off for various thermographic parameters. The incidence for SCM and CM ranged from 26.47 to 38.75% and 17.83-22.79%, respectively during different seasons in Sahiwal udder quarters. The thermogram analysis revealed a significant difference (p < 0.01) in the mean values of the udder and teat surface temperature of Sahiwal cows between healthy, SCM, and CM during different seasons. The mean values of udder skin surface temperature (USST) during different seasons ranged between 29.07 and 36.91 °C, 31.51 to 37.88 °C and 32.42 to 38.79 °C among healthy, SCM, and CM-affected quarters, and correspondingly, the mean values of teat skin surface temperature (TSST) were 28.28 to 36.77 °C, 30.68 to 37.88 °C and 31.70 to 38.73 °C, respectively. Further results revealed an increase (p < 0.01) in the mean values of USST during winter, summer, rainy, and autumn as 2.44, 3.35; 0.97, 1.88; 1.06, 1.83; 1.29, 2.39 °C and TSST as 2.4, 3.42; 1.11, 1.96; 1.21, 2.19, 1.3, 2.4 °C of SCM, CM-affected quarters to healthy quarters, respectively, in Sahiwal cows. Thermograms showed a strong positive correlation with the CMT scores of SCM, CM cases, and healthy samples. Henceforth, irrespective of the seasons studied in the present work, IRT is an efficient, supportive tool for the early identification of subclinical mastitis.

Complex Relationships between Milking-Induced Changes in Teat Structures and Their Pre-Milking Dimensions in Holstein Cows

The study aimed to explore the relationship between teat structure dimensions and their short-term reaction to milking, to find the optimal dimensions of teat structures in relation to milking-induced teat tissue changes. Teat structures (teat length, canal length, thickness at barrel and apex, wall and cistern width) were measured by ultrasonography before and after milking for 38 Holstein cows at the beginning, middle, and end of lactation. We found that milking-induced changes in teat structures significantly depended on their pre-milking size. Furthermore, we observed that some teat structures and their changes were interconnected, and some did not affect each other. For example, changes in the barrel thickness and cistern width were affected by all structures, while the canal and apex did not influence each other. We deduced that more favorable changes were observed for teats of medium length, medium barrel and apex thickness, with teat canals of medium length, but with wider cisterns and thinner walls. The results of this study may help improve research in the area of milking-induced changes in teat morphology. Our findings could help understand potential health risks to animals in relation to teat morphology, milking equipment, and machine settings.

Thermographic Examination of the Gingiva of 16 Dogs

Gingivitis is a common periodontal disease in dogs and refers to inflammation of the gingiva. Gingival Index (GI), Papillary Bleeding Index (PBI) and Plaque Index (PI) are oral indices that describe the health status of the gingiva and which are based on human observation. Thermal changes due to inflammation are expected in gingivitis. Thermographic imaging, a wide-spread diagnostic tool in veterinary science, can be used for identification when there is abnormal body surface temperature in an area of the animal body. In this study, oral examination results and thermographic images obtained from 458 teeth from 16 dogs were used. Firstly, a thermal imaging procedure for diagnosis of gingival diseases of dogs was defined. Secondly, reference surface temperatures of tissues for each oral indices were determined. And thirdly, statistically significant thermal differences between the levels of each index was compared. The statistical analysis showed that there are significant thermal differences in some index levels and that presence or absence of plaque is an important etiologic factor in thermal examination of gingivitis. The study showed that thermographic images can be used to determine thermal changes in oral tissues of dogs with gingivitis.

Ultrasonography and Infrared Thermography as a Comparative Diagnostic Tool to Clinical Examination to Determine Udder Health in Sows

Simple Summary

The udder health of sows is most important to raise healthy piglets. The aim of the study was to investigate a possible advantage of infrared thermography and ultrasonography over the clinical examination of the udder of sows. For this purpose, both clinically healthy sows with inconspicuous udders on palpation before and after birth (n = 35) and sows at the time of weaning (n = 107) were examined. Images of thermography and ultrasound revealed no pathological alterations in the clinically healthy sows. A physiological statistically significant increase in the udder surface temperature and the thickness of the parenchyma during the three weeks ante partum was observed. After weaning, abnormalities in the appearance of roundish nodules of the parenchyma were detected sonographically in 10.3% of the examined sows, while the demonstrated nodules were unrecognised clinically in two out of eleven sows. The changes could also be demonstrated thermographically because of a statistically significant lower surface temperature above the nodules compared to the remaining skin of the mammary gland. However, scratches on the udder skin showed similar temperature changes. Therefore, thermographic images without prior inspection of the udder can lead to misinterpretation.

Abstract

The aim of the study was to examine whether the use of infrared thermography and ultrasonography can complement or replace the clinical examination of the sows’ mammary glands for pathological alterations. Sows of different parities with inconspicuous udders on palpation before and after birth (n = 35) and sows at the time of weaning (n = 107) were examined. Thermal images were taken from both sides of the udder, while ultrasound pictures were taken from four sides of the respective mammary glands. Within three weeks before birth, a statistically significant increase in the average surface temperature of the glands of about 1.54 °C and of the thickness of the parenchyma of about 1.39 cm could be observed. After weaning, in 10.3% of the examined sows, roundish hyperechogenic nodules were detected sonographically in the glands´ parenchyma. The average skin temperature above the nodules was 1.24 °C lower compared to the total skin area of the altered complex. However, scratches on the udder skin showed similar temperature changes. In two sows, the nodules remained undetected during the clinical examination. Therefore, sonography seems to be superior compared to clinical and thermographic investigations, although it proved to be very time-consuming.

Delta thermal radiomics: An application in dairy cow teats

•

Infrared thermograms can indirectly detect blood flow and changes in blood flow on the skin.

•

Radiomics is a machine learning medical image analysis technique that reveals semantic and nonsemantic features.

•

Radiomics of dairy cow teat thermograms is a novel quantitative means of assessing changes in skin temperature before and after milking.

We describe a novel approach for analyzing thermal images by way of radiomics (i.e., thermal radiomics) and how it can be used to monitor short-term temperature changes of dairy cow hind teats; that is, delta thermal radiomics. The heat generated from metabolic activities and blood-flow patterns can be visualized using thermal radiography of the skin surface. The hind teats from 25 dairy cows were imaged with a digital thermal camera and the images were converted to medical images (DICOM format) by mapping the multi-channel colorized thermal image to a monochromatic image whose intensities represent temperature. The 50 teats (left and right hind) were then manually segmented by 2 investigators. Radiomics analysis, which is a common method of extracting semantic and nonsemantic image biomarkers from medical images for machine learning, was performed. To evaluate whether this approach can detect pre- and postmilking differences, 18 cows were imaged before and after milking, the teats were manually segmented, and radiomic calculations were performed. Student's t-test was used to provide an estimate of the likelihood of whether postmilking thermal image biomarkers are the same as premilking thermal image biomarkers, and Cohen's d was used to evaluate the size of the effect (d > 1.2). To evaluate uncertainties from manual segmentation, the Dice similarity score (DS) between the 2 investigators' segments was computed. The average DS (95% confidence limit) was 0.952 (0.913–0.982) when comparing the 2 investigators' segmentations. There was no significant difference in DS when comparing the left and right segmented teats, suggesting that teats can be segmented consistently. No differences (d < 0.36) were observed when comparing image biomarkers from one investigator's segments with the other's, suggesting that image biomarkers computed from one investigator's segmentation of teats are not likely to differ from those computed from the other investigator. When comparing image biomarkers before and after milking, 109 image biomarkers were analyzed, and 17 image biomarkers were simultaneously significant and exhibited effect size. Thus, delta thermal radiomics offers a noninvasive and quantitative method of monitoring skin temperature changes in humans and animals after an intervention. The advantage of this approach is that it can reveal both perceptible and imperceptible surface temperature features that may be useful for detecting and managing dairy teat health.

Development and evaluation of a standardized technique to assess teat skin temperature of dairy cows using infrared thermography

Much research has been done to develop methods to assess dimensional teat traits in dairy cows. In contrast, diagnostic techniques to reliably assess the circulatory system of teats are limited. Infrared thermography facilitates measurements of skin temperature and could be used to detect physiological and pathological changes to the teat tissue associated with machine milking, as temperature reflects the underlying blood circulation and tissue metabolism. Our objective was to develop and evaluate a scanning technique to quantify teat skin temperature in dairy cows using infrared thermography. Using a portable thermography camera, 2 operators obtained duplicate scans of both hind teats from 20 Holstein cows, resulting in 80 thermographic images (20 cows × 2 operators × 2 images). Average teat skin temperatures at the proximal, middle, and distal teat aspects were determined. We used Pearson correlation coefficients (r), intraclass correlation coefficients (ICC), and concordance correlation coefficients (CCC) to assess interoperator reproducibility (i.e., agreement between measurements performed by different operators) and intraoperator repeatability (i.e., agreement between measurements performed by the same operator). Pearson correlation coefficients revealed a very strong correlation for measurements at the proximal, middle, and distal aspects of the teat, respectively, between operators (r ≥0.95) and duplicate scans (r ≥0.94) within operators. Intraclass correlation coefficients and CCC indicated excellent interoperator reproducibility (ICC ≥0.95, CCC ≥0.95) and excellent intraoperator repeatability (ICC ≥0.94, CCC ≥0.94), respectively, for measurements at all 3 aspects. Least squares means (95% confidence interval) for average teat skin temperatures at the proximal, middle, and distal teat aspects, respectively, were 33.2 (32.6-33.8), 32.4 (31.5-33.2), and 30.9 (29.8-32.0) °C for operator 1, and 33.2 (32.6-33.8), 32.4 (31.6-33.3), and 31.0 (29.9-32.0) °C for operator 2. Average temperatures between duplicate scans within operators at the proximal, middle, and distal aspects, respectively, were 33.3 (32.7-33.9), 32.5 (31.7-33.3), and 31.0 (29.9-32.1) °C for the first scan and 33.2 (32.6-33.8), 32.3 (31.5-33.1), and 30.8 (29.7-31.9) °C for the second scan. We conclude that infrared thermography facilitates precise measurements of skin temperatures of cows' hind teats.

Vacuum Dynamics as an Alternative Method for Detection of Bimodal Milk Ejection in Dairy Cows

Simple Summary

We investigated the relationship between vacuum dynamics and milk flow curve characteristics using portable vacuum and milk flow recording devices, respectively, for the assessment of bimodal milk flow curves in dairy cows. For this purpose, we analyzed 241 vacuum and milk flow curve recordings that we collected concomitantly during eight milking center evaluations on five New York dairy farms. We found that vacuum dynamics could be a suitable measure to assess bimodal milk flow curves in dairy cows.

Abstract

The primary objective of our study was to assess the ability of a vacuum recorder to detect the presence of bimodal milk flow curves in dairy cows compared with a portable milk flow meter. In a cross-sectional study, 241 individual cow milking observations were analyzed. We simultaneously collected (1) individual cow vacuum events during milking using portable vacuum recorders, and (2) individual cow milk flow curves by attaching a portable milk flow meter to the same milking unit. Presence of bimodality was assessed with the vacuum recorder visually (BIM_VA) and with the gold standard method of a milk flow meter through automatic detection (BIM_LA). Kappa statistics revealed moderate agreement between BIM_VA and BIM_LA [κ, 95% confidence intervals (95% CI) = 0.59 (0.46–0.71)]. Diagnostic test statistics for BIM_VA for detection of bimodality indicated moderate performance for sensitivity [0.65 (0.52–0.76)] and positive predictive value [0.71 (0.58–0.82)] and high values for specificity [0.92 (0.87–0.95)] and negative predictive value [0.93 (0.84–0.93)]. We conclude that milking vacuum dynamics are a suitable measure to assess bimodal milk flow curves in dairy cows.

Increased teat wall thickness in response to machine milking

Transiently increased teat wall thickness in response to machine milking has been documented by various methods, including ultrasound. However, correlative ultrasonography and histology to detect the origin of this phenomenon is lacking. The first goal of the present study was to evaluate and compare milking-related changes of the teat tissue in 2 breeds of dairy cows (11 Simmental and 3 Holstein) using B-mode ultrasonography. Additionally, the observed changes were compared with ultrasonographic findings in a Holstein cow with periparturient udder edema. Finally, corresponding histological sections of the Simmental teats were analyzed and compared with those from a lactating nonmilked Angus cow. We hypothesized that the mechanical load of both stretching by the vacuum during phases of open teat cup liner and compression by the closed liner during machine milking results in a transient congestion of blood vessels in the teat wall. The barrel of 1 front teat of each cow was scanned immediately before and after machine milking (system vacuum: 42 kPa; pulsation rate: 60 cycles/min; pulsation ratio: 65:35). Shortly after milking (33 ± 6 min), the Simmentals were slaughtered, and their scanned teat was immediately removed and processed for investigation by light microscopy. Ultrasonography after milking revealed anechoic tubular structures mainly in the inner half of the teat wall. Histological examination revealed these structures to be thick-walled veins. The left front and hind teats of the nonmilked lactating cow, collected and prepared identically to those from the Simmental cows, showed the same histological features. Ultrasonographic measurements showed that the diameter of these veins significantly increased after milking compared with matching images before milking. This effect was most pronounced in the Holstein cows. Similarly, these veins were very prominent in the periparturient cow. However, neither the milked cows, including the periparturient cow, nor the lactating nonmilked cow provided any evidence of edematous extravasation on ultrasonography or histology. These findings corroborated our hypothesis that the increase in size of thick-walled veins in the teat tissue is the main reason for the thickening of the teat walls in response to machine milking.

Blood perfusion of teat tissue in dairy cows: Changes associated with pre-milking stimulation and machine milking

Mechanical forces during machine milking of dairy cows evoke circulatory impairment of the teat tissue that may affect the teats' defense mechanisms against mastitis pathogens. Ample research describes dimensional changes of different teat traits after machine milking, whereas reports that describe changes in blood circulation of dairy cows' teats are limited. Therefore, the objectives of this study were to (1) describe changes in teat blood circulation that occur after pre-milking teat stimulation and machine milking and (2) study the effect of 2 different milking liners on machine milking-induced changes in teat blood flow. In a randomized trial, Holstein dairy cows were stratified by parity, stage of lactation, and average daily milk yield during the previous week, and allocated to 1 of 2 treatment groups. Treatment consisted of 1 milking observation with either a round or multisided concave milking liner. Teat scans were taken of the left front and the right hind teats using power Doppler ultrasonography. Imaging occurred before pre-milking udder preparation (T1), after completion of pre-milking udder preparation but before milking-unit attachment (T2), and immediately after unit detachment (T3). Perfusion intensity measurements from teat scans were performed with a commercially available software program. Data from 109 cows were analyzed. A general linear mixed model showed differences in perfusion intensity between time points. Least squares means (95% confidence intervals) for T1, T2, and T3, respectively, were 0.035% (0.026-0.047), 0.124% (0.093-0.164), and 0.095% (0.073-0.124). Conversely, no statistically significant differences between treatment groups were observed. We conclude that teat blood circulation is subjected to several influences, including inherent circulatory regulation mechanisms, as well as extrinsic factors such as machine milking. Future research is warranted to decipher the magnitude of their influence and to further our understanding of how these changes relate to the susceptibility to intramammary infection and milking performance.

Short communication: Teat wall diameter and teat tissue thickness in dairy cows are affected by intramammary pressure and by the mechanical forces of machine milking

The objective of this study was to validate and apply 2 different methods to record changes in teat tissue related to machine milking. Teat wall diameter was measured via B-mode ultrasound cross sectioning with a 7.5-MHz linear probe. Teat tissue thickness was measured using a cutimeter (spring-loaded caliper, spring constant 6.5 N/cm, 0.5 N at closed jaws). Both methods were applied at the teat barrel, 2 cm above the teat tip. In experiment 1, 24 teats from freshly slaughtered cows were used to perform ultrasound imaging (12 teats) or cutimeter measurements (12 teats) while the teat cisterns were filled with water to increase the intracisternal pressure from 0 to 30 kPa in steps of 1 kPa. Teat tissue thickness did not change at an intracisternal pressure from 0 to 10 kPa but increased with intracisternal pressure at levels >10 kPa. In contrast, teat wall diameter decreased with intracisternal pressure between 0 and 7 kPa but did not significantly change at a pressure ≥7 kPa up to 30 kPa. Significant Pearson correlation coefficients between intracisternal pressure and teat wall diameter were observed from 0 to 7 kPa (r = -0.38), and between intracisternal pressure and teat tissue thickness from 10 to 30 kPa (r = 0.45). In experiment 2, ultrasound and cutimeter measurements were performed in 12 lactating Holstein cows. Measurements before and during milking, immediately after cluster removal, with normal milking or with a 5-min overmilking, were performed and continued at 5-min intervals for 60 min and at 10-min intervals until 120 min. Additionally, with the 5-min overmilking treatment, measurements were continued at 60-min intervals up to 10 h after milking. Teat wall diameter decreased in response to milk ejection, followed by a continuous increase during the course of milking, with highest values after 5 min overmilking. Teat tissue thickness did not change during milking but was significantly increased after overmilking. Teat wall diameter and teat tissue thickness recovered to premilking levels within 35 min after normal milking and within 60 min after overmilking. Until 10 h after overmilking, the teat wall diameter decreased steadily, whereas teat tissue thickness was unfluctuating. In the physiologically relevant range of intramammary pressure, ultrasound measurements of the teat wall were affected by both intramammary pressure and mechanical forces, whereas cutimeter measurements were not affected by the intramammary pressure.

Review: Milking machine settings, teat condition and milking efficiency in dairy cows

Because of technical limitations, an impact of machine milking on the teat tissue cannot be avoided. The continuance of this impact during and after milking depends on a variety of factors related to the physiological regulation of milk ejection, as well as the different production systems and milking machine settings. Milking machine settings aim to achieve a high milking performance, that is, short machine-on time at a maximum of milk harvest. However, a high milking performance level is often related to an impact on the teat tissue caused by vacuum or liner compression that can lead to pathological dimensions of congestion of the tissue or hyperkeratosis as a long-term effect. Toward the end of milking a decrease of milk flow rate causes a raise of mouthpiece and teat end vacuum levels and hence an increase of the impact on the teat tissue and the risk of tissue damage. The mechanical stress by the milking machine activates a cascade of cellular mechanisms that lead to an excessive keratin growth and thickening of the keratin layer. Consequently, a complete closure of the teat canal is disabled and the risk of bacterial invasion and intramammary infection increases. Another consequence of high vacuum impact is fluid accumulation and congestion in the tissue of teat tip and teat basis because of an obstruction in venous return. The present review paper provides an overview of the available scientific information to describe the interaction between different levels and types of system vacuum, mouthpiece chamber vacuum, teat end (claw) vacuum, liner pressure, and the risk of short-term and long-term impacts on the teat tissue.

Technical note: Development and evaluation of a standardized technique to assess blood perfusion in teats of dairy cows using power Doppler ultrasonography

Ample research has described the assessment of dimensional changes for different teat traits, whereas diagnostic techniques to reliably assess blood circulation in teats of dairy cows are limited. Here, we describe the development and evaluation of a scanning technique to quantify blood flow in teats of dairy cows using power Doppler ultrasonography. In 2 consecutive trials, 384 teat scans [trial 1, n = 256 (sagittal plane, n = 128; transverse plane, n = 128); trial 2, n = 128 (transverse plane)] from 16 cows were obtained by the same 2 operators. Perfusion intensity from single images (trial 1) and video images (trial 2) were assessed using a commercially available software program. Intraclass correlation coefficients (ICC) and concordance correlation coefficients (CCC) were used to assess interoperator reproducibility (agreement between measurements performed by different operators) and intraoperator repeatability (agreement between measurements performed by the same operator). In trial 1, interoperator ICC and CCC indicated poor agreement (ICC ≤0.26, CCC ≤0.26). Intraoperator ICC and CCC demonstrated poor agreement between duplicate measurements within operators (ICC ≤0.19, CCC ≤0.19). Modifications after trial 1 included (1) a different ultrasound device, (2) analysis of video clips rather than single images, (3) restriction to 1 sectional plane (i.e., transverse), and (4) a scanning sequence such that repeated scans within operators were measured one after another. Through these modifications, intraoperator repeatability in trial 2 yielded fair to good agreement, with intraoperator ICC and CCC over both operators ranging from 0.44 to 0.70 and from 0.57 to 0.69, respectively, whereas interoperator ICC and CCC showed poor agreement (ICC = 0.35, CCC = 0.34). We conclude that repeatable measurements of blood perfusion intensity of teats in dairy cows can be attained with power Doppler ultrasonography. Power Doppler ultrasonography is a suitable tool to quantify slow flow in small vessels and may be an acceptable diagnostic technique to assess changes in blood circulation that result from machine milking in teats of dairy cows, although further research is necessary to validate this hypothesis.

Thermal physiology of the lactating nipple influences the removal of human milk

The nipple has a critical role in successful breastfeeding. Nipple trauma or pain may negatively impact breastfeeding duration which has significant public health implications. The aim of this study was to examine changes in nipple temperature during breastfeeding and pumping within participants. Thirty lactating women participated in two pumping (electric breast pump) and one breastfeeding session. Nipple temperature of both breasts was monitored for two minutes before and after each session with the non-pumped/non-suckled nipple temperature recorded throughout each session. The mean increase in nipple temperature after milk removal by the infant was 1.0 ± 1.6 °C (range −3.2–3.2) and after expression was 1.8 ± 1.4 °C (range −0.9–6.1). Nipple temperature pre expression was significantly lower than post expression (Pre 32.6 ± 1.6, Post 34.3 ± 1.3, p < 0.001) with no difference between the two pumping sessions. For every 1 °C rise in temperature an additional 10 mL of milk was removed on average. The breastfed nipple temperature was significantly lower pre feed than post feed (Pre 32.4 ± 1.6, Post 33.2 ± 1.2 p = 0.01) with a significant but smaller change in nipple temperaturecompared to pumping (Breastfeed 1.0 ± 1.6, Pumping 1.7 ± 1.4, p = 0.03). Nipple temperature increases during pumping and breastfeeding suggesting the breasts have a similar physiological response to different stimuli. Further, the increased temperature potentially plays a role in effective milk removal.

The Use of Infrared Thermography for the Monitoring of Udder Teat Stress Caused by Milking Machines

Simple Summary

The aim of this study was to test the use of infrared thermography as a possible tool for detecting short-term stress, of cow udder teat, caused by milking procedures. Thermographic images were collected and evaluated to calculate the values of two indicators: the average and the maximum skin surface temperatures at the base, center, and tip of each teat. Obtained results confirmed a relationship between the two indicators (T_avg, T_max) and the level of teat stress generally evaluated by visual observation of its color. Nevertheless, the low accuracy reached by the two indicators does not seem to justify the development of an ad hoc infrared device for the monitoring of cow udder teat stress.

Abstract

The aim of this study was to test infrared thermography (IRT) as a possible tool for scoring teat color changes after cluster removal; thus, indirectly, to classify the short-term stress of teats caused by milking machines. Thermographic images (n = 137) from three farms were collected and evaluated to calculate the average and maximum skin surface temperatures (SSTs) at the base, center, and tip of each teat (T_avg,B, T_avg,C, T_avg,T, T_max,B, T_max,C, and T_max,T). Obtained results confirmed a significant relationship between the indicators T_avg, T_max and the levels of teat color change (level one: pink-colored teat; level two: red-colored teat; level three: blue or purple-colored teat). Nevertheless, when a teat was considered to be stressed because its scoring fell in level 3 of the color-change scale used, sensitivity and specificity in the classification of the teat status ranged respectively between 45.6% and 54.3%, and 54.4% and 59.2%, for the indicators T_avg; and 56.5% and 60.9%, and 59.7% and 61.8%, for the indicators T_max. When a teat was considered stressed because its scoring fell between the levels 2 and 3 of the scale adopted, sensitivity and specificity were between 49.0% and 55.8%, and 58.3% and 61.8%, for the indicators T_avg; and 55.8% and 59.9%, and 60.6% and 61.4%, for the indicators T_max. As a consequence, the low values of sensitivity and specificity do not seem to justify the development of an ad hoc infrared device for the monitoring of udder teat stress. Nonetheless, this technology can be a viable solution for a preliminary evaluation of the mechanical stress of teats if a milking system would be equipped with an infrared sensor already in place for other purposes (e.g., the monitoring of udder health status).

Investigation of the relationship between udder quarter somatic cell count and udder skin surface temperature of dairy cows measured by infrared thermography

The objective of the present study was to quantify the relationship between udder skin surface temperature (USST) and somatic cell count (SCC) in lactating dairy cows. Data were recorded on the same 14 Holstein-Friesian cows, at evening (15:00 to 16:00) milking every day over a 2-mo period. Surface temperature measurements of all udders were extracted from thermal images. After imaging, milk was extracted from each quarter and analyzed for SCC. Environmental and cow-related factors (i.e., ambient temperature, humidity, rainfall, wind speed, distance walked to the parlor, number of days since the udder was shaved, parity, and stage of lactation) were recorded on each day of the experiment. A large array of descriptive temperature parameters (DTP) were extracted from every udder image including temperature-based (e.g., maximum, average and minimum USST), pixel count-based, and textural-based DTPs. Several different analytical methods were tested in an attempt to relate any given DTP to SCC; this included investigating the relationship between USST and the log transform of SCC (i.e., somatic cell score; SCS). The temperature range within each udder was also compared with the natural log of the range in SCC of the respective quarters. In a separate analysis, the temperature difference between each DTP and its respective daily baseline (i.e., average of the 5 lowest values of that DTP across the herd) was compared with SCS. Finally, the association between environmental and cow-related factors with each DTP was investigated to create prediction models for each DTP, the residuals of which were compared with SCC. Results from the present study indicate that the correlation between any DTP and SCS was weak (range of -0.16 to 0.19) and so could not be used to identify quarters with high SCC. Although some alternative measures had a significant relationship with SCS, again, the correlation was too weak for practical use on its own. Maximum and average USST could be predicted with a root mean square error of 0.23 and 0.35 °C, respectively, although the residuals from the prediction model could not be used to identify animals with high SCC. This suggests that infrared thermography alone could not be used as a real-time automated tool to detect high SCC for dairy cows in a pasture-based system.

Evaluation of inner teat morphology by using high-resolution ultrasound: Changes due to milking and establishment of measurement traits of the distal teat canal

The teat canal is important in the defense against invading pathogens, but its functional features can be impeded by the milking process. The objective of our study was to compare teat morphology before and after a standard milking procedure using high-resolution ultrasonography. Tissue changes were determined by measuring inner traits of teat morphology: teat width, teat end width, teat cistern width, diameter of the lower and upper teat wall, teat canal length, and teat canal diameter. Additionally, 3 traits describing the distal teat canal and its external orifice were established: diameter of the distal teat canal orifice, distal teat canal perimeter, and distal teat canal surface. In the first trial, we verified the repeatability of scanning over time with a mixed model. During the second trial, significant changes after milking were observed for all measured traits of teat morphology except teat end width. The traits from the distal teat canal and its orifice were remarkably changed by milking: distal teat canal orifice, +28.9%; distal teat canal perimeter, +25.0%; and distal teat canal surface, +41.5%. Comparing multiparous versus primiparous cows, higher values of teat width, teat end width, and teat canal length were observed in the older animals. Testing the effect of milk yield on teat dimensions, cows with milk yields >11.0 kg/afternoon milking were found to have larger teat widths, teat end widths, and cistern widths before attachment of the cluster. Furthermore, we observed associations of inner teat morphology toward bacterial counts in the appropriate milk. Regarding this udder health-related parameter especially, the newly established traits showed a connection. Teats in which milk showed bacterial growth had larger distal teat canal perimeters and distal teat canal surfaces. High-resolution ultrasonographic scanning of dairy teats allowed a detailed visualization of the inner morphology. The applied procedure can therefore serve as a useful tool for comparison and evaluation of different milking techniques by analyzing the resulting changes of the morphological traits. The thorough description of teat tissue can also be applied for drawing conclusions on the status of the teat canal's physical and mechanical defense function.

Temporal, spatial, inter-, and intra-cow repeatability of thermal imaging

The objective of the present study was to quantify the within- and between-cow, operator, and day variances of various descriptive temperature parameters from different anatomical areas captured using thermal images on Holstein-Friesian cows. Three experiments were undertaken. In Exp. 1, 30 images were captured by a single operator of each of the eye, hoof, and udder from each of 45 cows; in Exp. 2, three different operators captured eye and hoof images from 12 cows; and in Exp. 3, eye and hoof images were captured by a single operator from 8 cows over a 5-d period. Maximum, minimum, and average descriptive temperature parameters were manually extracted from all thermal images within the study. The repeatability of thermal imaging and the number of replicates required to obtain a certain level of precision was evaluated. Precision was defined as the 95% CI range within which the (average of the) measured temperature(s) was expected to lie relative to the gold standard; the gold standard temperature of an entity in this study was the average of 30 temperature measurements. The partitioning of the variance into error, cow, operator, and day variances was undertaken using mixed models. Results show that the most repeatable anatomical area was the hoof, with the total proportion of variation attributed to the cow ranging from 91.37 to 99.28%. The descriptive temperature parameter with the lowest error variance was the maximum temperature for the eye (0.11°C) and udder (0.03°C) images, whereas the average temperature was the most precise descriptive temperature parameter for hoof (0.08°C) images. Additionally, no significant between-day variance was detected for maximum hoof temperatures. Results from the present study indicate that when the most precise descriptive temperature parameter is used, measurements made using infrared thermography can achieve a high level of precision in an agricultural environment if at least 3 replicate images of the eye, udder, or hooves of cows are captured and averaged. Additionally, when multiple operators capture thermal images in an agricultural environment, a standard operating procedure should be put in place to minimize the variance between operators.

The Use of a Pressure-Indicating Film to Determine the Effect of Liner Type on the Measured Teat Load Caused by a Collapsing Liner

During milking the teat cup liner is the interface between the teat of a dairy cow and the milking system, so it should be very well adapted to the teat. Therefore, the aim of the present study was to determine the effect of liner type on the directly measuring teat load caused by a collapsing liner with a pressure-indicating film. The Extreme Low pressure-indicating film was used to detect the effect of six different liners on teat load. For each liner, six positions in the teat cup were specified, and six repetitions were performed for each position with a new piece of film each time. Analysis of variance was performed to detect differences between the six liners, the positions within a liner, and the measuring areas. The pressure applied to the teat by a liner depends on the technical characteristics of the liner, especially the shape of the barrel, and for all tested liners, a higher teat load was found at the teat end. In conclusion, with the help of pressure-indicating film, it is possible to determine the different effects of liner type by directly measuring teat load due to liner collapse.

Veterinary applications of infrared thermography

Abnormal body temperature is a major indicator of disease; infrared thermography (IRT) can assess changes in body surface temperature quickly and remotely. This technology can be applied to a myriad of diseases of various etiologies across a wide range of host species in veterinary medicine. It is used to monitor the physiologic status of individual animals, such as measuring feed efficiency or diagnosing pregnancy. Infrared thermography has applications in the assessment of animal welfare, and has been used to detect soring in horses and monitor stress responses. This review addresses the variety of uses for IRT in veterinary medicine, including disease detection, physiologic monitoring, welfare assessment, and potential future applications.

Technological, environmental and biological factors: referent variance values for infrared imaging of the bovine

Background

Despite its variety of potential applications, the wide implementation of infrared technology in cattle production faces technical, environmental and biological challenges similar to other indicators of metabolic state. Nine trials, divided into three classes (technological, environmental and biological factors) were conducted to illustrate the influence of these factors on body surface temperature assessed through infrared imaging.

Results

Evaluation of technological factors indicated the following: measurements of body temperatures were strongly repeatable when taken within 10 s; appropriateness of differing infrared camera technologies was influenced by distance to the target; and results were consistent when analysis of thermographs was compared between judges. Evaluation of environmental factors illustrated that wind and debris caused decreases in body surface temperatures without affecting metabolic rate; additionally, body surface temperature increased due to sunlight but returned to baseline values within minutes of shade exposure. Examination/investigation/exploration of animal factors demonstrated that exercise caused an increase in body surface temperature and metabolic rate. Administration of sedative and anti-sedative caused changes on body surface temperature and metabolic rate, and during late pregnancy a foetal thermal imprint was visible through abdominal infrared imaging.

Conclusion

The above factors should be considered in order to standardize operational procedures for taking thermographs, thereby optimizing the use of such technology in cattle operations.

Short communication: effects of milk removal on teat tissue and recovery in Murciano-Granadina goats

The aim of this work was to study how machine milking (MM) carried out in appropriate conditions affects teat wall thickness and canal length and their return after milking to premilking conditions compared with other milk removal methods considered biological referents: kid suckling (KS), catheter removal (CATH), and hand milking (HM). Three Latin square experiments were designed, each divided into 2 periods. In the first period, the left glands of each animal were machine milked and the KS, CATH, and HM treatments were applied to the right glands in experiments 1, 2, and 3, respectively. Subsequently, in the second period, the removal methods were interchanged. Teat wall thickness, teat wall area, teat end wall area, and teat canal length were measured from the ultrasound images. Milk removal using the reference methods (KS, CATH, and HM) and by MM caused increases in teat wall thickness and teat canal length, which were greater with MM. The time needed for the teat walls and canal to return to their physiological conditions before milk removal was greater than 10h in the reference methods and following machine milking.

Effects of overmilking and liner type and characteristics on teat tissue in small ruminants

The aim of this work was to study the effect on teat wall thickness and canal length in sheep and goats of overmilking for 2 min (OM+2) and of milking with used (AL; +3000 milkings) and twisted (TL; 45°) liners in sheep and goats, as well as the effect of milking goats with liners designed for sheep (SL, shorter length and diameter than liners for goats). To this end, we performed four experiments in goats and three in sheep, in a Latin square design with two experimental periods. During the experimental period 4 controls were carried out, performing ultrasound scans before and immediately after milking to determine the teat wall thickness (TWT), teat wall area (TWA), teat end area (TEWA) and teat canal length (TCL). OM+2 caused a significant increase in TWT, TWA, TEWA and TCL in goats and in TWA, TEWA and TCL in sheep. Liner features had a strong influence on the variables studied; aged liners caused significant changes in TWT and TCL in goats and in TWT in sheep; twisted liners produced a significant effect on the increase of TWT and TCL in goats, without reaching significance level in sheep; and milking goats with sheep liners led to a significant increase in TWT, TWA, TEWA and TCL. In practice, it is therefore important to avoid overmilking and the use of worn-out liners. It is also necessary to use liners designed for the morphological features of each species, taking special care to carry out periodic liner positioning revisions to ensure the benefits of pulsation on the teat end. Finally, it would be necessary to carry out long-term experiments to study whether the increase in thickness observed in some experiments is sufficient to affect milking efficiency and mammary gland health status.

UDDER THERMOGRAPHY OF GYR COWS FOR SUBCLINICAL MASTITIS DETECTION

Aiming to evaluate the infrared thermography technique for early detection of subclinical mastitis in Gyrcows, 70 animals were selected in 2nd or 3rd lactation, with an average production of 7.2 kg / d between90 and 200 days in milking. Images of two quarters (front and backside) of the same udder side weremonthly performed during three months using a thermal camera to evaluate the surface temperature atthree different heights (upper, median and lower), totalizing 420 measurements. Milk samples fromeach quarter were also collected to evaluate the SCC and microbiological culture. The SCC did notinfluence udder temperature at different heights (p>0.05). However, temperatures among the regionsof the quarter were different, the upper area had higher values than the median and lower regions(p<0.05). There was no difference in udder temperatures in relation to the type of microorganismsisolated in milk (p>0.05). The use of thermal camera allowed the identification of temperature variationsof skin surface at different udder regions of Gyr cows. However, this technique was not effective in thedetection of subclinical mastitis.