An investigation into the use of infrared thermography (IRT) as a rapid diagnostic tool for foot lesions in dairy cattle

Previous research has suggested that temperature at the coronary band increases in the presence of claw horn lesions in dairy cattle. However the reliability of using infrared thermography (IRT) as a method of distinguishing between lesions has not been investigated. The objective of this study was to examine the potential of IRT as a non-invasive tool for rapidly screening for the presence of digital dermatitis (DD). Eighty-two cows which either had no skin lesions on the hind feet (controls, n=41feet) or a DD lesion on one or both feet were selected during milking. Following selection, each cow was moved into the farm crush where thermal images were taken from the plantar aspect of each foot at the pastern when the foot was dirty, cleaned and raised for visual inspection. Following recording of thermal images each hind foot was trimmed and the presence of any lesion recorded. It was found that the temperature did not differ significantly between feet with DD lesions and other skin or claw horn lesions, regardless of whether the feet were dirty, clean or raised for inspection. As IRT was not sensitive enough for lesion specific detection, the reliability of setting a temperature threshold above which any type of lesion causing lameness could be detected was investigated. The optimal trade off between sensitivity and specificity could be reached without having to either clean or lift the feet. Setting the threshold for disease at 27°C for dirty feet identified 80% of feet with lesions and 73% of feet without lesions correctly. In conclusion, IRT was reliable in detecting elevated temperature associated with foot lesions. Future research investigating the development of lesions may identify a temperature threshold for early treatment intervention. This technique may also be useful to quantify the effectiveness of early treatment by tracking recovery and recurrence of cases.     

Financial comparison of three testing strategies for detection of estrus in dairy cattle

Three commercial tests that measure progesterone content in milk were evaluated for accuracy of estrus detection. The tests were evaluated on 96 milk samples collected from Holstein cows at a commercial dairy farm in central Florida. The test results were compared with the results of radioimmunoassay on the same sample. Comparisons were made by calculating the sensitivities, specificities, and predictive values. The significance of the statistical association between the tests and the radioimmunoassay was evaluated by use of the McNemar chi 2 test. Decision-tree analysis was used to determine the most useful testing strategy, considering both cost and accuracy. The cowside progesterone assay on estrus-mount detector-positive cows was more profitable than use of estrus-mount patches alone. The return on investment was higher with the cowside test, making it preferred as a field test for detecting estrus.     

Mycoplasma bovis infections in Swiss dairy cattle: a clinical investigation

Mycoplasma bovis causes mastitis in dairy cows and is associated with pneumonia and polyarthritis in cattle. The present investigation included a retrospective case–control study to identify potential herd-level risk factors for M. bovis associated disease, and a prospective cohort study to evaluate the course of clinical disease in M. bovis infected dairy cattle herds in Switzerland. Eighteen herds with confirmed M. bovis cases were visited twice within an average interval of 75 d. One control herd with no history of clinical mycoplasmosis, matched for herd size, was randomly selected within a 10 km range for each case herd. Animal health data, production data, information on milking and feeding-management, housing and presence of potential stress- factors were collected. Composite quarter milk samples were aseptically collected from all lactating cows and 5% of all animals within each herd were sampled by nasal swabs. Organ samples of culled diseased cows were collected when logistically possible. All samples were analyzed by real-time polymerase chain reaction (PCR). In case herds, incidence risk of pneumonia, arthritis and clinical mastitis prior to the first visit and incidence rates of clinical mastitis and clinical pneumonia between the two visits was estimated. Logistic regression was used to identify potential herd-level risk factors for M. bovis infection. In case herds, incidence risk of M. bovis mastitis prior to the first visit ranged from 2 to 15%, whereas 2 to 35% of the cows suffered from clinical pneumonia within the 12 months prior to the first herd visit. The incidence rates of mycoplasmal mastitis and clinical pneumonia between the two herd visits were low in case herds (0–0.1 per animal year at risk and 0.1-0.6 per animal year at risk, respectively). In the retrospective-case-control study high mean milk production, appropriate stimulation until milk-let-down, fore-stripping, animal movements (cattle shows and trade), presence of stress-factors, and use of a specific brand of milking equipment, were identified as potential herd-level risk factors. The prospective cohort study revealed a decreased incidence of clinical disease within three months and prolonged colonization of the nasal cavity by M. bovis in young stock.     

Anti-Neospora caninum antibodies in milk in relation to production losses in dairy cattle

A comprehensive field study was carried out with the following objectives: (a) to assess the usefulness of individual and bulk tank milk analysis for determining Neospora caninum serostatus in individual cows and herds, and (b) to study the associations between N. caninum infection status (based on milk testing), and several productive and reproductive parameters in the animals. Antibodies were detected with a commercially available ELISA test (Bio K 192/5). Analysis of paired serum and milk samples from 1134 lactating cows on 38 farms revealed that 97.6% of the ELISA results were coincident, irrespective of whether serum or milk samples were used. Moreover, multiple linear regression analysis revealed that 86.0% of the variations in ELISA values in milk were due to variations in the serum. The measurement of antibodies in bulk tank milk was a good estimator of the herd level status of N. caninum infection, and enabled detection of infection in 94.7% herds with ≥10.0% seropositive cows and/or in all herds with >4% highly seropositive cows. The odds ratio for abortion in seropositive animals was 9.1 times higher than in seronegative animals. The infection serostatus was also a significant risk factor, as the odds ratio for abortion was even higher (12.0 times) in cows categorized as highly seropositive. ELISA values for the bulk milk from 387 randomly selected herds were negatively associated with average milk production. Moreover, milk production losses mainly occurred on farms categorized as highly positive (i.e. herds with ≥20.0% seropositive cows).     

An outbreak of sarcocystosis in dairy cattle

Sixteen of 32 Friesian calves, 8 to 10 weeks old, died over 4 weeks. The calves were housed in pens previously used by dogs. Clinical signs included anorexia, pale mucous membranes, rapid weight loss, coughing and palpably enlarged superficial lymph nodes. At necropsy, calves were emaciated and had generalised enlargement of lymph nodes, pale mottling of skeletal muscles, excess peritoneal, thoracic and pericardial fluid and subpleural and subepicardial haemorrhages. Histologically there was a lymphadenitis, myositis, myocarditis, glomerulonephritis, interstitial pneumonitis and encephalitis. Schizonts of a sporozoan parasite, presumably Sarcocystis cruzi were found in the endothelial cells of blood vessels in many organs.     

A field investigation of causes of abortion in dairy cattle

Cases of abortion on dairy farms on the Lancashire/Cumbria border were investigated by means of a systematic diagnostic procedure, using the facilities of a veterinary practice's laboratory, and the Ministry of Agriculture, Fisheries and Food veterinary investigation centre. Among approximately 3600 animals, 149 abortions were investigated on 54 farms in two years, an annual abortion rate of 2 per cent. A diagnosis was made in 34 per cent of the cases, based on a pathological examination of aborted material and bacteriological and serological findings. The most common pathogens associated with abortion were bovine viral diarrhoea virus (39 cases), bacterial or fungal infections (20 cases), infectious bovine rhinotracheitis virus (19 cases), and Leptospira hardjo (18 cases), either as single or multiple infections.     

Use of prostaglandin F2 alpha in the treatment of unobserved estrus in lactating dairy cattle

A field trial was conducted to evaluate the use of prostaglandin F2 alpha (PGF2 alpha) (lutalyse)a in lactating dairy cattle with unobserved estrus in the presence of a functional corpus luteum (CL) and clinically normal reproductive tract. Seventy-three Holstein and 9 Jersey cows, weighing between 340.0 and 772.7 kg, were allotted to treatment and control groups. All treated cows were inseminated within 80 hours after treatment as assigned by this trial. Control cows were inseminated at the first observed estrus. Of the treated cows, 50% showed estrus within 80 hours after treatment. In this trial, 96% of the treated cows and 92% of the control cows were determined to have at least 1 functional CL on the day of treatment. For the treatment group and the control group, mean serum progesterone concentrations were 4.1 ng and 3.5 ng (P less than 0.2, by Student's t test), respectively, on day of treatment and were 0.4 ng and 5.0 ng (P less than 0.005, by Student' t test) on day 5 after treatment. Pregnancy rates were 57% for treated and 47% for control cows (P = 0.5, by X2). Days from treatment to first-observed estrus, treatment to first service, and treatment to conception were significantly reduced in the treatment group compared with these criteria for the control group (P less than 0.05, 0.005, and 0.01 respectively). It was concluded that induction of luteolysis with PGF2 alpha in lactating dairy cattle with unobserved estrus and a palpable functional CL will be an effective addition to reproductive health programs.     

Distribution of time to first postpartum estrus in beef cattle

The function of a distribution that describes postpartum interval (PPI) under any experimental treatment is useful for simulation modeling, understanding the effects of stimuli on the endocrine system, and estimating the average PPI in experiments terminated before all animals have expressed estrus. This study was undertaken to compare the fit of three statistical distributions, the Weibull, the log-normal, and the linear hazard rate (LHR), to the empirical distribution of PPI for five treatment regimens: no bull exposure postpartum, bull exposure from 53 d postpartum, bull exposure from 3 d postpartum, and bull exposure from an average of 63 d postpartum for 2-yr-old cows and for mature cows. The Weibull and the log-normal distributions deviated considerably from the empirical distribution. The LHR distribution with parameters changing over three different regions gave an excellent fit. The resulting hazard rate (instantaneous probability of a cow expressing her first estrus at time t postpartum) revealed a low probability of expressing estrus within 27 d postpartum (43 d for 2-yr-olds). For cows not exposed to bulls, the hazard rate increased slowly with time. For cows exposed to bulls after 3 d postpartum, the hazard rate increased rapidly between d 27 and d 50. For cows exposed to bulls after 53 d postpartum, the hazard rate increased instantaneously approximately 12 d after initial exposure to bulls. This increase was also seen when cows were exposed to bulls beginning at a constant date (at an average of 63 d postpartum). Because of lack of fit, the Weibull and the log-normal distributions should not be used in survival analysis of PPI.(ABSTRACT TRUNCATED AT 250 WORDS)     

奶牛饲养管理技术要点

1 综合配套技术 1.1 优良品种 选择黑白花专用奶牛品种. 1.2 圈改扣棚 牛舍选在地势较高、开阔干燥、无污染源、水源充足、交通方便、避风向阳之地.建暖棚规范牛舍,座北朝南,东西走向,后墙高1.8 m,中梁高3 m,前墙高1.2 m,总跨深5.5 m,其中工作道宽2 m,饲槽0.7 m,牛床2.5 m,尿沟0.3 m.牛舍门宽1.8 m,高2 m;工作道门宽1.2 m,高2 m.扣棚时间当年10月上旬至翌年5月上旬.     

An evaluation of milk temperature measurement for detecting oestrus in dairy cattle. I factors affecting measurement of milk temperature

The paper reports the development of an electronic system of milk temperature measurement and the results of investigations into the influence of milk yield, milk flow and ambient temperature on milk temperature. The milk and body temperatures of randomly selected multiparous Friesian cows were recorded at afternoon milkings. Temperature was measured by bead thermistors housed in perspex probes from which a digital read-out with an accuracy of ±0.1°C was obtained. Milk tempetature was measured at four sites: the short milk tube (SMT), claw piece (CT), and the beginning (BLT) and end of the long milk tube (ELT) with readings being taken every 30 a from the commencement of milking. Body temperature measured with a probe in the vagina (VT) 38.85±0.02°C) was significantly higher than milk temperature at any of the four sites although a significant positive correlation existed between milk and body temperature. Milk temperature measured at each site decreased with distance from the cows (SMT: 38.64±0.03°C, ELT: 37.92±0.04°C). The difference between body and milk temperature was greatest in cows in which milk flow rates were below average (<1.37 kg/min) and/or milk yields were below average (<7.82 kg/milking). Milk temperature sites SMT and CT were least affected by variation in milk yield or flow, and showed the closest relationship between maximum milk temperature and body temperature. Milk temperature measurement was most reliable when taken during the full flow of milk.     

Influence of environmental factors on infrared eye temperature measurements in cattle

Environmental factors were evaluated to determine potential limitations in using cattle eye temperatures obtained through infrared thermography (IRT) for early disease detection systems or in animal welfare research studies. The effects of the following factors on IRT eye temperatures in cattle and a fabricated surrogate “eye” were evaluated: camera to object distance, wind speed, camera settings (distance, emissivity, and humidity), and solar loading. Wind speed in both live animals and using a surrogate “eye” was found to decrease the IRT temperature. In the presence of ∼7 km/h wind, the mean IRT eye temperature decreased by 0.43 ± 0.13 °C and; at higher wind speeds (∼12 km/h), the temperature decreased by 0.78 ± 0.33 °C. Direct sunlight was found to increase the IRT eye temperature by 0.56 ± 0.36 °C. It was determined that environmental factors impact IRT temperature measurements significantly and therefore must be managed to ensure reproducible and accurate readings.     

Use of thermal imaging for identification of foot lesions in dairy cattle

The objective of this study was to investigate the use of infrared thermography (IRT) for detection of foot lesions in dairy cattle. Thermal images of the rear feet of 139 lactating dairy cows were taken with a thermal camera and evaluated using imaging software. Foot lesions identified in the study included white line disease (WLD), sole ulcer (SU) and digital dermatitis (DD). Temperatures at the coronary band (CBT) and the skin (ST) were recorded. Cows were scored for locomotion on a scale of 1–5 (1?=?normal and 5?=?severely lame). CBT was higher for all types of foot lesion (34.1?±?2.3, 33.8?±?1.6 and 33.1?±?1.6°C for WLD, SU and DD, respectively) than for healthy (32.6?±?1.9°C) feet. ST was higher only for WLD (33.2?±?2.0°C) compared to healthy feet (31.5?±?1.7°C). ΔT (temperature difference between CBT and ST) was higher for SU (2.1?±?0.8°C) than healthy feet (1.1?±?0.9°C). Locomotion scores (LSs) were similar between healthy cows (2.2?±?0.7) and DD (2.4?±?0.7) but greater for SU and WLD cows (3.0?±?0.9, 3.0?±?0.8) than healthy cows. The threshold values established for CBT and ST were 33.5°C (sensitivity?=?77.8%, specificity?=?65.2%) and 33.7°C (sensitivity?=?44.4%, specificity?=?92.9%) for SU, and 34.4^oC (sensitivity?=?28.1%, specificity?=?88.6%) and 31.8°C (sensitivity?=?60.7%, specificity?=?55.4%) for overall lesion, respectively. These results indicate that IRT can be a useful tool for detection of SU, but not WLD and DD. In addition, CBT and ΔT were the best indicators for the detection of foot lesions.