Pregnancy detection and monitoring in cattle via combined foetus electrocardiogram and phonocardiogram signal processing

Abstract

BackgroundPregnancy testing in cattle is commonly invasive requiring manual rectal palpation of the reproductive tract that presents risks to the operator and pregnancy. Alternative non-invasive tests have been developed but have not gained popularity due to poor specificity, sensitivity and the inconvenience of sample handling. Our aim is to present the pilot study and proof of concept of a new non invasive technique to sense the presence and age (limited to the closest trimester of pregnancy) of the foetus by recording the electrical and audio signals produced by the foetus heartbeat using an array of specialized sensors embedded in a stand alone handheld prototype device. The device was applied to the right flank (approximately at the intercept of a horizontal line drawn through the right mid femur region of the cow and a vertical line drawn anywhere between lumbar vertebrae 3 to 5) of more than 2000 cattle from 13 different farms, including pregnant and not pregnant, a diversity of breeds, and both dairy and beef herds. Pregnancy status response is given “on the spot” from an optimized machine learning algorithm running on the device within seconds after data collection.ResultsUsing combined electrical and audio foetal signals we detected pregnancy with a sensitivity of 87.6% and a specificity of 74.6% for all recorded data. Those values increase to 91% and 81% respectively by removing files with excessive noise (19%).Foetus ageing was achieved by comparing the detected foetus heart-rate with published tables. However, given the challenging farm environment of a restless cow, correct foetus ageing was achieved for only 21% of the correctly diagnosed pregnant cows.ConclusionsIn conclusion we have found that combining ECG and PCG measurements on the right flank of cattle provides a reliable and rapid method of pregnancy testing. The device has potential to be applied by unskilled operators. This will generate more efficient and productive management of farms. There is potential for the device to be applied to large endangered quadrupeds in captive breeding programs where early, safe and reliable pregnancy diagnosis can be imperative but currently difficult to achieve.

A Wearable Contactless Sensor Suitable for Continuous Simultaneous Monitoring of Respiration and Cardiac Activity

“…Although such dependence is expected, as is a delay between the electrical activity of the heart (ECG) and the changes in volume resulting from the pumping action, we assume that there is a further delay added by the response time of the ERBs. For this reason, the time interval that in Figure 4 is marked with "A" measured as time interval between the peak of the QRS and the local minima of the volume signal may be larger than normal physiological values of ∼30 ms [4,28]; see Section 4. Similarly, the cardiac stroke volume is measured as peak-to-peak value between the first local minima and the first local maxima after the heart beat (see Figure 4) may be influenced by the delay and damping impressed by the ERB as well as by the amplitude modulation impressed by the respiration.…”

Individual identification using electrocardiogram morphology

“…During or after physical activity some ECG parameters [17] can result modified and this may complicate individuals' identification. Other difficulties can arise using different devices or sensors, particularly with dry electrodes [18][19][20][21] frequently used to allow more pervasive and userfriendly applications [22,23]. Relative motion between patient and electrodes (but also if an individual is subjected to vibration for example in a vehicle [24]) can generate large artifacts in bioelectric recordings that should be appropriately processed [25,26].…”

Effects of Regent Suit on lower limb electromyographic patterns

“…Use of dry electrodes [15] [16], especially in long lasting recording [17] [18] [19], or alternative signal front-end [20] should be considered.…”