Potential of connected devices to optimize cattle reproduction

Estrus and calving are two major events of reproduction that benefit from connected devices because of their crucial importance in herd economics and the amount of time required for their detection. The objectives of this review are to: 1) provide an update on performances reached by sensor systems to detect estrus and calving time; 2) discuss current economic issues related to connected devices for the management of cattle reproduction; 3) propose perspectives for these devices. The main physiological parameters monitored separately or in combination by connected devices are the cow activity, body temperature and rumination or eating behavior. The combination of several indicators in one sensor may maximize the performances of estrus and calving detection. An effort remains to be made for the prediction of calvings that will require human assistance (dystocia). The main reasons to invest in connected devices are to optimize herd reproductive performances and reduce labor on farm. The economic benefit was evaluated for estrus detection and depends on the initial herd performances, herd size, labor cost and price of the equipment. Major issues associated with the use of automated sensor systems are the weight of financial investment, the lack of economic analysis and limited skills of the users to manage associated technologies. In the near future, connected devices may allow a precise phenotyping of reproductive and health traits on animals and could help to improve animal welfare and public perception of animal production.

Using estrus detection patches to optimally time insemination improved pregnancy risk in suckled beef cows enrolled in a fixed-time artificial insemination program

A multilocation study examined pregnancy risk (PR) after delaying AI in suckled beef cows from 60 to 75 h when estrus had not been detected by 60 h in response to a 7-d CO-Synch + progesterone insert (CIDR) timed AI (TAI) program (d -7: CIDR insert concurrent with an injection of GnRH; d 0: PGF injection and removal of CIDR insert; and GnRH injection at TAI [60 or 75 h after CIDR removal]). A total of 1,611 suckled beef cows at 15 locations in 9 states (CO, IL, KS, MN, MS, MT, ND, SD, and VA) were enrolled. Before applying the fixed-time AI program, BCS was assessed, and blood samples were collected. Estrus was defined to have occurred when an estrus detection patch was >50% colored (activated). Pregnancy was determined 35 d after AI via transrectal ultrasound. Cows ( = 746) detected in estrus by 60 h (46.3%) after CIDR removal were inseminated and treated with GnRH at AI (Control). Remaining nonestrous cows were allocated within location to 3 treatments on the basis of parity and days postpartum: 1) GnRH injection and AI at 60 h (early-early = EE; = 292), 2) GnRH injection at 60 h and AI at 75 h (early-delayed = ED; = 282), or 3) GnRH injection and AI at 75 h (delayed-delayed = DD; = 291). Control cows had a greater ( < 0.01) PR (64.2%) than other treatments (EE = 41.7%, ED = 52.8%, DD = 50.0%). Use of estrus detection patches to delay AI in cows not in estrus by 60 h after CIDR insert removal (ED and DD treatments) increased ( < 0.05) PR to TAI when compared with cows in the EE treatment. More ( < 0.001) cows that showed estrus by 60 h conceived to AI at 60 h than those not showing estrus (64.2% vs. 48.1%). Approximately half (49.2%) of the cows not in estrus by 60 h had activated patches by 75 h, resulting in a greater ( < 0.05) PR than their nonestrous herd mates in the EE (46.1% vs. 34.5%), ED (64.2% vs. 39.2%), and DD (64.8% vs. 31.5%) treatments, respectively. Overall, cows showing estrus by 75 h (72.7%) had greater ( < 0.001) PR to AI (61.3% vs. 37.9%) than cows not showing estrus. Use of estrus detection patches to allow for a delayed AI in cows not in estrus by 60 h after removal of the CIDR insert improved PR to TAI by optimizing the timing of the AI in those cows.

Comparison of three devices for the automated detection of estrus in dairy cows

Considerable technological advances have been made in the automated detection of estrus in dairy cattle, but few studies have evaluated their relative performance on the same animals or assessed cow-related factors that affect their performance. Our objective was to assess the performance and reliability of three devices commercially available in France for cow estrus detection. The devices were a pedometer (PM; Afitag) and two activity meters (AM1; Heatime-RuminAct, and AM2; HeatPhone). Two algorithms were tested for AM2. We fitted 63 lactating Holstein cows with the three detectors from calving to 90 days after calving. The onset and pattern of cyclicity were monitored from 7 to 90 days postpartum measuring progesterone concentration in milk twice weekly. A total of 211 ovulations were identified. Cyclicity was classified as normal in 60% of cows (38/63). Calculated over the operating period of all the devices (179 periods of estrus), the sensitivities and positive predictive values were, respectively, 71% and 71% for PM, 62% and 84% for AM1, 61% and 67% for the first algorithm of AM2, and 62% and 87% for the second algorithm of AM2. Both activity meters had a lower sensitivity but a higher positive predictive value than the PM (P < 0.05). For all devices, the performance in estrus detection was much poorer at the first postpartum ovulation than at subsequent ovulations (P < 0.05). Lactation rank and milk production affected some devices (P < 0.05). These devices could be used to reinforce visual observations, especially after 50 days postpartum, the minimum recommended delay to insemination. However, their full benefit remains to be verified in different farming systems and taking into account the specific objectives of the dairy farmer.

Pedometer readings for estrous detection and as predictor for time of ovulation in dairy cattle

The objective of this study was to study the relationship between increase in number of steps measured by pedometers, behavioral estrous parameters and time of ovulation, in order to investigate whether the number of steps can be used as a tool for estrous detection and as a predictor for time of ovulation. In total, 63 ovulations were observed in 43 Holstein-Friesian cows. Different behavioral signs of estrus were observed at 3h intervals. Cows were equipped with pedometers, which stored number of steps in 2h time periods and pedometer estrus alerts were defined using different algorithms and thresholds. The percentage of behavioral estruses also detected by pedometers measurements, ranged between 51 and 87% for all estrous periods. When only estrous periods where taken into account in which more than one animal was in estrus, detection percentages increased up to 95%. Number of steps taken during the estrous period was higher when more animals were in behavioral estrus at the same time, and number of steps taken during the estrous period was also higher for primiparous cows compared to multiparous cows. Ovulation occurred 29.3+/-3.9h after onset of increased number of steps (ranging between 39 and 22 h) and 19.4+/-4.4h after the end of increased number of steps (ranging between 35 and 12h). The intervals were not influenced by the number of animals that were in estrus at the same time or by parity. In conclusion, pedometers can detect estrus accurately and appear to be a promising tool for prediction of ovulation and hence could be a tool for improving fertilization rates.

Development of a method of diagnosing ovarian disorders in sows and gilts using uterine ultrasonography

In ultrasonographic diagnosis of ovarian disorders and the estrous cycle in sows, transverse observation of the uterus yielded more characteristic findings than observation of sagittal sections. Transverse ultrasonography revealed that the low progesterone (P) type uterus showed a round structure, while the high P type uterus showed a flattened structure. These results corresponded well with rectal palpation findings: the low P type uterus had a hard, pipe-like structure and the high P type a soft, balloon-like structure. For gilts, we employed a minimum convex type transrectal prostate probe that had an approximately 18 cm insertion handle. The images of the uterus obtained thereby were a similar to those obtained from sows. The above results suggest that it should be possible to diagnose and treat many ovarian disorders in sows and gilts based only on the ultrasonograhic findings. In short, ultrasonograhic findings of a round structure of the uterine wall might be an indication for PMSG (pregnant mare serum gonadotropin) treatment, while findings of a flattened structure might be an indication for PGF(2) (alpha) administration.

Application of electronic estrus detection technologies to reproductive management of cattle

Artificial insemination and embryo transfer programs are dependent on efficient and accurate detection of estrus. Visual observation is accurate at detecting animals in estrus, but efficiency ranges from approximately 50 to 70%. Electronic technologies have been developed in attempts to improve estrus detection efficiency. Commercially available electronic devices for estrus detection are based on changes in physical activity (pedometers), changes in electrical resistance of reproductive tract secretions (intravaginal resistance probes) or mounting activity (mount detectors). All of the commercially available electronic estrus detection devices can improve the efficiency of estrus detection in cattle. Pedometers are most applicable to lactating dairy cattle and have greater accuracy and efficiency when combined with visual observation. Intravaginal resistance measurement is perhaps the least practical method of estrus detection because of labor and animal handling requirements. Individual resistance measurement may have practical application for confirming other inconclusive signs of estrus. Mount monitors have the broadest application to beef and dairy cattle. HeatWatch, the only real-time radiotelometric system available, requires the least labor and animal handling and provides data on the time and duration of each mount. The less expensive stand-alone mount monitors also provide the necessary information for optimum timing of insemination and embryo transfer, but are more labor intensive.

Expression and detection of oestrus in cattle

For herds using AI heat detection rate and calving rate are the two major determinants of compactness of calving, of the proportion of cows that fail to conceive in a defined breeding season. Numerous factors affect the expression of heat including, housing arrangement, floor surface, feet and leg problems and status of herd mates. The number of mounts a cow receives increases with the number of cows that are in heat simultaneously up to about 3-4 cows in heat. Generally, cows that are themselves in heat, coming into heat or were recently in heat are most likely to mount a cow that is in heat. Cows that are at the mid-stages of their cycles (day 5 to about day 16) are least likely to mount a cow that is in heat and consequently could be termed "poor heat detectors". Similarly, cows that are pregnant show less interest in mounting other cows that are in heat. In smaller herds and as more cows become pregnant the likelihood of more than one cow being heat on any given day becomes less, consequently, making heat detection more difficult. The single most important factor affecting heat detection efficiency is that those responsible for checking for heat should fully understand the signs of heat and be fully committed to heat detection for as long as it is planned to use Al. Technological aids to improve heat detection include the use of tail paint, oestrous synchronisation, vasectomised bulls, pressure activated heat mount detectors, radio telemetric devices, pressure sensitive mount count devices and pedometers. As herd size increases and labour become more expensive there will be a greater adoption of some of these technological aids.

An electronic nose to detect changes in perineal odors associated with estrus in the cow

Changes in perineal odor as estrus is approached could form the basis of a new method of estrus detection. Perineal odor of cyclic cows was monitored. Estrus was identified using ovarian ultrasound, behavioral observations, and plasma assay for progesterone and estradiol. Samples were taken from the dorsal lateral perineal (perivulval) area using cotton bud swabs and presented to an electronic nose. Twelve conducting polymer sensors were used to quantify odor in terms of a change in sensor resistance. Preliminary data (Experiment 1) indicate that the odor signals between the luteal phase and estrus could be distinguished for a group of five cows. In Experiment 2, samples were obtained daily from eight cows during the midluteal phase and from d -2 to d 8 of the cycle (d 0 = day of estrus, induced using cloprostenol). Seven of the eight cows cycled normally. Of the 12 sensors, 7 showed a significant change in resistance that was dependent on the day of the estrous cycle. Basal values were those taken in the luteal phase; values peaked on d -1, rose transiently on d 3, and returned to baseline on d 5 to 6. This pattern is strongly correlated with plasma estradiol concentration. The use of artificial olfaction could enable more accurate detection of estrus and has the potential to increase fertility in cows.

Efficiency of the OVATEC unit for estrus detection and calf sex control in beef cows

Seventy five spring calving Gelbvieh and Angus cows were utilized over a three year period to evaluate the usefulness of the OVATEC intravaginal probe for indicating the onset of estrus and providing the possibility to influence the sex of the offspring by choosing a breeding time in relation to critical changes in cervical mucus conductivity. Cows were randomly assigned by breed each year into one of four treatments: (1) probed and inseminated when impedance values declined, creating conditions expected to favor X-bearing sperm and with it an increase in the conception of females (PF); (2) probed and inseminated when impedance values were rebounding, expected to favor Y-bearing sperms and with it an increase in the conception of males (PB); (3) standing estrus (AI); or (4) natural service by bull (NS). Cows grazed or were fed hay from tall fescue-legume pastures. Lutalyse was used to synchronize estrus in a two injection scheme. Vaginal probe readings were taken at first injection, second injection and every 12 h thereafter for 6 days. Visual observations for estrus were obtained for PF, PB and AI every 12 h postsecond injection. Rectal palpations of ovaries were obtained at standing heat in all but NS treatments. In cycling cows, probe readings increased prediction of estrus onset (P < 0.10) compared to visual observations and were similar (P > 0.95) to rectal palpations in all probed cows. PF cows delivered heifer calves at greater rates (P < 0.025) than all other treatments whereas PB cows delivered bulls at greater rates (P < 0.05) than all other treatments. Heifer to bull ratios were not different (P > 0.95) for AI or NS treatments. The results of this study indicate that the potential exists for increasing female offspring conceptions utilizing cervical mucus conductivity as a gauge for insemination times.

Automated electronic activity measurement for detection of estrus in dairy cattle

Two trials were conducted to characterize the performance of an automated electronic activity tag system as an aid for detection of estrus in dairy cattle. In trial 1, activity tags were attached to the rear leg of 24 cows at approximately 35 d postpartum and remained attached until pregnancy. Data collection included 66 periods of predicted estrus (cyclic periods of 18 to 24 d prior to the date of pregnancy). A summary of the data recorded in the activity tags was transmitted telemetrically to a personal computer at each milking via stationary antenna in the milking parlor. An electronic flag used an increased activity ratio to determine the ratio of activity in a test period of the previous 12 h to activity in the same 12 h during the 2 d previous to the test period, thus indicating estrus. Activity patterns were characterized from data recorded on the tags at 2-h intervals. The tag detected 74% of predicted periods of estrus versus 58% reported by herders. An increased activity ratio for at least 4 consecutive h reduced false-positive designations. In trial 2, activity tags were attached to front and rear legs on five cows, and activity patterns from the two sites were compared for 2 mo. Patterns of activity were similar from tags attached at either site, and the sites were not different in their discrimination between periods in which estrus did or did not occur. The activity tag system was an effective practical tool to detect estrus.

The effect of parasite control on fertility in beef heifers

The effect of anthelmintic treatment on the growth and conception rate in beef heifers was studied in southwestern Virginia, USA. Forty mixed-breed heifers were divided into two groups at weaning and placed on experimental pastures. Control heifers did not receive anthelmintic treatment, while animals in the treatment group were given ivermectin (200 micrograms kg-1) at the time of allocation to groups in October and again in April the following year. Supplemental feed was provided throughout the winter to ensure adequate weight gains. In May, the heifers were exposed to bulls for natural breeding for a period of 6 weeks. Weight gains, fecal egg counts, serum pepsinogen levels and pasture larvae counts were monitored throughout the experiment. No difference in conception rate was observed between the two groups, although the cumulative weight gain was significantly greater in treated than non-treated animals. Serum pepsinogen levels and fecal egg counts were also generally lower in treated than non-treated heifers.

[The use of a heat detector in sows]

In the present study a Miyashita heat-detector was tested. It is concluded, that this detector is not suitable for establishing the optimal insemination time.

[A prospective study of the usefulness of an intravaginal electric resistance meter for estrus detection in cattle]

The use of a device for measuring vaginal electrical resistance was tested in dairy cattle at the time of 496 inseminations as well as in five heifers and four gilts throughout the oestrous cycle. The device can be used in oestrus detection when there is a reliable and consistent difference in vaginal electric resistance, which can be estimated between the day(s) of oestrus and during the other days of the oestrus cycle. However, the results of tests using this device in cattle and gilts showed marked variations within animals during successive heats and cycles as well as between animals on corresponding days of the oestrus cycle. This experiment therefore showed that the device was not an effective aid in heat detection.

Electronic probe measurements of cervico-vaginal mucus for detection of ovulation in dairy cows: sanitation, clinical observations and microflora

An electronic vaginal probe with a sanitizing carrier unit has been designed to measure changes in the electrical resistance of cervico-vaginal mucus in the cow. Over 400 cows and heifers have been probed during the period prior to breeding. When 33 heifers and cows were probed 2-3X per day for 30 days, mild irritation of the vaginal mucosa developed during the luteal phase. In all other studies no grossly detectable lesions or other complications resulting from probing were observed either in experimental herds or in farmer herds where breeding tests were conducted. Fertility of probed cows was equal to cows inseminated when estrus was detected visually. Weekly culture of microorganisms from cervico-vaginal mucus collected from three cows probed 3X per week for 22 days resulted in no detectable change in the population of microorganisms. The number of isolates each successive week was 11, 8, 8 and 5, respectively. The sanitary procedures followed appeared to prevent introduction of organisms of any consequence, as judged by the decreasing number of isolates during the probing sequence.

Estrous cycle patterns in cattle monitored by electrical resistance and milk progesterone

An electronic probe with parallel stainless steel electrodes was designed to measure changes in electrical resistance in the anterior vagina associated with increased cervical mucus secretion at estrus. Three groups of Holsteins were probed, and a sample of residual milk after milking was taken for progesterone assay every 2nd day for 28 to 40 days. Group I consisted of 29 cycling virgin heifers, Group II consisted of 24 lactating cows in the Cornell herd, and Group III consisted of 62 lactating cows in three commercial herds. Lactating cows were 26 or more days postpartum when sampling began. In Group I, 77% of the measurements at the ventral surface of the anterior vagina were lowest on the day of estrus and correlated well with days KaMaR Heatmount Detectors were triggered or chalk was erased. In Groups II and III, average electrical resistance also was minimal at estrus and was correlated .92 to .99 with average milk progesterone during the 4 days preceding and including estrus. The electronic probe appears to enable one to detect which cows are cycling normally and to aid in determining when to expect estrus.

The use of heat mount detectors in a large Iranian dairy herd

Heat mount detectors were applied in a large Iranian dairy herd in an attempt to appraise their value for fertility improvement. A total of 100 cows with a recorded anoestrous period of at least 60 days were selected, 69 of them suffering from suboestrus or silent heat and 31 from true anoestrus due to inactive ovaries. The results indicate that inaccurate observation of heat is a major limiting factor in the reproductive performance of this herd and that heat detectors could be a valuable tool for improvement of oestrus detection and consequent reduction of the interval from calving to conception.