Price and warranty
Worldwide price for basic Ovi-bovi versionIn the basic version we guarantee 1 km range of wireless tag-to-receiver transmission in the worst case conditions (actual range is normally up to 2 to 5 km) and we also equip the tags with ISO 15693 complying microchips compatible with modern NFC-enabled smartphones and equipment installed on a farm (NFC scanners at selection gates, in milking parlors etc.) is $65 per tag + $1700 for the receiver unit, no subscription fee or additional hidden fees charged. Considering the benefits of implementing real-time wireless oestrus detection system, its payback period in a typical farm at these prices is 1 year.
Why heat alerts are urgent
Timely notifying inseminator about the onset of a cow’s oestrus is a key to achieving high insemination rate on a farm. Scientific research shows it may take as little as 8 to 16 hours from the onset of cow heat to the moment of her insemination for the best resultsFor extensive discussion with references to most recent studies see J.B. Roelofs, “Estrus detection tools and their applicability in cattle: recent and perspectival situation,” Animal Reproduction 12 (2015) 498–504. In the paper by S.T. Nelson et al., “Automated activity monitoring and visual observation of estrus in a herd of loose housed Hereford cattle: Diagnostic accuracy and time to ovulation,” Theriogenology 87 (2017) 205–211, even tighter schedule is propelled for beef cows: AI should be performed approximately 6 hours after detection of estrus to maximize reproductive performance. Further research on optimal insemination timing is clearly needed.; worse, none of activity tags can detect the onset of heat at that very moment, so even less time is left for insemination from the moment the heat is detected.
One reason for this can be seen from activity plots: in heat, aggregated cow activity rises gradually, so that it takes about 3 hours for the curve to reach activity level of one standard deviation, at which instance the onset of heat can be determined reliably, after passing through the half-threshold of 0.5 std deviation, i.e. after the moment the heat actually started. Furthermore, any type of running-time data aggregation and smoothing (such as calculating the moving means needed to determine heats as spikes over the “normal” activity level) induces phase shift in the smoothed data. This shift depends on the type of averaging (simple or weighted) and roughly equals half the averaging interval: for example, with 10-hours simple averaging the curves lag behind actual activity pattern by 5 hours. Thus up to 8 hours may be needed for accurate and reliable automated detection of estrus after its onset,Attempts to shorten this interval invariably lead to sufficient increase in the number of false-positive heat alerts — a problem encounted with many commercial activity detection systems. so that no more than 8 hours more are left for insemination — given the signal from the tag is obtained immediately.
When designing Ovi-bovi system we made sensors capable of communicating with the receiver on a 24-hour basis, followed by immediate data processing and automated sending of cow heat or health alerts via Telegram bot (preferred way) or old-fashioned e-mail to inseminator, veterinarian and other registered users. Automatically and in time — not waiting till cows show up at the parlor to get their tags scanned — you are alerted if a cow is in heat or on low activity.
Economics of estrus detection and ROI estimate
Reproductive issues may stem from poor herd health. This may be caused by an unbalanced diet—too much corn silage and concentrates aimed at a short-term milk boost—or from feeding rotten, poorly preserved forage (a common issue when weather forces a rushed harvest). But just as critical—and even more common—are missed heats and poorly timed inseminations in both cows and heifers.
The mainstream means of cow heat detection today is simple visual observation of the herd — sometimes assisted with pressure sensors or color markers attached mechanically to the cows’ tails, such as Kamar or EstroTect. In a small herd, detection rate of approximately 70% can be achieved with two or three observation periods of 30 min a day.J. H. Van Vliet & F. J. C. M. Van Eergenburg, “Sexual activities and oestrus detection in lactating Holstein cows,” Applied Animal Behaviour Science 50 (1996) 57–69. More recent and reasonable models assume heat detection rate of 60% for cows and 30% for heifersR. M. Demeter et al., “A multi-level hierarchic Markov process with Bayesian updating for herd optimization and simulation in dairy cattle,” Journal of Dairy Science 94 (2011) 5938–5962. or 50% on average and 70% in a “good” scenario.C. Inchaisri et al., “Economic consequences of reproductive performance in dairy cattle,” Theriogenology 74 (2010) 835–846. An assumption of 50% for heat detection rate on a typical large-scale farm seems quite generous thus — while years of Ovi-bovi system usage showed at least 90% of heat detection for cows in free-stall barns.
But it is not detection rate as such, but overall conception efficiency that directly determines breeding results and profitability in a herd. For a successful insemination, simply detecting a heat isn't enough—what truly matters is accurately determining when the heat began and timing the insemination accordingly to maximize the chances of pregnancy. When relying on visual observation alone, you have no way of tracking the progression of the heat (which typically lasts 10 hours or more), making it nearly impossible to pinpoint the optimal window for insemination. We assume first-service conception rates with this method hover around 50%. In contrast, farms using Ovi-bovi tags consistently achieve first-service conception rates of 67%. Overall, these numbers allow us to compare breeding efficiency in three senarios:
| Insemination upon visual heat detection | Insemination with Ovi-bovi tags | Hormonal synchronization protocol |
| If detection probability p1 = 50% and first-service conception probability p2 = 50% (with visual detection, it's difficult to pinpoint optimal insemination timing), then the overall probability of successful conception is p1 × p2 = 0.5 × 0.5 = 0.25 |
Years of operation show that with loose housing, Ovi-bovi tags achieve a heat detection probability of at least p1 = 90%, and first-service conception probability p2 = 67%. Overall probability of successful conception: p1 × p2 = 0.9 × 0.67 = 0.6 |
Let's take p = 45%—this is an overly optimistic estimate, achievable with imported drugs. When using low-cost alternatives (Surfagon instead of gonadoliberin, Magestrophan instead of cloprostenol), the probability of successful conception can drop to 0.3 |
| A herd of n cows requires n + (1−p)n + (1−p)2n + … = n/p inseminations, or an average of 1/p inseminations per cow. For the scenarios above, this equals: | ||
| 4.0 | 1.7 | 2.2 |
| The average extension of the calving interval (given a 21-day estrous cycle) compared to an imagined 100% conception efficiency would be (1/p − 1) × 21 days: | ||
| 63 days | 14 days | 26 days |
As the table shows, switching from visual observation to sensor-based detection and insemination delivers three key benefits: first, it roughly cuts semen usage in half; second, it reduces the average calving interval by 49 days; and third, it delivers a corresponding increase in calf crop.
We recommend attaching tags and beginning insemination from day 60 post-calving—this is the minimum physiological window, as earlier insemination risks incomplete involution of the reproductive tract, which drastically reduces fertility and increases the risk of embryonic mortality and pregnancy complications. Under this protocol, the average time to first detected heat is 60 + 21/2 = 70.5 days post-calving, the average service period is 70.5 + 14 ≈ 85 days, and the calving interval is 280 + 85 = 365 days—delivering an ideal 100 calves per 100 cows per year.
With a milk price of $0.5 per liter and a 10-liter daily difference between peak and late-lactation production, shortening the calving interval by 49 days generates an additional $245 per cow annually from milk alone (0.5 $/L × 10 L/day × 49 days). Add to this the savings on semen—especially significant when using sexed semen—plus the revenue from additional calves sold. We leave it to the reader to calculate those numbers for his case.