Table 1 shows the time periods when cows are most likely to exhibit signs of heat. This data can be used as a guide to help determine when you should be observing cows.

Table 1:
When Cows Show Heat

---

Time	Percent cows showing heat signs
6 a.m. – noon	28.4%
noon – 6 a.m.	19.8%
6 p.m. – midnight	27.3%
midnight – 6 p.m.	44.5%
Source: Department of Dairy Science Virginia Polytechnic Institute

---

HEAT DETECTION ECONOMICS

Failing to detect heat and/or incorrect detection of estrus can result in significant economic losses. The cost of a day open for beef cows is $2 per day and up to $6 per day for dairy cows. Missing a heat cycle can cost anywhere from $42 to $126 for an individual cow. At approximately $1.30 per ESTROTECT patch, the economics show the value of a heat detection aid that works.

A 2005 South Dakota State University study showed heat detection accuracy using scratch-off technology at greater than 90% when compared to vigorous visual observation (every 3 hours) and penile deviated bulls. See Table 2 for details.

Table 2:
Accuracy of visual estrus detection, a penile deviated bull and scratch-off heat detection technology.

---

Observation	Visual	PenileDeviated Bull	Scratch-off Technology
% identified correctly	92% (83/90)	92% (34/37)	91% (82/90)
% identified incorrectly	8% (7/90)	8% (3/37)	9% (8/90)
% suspect	2% (2/90)	3% (1/37)	2% (2/90)
% identified in standing estrus	97% (67/69)	100% (34/34)	97% (66/68)
% identified in standing estrus that ovulated (including ovulated animals)	97% (69/71)	100% (35/35)	97% (68/70)
Source: 2005 South Dakota State University

---