Research and Studies

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 p.m.
19.8%
6 p.m. – midnight
27.3%
midnight – 6 a.m.
24.5%
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
Penile Deviated 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