Top ten priorities for a successful heat detection program

1. Establish standard operating procedures: Cows should be observed at times and at a location where they are likely to express estrus. Establish a hormone program to induce estrus in cows and heifers. The standard operating procedures: When‚ Where‚ Signs of Estrus Observed‚ Who to Notify should be followed by everyone that has the responsibility for observing cows for the expression of estrus.

2. Utilize records: All heat periods detected should be recorded. A 50% conception rate means half the cows bred will become pregnant and half will return to heat in 18 to 24 days. Breeding wheels, calendars, and heat expectancy charts are inexpensive and effective tools.

3. Group interaction: Watch for sexually active groups of cows. Cows in heat and cows that will be in heat in the next 48 hours commonly congregate together. Cows usually alter their normal routine of behavior when approaching heat.

4. Minimize sore feet: A cow with sore feet usually does not mount or permit other cows to mount her. Treating infected or sore feet as soon as possible is important. Allowing cows time off of concrete is important.

5. A little is good but more is better: Cows should be observed many times per day. Three daily observation periods is a minimum and four is even better but WHO wants to be that good. The average heat period lasts for only 8 hours so twice a day observation periods will miss many cycling cows.

6. Timing is everything: Use time efficiently. Not during feeding or milking times. Cows should have space to interact with good footing and no distributing interactions by YOU.

7. Location, Location, Location: Visual observations should be where cows have a good footing surface with few obstacles to hinder interaction.

8. Use aids wisely: Heat detection aids, such as Kamar® or Beacon® heatmount devices should be used to supplement not replace visual detection. The HeatWatch® electronic heat detection system requires management decisions on suspect cows, interpretation of information for timely insemination and weekly maintenance to keep transmitters on cows.

9. Induced heat or ovulation programs: Inducing heat and/or ovulation with hormonal treatments that include GnRH and PGF2a increases the probability of detecting estrus or allows AI without estrus detection (timed insemination). However, make sure you have a program to catch the cows that return to estrus in three weeks or a procedure to re-synchronize cows as quick as possible so time is not lost because of the elimination of heat detection.

10. Don't take shortcuts: Is she or isn't she? Know when she was in heat last. Spend time observing cows. Make sure you are giving the hormone injections correctly so the complete dose of hormone will be administered. Write down your observations so others will know and you will not forget.

The bottom line: Cows come into heat equally during all hours of the day, are not very active, and do not stay in heat very long, making it difficult to observe them in heat. The equal distribution of the onset of estrus during the day combined with the average estrus duration of 7 hours dictate that heat detection observations should occur 3 to 4 times daily, approximately 6 to 8 hours apart. Providing an environment that encourages cows to express heat and conducting frequent heat detection are essential to improve reproductive efficiency. Allow cows to interact in a small, un-crowded area with secure footing and make use of heat detection aids to catch as many cows as possible. Eight times out of ten, the area of reproductive management that needs improvement is heat detection. There are very few dairy farms that could not reduce the average calving interval and culling rate by spending a little more time and effort on heat detection. To achieve accurate and efficient heat detection requires extra effort and doesn't just happen. Cycling cows require good nutrition, excellent cow comfort, the best hoof health possible and attention to details.

By Ray L. Nebel, Extension Dairy Scientist, Reproductive Management
Dairy Pipeline newsletter - Virginia Cooperative Extension