Artificial insemination (A.I.) has become one of the most common tools for a dairy operation’s reproduction program. It is advantageous over natural service because of dramatic gains in genetic improvement and reduced dangers of dealing with unruly bulls.

Visual estrus detection is still of importance to dairy producers, even for those utilizing timed A.I. protocols.

Days open is currently the most common measure of reproductive efficiency. The average gestation length is 280 days for most dairy breeds and the ideal calving interval is 12 to 13 months. Therefore, the days open average required to reach these goals is 85 to 115 days.

Many factors affect the ability of an operation to obtain this level of reproductive efficiency. These include:

  • good dry cow and transition cow programs to eliminate health-related problems after calving
  • adequate nutrition
  • having environmental conditions that allow cows to express visual signs of estrus (facilities, decreasing heat stress, preventing lameness)
  • correct A.I. techniques
  • efficient and accurate heat detection

If you are aiming to get a cow pregnant at day 85 of her lactation, you only have 25 days after a 60-day voluntary waiting period to get a cow to conceive. On average, this is only long enough for a cow to come into heat once. To be able to breed her during this time, a great heat detection protocol is a must.


Improving heat detection to reduce days open

  • Observe 3 times a day for 30 minutes each.
  • Observe all cows and record all observed heats.
  • Observe when moving cows from concrete to dirt.
  • Keep all records and organize them to help pinpoint a cow’s next possible heat. PD

Excerpts from Kentucky Dairy Notes, August 2009

PHOTO:Heat detection imageby PD staff.