Whether you have a seasoned staff in your breeding barn or have brought in someone new, here Mark Wilson, reproductive physiologist, Zinpro Corp., offers some pointers to boost your heat detection and insemination timing.

Effective estrus detection starts with a thorough recordkeeping system. “You want to inseminate boar semen prior to the sow ovulating to optimize farrowing rate and litter size,” Wilson explains. “From the time sows or gilts begin their estrus until the end, most animals will ovulate about two-thirds of the way through their standing estrus.”

Observe sows carefully throughout the day for behavior changes. The estrus cycle can last anywhere from 18 days to 24 days ­— 21 days is the average. These observations will provide valuable clues as to how things are progressing, Wilson says.

Estrus behavior is the physiological response to the boar. “The first five minutes to 15 minutes after a sow ‘locks up’ for the boar is your best opportunity to get her bred.” However, Wilson stresses the importance of not exposing females to the boar before you check for the standing response.

Some of the signs you should look for to identify animals in estrus include:

  • Animals that are off feed or restless.
  • Viscous vaginal discharge. “A discharge that strands between thumb and finger indicates that the animal is in pretty ideal breeding state,” Wilson explains.
  • Vulva redness begins to fade.
  • Sow or gilt has perked ears.
  • Animals quiet down when back pressure is applied. “If they don’t quiet down, it tells you they’re still a little pre-estrus,” Wilson says.

Don’t overcrowd sows and gilts, and watch for other signs such as quivering or an erect tail. The key is not to rely on just one signal.

Be patient; breed only when the animal is in good standing estrus. “If an animal is really locked up, inseminate it, and on the next day get another dose in if the animal is still locked up,” Wilson says.

As for the heat-check boars, watch them closely. “The boar rarely picks out a female in heat. The boar is only a stimulus to the female,” Wilson explains.

He suggests having four to six heat-check boars per 2,400-sow breeding barn. “It’s more than you absolutely need, but I don’t like exposing the same females to the same boar every day,” Wilson says.

A common mistake with heat-check boars is not collecting semen or allowing them to breed often enough — once a week is the minimum. “Operations that collect boars 1.5 times per week (three times in a two-week period) are likely getting better results in maintaining libido responses,” he adds.

High libido responses include chomping, barking or vocalizing around females, huffing/puffing, bristling up and even being a bit aggressive. Don’t use a boar younger than 10.5 to 11 months old. Don’t keep boars that fail to stimulate females.

Daily exposure to boars is important. Taking gilts to the boar pen or a neutral pen will optimize their response. “In the summer months, you may need to intensify boar exposure because of fans and air movement,” Wilson says.

If the boars themselves can’t provide enough exposure to the females, he suggests using more boars or an idea from Don Levis -- boar “stink stick” rags soaked with boar saliva or urine on the end of a stick.

“Don’t do heat checks without a boar — it still creates the best stimulus,” Wilson notes.