Better manage your sow herd with uniform body-condition technique

After noticing an alarming difference in sow body conditions in several herds, Cary Sexton, DVM, Four Star Veterinary Service (FSVS), became concerned.

“I saw people that were highly subjective in their ideal animal body conditions,” he said. “On farms with multiple employees who evaluate sows, I saw a lot of group-to-group variability among sow groups in crated gestation. Pen gestation was even more variable.”

The variability among sows was especially concerning because feed budgets are based on sow condition, explained Sexton who is with the FSVS Kinston, North Carolina office. If the herd isn’t uniform, then some sows eat too much feed, and others don’t get enough.

The solution

Sexton looked at different ways to objectively determine sow body condition. Most were eliminated including ultrasound and fat-depth measurements, which requires a high level of technical skill.

He decided to focus on a sow caliper designed by Mark Knauer, PhD, swine specialist at North Carolina State University Extension. Knauer agreed to meet with Sexton and some pork producers to discuss the caliper.

Knauer designed the sow caliper to standardize sow body condition instead of relying on visual scores, which can lead to expensive herd problems. Underfed sows more frequently experience impaired reproduction and well-being issues. Overfeeding sows leads to higher feed costs, more farrowing problems and higher pre-weaning mortality.

Implementing sow caliper

The sow caliper is a sturdy metal device that’s designed for easy use on sows. After Knauer demonstrated the caliper, Sexton said producers were supportive about trying it in their herds. Employees were less supportive, with concern about how long it would take to measure sows with the caliper.

“But once they used it, the employees felt they were doing a better job determining body condition than previously,” Sexton said. “And most employees can do it in about the same time as they previously were taking in performing visual scoring.”

The caliper must be used properly to accurately determine body condition. Sexton said the caliper must be placed at the last rib and with the pivot point on the spine for proper calibration.


He recommends checking sows with the caliper at breeding, pregnancy check at 50 to 60 days, and at 90 days. Gilts can be started at pregnancy check or after to prevent interfering with conception. It can also be used in a gestation pen system if the animals are housed in crates until pregnancy check or beyond.

“The first few weeks of pregnancy are the cheapest time to recover condition lost during lactation as the sows have less nutritional demand from the next litter,” Sexton said. “The condition can also be carried over into the gestation pens in assigning them and being able to more closely manage the amount offered each animal.”

$250,000 feed savings

Some of Sexton’s clients have used the sow caliper for several years. The biggest change for them was sow feed management.

“We saw huge feed savings for some companies, and one system saved $250,000 a year,” he said. “For a few systems where the sows tended to be thinner, there was a feed increase but with better management and feed utilization.”

Sexton said his biggest surprise was seeing how the small differences between body conditions can cause big variabilities in the animal. For example, he’s noticed sows in good body condition with adequate nutrition will handle disease challenges better.

Another benefit of well-conditioned sows is more piglets born live at the second and third farrowings, he said. The sows also continue to hold the higher numbers in subsequent farrowings.

Employees regularly using the sow caliper also observe sows more frequently. Health issues like lameness can be caught early and addressed before growing into major health problems, Sexton added.

For more information on the sow caliper, contact Mark Knauer.



Best sow-cooling strategies from North Carolina

Sow farms struggling to breed and farrow during hot, humid weather can pick up some tips from North Carolina, where this type of weather hangs around a long time.

“We have a big corner on heat and humidity with 40 to 45 days with the heat index above 100°,” reported Cary Sexton, DVM, veterinarian with Four Star Veterinary Service in Kinston, North Carolina. “We definitely have to employ sow-cooling strategies.”

After many years of experience, he has seen what works best to keep sows productive through hot weather.

Cooling sow in farrowing

The top of the line for cooling sows in farrowing are cool cells, according to Sexton. Compared to drippers, which are the next best option, cells aren’t as likely to plug and do not drip water on the pigs.

“The problem is cool cells affect ventilation efficiency and restrict air flow,” he said. “Some farms have gone in and put in drippers with the cool cells as an additional stage. The cool cells should stage in after the last fans are running.

“If the temperature continues to rise, the drippers will turn on to get a small portion of each sow wet and then shut off, leading to a more local evaporative cooling effect. But it all needs to be timed.”

Drippers in farrowing must be monitored because excess moisture can cause shoulder sores. Sexton recommends positioning a dripper between the sow’s ears and shoulders to prevent udder or shoulder problems. The extra moisture from drippers can also lead to diarrhea in piglets.

But overall, cool cells with timed drippers work. “We will see 90° to 95° in buildings on high-humidity days,” he said. “This is when drippers on the farrowing sows do a good job. We’ve seen how the sows’ respiratory patterns decrease with the drippers and cool cells running in tandem, and we don’t see as dramatic a drop in lactation feed intake.”

Focus on sow condition

Most gestation units among Sexton’s clients already use intensive management to keep sows in good condition. But some units have experienced problems getting the sows bred back during and following the hottest parts of the summer.

“In previous summers, some units had increased wean-to-first-service intervals because the sows wouldn’t eat in lactation,” Sexton explained. “So, we now put more effort into sow conditioning in the months leading into summer.”

Starting in the spring, sow farms focus on getting sows in proper condition to handle the hottest parts of the summer.

“We use a body-condition sow caliper to consistently evaluate body condition and feed the amount needed to achieve a condition score of 3 in a 30- to 60-day time period,” he explained.

“We have more problems with heavier sows. These sows have more insulation and hold more of their heat in the summer, in combination with the fact that their body temperature goes up as they eat.”

Feeding strategies

Lactation feed-time strategies help. “Get the sows fed early in the morning and fed last in the afternoon so they are eating during cooler times are top priorities,” he said.

This feed regimen is also practiced on farms that utilize automatic feed systems in farrowing. These farms also drop additional feed to sows that have cleaned up since their last feeding when employees walk through the rooms, Sexton explained. These same farms also offer smaller, more frequent meals up to five times a day.

The automatic feed technology also allows the sows to be fed consistently, even on weekends which also is a huge advantage due to labor availability on weekend shifts, he added.

Room temperatures in gestation and farrowing will affect how sows eat. Sexton recommends setting the temperatures to favor the sow’s comfort. Heat lamps or pads provide supplemental, zone heating to warm piglets without affecting the sows. These items must be removed as soon as piglets can maintain their own body temperatures.

He suggests tying these heat sources into the ventilation system to allow adjustment to weather events like an afternoon thunderstorm, which dramatically changes the temperature profile of farrowing rooms.

“Without connecting heat to ventilation, the heat source may not return to full power and respond to the pigs’ need for supplemental heat, leading to increased piglet mortality or illness,” Sexton added.

Be attentive to sows

Overall, the best strategy is to “be very attentive to your sows,” Sexton concluded. “When you have things occur, ask yourself what strategies and technology do I have available for the overall comfort of that sow? And remember for sows not acclimated to the heat and humidity, hot and humid weather can be as tough if not tougher on them than the workers.”




Tips to improve pen gestation for sows

Many pork producers successfully manage sows in group gestation pens after completing breeding and pregnancy checks in crates. Veterinarians with Four Star Veterinary Service (FSVS) offer management suggestions to help maximize sow productivity in pen gestation.

“Most of our clients are converting to pen gestation,” reported Randy Jones, DVM, FSVS, Kinston, North Carolina. “Some of our better performing farms are pen gestation. After all, we managed sows in pens before we put them in crates.”

Pen size

“Give the sows plenty of space,” stated James Kober, DVM, FSVS, Holland, Michigan. “There are no space regulations in the Michigan law, but there are guidelines available that suggest 18 to 20 square feet per sow. If you get under 18 square feet, sows will start experiencing pregnancy problems.”

If crates are remodeled into pen gestation, utilize the walkway behind the crates for pen space to maximize space per sow. The extra room helps deter fighting.

Reduce fighting

When sows are first mixed, they fight. Kober suggests mixing sows late in the evening, feeding them and then turning off the lights.

“Some producers will mix sows every week and have a dynamic group,” he added. “The sows will fight some, but if the pens are big enough, they can move away.”

Feed and water

Adequate feed and water are vital for sow productivity, especially in pen situations, according to Jones. Boss sows will “hog” the feeders and waterers if not enough are available.

Jones recommends feeding all sows at once in some type of feed stall. The design and size of the feed stall varies among manufacturers and producers. But the important thing is offering some protection for sows while they eat.

“Another aggression point is not enough waterers,” reported Cary Sexton, DVM, FSVS, Kinston, North Carolina. “I’ve had some farms put in additional waterers because of [sow fighting].”

The waterers should be installed on different side panels of the pen to prevent sows from congregating and fighting.

Treat immediately

“I always tell clients if you think there’s anything wrong with a sow, pull her out now and treat her right away,” said JoAnna Kane, DVM, FSVS, Holland, Michigan.

“If you think you can come back later to do it, all the sows will be lying down and you won’t be able to find her.”

Sows needing treatment or time to recover from an injury are moved to individual hospital stalls.


Sows bred for gestation crates may experience leg and feet issues when housed in pens. Genetics will need to address those issues. For Sexton who works with many herds already in pen gestation, that has already occurred.

“Genetics have changed to a much hardier animal,” Sexton said. “The animal I started practicing with early in my career would not handle the competitive nature of today’s group-housing environment.”