Plan now to better manage pastures for healthy cow-calf herd

Hog manure helps sustain profitable cow-calf herds when pasture grazing is well managed. But pork producers often lack the knowledge to manage pastures for calf production, according to Harrison Dudley, DVM, Four Star Veterinary Service in Kinston, North Carolina.

“I have some producers who have tried to make the cattle part of their business more productive,” Dudley said. “They have tried to maximize the number of head per acre and end up in trouble because they run out of grass at certain times of the year.

“The producers doing the best job in this type of system manage the grass and match the cattle to their ability to grow the grass,” he explained.

Dudley offers suggestions to better manage pastures fertilized with hog manure for a successful cow-calf herd.

Manage the grasses

“Most of our forage base is a warm-season perennial so when winter comes around, there’s not much growing there,” Dudley said. Compounding the problem are dry summers with periods of heavy tropical rains that produce marginal-quality hay.

“We see a lot of mono-crop pasture management,” he explained. “We need more biodiversity in the pasture. Plant two- or three-variety grazing mixes or have different plots for different grass peaks.”

For example, Dudley suggests a rotation of oats, ryegrass and wheat, each planted in 30-acre pastures.

“Instead of planting the cheapest grass on all your ground to produce a ton of grass for 30 days and then nothing after that, you have staggered pastures with different grass peaks,” he explained.

Match stocking density to grass

A common mistake made by many cow-calf producers is stocking the pastures for peak grass production. When grass production starts to drop, overgrazing occurs, and cattle start experiencing nutritional issues.

“Cows drop body condition really quick,” Dudley said. “Stage your stocking density so you can carry cows through lighter parts of the year.

“Focus on producing good quality and adequate quantity as well. Sometimes people focus on quality but don’t have the quantity.”

Stocking densities vary by region. In the Kinston area, Dudley said they stock a cow-calf pair on 1.25 to 1.5 acres. Two hours west, the stocking density for a cow-calf pair is 2 to 2.5 acres.

Select genetics for environment

“Match the genetics of the animal to work in your environment,” Dudley continued. “We may pick animals that are the best but are developed in a very different system than an eastern North Carolina hog farm. They may perform really well on wheat pasture and cornstalks in Nebraska but probably don’t have the same genetic composition as animals that will do well in North Carolina.

“You should select females that have proven they can work in your system,” he emphasized.

Dudley works with some producers who select and develop their own heifers for their cow-calf herd. “They are developing their own heifers, making the right bull selections and keeping the cows around until they are 10 to 15 years old,” he said. “It does require a special type of producer to keep a heifer.”

Producers looking for help with a cow-calf herd and pasture management should contact their local veterinarian or click here to email Dudley.


Combat seasonal infertility with strong husbandry

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Seasonal infertility continues to be a widespread problem for sow herds across the US. And if you don’t have a problem with seasonal infertility, it may mean you are not recognizing it, reported Daniel Gascho, DVM, with the Four Star Veterinary Service office in Mexico, Indiana.

Gascho offers several suggestions for recognizing and dealing with seasonal drops in fertility that occur in late summer and early fall but may not be noticed until winter.

“The signs can range from the obvious of just a lot of sows and gilts are not pregnant and I don’t know why,” he said. “But for people focused on breeding, they may notice delayed return to heat after weaning. You may notice, when they do cycle again, that it’s at an unusual time and not on a normal 21-day cycle. Or you may notice she was pregnant and then she lost it.”

Causes for seasonal issues

Many factors are involved in seasonal infertility. Top of the list is hot weather when sows don’t like to eat or breed, according to Gascho.

Another big factor is poor nutrition caused by mycotoxins or poor corn quality. “We sometimes jokingly refer to it as ‘combine-itis’ because people working in the fields this time of year are busy, and general husbandry drops a bit,” he explained. “They are not paying as close attention to the things that play a role in infertility.”

Other stressors can cause infertility problems like moving sows too quickly after breeding, crowding or fighting in gestation pens, and not pushing feed intake while sows are nursing piglets.

“But you could have a perfect farm, and you’re still going to see a drop in fertility this time of year,” he added. “That’s the part we don’t fully understand. A lot of people suspect it has to do with natural hereditary instinct of swine where wild pigs quit breeding in September so they don’t have litters during the winter.

“Our commercial animals aren’t affected by temperatures, but some scientists hypothesize it has to do with photosensitivity — the length of the day.”

Strategies to manage infertility

Regardless of the cause, producers can follow management strategies to minimize the seasonal infertility issues.

Because heat is the leading cause of infertility, Gascho recommends using cool cells, misters and ventilation rates to keep ambient temperatures low and sows comfortable. This equipment also must be checked regularly to make sure it is working.

“When sows are too hot, they don’t feel like eating, which makes them not maintain their weight, which makes them not breed well,” he said.

Reduce feed issues by paying attention to quality, especially in the fall when last year’s crop has been stretched to cover until the new crop is harvested. That’s when Gascho sees a spike in feed-related issues like mycotoxins, mold contamination, odor, lower quality and poor nutrition.

Keep sows healthy by providing adequate feed. “Make sure you’re pushing feed intake during stressful times in their lives when they are nursing piglets or you are trying to get them to ovulate,” he added.

To help manage infertility problems, Gascho suggested, “Heat checking twice a day to find [females] that are not bred. Sort them out and get them rebred. This may require ultrasound to check for pregnancy at 4 weeks if that’s appropriate for your farm.”

Focus on animal husbandry

In addition, Gascho recommends closely following good husbandry practices to reduce infertility issues.

“We just have to focus extra hard and make sure we do all of the things that we can control exactly right so we don’t have that on top of this seasonal or inherent thing that always happens,” he said. “Don’t get discouraged because everybody fights this.

“The best way to manage it is to find [unbred females] right away and do something about it so they don’t disappear into your herd and 3 months later, half of them aren’t pregnant.”


Well-managed estrus helps gilts, sows achieve top performance

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Success in pork production starts with a well-managed sow herd that cycles together and on time. Unfortunately, reproductive problems can derail the breeding process.

“One of the biggest [challenges] we battle is making sure we get these gilts cycling and breeding appropriately,” said Daniel Hendrickson, DVM, Four Star Veterinary Service in Farmland, Indiana. “It’s very, very important that we get these gilts off to a good start and get them bred in the herd.”

A successful first parity sets gilts up for successful parities throughout their lifetime, Hendrickson added.

Getting gilts bred

The main reason gilts do not get bred on time is lack of good boar exposure, according to Hendrickson. Boar exposure should start in the gilt-development unit and continue when they enter the sow farm.

“Make sure not only are gilts getting more exposure, but multiple boar exposures,” he explained. “Gilts react differently to different boars because different boars put off different amounts of pheromone.

“And sometimes it takes getting those boars in with the gilts…You’re not going to get very good exposure if you don’t actually get that boar into the pen and let him get in contact with the female.

“Also, gilts [should be] at adequate size, adequate age, adequate body condition. All those things can affect estrus.”

Hendrickson wants gilts bred at 36 to 38 weeks of age and farrow at 1 year of age. He also wants gilts weighing at least 300 pounds. “We want them old enough and big enough so when they do farrow…there are fewer dystocia problems,” he said.

Sow challenges

In sows, Hendrickson sees some seasonal influences on breeding. In late summer, there can be an uptick in sows with delayed estrus. Instead of coming into heat at 5 days post-weaning, they come into heat 6, 7 or 8 days post-weaning. In the winter, he notices another delay in estrus due to the cold weather.

“I believe the main [problem] that affects sows coming out of farrowing is body condition,” he said. “If they go into the farrowing house too skinny, then they come out of the farrowing house too thin. Then the sow’s body goes into a protective mechanism where they know they’re not in good enough condition to cycle like they need to.”

When sows and gilts do not come into heat, Hendrickson said to look for the cause in genetics, management and boar exposure. If the cause is not apparent, then he uses estrus manipulation products.

How to manipulate estrus

“Our ideal situation is to use our hormones or injectables, P.G. 600 and Matrix, at a bare minimum,” he said. But if the cause for estrus delay is not found, then he will use a product to get females in heat and bred.

“The only time P.G. 600 is successful is when a gilt’s either been cycling and quit cycling through her estrus, or she’s never cycled before,” he explained. “That’s when we can use P.G. 600 to stimulate that gilt to cycle that first time and then go from there.”

But if a gilt cycled 7 days ago and the breeding crew missed it, or the gilt didn’t have a very strong heat, P.G. 600 will not change the cycle or help it.

“An example of how I suggest my clients use P.G. 600 is once we definitely know those gilts are of age and the right size, we really stimulate them with multiple boars…for 4-, 5- and even 6-week period…Then we’ll go in and use P.G. 600 to help stimulate those gilts that haven’t cycled within that first window.”

Matrix is a product Hendrickson uses to help organize a group of sows or gilts for possibly batch farrowing or a breeding project. The product delays estrus and works well on females that have been cycling, he added.

To organize a group of gilts where some have and some have not been cycling, he suggested putting the group on Matrix or a progesterone product for 14 days. On the last day or after the last dose, he gives the gilts a dose of P.G. 600. This results in a high percentage of gilts coming into estrus together.


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.



Parasites persist in hog production, especially in niche markets

Environmentally controlled hog facilities eliminated most swine parasites. But Ascaris suum (roundworm) continues to persevere on some conventional farms and frequently on farms for niche markets.

“Bringing pigs indoors onto slatted floors has decreased the overall prevalence of parasites in swine,” reported Laura Carroll, DVM, Four Star Veterinary Service in Elizabethtown, Pennsylvania. “But roundworms can still be a problem in conventional swine units.

“Niche production systems where pigs are raised on pasture or on solid floors with bedding are more prone to developing parasitic infections,” she said. In addition to roundworm, these farms can also face issues with Trichuris suis (whipworm).

Roundworm encounters

Roundworms continue to persist in hog systems because they are difficult to eliminate with common sanitation methods, Carroll explained. The adult female can lay up to 2 million eggs a day — eggs that are resistant to disinfectants and chemicals.

The clinical signs of roundworms may include a cough that is non-responsive to antibiotics, thumping, unthriftiness, poor hair coat, decreased growth rates and presence of adult worms in feces. On necropsy, the most prevalent lesions are milk spots on the liver due to larval migration of worms and detection of adult worms in the small intestine.

“Roundworms can cause decreased growth rates and feed efficiency, and increased mortality — particularly in younger animals,” Carroll said. “They can also cause liver condemnation and decreased carcass value at slaughter plants.”

Roundworm treatment

Carroll recommends routine monitoring for roundworm on all sow farms, both conventional and niche. Roundworm eggs can be detected either in fecal samples or oral fluids.

“In our niche production systems, we detect roundworm eggs in probably 75% of the samples,” she added.

“Depending on the severity of the infection and management goals, we may implement a mass herd deworming program or manage with a strategic control program at critical time points based on prepatent period of the worm and type of anthelmintic used.

“At the sow farm level, this could entail administering an anthelmintic to gilts just prior to introduction into the sow herd and deworming sows 2 to 3 weeks prior to farrowing,” Carroll explained. “Sows can transmit roundworms to their piglets…deworming sows a couple of weeks before farrowing prevents them from contaminating their pigs.”

Several anthelmintic products are available for roundworm treatment and control. Carroll recommends working with a veterinarian to determine which one is most appropriate for their herd.

“Anthelmintics can vary in their spectrum of activity,” she explained. “Some are effective at eliminating the mature (adult) worms but not effective against immature worms. Depending on what’s going on at your farm, one product may be preferred over another. If the appropriate product is used and it is administered at the correct timing interval, then generally we have a good response to treatment.”

In addition, increased sanitation and washing sows pre-farrow to remove feces will help reduce the number of roundworm eggs in the environment which may subsequently infect piglets.

Whipworm issues

Niche production systems also are more prone to whipworms than other hog systems, Carroll said. These parasites are more difficult to detect because females are sporadic egg layers. Infected pigs may not be passing eggs when a fecal sample is taken.

The clinical signs are more obvious than roundworms. Young pigs will have mucohemorrhagic diarrhea and exhibit signs of wasting and lethargy; there will also be increased mortality. Diagnosis on necropsy is the presence of worms in the large intestine and cecum.

“If whipworm eggs are found, we implement treatment with an anthelmintic that’s effective,” she said. “There are less products effective against whipworms than roundworms. So it’s important to discuss with your veterinarian what’s effective.

“We also work hard to clean up the facility as much as possible. Disinfect between groups, but it is still difficult to control because the eggs are very persistent in the environment.” The eggs can remain viable for several years in favorable conditions.

“Control can be challenging based on the facility design, solid floor, pastures,” she added. “We do pasture rotation to minimize how many worms are shed into the environment.”

In herds where whipworms are established, Carroll uses an anthelmintic as a preventative to keep whipworm levels lows. All new groups of pigs added to the herd are treated.

“Prevention is the key to parasite control,” she said. “This goes back to having a good relationship with your veterinarian and making sure you have good control programs in place to minimize the transmission and keep the burden level as low as possible.”



From veterinarian to forensic detective: Solving a mysterious swine disease

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In fall 2019, a client called into Four Star Veterinary Service clinic in Mexico, Indiana, and reported the loss of a lot of sows. Daniel Gascho, DVM, knew the client and headed out to the business site, which was a buying station.

On the way there, Gascho said he had several ideas of what could cause the sow mortalities before arriving. But once he was on site, he knew he was wrong.

“It’s really a good reminder that no matter how many times you think you know all the diseases…Then you get there and it wakes you up and reminds you, ‘Oh, there’s stuff out there you’ve never seen before,’” Gascho said.

Heavy death loss

The first clue of an unusual situation was the high number of mortalities. Gascho estimated a capacity of about 1,000 hogs at the site. About 500 head died in a week.

“If that many pigs are dying that fast, I initially wasn’t thinking a pathogen…because in this country we don’t have many diseases that kill pigs that fast, that many,” Gascho explained.

Then he explored the possibility of other “one-off stuff that they mention in vet school that you almost never actually see.” One was a lightning strike but that didn’t make sense. The other was a toxin in the water or feed.

“But the odd thing was, at the same buying station were multiple species. They were not affected. If it was something in the water, it’s pig specific.”

Next, he checked out the feed for the possibility of botulism, excess ionophores or anything else. But he learned the company bringing in the feed takes the exact same diet to other finishers in the area, and no other site was affected. He also looked at other environmental issues like stray voltage, ventilation failure or pit gases. These were dead ends too.

Forensic investigation

“I felt like a forensic investigator,” Gascho said. “I’m taking feed samples and water samples, checking other species, checking the environment and just really scratching my brain.”

During the first visit to the site, Gascho did report the situation to the authorities in case it turned out to be a foreign animal disease. He also took a full set of samples for testing at Iowa State University’s (ISU) diagnostic lab.

“Of course, they tested for everything under the sun,” he said. “Negative, negative, negative.”

Smoking gun

Gascho was called out to the buying station again. This time, the client had brought in 500 to 600 feeder pigs for a roaster market. The pigs were in perfect health, but half of the pigs died within 48 hours of arrival.

“It was still a disaster at this point,” he said. “I’m standing in a pen…and pigs were literally dying in front of me.”

Gascho again collected sets of tissues from multiple pigs as well as samples of feed, water, etc. He sent everything off to the ISU lab for more testing.

Eventually, the lab noticed an unusual pattern with a pathogen that normally causes disease in horses and not swine. But in every sample cultured from the sick pigs, the same pathogen showed up.

S. zooepidemicus

The mystery was soon solved. Repeated lab tests showed the pigs were dying from Streptococcus equi ssp. zooepidemicus. It was the first diagnosis of the disease in swine in the US.

“It’s just an extremely acute, full-bodied systemic bacterial sepsis, raging inflammation of every organ, organ failure and death,” Gascho explained.

There was a silver lining to the diagnosis. “It was susceptible to about every readily available product we have,” he added. And the pathogen also did not appear to aerosolize.

Gascho and the client were able to depopulate pens, clean and disinfect them, and successfully move new pigs in without any further problems.

Mystery solved.


Inadequate iron supplements lead to subclinical anemia in young pigs

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A field trial evaluating iron supplementation for baby pigs found the typical 200 mg iron shot at birth is not enough. The trial was prompted by a client who wanted to compare different iron supplementation methods, reported Brittney Scales, DVM, Four Star Veterinary Service in Mexico, Indiana.

Using a handheld device called a HemoCue, Scales was able to easily test pig hemoglobin levels during the trial. The device identified subclinical anemia in pigs that were not exhibiting signs of anemia.

“A lot of farmers think if they don’t have pale pigs, then they don’t have a problem with anemia,” Scales said. “We just take an ear prick [with HemoCue] and get a blood sample really quick…and actually have a concrete number to show [the producers] that their pigs are subclinically anemic.”

Field trial results

The three iron-supplement treatment groups used in the field trial include:

  • One 200 mg iron shot at day 1
  • One 100 mg iron shot at day 1 and a second 100 mg shot at day 10
  • One 200 mg iron shot at day 1 and oral iron 7 days pre-weaning

The best outcome came from the 200 mg iron shot followed by oral iron, a protocol her client requested. However, Scales prefers to use a second 200 mg shot at 10 days of age.

“We’re finding in a lot of research that two 200 mg injections are best…with over 70% of the pigs in the optimal range of hemoglobin,” she explained.

The protocol producing the worst outcome was the one 200 mg shot with no iron follow-up. The protocol with two 100 mg shots spaced apart did better, with higher levels of iron.

“When you break up that iron, you get better results,” Scales said. “We found if you do two shots of iron, whether that’s 100 mg or at best 200 mg shots twice, that is where we find the best results in pigs.”

Two-shot iron extra labor

“The first shot is typically within the first day or so of age,” she explained. “Depending on how labor is on the farm, we’d like for the follow-up shot to be over a week past the first shot. I think there are producers who still do just one shot because of labor costs and not having enough labor to pick up those pigs the next time.”

The cost of not following up with the later, second shot may be more expensive than previously thought.

“When the piglet’s blood is low in iron, the red blood cells do not do as well carrying oxygen throughout the body,” Scales said. Adequate levels of iron are required to optimize growth and support a healthy immune system. This means downstream, these subclinically anemic pigs will have lower weights and lower average daily gain than pigs that are not anemic.

“It’s a very costly, well-hidden problem that we don’t even recognize,” she added.


Don’t forget rodent, insect control during biosecurity checks

By Brad Schmitt, DVM, Four Star Veterinary Service, LLC

Biosecurity in a hog operation usually focuses on people and practices like showering in, UV irradiating supplies and filtering incoming air. But rodents and insects can bypass all those critical control points on a hog farm.

Biosecurity is only as good as its weakest link, so pest control needs to be a top priority, whether you’re operating a genetic multiplier, sow farm or a wean-to-finish barn.

Spread disease, damage property

Brad Schmitt, DVM

Rodents and insects act as mechanical vectors to introduce new pathogens into naïve populations from the outside world. These pests will spread dormant viruses from a manure pit to the pig level. The viruses may include porcine reproductive and respiratory syndrome, porcine epidemic diarrhea, sapelovirus and teschovirus.

The pests can also track bacterial pathogens like Lawsonia and Brachyspira (swine dysentery) from pen to pen or crate to crate.

Rodents and insects including ticks, lice and biting flies also propagate diseases like leptospirosis, Mycoplasma suis, swine pox and African swine fever.

Rodent populations, when left unchecked, can cause significant damage to swine facilities. They can quickly deteriorate curtains, walls and insulation, leading to costly, ongoing repairs. In addition, ventilation and temperature controls are compromised when buildings deteriorate, which negatively impacts pig performance.

Feed waste erodes workplace

Feed wastage occurs from rodents eating and digging through feeders and pushing feed into the pit. This may not seem like a big deal, but a large population of rodents can really amplify the issue. In today’s economic climate, every penny counts.

In addition, pest infestations make for undesirable working conditions. In an era where steady farm labor is hard to secure, it’s important to provide an optimal work environment.

If you’ve ever inhaled a swarm of gnats, donned a mouse-inhabited boot or showered-in with cockroaches, you’ll understand the impact that pest control can have on workplace satisfaction.

Setting up effective rodent control

Effective rodent control starts with a rodent audit to assess the situation, sometimes employing the use of infrared surveillance cameras to monitor night-time activity. This process determines points of entry, heavily infested areas and paths most travelled. Once these are determined, bait stations can be strategically placed inside and outside of barns. Spacing and location of bait stations will depend on mouse versus rat infestation in addition to other factors.

Bait-station maintenance should be done on a regular basis, with frequency depending on the severity of infestation. One or two people should be designated to this task, as giving ownership of the process helps with compliance. Ongoing assessment of bait disappearance will determine if bait rotation, supplementation or adjustment of stations is necessary.

Bait rotation important

Bait rotation is periodically used to change the active ingredient, flavor and texture. Doing so prevents monotony and promotes bait intake, which prevents resistance. This can also be accomplished by rotating between anticoagulant and neurotoxin-type baits, especially in cases where the resident population becomes resistant to one mechanism of action. For example, as anticoagulant resistance starts to build, neurotoxin baits are implemented to reduce the resistant population, then anticoagulants again become an effective mode of control.

Just because one particular bait has been effective on your farm in the past does not mean it should be used continuously. Rotation of baits will preserve that efficacy for the long-term future.

While rodenticide can be an effective means of rodent control, prevention must also be practiced. Management practices to eliminate rodent habitats and feed sources are an integral part of keeping the population to a manageable level.

By removing debris and vegetation from the building perimeter and creating a 3-foot-wide buffer zone with coarse gravel, rodents are deterred from entering or burrowing under the barn. In addition, timely clean-up of feed spills and maintaining leak-free bins and augers prevent the rodent population from flourishing.

Insect-control tips

Much like rodent control, an insect-control plan starts with identifying the target and being familiar with its life cycle. Some insects such as flies lay eggs and persist in the environment, while mites and lice require a host to survive.

Insect life cycles and hatch times dictate control strategies and dosing frequencies. When selecting insecticides, look for those with a longer residual effect, reducing the need for frequent application.

Many great insecticides exist, but none are effective at killing all species. For this reason, multiple products and routes of exposure may be warranted. Combinations of premise sprays, injectables, pour-ons and feed-grade insect growth regulators may be used in addition to proper sanitation.

Sanitation is crucial as flies and other insects are attracted to manure. By thoroughly cleaning and disinfecting barns between turns, minimizing manure build-up while pigs are present and keeping pits pumped down to acceptable levels, fewer insects will reside at animal level.



Slaughter checks pinpoint subclinical disease like atrophic rhinitis

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Slaughter checks performed at a packing plant are an underutilized tool for diagnosing subclinical disease, says Brad Schmitt, DVM, Four Star Veterinary Service, Rushville, Indiana.

“We as swine veterinarians do a really good job of recognizing and treating clinical diseases that may be causing an obvious morbidity and mortality in the population,” Schmitt said. “I think we’ve got room to grow in recognizing subclinical issues that may not jump out at us, but they’re still there and affecting finishing performance.”

Atrophic rhinitis shows up

One disease Schmitt sees frequently on slaughter checks is atrophic rhinitis, a disease that was easily spotted by twisted snouts in the past.

“Now it’s become more of a subclinical issue where you might not see it in your live pigs, but essentially, it’s a damage to the filter that’s removing particulate going into the lungs,” he explained. “It’s predisposing those pigs to more pneumonia and respiratory issues.”

During a slaughter check, Schmitt tries to observe at least a couple of loads of hogs. Standing on the processing line, he is able to scan the viscera, cut snouts and determine the types of lesions in pigs. Other pathogens and disease processes that might be detected during a slaughter check include Mycoplasma hyopneumoniae, Mycoplasma hyorhinis and roundworm infestation. These often go undetected while still affecting growth and efficiency.

“It gives us a good idea of what’s going on with the overall population rather than just a few sick pigs that you might normally do a post-mortem on,” he said.

Setting up slaughter checks

Slaughter checks must be scheduled ahead of time with the processor. Schmitt said some packers are more willing to work with veterinarians than others, and Covid-19 fears will certainly play into this as well.

“You are right there on the line interacting with the USDA veterinarian and other inspectors,” he explained. “Sometimes it is difficult to get in there without disrupting a production line.”

The extra effort to organize and perform slaughter checks is well worth it, according to Schmitt.

“I think it’s a very underutilized tool,” he said. “[Because] we’ve had ractopamine removed from our toolbox to help promote performance, I think we need to focus on other ways to do so. And this is one of those ways to fine-tune the health of our animals. Without knowing what kind of subclinical issues the pigs may have, they’re difficult to improve upon.

“We need to do a better job of promoting [slaughter checks] and making them a routine occurrence,” Schmitt concluded.

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.”