Summertime coccidiosis challenges in pigs

The hot, humid days of summer often bring the challenge of coccidiosis in pre-weaned piglets in the farrowing barn, but that challenge has now become more prevalent year-round, according to Dr. Laura Bruner with the Swine Vet Center in St. Peter, Minn.

In the last couple of years, coccidiosis in young pigs has been a hot topic because the disease management tools available in the past have not been available due to supply chain issues, she added.

Typically, the classic presentation of a coccidia infection on a sow farm is a yellow and pasty diarrhea that develops around 7–14 days of age in piglets. The diarrhea is very noticeable – it’s thicker, not a watery diarrhea that would go through the flooring – and it builds up in the crate and environment, she explained.

Coccidiosis generally does not cause mortality in piglets but does cause significant loss of gain – so it wouldn’t be surprising for pigs with a heavy coccidia infection to weigh 1–2 lbs. less at weaning than uninfected pigs. “It definitely hurts the gain of the pig, and when you talk about gain in pigs, that’s everything. How fast can I get them to market?” Bruner said.

Along with coccidia challenges, secondary infections are possible because enteric cells of the gut become disrupted, which allows other enteric bacterial and viral pathogens to invade the intestinal lining. These secondary infections are more likely to cause mortality, especially if the pig becomes really chronic.

Prevention and control

It takes seven days for coccidia to mature and sporulate oocytes, which are then shed allowing infection to spread. Anti-coccidial or anti-protozoal medications such as ponazuril (trade name Marquis) have been developed for other animals such as horses and companion animals that kills coccidia at the right time in its life cycle so sporulation does not occur.

With a valid veterinarian-client-patient relationship (VCPR), veterinarians can recommend these medications for use in piglets. Oral administration of ponazuril to piglets starting on day 3 would break the sporulation cycle and eliminate coccidia from the farrowing unit environment.

However, due to supply issues, product availability is low and what is available typically goes toward horses. This has left the swine industry without many preventative tools, Bruner said.

Given that coccidia are exceptionally hardy organisms that build up in the environment, if a producer never has a way to decrease coccidia shedding or decrease the environmental load in their barns, it just continues to build up. “I think that’s part of the reason why we’ve more recently had problems in the winter, when we wouldn’t typically have them, because we haven’t been able to knock down that cycle,” Bruner added.

There are other products developed for cattle and poultry species that have been tried under the VCPR provisions that allow the use of medications off-label, but those products are not coccidiacidal – so they don’t kill the coccidia – but are coccidiostatic, meaning they inhibit coccidia’s life cycle but don’t eliminate it.

Generally, coccidiostats need to be fed continuously to keep the coccidia at bay so disease can be prevented until the pigs are weaned off the farm. Bruner added that this option is labor intensive and not that effective, since the piglets really need to consume the coccidiostat for the entire period they’re in the farrowing unit, meaning the return on investment for this practice is not good.

By providing a coccidiostat, Bruner said clinically, the disease effects get better but the coccidia are not gone. “I think all it’s really doing is decreasing the environmental load to give you a chance to sanitize your way out of it,” she said, leaving the industry kind of stuck between a rock and a hard place.

Whitewashing

To sanitize against coccidia, historically, producers would use a very strong bleach or ammonia solution when cleaning a farrowing room between groups, but those solutions can create human safety concerns.

Instead, producers have moved to whitewashing – spraying hydrated lime and coating the crates and all of the contact areas that piglets would touch – to try to eliminate coccidia with a really high pH solution.

Bruner said whitewashing has been fairly effective, but the right amount of hydrated lime needs to be applied in a thick coating on all contact surfaces for it to work well.

With coccidia challenges extending throughout the year, producers may have to start applying whitewash earlier in the year, such as in March or April, and not wait until June or July when it gets hot and there already are coccidia problems, Bruner said.

Another key step, Bruner said, is to routinely inspect sanitization efforts – after sanitizing the room, ask “how good of a job did I do?” and then after the room is sprayed with whitewash, ask again, “how good of a job did I do?” Inspect what you would expect to see and how well you covered contact surfaces.

Post-weaning

After weaning, coccidia is less of a problem, but if secondary infections were present in the farrowing crate, there can be lingering effects in addition to other post-weaning stresses.

There is a portion of the population that doesn’t recover from a coccidia infection, but for the most part, it is mostly a weight-loss issue, depending on how fast the pig’s intestinal tract can heal. Any post-weaning infections with rotavirus or E. coli will just add fuel to the fire of health challenges.

According to Bruner, the key to managing coccidiosis is knowing when it will be at its peak and getting ahead of environmental contamination. Coccidia enter the farrowing house from animals – typically from gilts that may be shedding – so in theory, batch systems would have fewer issues.

Once coccidia gets into a farrowing house, it is hard to get out, but staying on top of sanitization practices and inspecting procedures to ensure full coverage will help minimize any health and performance challenges.

APP focuses attention on finisher unit biosecurity

While biosecurity remains the best option for managing Actinobacillus pleuropneumoniae (APP) outbreaks in swine finishing barns, the recent APP outbreaks in the Midwest has spotlighted biosecurity gaps in this phase of production, according to Swine Vet Center veterinarian Dr. Ethan Spronk.

APP is a gram-negative bacteria that requires swine as its host. There are 15 known serotypes, with serotypes 1, 3, 5 and 7 the most common, Spronk said, noting that serotype 15 is a newer strain currently challenging the industry.

Clinical signs of APP include sudden death in finishing hogs, especially in the mid-weight to early marketing periods, with occasionally bloody discharge from the nose. Prior to death, pigs experience respiratory distress, open-mouth breathing or gasping for air. On necropsy, lungs are found with dark purple abscesses with adhesions. Death is often caused by cyanosis – decreased oxygen supply to tissues – from the adhesions and abscesses in the lungs, Spronk noted.

APP develops very quickly once it starts, he said, and it is usually set off by a stress event – poor ventilation, high outside temperatures, other viral or secondary challenges or outbreaks, as well as sorting and/or loading for marketing purposes.

APP is spread on fomites, such as all the equipment – i.e., boots, coveralls, sorting panels, shockers, etc. –used for sorting/loading or mortality removal, he said.

Treatment of APP is a whole-herd or pen antibiotic injection, Spronk said, noting that products that have been the most successful include enrofloxacin (Baytril® or Enroflox®), tulathromycin (Draxxin®) and ceftiofur (Exenel®/Naxcel®). See product labels for use directions, etc.

There are also autogenous vaccines that offer cross protection among APP strains, he noted.

Biosecurity protocols

The recent APP outbreak is focusing attention on finishing unit biosecurity, Spronk said, explaining that due to porcine reproductive and respiratory syndrome (PRRS) and porcine epidemic diarrhea, a high degree of attention has more typically been placed on sow farm biosecurity, but finishing barn biosecurity practices haven’t gotten the same attention until now.

At least nine central Iowa pork production systems have been affected, but there doesn’t appear to be a common link among the systems. Iowa State University has been diligently seeking to better understand the epidemiology of the current outbreak as it seems to be moving differently through pork flows compared to prior outbreaks with more lateral breaks versus the usual sow farm flow outbreaks.

One concern identified in Iowa, Spronk said, was the presence of rendering trucks on affected premises, or epidemiological links were identified to positive sites that did have rendering trucks, a common service provider or marketing crew.

These findings highlight the need for good biosecurity on swine finishing sites, Spronk said. Barns should be set up with a “clean/dirty line” at entry, and personnel should wash hands and change boots and coveralls on entry to a barn. When doing chores in barns, personnel should think through how they move through the barns, working the smallest, healthiest pigs first and moving toward the oldest pigs, he added.

Separate equipment and clothing should be used inside the barn when removing mortalities, with dedicated sleds/carts outside the barn to move dead animals to the rendering box. Mortality collection points should be far enough away from buildings to avoid the potential for cross traffic with where the rendering truck would travel, Spronk said.

He suggested that adopting composting or incineration could be better options for mortality management instead of rendering to avoid disease spread, especially as the industry considers the potential for foreign animal diseases such as African Swine Fever (ASF).

Spronk noted that if producers experience sudden or high death loss in their finisher units, it is important to contact a veterinarian because it is critical to determine which disease(s) are present. While ASF has a different pathogenesis, it shares some visible symptoms with APP, so it needs to be ruled out. Also, PRRS and influenza can be coinfections with APP that can trigger an APP outbreak.

According to Spronk, in the past, APP would have been flow dependent, so on an APP-positive sow farm, those pigs would get exposed in the farrowing crate and then when a stressor hits them in finishing, a disease outbreak would occur. A lot of systems moved to eliminate the virulent APP strains because outbreaks would be so costly producers couldn’t live with them.

Depopulation is the best way to clean it out completely, he said, noting that the cost of medication programs to control APP is expensive, so removing the positive sows from a system is the better option.

APP has been extremely costly to the industry, with the highest value mortality happening right before marketing. Once it gets into a system, it is harder to stop APP, Spronk concluded, leaving the best option to be prevention through good biosecurity and keeping the disease out of a pig production system.