Differential Diagnosis of Several Common Types of Piglet Diarrhea in Clinical Practice

Recently, due to the large number of sows in the farrowing phase and a relatively high proportion of first-parity gilts, piglet diarrhea has become increasingly severe. Many pig farms are unable to promptly identify the underlying causes, missing the optimal window for effective prevention and control, which has led to increased mortality and substantial economic losses. We have compiled information on several common types of diarrhea encountered during the farrowing stage and corresponding management strategies, with the hope of providing practical guidance for frontline production.

Diarrhea in piglets within 7 days of age

Piglet red dysentery: Caused by Clostridium perfringens type C, it is transmitted via the gastrointestinal tract. Piglets aged 1 to 3 days often become infected after suckling from contaminated teats or ingesting contaminated material. The disease has an abrupt onset, frequently resulting in acute mortality; clinically, it is characterized by reddish-brown, bloody stools with a foul odor, and it carries a high mortality rate.

Piglet yellow scours: Caused by Escherichia coli, it can occur throughout the year, most commonly in piglets from a few hours to seven days old. Clinically, affected piglets typically present with yellow, mucoid, watery diarrhea, accompanied by acute dehydration, emaciation, and a high mortality rate. Body temperature remains normal, and the animals’ general condition is usually satisfactory; however, as the disease progresses, massive mortality may ensue.

Diarrhea in piglets aged 7–21 days

Coccidial diarrhea: Piglets typically develop diarrhea around 10 days of age, with feces that are often pasty and white, gray, or yellow; watery diarrhea may occasionally occur, accompanied by a foul odor. The incidence is high, but mortality is low. Affected piglets gradually become emaciated, growth stalls, and littermates show uneven development. The loose stools frequently contain bubbles.

Nutritional diarrhea: Often caused by inadequate feed intake or nutritional deficiencies in the sow, it leads to a decline in milk quality after about one week. Meanwhile, the piglets’ digestive systems are still immature, resulting in diarrhea. The disease typically occurs between 10 and 15 days of age and within the first week after weaning. Clinically, affected piglets exhibit lethargy, dull coat condition, and pass yellow, shiny, pasty feces; occasionally, yellow, watery stools may also be observed. If left untreated, this condition can lead to dehydration and death.

Pseudorabies‑induced diarrhea: Often triggered by early‑stage pseudorabies infection, it commonly affects piglets aged 7–15 days. Clinically, it manifests as neurological signs, yellow, watery diarrhea, and sometimes vomiting. The incidence ranges from 20% to 40%, with a mortality rate of 10% to 20%.

Piglet white diarrhea: Caused by Escherichia coli, it can occur throughout the year. Affected piglets pass gray‑white, pasty, watery feces with a fishy, foul odor, which contaminate the perianal area and hind limbs. Sick pigs exhibit reduced or absent feed intake, dehydration, progressive emaciation, and eventually succumb to exhaustion; body temperature remains normal.

Diarrhea from 21 days of age to the period around weaning

Leptospirosis: Caused by Leptospira interrogans, it typically has an abrupt onset, with body temperature rising to 40–41°C. Affected pigs exhibit depression, anorexia, and diarrhea; their skin becomes dry, and jaundice develops in the mucous membranes. Neurological weakness and tremors may appear in the hind limbs. In some cases, hemoglobinuria occurs, producing urine that resembles strong tea. Feces are green and have a foul odor; prolonged illness may be accompanied by bloody stools. Mortality can exceed 50%.

Rotavirus: Caused by rotavirus, it is most common during the cold winter and spring seasons. Clinically, it is characterized by lethargy, anorexia or reduced feed intake, frequent vomiting, watery or pasty diarrhea that may be yellow‑white or dark black in color, and rapid dehydration. A key distinction from transmissible gastroenteritis is that adult pigs are relatively resistant to infection.

Pigs of all ages are susceptible to diarrhea.

Infectious gastroenteritis and epidemic diarrhea: Caused by gastroenteritis virus and epidemic diarrhea virus, both members of the Coronaviridae family, these diseases clinically manifest initially with vomiting, followed by acute watery diarrhea. The feces are often yellow‑green or grayish‑brown and contain curd‑like clumps. Piglets rapidly dehydrate, become emaciated, and exhibit high mortality; even surviving piglets may develop stunted growth, resulting in “stiff pigs.” Pigs at any stage of life are susceptible, and outbreaks typically affect entire herds, leading to heavy losses.

Recommendations for Preventing and Controlling Diarrhea

1. For bacterial diarrhea, neomycin, gentamicin, flufenicol, colistin, cefoperazone sodium, and quinolones are often effective. In addition, maintaining optimal rearing conditions and treating both the mother and her offspring simultaneously are essential for achieving favorable outcomes.

2. For nutritional diarrhea, it is necessary to improve the sow’s nutrition and formulate a balanced diet; additionally, microbial preparations and intestinal regulators can be added to the feed or drinking water of both sows and piglets.

3. For stress‑induced diarrhea, the primary step is to eliminate the underlying cause and minimize stress in the pig herd. Administering a multivitamin supplement in the drinking water prior to group transfers or feed changes, along with maintaining an appropriate temperature and dry conditions in the pig house, can help facilitate recovery.

4. For viral diarrhea, the first priority is to select a safe and highly effective vaccine targeting the prevailing strain, employing a live‑plus‑inactivated vaccination regimen. This ensures comprehensive herd‑wide immunization during the annual peak season, as well as maternal booster vaccinations prior to farrowing. In addition, a robust biosecurity system and sound management practices are essential to achieve optimal disease prevention and control.