Post-weaning diarrhea in pigs weaned without medicinal zinc: risk factors, pathogen dynamics, and association to growth rate

Abstract

Background Porcine post-weaning diarrhea (PWD) has reemerged as an important topic in pig production, as common control strategies based on prophylactic use of antimicrobials and zinc oxide have been deemed unsustainable. The objectives of this study were to estimate the cumulative incidence of porcine post-weaning diarrhea with different etiologies in production systems weaning without zinc oxide and prophylactic antimicrobials, to assess risk factors for post-weaning diarrhea, and to estimate the impact of post-weaning diarrhea on growth rate. A cohort study was conducted at two commercial indoor producers weaning without medicinal zinc oxide and prophylactic antimicrobials. Results Piglets were included at birth (n = 300) and 272 survived until weaning. After insertion to the nursery units, the piglets were clinically examined every day for 14 days, and rectal swabs were collected and analyzed for enterotoxigenic Escherichia coli (ETEC) and rotavirus A. The cumulative incidences of PWD the first 14 days after insertion to the nursery units were 41.8% (CI 33.6, 50.4) and 51.1% (CI 42.3, 60.0) at the two producers, respectively. We found a low incidence of cases associated to ETEC, and detected a substantial proportion of cases associated to rotavirus. We observed a biphasic pattern in the assumed etiology with rotavirus occurring first, and then a shift towards cases associated to ETEC/non-ETEC hemolytic E. coli. Being offspring of older sows was a protective factor for the development of PWD (Hazard ratio = 0.88 [CI 0.78, 0.99] per unit increase in parity of the dam). Low birth weight reduced the post-weaning growth rate (− 5.2 g/day [CI − 7.5, − 2.9] per 100 g decrease in birthweight) and increased the hazard of developing PWD (Hazard ratio for birthweight below 1100 g: 2.30 [CI 1.41–3.74]). The combined effect of having diarrhea for 2 days or more and receiving antimicrobial treatment was associated with an increased average daily weight gain. Conclusions This study suggests novel insights regarding pathogen dynamics and risk factors for PWD in productions not using prophylactic antimicrobials and medicinal zinc. The findings may have important implications for both antimicrobial usage and prevention strategies.

Oral and Parenteral Vaccination against Escherichia coli in Piglets Results in Different Responses

“…Additionally, the use of zinc oxide has been banned without the possibility of a moratorium in June 2022 due to environmental problems resulting from the accumulation of this metal in areas where pig manure is used as an organic amendment in agriculture or where there is accidental or intentional dumping of manure. The enteric health situation in piglets has worsened markedly in the last 5 years, with increasing outbreaks of diarrhea and mortality in nurseries [ 7 ]. Not only has there been a worsening of piglet intestinal health, but there has been a re-emergence of diseases such as porcine streptococcal disease caused by Streptococcus suis , which could be due to a loss of intestinal integrity as proposed in a model of intestinal translocation of Streptococcus suis bacteria [ 8 ].…”

Swine enteric colibacillosis: Current treatment avenues and future directions

“…Pig producers have been successful with weaning at an early age with limited signs of gastrointestinal disease shortly after weaning ( 25 , 26 ). In fact, it has been described that feed containing between 2,400 and 3,000 ppm of zinc reduces diarrhea and mortality, and improves the growth of piglets.…”

Review on Preventive Measures to Reduce Post-Weaning Diarrhoea in Piglets

“…Although PWD is a multifactorial disease [ 10 , 11 , 12 ], enterotoxigenic E. coli ( ETEC ) expressing the fimbriae F4 and F18 are considered as main etiological agents [ 11 , 13 ]; therefore, challenge studies with these two bacteria are models often used to investigate the impact of strategies to prevent PWD; these type of studies, as well as non-challenge studies, are included here. On the other hand, no association between the detection of pathogens (ETEC F4 and F18, Lawsonia intracellularis and Brachyspira pilosicoli ) and diarrhoea status of individual pigs, or between the detection of pathogens in a pen and diarrhoea floor pools has been reported [ 14 ].…”