Preweaning mortality is influenced by several factors affecting the sow and her litter. These factors include disease, environment, neonatal pig care, equipment design and nutrition. If we assume the sows are healthy and located in a comfortable environment at farrowing, then the piglet becomes the likely focus to reduce death losses. On most farms, the majority of preweaning mortality occurs in the first 24-48 hours of birth, the time to apply the majority of our efforts to have a positive response.

 

Case Study No. 1

Weaned pigs at a 1,200-head, farrow-to-finish, three-site operation are moved to an off-site nursery and finisher. The farm follows a basic sow vaccination program, which includes vaccinating all sows three and five weeks prefarrowing with a commercial E. coli vaccine. This winter, the farm’s preweaning mortality jumped about 5% and was not showing any signs of improving.

Earlier this winter, the farm staff expressed concerns about an unresponsive diarrhea affecting piglets at 2 days of age. Piglets were treated at Day 1 processing with an oral antibiotic, but were not responding. The diarrhea affected about 30% of the 2-day-old pigs and lasted for 2-3 days, dehydrating the pigs and making them weak.

I gathered information about the scours problem and euthanized some pigs showing clinical signs of diarrhea. I submitted a complete set of tissues from four pigs to the diagnostic lab.

The lab results came back with a diagnosis of rotavirus and Clostridia perfringens Type A, and not an E. coli bacteria as suspected by farm staff.

The farm initiated a sow vaccination program for rotavirus, changed the antibiotic used on the piglets at Day 1 processing and improved washing and sanitation procedures of the farrowing crates. When I returned to the farm two months later, the newborn pigs were not showing any signs of diarrhea. Weaning weights were 1.6 lb. heavier, on average, and preweaning mortality had decreased to 11%.

 

Case Study No. 2

A 750-sow, breed-to-wean farm called because they were having difficulty maintaining weaning average at last year’s target. This farm was negative for porcine reproductive and respiratory syndrome but positive for Mycoplasma pneumonia. Total pigs born per litter and number of liveborn pigs had actually increased since last fall.

But piglet survivability had declined to 80%, meaning preweaning mortality had also increased, leaving the farm with less weaned pigs per litter.

I conducted a walkthrough of the sow unit along with the owner. Most of the litters appeared healthy and very few had been treated for scours. The older pigs looked fine.

However, in new litters I found several weak pigs, some piling under the heat lamps and others already recorded on the death loss chart. I also learned that the regular person in charge of farrowing was off the past two months on maternity leave. The fill-in person wasn’t spending much time attending farrowings because of other farrowing duties.

I submitted some diagnostic samples and the lab cultured a non-hemolytic E. coli and Bordetella bronchiseptica (from the lungs). I reviewed the lab results with the owner and told him these diseases were likely not the cause of the preweaning mortality problem. Most relevant was lack of assistance to sows at farrowing time, not warming or drying off piglets at birth, not verifying all piglets nursed early to receive colostrum milk, inconsistent heat lamp adjustment, not placing the mats under heat lamps after washing, not resetting the room temperature controller for sows that are farrowing and overall lack of attention to detail.

The owner contacted the employee on maternity leave to make up a checklist for sows in labor and the first week in lactation. A new employee was assigned to this task. When I contacted the owner three weeks later, he said that preweaning mortality was dropping noticeably. He estimated that the weaning average that week was up by half a pig per litter.

Preweaning mortality can be influenced by many factors, including disease, environment, nutrition and human influence. It takes a synergistic influence in all of these areas to drive up piglet survivability in a farrowing house. This can have a significant impact on pig throughput. A 3% mortality in the farrowing house is much easier to recover than it is in the finishing phase. Consult with your veterinarian today to discuss methods to improve piglet survivability on your farm and learn how to wean more pigs per sow.