2016 Projects

Study Name: Effects of Preweaning Factors on Sow Lifetime Productivity
Principal Researcher:
Dr. Mark Knauer, North Carolina State University
Key Points:

  • Cross–fostered gilts were 2.45 percent less likely to farrow litters of their own.
  • Increasing weaning age by one day increased a gilt’s subsequent reproduction by 0.185 piglets per year.
  • Greater piglet birth weight increased the proportion of gilts that farrowed a litter.
  • Greater piglet preweaning growth improved the proportion of gilts that farrowed a litter as well as lifetime reproductive throughput.

Summary: The objective was to associate preweaning factors in gilt multiplication with the subsequent lifetime productivity in commercial sow herds. Sows were farrowed at two multiplication farms in North Carolina between May and December 2013. Preweaning data was collected on 12,943 gilts and their birth litters, including total number born, number nursed, number weaned, litter sex ratio, cross–foster status, weaning age, birth dam parity and individual traits such as birth weight, weaning weight and preweaning average daily gain. Gilts were traced from finishing facilities to commercial sow farms in eastern North Carolina. Of the 12,934 gilts individually tagged at birth, 6,249 entered a commercial sow farm. When including all gilts tagged at birth in the analysis, a lower litter size at birth, gilts not cross–fostered, greater piglet birth weight, piglet weaning weight and preweaning average daily gain were associated with increased ability to remain to parity 1. Yet only a lower litter size at birth tended to increase the ability to remain to parity 4. When including all gilts that were delivered to commercial sow farms, a greater weaning age, weaning weight and preweaning average daily gain were associated with more total pigs farrowed through four parities. Similarly, when including all gilts that were delivered to the sow farms, a greater weaning age, weaning weight and preweaning average daily gain were associated with more total pigs produced per day of herd life through four parities. Results suggest gilt multiplication farms should not cross–foster gilts, increase weaning age to 25 days, increase piglet birth weight and preweaning average daily gain to enhance subsequent sow lifetime productivity. 

2015 Projects

Study Name: A Physiological Test for Sow Longevity
Principal Researcher:
Dr. Billy Flowers, North Carolina State University
Key Points:

  • Farrowing rates and pigs born alive were similar between gilts responding to PG600 and early boar exposure.
  • Vulva redness and swelling in response to PG600 administered as early as 140 days of age is an accurate predictor of sow longevity.
  • Sixty-five percent of the gilts exhibiting vulva response within 7 days of the PG600 administration were still in production after three parities.

Summary: The objective was to determine whether vulva reddening and swelling in response to low levels of gonadotropins given to gilts at an early age could provide a screening tool to estimate potential longevity. Results demonstrated that 140-day-old gilts exhibiting any degree of vulva reddening and swelling in response to 200 IU of PG600 had retention rates similar to gilts that exhibited estrus in response to boar exposure. By the end of the third lactation, 62 percent of females from both groups that entered the farm as replacement gilts were rebred. There was no difference in farrowing rates or number of pigs born alive between those given low levels of PG600 and their counterparts exposed to boars at 140 days of age. Using low levels of PG600 and subsequent monitoring of gilts for about 1 week has good potential as a prospective physiological test for sow longevity. In some multiplication systems this option may be more practical and safer from a biosecurity perspective than providing direct boar contact.

Study Name: Enzyme Technology to Optimize Fibrous Feed Ingredients in Swine Diets
Principal Researcher:
Dr. Eric van Heugten, North Carolina State University
Key Points:

  • In DDGS-based diets, neither adding endo-1, 4-β-xylanase (Xyl) nor the feeding method improved the total tract or ileal digestibility; thus, Xyl did not increase available energy or nutrients.
  • In wheat middlings-based diets, Xyl improved the total tract digestibility of energy and nitrogen (N), as well as the ileal digestibility of energy and Neutral Detergent Fiber (NDF).
  • Pre-steeping DDGS or wheat middlings with enzymes and feeding in liquid form did not improve the nutritional value of either feedstuff.

Summary: Co-products of biofuel production are a short-term solution for pork producers to control feed cost, but the co-products are high in fiber, which decreases nutrient digestibility in pigs. Applying fiber-degrading enzymes and liquid feeding may help improve the nutritional value. The objective was to evaluate the effect of endo-1,4-β-xylanase supplementation (Xyl), feeding method (dry or liquid) and feedstuff (corn-based distiller’s dried grain with solubles (DDGS) or wheat middlings) on the digestibility of energy and nutrients, intestinal morphology, cecal pH and volatile fatty acids concentrations in growing pigs. For the study, we placed 64 pigs in individual pens and randomly assigned eight dietary treatments. Diets were fed for 16 days and then pigs were euthanized. Under the conditions of this experiment, the liquid feeding method and the application of Xyl demonstrated limited potential to enhance nutrient digestibility in pigs fed corn DDGS-based diets. However, supplementation of Xyl in wheat middlings-based diets improved the ileal digestibility of gross intake energy (GE) and NDF and fecal digestibility of GE and N. Liquid feeding as a pretreatment did not enhance the nutritional value of wheat middling-based diets.

Study Name: Effect of Regrinding Ingredients on Pellet Quality, Performance and Profitability
Principal Researcher: Mark Knauer
, North Carolina State University
Key Points:

  • Adding 30 percent dried distillers grains with solubles (DDGS) improved pellet durability.
  • Regrinding soybean meal improved pellet durability, but regrinding DDGS did not.
  • Neither regrinding DDGS nor the level of pellet fines impacted finishing pig performance.

Summary: Two experiments evaluated the effect of regrinding major feed ingredients on pellet quality and pig performance. The first study evaluated whether adding DDGS or whether regrinding soybean meal or DDGS improves pellet quality. Diets consisted of two DDGS levels, two DDGS particle sizes and two soybean meal particle sizes. Each batch was sampled to determine pellet quality, as measured by pellet durability index (PDI) and modified PDI, which was designed to simulate moving feed from the mill to the barn. For experiment No. 2, the goal was to determine if regrinding DDGS or reducing pellet fines improved finishing pig performance. This involved four treatments, with two DDGS particle sizes and two levels of pellet fines. Mixed sex pigs were housed in a curtain-sided, mechanically ventilated and slatted facility. Diets were delivered and pen feed intake recorded. In study No. 1, adding 30 percent DDGS to swine finishing diets improved modified PDI by 9.5 percent. Regrinding soybean meal improved modified PDI by 4.7 percent, but regrinding DDGS had no effect. In No. 2, neither regrinding DDGS nor the level of pellet fines impacted average daily gain, average daily feed intake or feed efficiency.  

2014 Projects

Study Name: Volatile Organic Compound Removal from Swine Facilities via Adsorption
Principal Researcher:
Dr. Praveen Kolar, North Carolina State University
Key Points:

  • A simple, inexpensive, and effective technology is needed to mitigate swine odors.
  • Biochar is capable of adsorbing odors from swine operations.
  • Due to intensification of biomass energy, large amounts of biochar will likely be available.

Summary: We evaluated biochar derived from pinewood, swine manure and coconut shells as an adsorbent to mitigate p-cresol as a model odorous volatile organic compound (VOC) from swine lagoons. Specifically we investigated how much p-cresol can be removed using biochar, how fast biochar can adsorb p-cresol and how much will it cost to remove a gram of p-cresol. The data show that biochars can potentially remove 6 to 30 mg/g of p-cresol within 100 to 1,440 minutes, depending on the type of char employed. Considering the fact that p-cresol and other VOC concentrations in swine lagoons are normally less than 5 mg/L, biochar-based adsorption may be considered a viable alternative for treating swine wastewater. Based on predicted biochar production by the bioenergy industry, estimated treatment cost is about $0.79/Kg of biochar.

Study Name: Determine Salmonella serovars and identify risk factors in a commercial swine farm
Principal Researcher:
Dr. Sid Thakur, North Carolina State University
Key Points:

  • Twenty-two different Salmonella serotypes were found in pig and environmental samples on-farm and at slaughter—Salmonella Typhimurium was the most common.
  • Results show certain serotypes and strains are present in pigs and their environment throughout the pork chain, irrespective of the farm or production stage.
  • The environment plays a clear role in the persistence and dissemination of Salmonella to pigs at farm and slaughter.

Summary: The purpose was to determine the Salmonella serotypes present in pigs and their environment on commercial swine farms, also to characterize and compare Salmonella from different sources. Samples were obtained from pigs and their environments from 30 commercial swine farms. The study followed 10 groups from farrowing to slaughter, sampling the pigs, farm environment, pig carcasses and the slaughter environment at various production stages from October 2008 to December 2010. Salmonella isolates were sent to the National Veterinary Services Laboratories to determine the serotype. A representative Salmonella subset was genotyped to determine the specific strain or fingerprint profile at different production stages. Comparisons were then made between strains and serotypes found in pigs and the farm environment. The study also compared fingerprint profiles of Salmonella isolated from carcasses with the farm isolates for the same pigs. Genotyping revealed 47 clusters containing 100% similar Salmonella isolates among pigs and their environment, including feed, water, soil, lagoon, floor swabs and slaughter lairage, within and between cohorts. Another 41 unique strains also were detected.