NCSU Extension Swine Husbandry 2003
A more printable version of Swine News in Adobe Acrobat.

December, 2003 . Volume 26, Number 11

The Science of Odor


The Carolina Swine Nutrition Conference, held October 29, 2003, in the Research Triangle Park, opened with a discussion of the problems of the baby pig. Dr. Jeff Hansen of Murphy-Brown LLC talked about the challenges surrounding lightweight baby pigs. He noted that as sow productivity increases, the opportunity for starved-out piglets also increases due to lack of feeding space on the sow. The majority of pre-weaning mortality occurs during the first three days postpartum, and it is reasonable to imagine that the lightweight pigs may be at highest risk. Dr. Hansen suggested that there may be an opportunity to save pigs weighing less than 2.5 pounds by moving them to an intensely managed small pig center. Dr. Robert Harrell of North Carolina State University continued the discussion of small pigs and focused on nutrition. His presentation keyed on the composition of sow milk and the possible energy sources that can be used to feed two- to three-day-old pigs. Dr. Rafael Cabrera of Ralco-Mix Products talked about his experiences in applying the technology discussed by the previous speakers in the form of a "small pig center." This facility would house two-day-old healthy and viable pigs, and pigs would be fed a high quality milk replacer. His research showed that with intensive management and high levels of sanitation, these pigs could be raised successfully.

Dr. Doug Webel of United Feeds provided a critical evaluation of phytase products. He discussed the characteristics that are essential in a phytase enzyme for it to provide optimum functionality in the animal. Novel enzymes, primarily of bacterial origin, may function better under gastric conditions due to their pH optima and resistance to breakdown by proteases, he said. With a more efficient release of phosphorus from phytase, he estimated that it may be possible to more than double the amount of phosphorus released. These novel products are not approved yet for use.

Dr. Theo van Kempen of North Carolina State University discussed the Re-Cycle project, which aims to achieve zero-waste swine production while maintaining profitability. In this system, swine feces are collected from a belt system located under the pigs, while urine flow is diverted and collected separately. Swine manure is subsequently gasified, which results in gases that can be used for ethanol production and ash. The ash has been evaluated as a mineral source in pigs with success. The urine stream could be used as fertilizer (primarily nitrogen) or it could be treated to trap ammonia. This system may provide a cost-effective method of manure disposal in areas with intensive swine production, such as North Carolina.

Dr. Allen Harper of Virginia Polytechnic Institute and State University provided an overview of using hulless barley and other non-traditional ingredients to feed swine. Barley is a non-traditional ingredient that has agronomic advantages, but production in the Southeastern part of the U.S. has declined. Efforts to improve the value of barley initially centered on improving yield and test weight. Feeding high-test-weight barley in pelleted diets has resulted in good swine performance when energy density of the diet was properly adjusted. Another more recent method to improve barley has been the development of hulless barley. Swine feeding trials with hulless barley have demonstrated improvements in performance, compared to conventional varieties, which may be related to lower fiber content and increased digestible energy.

Dr. Roger Campbell of United Feeds and Ausgene International addressed the question of whether there would ever be a reliable and practical growth model. He discussed the reasons why simulation models have generally not been well accepted. One of the biggest challenges is to properly define the genotype being fed. Even when that has been accomplished, other factors such as health, stocking density, temperature, etc., must be taken into account. Further, some estimate of economic effects should be included. The cost of model development and strategic management (implementation) are additional factors that have hampered the development of successful models. Dr. Campbell further described the areas in which we have sufficient information and those in which we lack knowledge to allow for development of a functional model.

The Carolina Swine Nutrition Conference is sponsored by the Carolina Feed Industry Association, in cooperation with North Carolina State University and the North Carolina Department of Agriculture and Consumer Services. For further information, refer to the Carolina Feed Industry Association web site at

Eric van Heugten


The biggest challenge for the animal industry is likely air quality. Odor may affect the quality of life of those down-wind from a swine farm. Ammonia may contribute to eutrophication. Dust may affect the health of both animals and people, especially in facilities.

Air quality has received attention in courts, in legislation, and in many research projects. However, the current picture of how large the problem is and what can be done about it is not very clear. The reason is that the effects of animal production on air quality are hard to quantify and, therefore, hard to control.

Odor, for example, is a subjective observation. Some people like one perfume; others hate it. Some people can smell a flower from a yard away; others have to stick their nose in it to smell anything. These differences between people become even more complicated because such conditions as a runny nose can affect our odor perception drastically. Fortunately, that one condition is easy to check for. However, spicy food, a person's mood, exposure to other odors, etc., all affect odor perception. Under well-controlled research conditions, this variability in odor strength can result in researchers' inability to distinguish sources of odor that are chemically up to two-fold different. In real life, differences many-fold larger may not be noticed.

This situation poses a major hurdle for odor legislation and research. If people can't tell that something is better, even when the emission is halved, based on chemical measures, then why bother? Where swine odor is concerned, the problem becomes even worse because emotional issues are involved.

The alternative is to chemically analyze odor. By using equipment like gas chromatography, it is possible to quantify the compounds that make up odor. For swine odor, there are probably 30 to 50 compounds of major importance to odor perception. However, the total number of compounds likely exceeds 200. This large number poses its own challenges. Currently, there is no agreement as to which compound is the major one causing the strong odor. Also, there is no agreement on how the different compounds or even classes of compounds interact with each other to result in an odor sensation.

The underlying reasons for this are several. First, it is difficult to assess odor, as it requires the human nose. Second, it may well be that odor is not odor. Pigs in Minnesota don't quite smell the same as pigs in North Carolina. But as long as there is no agreement, we will simply end up with large sets of numbers and no conclusions as to what they mean.

For compounds like ammonia, dust, and methane, the problem is more manageable in theory, as they are relatively easy to measure (although there is still no consensus on what methodology to use). In practice, though, emission values that are now available are only rough estimates. North Carolina State University published a report in which different techniques for measuring ammonia were evaluated at the same site, and agreement among the techniques was very poor.

Other factors that cloud on-site measurements are that several sources of odor exist, each of which is hard to characterize. First comes the house. If this is mechanically ventilated, it is relatively easy to measure airflow through each fan and to sample this air. However, if it is naturally ventilated, then it is virtually impossible to quantify how much air moves through the building. Air speed may vary in different parts of the building; air may even enter and exit on the same side of the building, depending on wind. And the air inlets can't be ignored, as background levels of ammonia, methane, and dust should be corrected for.

Emissions will vary greatly throughout the day, as temperature, airflow, and animal activity fluctuate. Over time, animals grow, eat different diets, and increase fermentative activity with age: emission again changes. Seasons change, and emissions change.

As far as odor from manure storage is concerned, we see the same problems here as we do in a naturally ventilated house. It is virtually impossible to measure accurately how much air moves across the surface of a lagoon and thus how much odor or ammonia this air picks up: the airflow is different in different parts of the lagoon, throughout the day, and throughout the year.

Odor from land application is probably the most difficult to measure. Large surfaces need to be considered, as well as very drastic changes in emission over time and tremendous fluctuations due to sun, rain, soil conditions, etc.

Thus, to obtain good-quality data on air-quality issues on swine farms, it will be necessary to measure in all seasons, at all times of the day, and under all possible housing, management, and nutrition regimens. Clearly, each farm is unique when it comes to air quality, and each week the outcome of measurements will be different. This is exactly why the North Carolina Division of Air Quality has such difficulty substantiating claims from neighbors of farms that odor is affecting the quality of their lives.

The Environmental Protection Agency also has recognized the challenges that air-quality regulations will pose. For this reason, it has announced that it is negotiating with farmers to join an effort to quantify air-quality issues. The general concept behind this proposal is that farmers agree to participate in an air-quality monitoring effort by supplying both funds (levied through a fine) and access to farms (28 total across the country, covering all species). Based on the data to be gathered at the 28 test farms, all farms participating will subsequently be regulated under existing rules (maximum emission of ammonia and hydrogen sulfide is 100 pounds per day, which for ammonia is about average on a farm with 3,000 grow/finish pigs, if available data are accurate). All farms will have to apply for all applicable permits. Farms that exceed emission limits will have to notify authorities and install approved methods for reducing emissions.

However, there is an incentive for farms to participate in the program. It is that while they are part of the program, they cannot be sued under the Clean Air Act or the CERCLA Section 103 hazardous substance reporting, as long as the rules are followed.

Efforts like this underscore the importance of keeping air quality in mind, but they also underscore the fact that the current lack of knowledge hampers efforts to reduce and control emissions. Data to be gathered on the 28 farms over 22 months will help, but as this effort covers five species of animals and several distinct production systems, it is questionable whether it will go far enough to help our understanding.

Theo van Kempen


The 2003 North Carolina State Fair exhibited a great set of 329 market hogs.

The Junior Market Barrow Show was divided into 14 classes and three divisions with 201 pigs weighing between 230 and 280 pounds. The show was held Friday morning, October 17, beginning at 9 a.m.

Class winners in Division 1 were Abi Earle, Katelyn Earle, Garrett Jones, Adriene Locklear, and Daniel Sharp. Daniel Sharp drove the Division 1 Champion and Katelyn Earle had the Reserve Champion.

Division 2 class winners were Abi Earle, Tyler Lamm, Heather Ogilvie, Emma See, and Dale Winstead. Heather Ogilvie drove the Division 2 Champion and Dale Winstead had the Reserve Champion.

Division 3 class winners were Jared Barwick, Adam Kaufman, Garrett See, and Tyler Sharp. Jared Barwick had the Division 3 Champion and Loren Hollis had the Reserve Champion. Both pigs came out of Class 11.

Judge Gary Childs of Pelham, Ga., named Jared Barwick's 268-pound pig from Class 11 the Grand Champion Junior Market Hog; Loren Hollis' 266-pound pig from the same class was the Reserve Champion Market Hog.

In the Sale of Champions on Saturday, October 18, the Grand Champion Barrow sold for $8,000, and the Reserve Champion brought $6,500. Both champions, along with other entries in the Sale of Champions, were bought by Harris Teeter. The supermarket chain spent $54,000 in the event in the Kelley Building, which began at 3 p.m. Each of the individual exhibitors was allowed to sell one pig in the auction. Smithfield Packing, through Gwaltney, placed a floor of $39.50-per-cut-weight on the pigs. There were several buyers, but Farm Bureau purchased a majority of the pigs.

The Performance Market Hog Show, held at 2:30 p.m. Friday afternoon, attracted 63 pigs in 5 classes. These pigs were from a large group of pigs placed on test in July, and each pig carried its average daily gain paint-branded on its rump. Class winners were Looper Farms, Nahunta Farm, Dixie Looper, Sharp Farms, and Caleb Sharp. Caleb Sharp had the Grand Champion, a 280-pound pig from Class 5. Dixie Looper had the Reserve Champion, a 252-pound pig from Class 3. The Grand Champion carcass was third in Class 4 on foot and the Reserve Champion carcass was sixth in Class 3 on foot.

The Champion carcass belonged to Jennifer Giles; it had 0.54 inch backfat and 10.01 inches loin eye. The Reserve Champion carcass belonged to Wesley Looper; it had 0.67 inch backfat and 10.22 inches loin eye.

The average carcass measurement for 65 pigs at 255.2 pounds was 0.60 inch backfat and 7.56 inches loin eye. Carcass data were obtained for the Performance Market Hog Show through Real-Time Ultrasound measurements.

The Open Barrow Show held Saturday, October 18, included 675 pigs shown in 5 classes and ranging from 230 to 280 pounds. Class winners were Connie Byrum, Frank Feeser, Dixie Looper, Douglas Williams, and Nichols Farms. The Grand Champion was shown by Connie Byrum with a 280-pound pig from Class 5. Nichols Farms had the Reserve Champion, a 260-pound pig from Class 4.

The only pigs not in competition were the sow and nursing pigs on the porch of the Kelley Building.

Some of those assisting with the swine show, under the coordination of Bruce Shankle, were Todd See, Bob Jones, Frank Hollowell, David Lee, James Pope, Ron Hughes, and W.G. Simmons.

James R. Jones


The following breeders with validated herds have tested animals in the past 30 days.

Breeder Address Breeds
Bob Ivey* 314 N.C. 111 S, Goldsboro 27530 L, D, H, Y, CW, X
Wesley Looper* 4695 Petra Mill Rd., Granite Falls 28630 L, D, H, Y, X
Thad Sharp, Jr., & Sons 5171 N.C. 581 Hwy., Sims 2788030 D, Y, X
Tidewater Research Farm* 207 Research Station Road, Plymouth 27962 D, Y, L
Thomas Farms 8251 Oxford Rd., Timberlake 27583 X
*Real-Time Ultrasound

—Frank Hollowell and David Lee

Number of accesses to this file:
Last modified January 4, 2004.