NCSU Extension Swine Husbandry 2002
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December, 2002 . Volume 25, Number 11

The Science of Odor

WHICH PIGS SHOULD YOU EUTHANIZE AND WHEN?

Generally speaking, an animal should be culled when it is no longer profitable or euthanized when it is inhumane to let it live. The difficulty all farm managers encounter is defining when animals become uneconomic and whether to treat or euthanize the compromised animal.

Industry-specific guidelines for euthanasia, such as the National Pork Producers Council guide, On-Farm Eutha-nasia of Swine[1], and university-produced Extension training materials, such as On-Farm Euthanasia: Better Ways[2], generally agree closely with methods and processes accepted by the American Veterinary Medical Association (AVMA). Unfortunately, these guidelines do not help producers decide if and when an individual animal should be euthanized to end its suffering.

Suffering can be conceptualized as the product of pain and its duration. By daily monitoring, farm managers usually can estimate duration, but the difficulty of estimating the intensity of pain remains. Further, overt pain behaviors in pigs can be difficult to evaluate. Pain may reduce normal pig social behaviors and vocalization, while vocalization in response to handling may be more pronounced. Changes in gait and a reluctance to move also may be observed (Dombromylskyj, et al.)[3]. Managers usually can identify those animals suffering the most because they exhibit aberrant behavior or the presence of visible lesions (e.g., burns, lacerations, compound fractures) makes it obvious. However, the issue often is clouded because a condition may be visually striking but less painful (e.g., prolapses) or inconspicuous but more painful (e.g., arthritis).

Various methods of generating a pain score and assessing animal pain have been reviewed by Dombromylskyj and coworkers[3]. Objective measures, such as heart rate, respiratory rate, and temperature are unreli-able guides to the presence of pain, as are humoral factors such as epinephrine, norepinephrine, and cortisol. These measures may be useful when integrated into a pain-scoring system, but they are of limited use when used alone, as they are influenced by many factors other than pain.

Nonverbal human-infant pain scales adopted for use in animals include the simple descriptive scale (SDS), the numerical rating scale (NRS), and the visual analog scale (VAS). Although the SDS is less sensitive than the NRS or the VAS, comparisons of inter-observer variability have shown reasonable agreement between observers using the SDS to assess postoperative pain in dogs (Holton)[4].

Individual managers usually resort to a very subjective assessment often heavily weighted by the perceived ability of the animal to return a profit. Focus groups consisting of North Carolina farm managers have told us that having clear criteria for when to euthanize an animal would help reduce some of the job stress they feel.

Unlike the companion animal arena, where there is much discussion and many suggested guidelines on the appropriateness and timing for euthanasia, there are relatively few guidelines for when a farm animal should be euthanized. Most of the companion animal guidelines are very subjective (e.g., ability to enjoy food, ability to breathe freely and without difficulty, ability to eat and drink without pain, ability to respond to owner and family), but when taken together they are helpful in creating a euthanasia profile. Other guidelines are more objective. Duncan[5] recommends euthanizing companion animals if they have:

  • Weight loss: 20 to 25 percent of total body weight, characterized by muscle wasting.
  • Extreme weakness/Inability: No desire to eat or drink, persisting for 24 hours or more.
  • Moribund state: Depression and body temperature below 99o F.
  • Infection: Involving one or more organ systems, and the condition fails to respond to treatment within an appropriate amount of time.
  • Respiratory/cardiovascular problems: Failure of these systems, including blood loss or anemia resulting in a hematocrit below 20%.
  • Nervous/musculoskeletal problems: Injuries that cannot be healed, resulting in uncontrolled seizures or the loss of a limb.

Similar guidelines could be adapted for farm animals. For example, the following general guidelines could apply to pigs of any weight or age:

  • Weight loss of 20 to 25 percent of total body weight, characterized by muscle wasting.
  • Extreme weakness or inability, with a lack of desire to eat or drink persisting for 24 hours or more.
  • Suffering from any infection/disease that fails to respond to treatment.

Some farming systems have adopted specific protocols to help managers cope with the difficult decision of what to euthanize and what to keep. For example, the "two-strike" system has two criteria that must be fulfilled before a weaner pig is euthanized: Underweight (e.g., less than 6 pounds on a farm with an 18-day weaning) and has a disability such as a rupture, or navel ill, or lameness, or poor body condition. This introduces a special category of concern for pork producers - the lightweight pig. It has been long accepted that lightweight piglets at birth are lightweight at weaning (England)[6]. Others have established that lightweight pigs at weaning remain small, are a significant contributor to variation in slaughter weight, and, as such, are a major problem in assembling slaughter loads. In 3-site production, where the system rewards farrowing house and nursery managers for dispatching more pigs, there tend to be more pigs shipped than there should be. Consequently, nursery and finishing managers then struggle with the issue of how to handle the underweight/disadvantaged pigs they receive.

To help us better understand the issues involved and the compromises producers will have to make, we at North Carolina State University are working on a project designed to develop the protocol for handling compromised pigs. For our project, we are collecting economic and pig welfare information that producers can use to make informed decisions on which pigs should be euthanized and when.

References

1. On-Farm Euthanasia of Swine - Options for the Producer. 1997. Booklet #04259-4/97. American Association of Swine Practitioners and the National Pork Producers Council, Des Moines, Iowa.

2. On-Farm Euthanasia: Better Ways. 2001. Produced by W.E. Morgan Morrow and Robert E. Meyer, North Carolina State University College of Veterinary Medicine Biomedical Communications.

3. Dobromylskyj, P., P. A. Flecknell, B. D. Lascelles, A. Livingston, P. Taylor, A. Waterman-Pearson. . Pain Assessment, in: Pain Management in Animals, P. A. Flecknell and A. Waterman-Pearson, eds. W.B. Saunders, London.

4. Holton, L.L., E. M. Scott, A. M. Nolan, J. Reid, E. Welsh, D. Flaherty. 1998. Comparison of three methods used for assessment of pain in dogs. J Am Vet Med Assn, 212:61-66.

5. Duncan, J. C. 1988. Careers in Veterinary Medicine. Rosen Pub. Group (New York).

6. England, D.C. 1974. Husbandry components in prenatal and perinatal development in swine. J. An Sci, 38:1045.

—Morgan Morrow and Robert Meyer

A NEW NORTH CAROLINA PORK CONFERENCE IN 2003

The annual North Carolina Pork Conference will open at both a new date and new location in 2003. The event will be held February 19-20 in Greenville, N.C. at the city’s new convention center. The annual Pork Conference always offers a top opportu-nity to bring the industry together, make and renew friend-ships, evaluate new products, and learn cutting-edge information. This year, participants can get the latest facts on virtually every facet of our industry, as educational programs will be offered on both Wednesday and Thursday. In addition, the program will include activities that will provide up-to-the-minute information and directly engage producers in a much more interactive environment.

Two sessions are planned on February 19 th, starting at 9 a.m. with a look at the future of pork production. Speakers will address the future of antibiotic usage, automation of farms, and the potential for new reproductive technologies. This session is designed for decision-makers, managers, and people involved with animals on a daily basis. In the afternoon, key legislators from the North Carolina delegation have been invited to share their views and participate in a "town hall" meeting.

The Thursday topics will address swine manure. NC State University researchers, state officials, and producers will address odor control and management. Session participants will be able to earn three hours of Continuing Education credit for operators of animal-waste-management systems. Topics include the status of on-going evaluations of Environmentally Superior Waste Management Technologies, Environmental Management System Certification for pork production, and the latest information on NPDES permits.

I look forward to seeing you at the 2003 Pork Conference.

—Todd See

320 MARKET HOGS SHOWN AT NORTH CAROLINA STATE FAIR

The 2002 North Carolina State Fair exhibited a tremendous set of 320 market hogs.

The Junior Market Barrow Show, held at 9 a.m. Friday, October 18, was divided into 12 classes and three divisions to handle the 169 pigs weighing between 220 and 270 pounds.

Class winners in Division 1 were Lauren Hollis, Reese Looper, K.T. Bottoms, and Landis Looper. Lauren Hollis drove the Division 1 Champion and Reese Looper the Reserve Champion.

Division 2 class winners were Joseph Hollis, Chad Byrum, Heather Ogilvie, and Rebecca White. Joseph Hollis had the Division 2 Champion and Chad Byrum the Reserve Champion. Division 3 class winners were Jared Barwick, Daniel Winstead, Garret Barwick, and Joseph Hollis. Jared Barwick had the Division 3 Champion and Daniel Winstead the Reserve Champion.

Judge Rick Maloney of Minco, Oklahoma, named Jared Barwick’s 265-pound pig out of Class 9 the Grand Champion Junior Market Hog; Joseph Hollis’ 255-pound pig out of Class 6 was the Reserve Grand Champion Market Hog.

At the Sale of Champions on Saturday, October 19, in the Kelley Building, the Grand Champion Barrow sold for $6,500 to Harris Teeter Stores, Inc., which also bought the Reserve Champion for $5,000. Harris Teeter purchased all champion and reserve champion steers, pigs, lambs, and turkeys for a grand total of $49,000. The company then donated all the champions to the Food Bank of North Carolina. Later in the sale, each individual exhibitor was allowed to sell one pig through auction. Lundy Packing Co. of Clinton placed a $34- per-cut-weight floor 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 64 pigs shown by 15 exhibitors in 5 classes. These pigs were from a large group of pigs placed on test by producers in July, and each pig carried its average gain paint-branded on its rump. Class winners were A.C. Locklear, Wesley Looper, and Dixie Looper. A.C. Locklear drove the Grand Champion, a 216-pound pig out of Class 4. Wesley Looper exhibited the Reserve Champion on foot, which was a 233-pound pig out of Class 1. The Reserve Grand Champion on foot was third in the carcass placing, while the Grand Champion on foot was eighth in the carcass class.

A.C. Locklear had the Champion Market Hog Carcass, which came from a 262-pound gilt that placed first in Class 5 with 0.40-inch backfat, a loin eye of 8.89 inches, and 0.995- pound lean gain per day on test. Locklear also had the Reserve Grand Champion Carcass, which was the eighth-place pig in Class 4. Its carcass measured 0.36 inches backfat, 8.39 inches loin eye, and 0.979 pound lean gain per day on test.

The average carcass measurements for the 64 pigs at 248 pounds were 0.49 inches backfat, 7.84 inches loin eye, and 0.821 pound of lean gain per day on test. The pigs had averaged 91 pounds on test and 248 pounds off test for an average of 1.90 pounds daily gain. Carcass data was obtained for the Performance Market Hog Show through Real-Time Ultrasound measurements.

The Open Barrow Show held Saturday, October 19, featured 32 exhibitors and 87 pigs shown in 6 classes ranging from 230 to 280 pounds. Class winners were Wesley Looper, Dana Sue Sauls, Betsy White, and Angus Carousel. Wesley Looper showed the Grand Champion, a 265-pound pig out of Class 5. Dana Sue Sauls showed the Reserve Champion, which was a 268-pound pig out of Class 6. The barrows averaged 252 pounds and had adjusted backfat of 0.67 inches, adjusted loin eyes of 7.53 inches, and 57.74 percent lean.

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

ON-FARM PERFORMANCE TESTING

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
Tommy Spruill Rt. 1, Box 149, Columbia 27925 L, X
Caswell Farm Unit 2415 W. Vernon Ave., Kinston 28501 X
Thomas Farms 8251 Oxford Rd., Timberlake 27583 X
UCPRS (Swine Dev. Center) Rt. 2, Box 400, Rocky Mount 27801 X
*Real-Time Ultrasound

—Frank Hollowell and David Lee

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Last modified December 2, 2002.