HERD HEALTH PIH-93
PURDUE UNIVERSITY. COOPERATIVE EXTENSION SERVICE.
WEST LAFAYETTE, INDIANA
Slaughter Checks-An Aid to Better Herd Health
Authors
Kenneth Meyer, Purdue University
LeRoy Biehl, University of Illinois
David Reeves, University of Georgia
Reviewers
Donald R. Barnes, Owensboro, Kentucky
Richard Nash, Sharpsville, Indiana
Willard Upchurch, Crossville, Tennessee
Diane and Gary Wallin, Milnor, North Dakota
Pork producers should have a herd health program to evalu-
ate, on a routine basis, the health and management practices in
the production unit. Evaluation is based on preset production
goals and available options in health and/or management that
might influence the attainment of those goals. The producer, the
herd veterinarian and other professional advisors periodically
update herd goals and set parameters which will aid in obtaining
projected goals.
A good herd-health evaluation program includes on-farm
inspections, laboratory diagnosis, necropsy of dead animals,
examination of cull breeding stock and market animals at
slaughter, evaluation of production records, financial record
analysis and personal counseling. Written reports regarding find-
ings and corrective measures to be implemented should be submit-
ted by the veterinarian at frequent intervals to the management
team.
Slaughter animals are an important, but often overlooked,
source of health information. During a slaughter check, large
numbers of animals can be examined in a relatively short period
of time for evidence of disease and parasitism. Many of these
health problems often cannot be efficiently detected in the live
animal.
Purposes
The purpose of a slaughter check is to look for abnormal
tissues so that specific problems can be identified and to moni-
tor the effects of drug use, vaccination programs and management
changes. With this information, the producer can work toward
eliminating or controlling disease problems. A slaughter check
reveals information about disease prevalence, severity of lesions
and possible causes of disease that may not be apparent during a
farm visit or an occasional necropsy. It is important to remember
that the incidence and severity of disease, especially subclini-
cal disease, must be evaluated with performance. Alterations in
the herd health and management program must be considered care-
fully and expectations for improved performance must be realis-
tic.
Pneumonia, atrophic rhinitis and parasite migration are the
three primary disease problems investigated during a slaughter
check. Other diseases such as mange, erysipelas, arthritis,
mycobacteriosis and streptococcosis may be detected. Evaluation
of the reproductive tract of slaughter sows may reveal evidence
of possible causes of reproductive failure. Some veterinarians
collect blood samples for serology and tissue or swabs for cul-
ture at the slaughter facility.
Pneumonia
Pneumonia in slaughter swine is common (Figure 1). These
animals are rarely clinically ill, so it is seldom that carcasses
are condemned because of the lesions. Monitoring the lungs of a
group of slaughter hogs gives excellent information on the extent
of the lung damage and possible causes. Mycoplasma, pasteurella,
bordetella, actinobacillus (hemophilus), salmonella, lungworms,
pseudorabies, influenza and migrating roundworm larvae all can
cause pneumonic lesions in swine. It is important to relate the
probable cause, extent of the lesions, number of pigs affected
and percentage of the lung involved, to average daily gain (days
to market), feed efficiency and percent mortality when formulat-
ing a plan for drug treatment, feed additives, vaccination, or
change in environment.
Atrophic Rhinitis
Atrophic rhinitis is associated with bordetella, pasteurella
and poor air quality (Figure 2). It is most common in herds where
younger pigs are placed in the same air space with older pigs or
where ventilation is inadequate. The severity of atrophic rhin-
itis (AR) is determined by cutting the snout at the level of the
second cheek tooth and measuring the turbinate atrophy and the
septal deviation. This examination is the most accurate way to
determine the presence of AR in a herd. Only a very low percen-
tage of AR can be detected by visual observation of the live
animal. By conducting routine slaughter checks, the efficacy of
vaccination programs, air quality control and management pro-
cedures can be evaluated in conjunction with performance data.
Parasite Control
The most common parasite of swine is the large roundworm
(ascarid). The kidneyworm (stephanurus) is common in the
southeastern United States. The success of a deworming program
can best be monitored by slaughter examination. Because of the
nature of the life cycle of these two parasites, fecal examina-
tions may not be an efficient means of determining a herd prob-
lem. Part of the life cycle of the roundworm and kidneyworm
involves migration through the liver. As this migration occurs, a
white spot will form in the liver tissue when the body defenses
react to the foreign invader. White spots in the liver may indi-
cate a roundworm or kidneyworm problem in the herd. The white
spots gradually heal and disappear if migration occurs early in
life. Liver condemnations due to severe larvae-migration scars
indicate that the deworming program needs to be evaluated.
Hogs kept in environmentally controlled units, though less
likely to be infected than outside units, should still be moni-
tored for parasites and producers should not be misled into
thinking that their operations will be parasite-free.
Reproductive Examinations
Examinations of the reproductive tract of slaughtered
animals can be useful in determining the status of ovarian func-
tion and infectious reproductive disease in cull sows. Cases of
aberrant reproductive performance such as anestrus, irregular
estrous cycles, vaginal discharges, decreased conception rates
and decreased farrowing rates would be indications for examina-
tion and collection of tissues during a slaughter exam. The find-
ings should be related to the clinical picture for an accurate
diagnosis. Some producers find that evaluation of underline qual-
ity (number and placement of teats) at slaughter is indicative of
whether progress is being accomplished in the herd.
Other Disease Problems
Other diseases may be found on a slaughter check. Occasion-
ally, carcasses exhibit lymph nodes with abscesses caused by
streptococcus or mycobacteria (TB). Mange and the mild skin form
of erysipelas can be easily observed in dehaired hogs. Carcass
trim due to arthritis can also be noted.
Slaughter Check Procedures
Once the decision has been made to conduct a slaughter
check, the producer or veterinarian should contact the packing
plant so appropriate arrangements can be made for a delivery time
and date. The plant inspector should also be notified.
To maintain identification of the pigs, the animals will
need to be delivered to the plant as a group or slap-tattooed at
the first point of concentration. The buyer will need to be
notified when the animals are delivered for a slaughter check so
the animals can be grouped properly. Some slaughter plants charge
a small fee per hog for the privilege of doing examinations in
the plant, primarily because of the delay in the speed of the
line. An alternative to the expense of conducting a check in a
packing plant is slaughter at a local plant with the intention of
home use. Even though sufficient numbers may not always be accom-
modated, often valuable information can be obtained from the two
or three pigs that may be slaughtered at a local plant.
A commercial producer should have at least two slaughter
exams per year, one in the fall-winter and the other in the
spring-summer. A seedstock producer should have slaughter checks
made on a more frequent schedule, such as every quarter.
The number of animals examined depends upon the size of the
herd and the incidence of the specific disease in the herd. Gen-
erally, at least 30 pigs representative of the herd should be
used. Obviously, the more pigs examined the more reliable the
data generated. In some large plants with fast-moving lines, it
may be necessary to submit several extra pigs in order to get a
representative sampling.
Additional slaughter information can be obtained from the
federal or state meat inspector's reports. These reports contain
information about the condemnation of parts of the carcass, such
as abscesses, enlarged joints, or adhesions found in the lungs or
abdominal cavity.
It is important to check fast-growing pigs as well as those
doing poorly. Fast-growing pigs may show more pneumonia at
slaughter because they either have developed pneumonia later in
life or grown so rapidly that they have not had an opportunity to
heal. Pigs with poorer performance may have contracted pneumonia
earlier in life or grown so slowly that their lungs may have
healed prior to slaughter. If a choice has to be made between the
two, the slow-growing pigs usually reveal more evidence of
chronic disease problems. Ear notching at birth, to indicate the
week of birth, will identify slow-growing pigs.
Table 1. Example of a slaughter test report.
__________________________________________________________________
Date
Farm
Address
Phone no.
No. examined
Market hogs
Breeding stock
Number Number
Nose, turbinate normal __________ abnormal ________
Nose, septum normal __________ abnormal ________
Lungs normal __________ abnormal ________
Heart normal __________ abnormal ________
Liver normal __________ abnormal ________
Intestines normal __________ abnormal ________
Reproductive tract normal __________ abnormal ________
Other conditions observed:
Abscesses yes __________ no ________
Mycobacteria yes __________ no ________
Mange yes __________ no ________
Arthritis yes __________ no ________
List others:
Comments/Recommendations
Examining Veterinarian
_____________________________________
The cost of slaughter exams can be reduced if two or more
producers arrange for a slaughter check on the same day. If a
suitable packing facility is not located nearby, veterinarians
may refer a client to another veterinarian who is closer to a
plant. The veterinarian's fee usually will be either on an hourly
or on a per-head basis, and should be agreed upon before the
slaughter check is conducted. The producer should insist on a
written report (Table 1) from the veterinarian documenting the
findings. Most veterinarians grade the severity of the lesions
found in each tissue or organ examined and report the results as
both individual and average scores. Once the slaughter check
information is obtained, the producer and the veterinarian can
evaluate the data collected and begin to implement a sound health
program for the herd.
Contact your state veterinarian, university Extension veter-
inarian or county extension agent for information on slaughter
plants and veterinarians who cooperate in providing this service.
REV 6/90 (5M)
Figure 1. Chronic pneumonia due to mycoplasma. The dark-colored
areas in the lung are diseased.
Figure 2. Atrophic rhinitis. The cross section of the nose on
the left is normal. The three on the right show vari-
ous degrees of atrophic rhinitis. Note the condition
of the cartilage separating the two sides of each
nose, and the amount of destruction of the turbinates.
% Figures are available in hard copy
______________________________________________
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