HERD HEALTH                                       PIH-93


            Slaughter Checks-An Aid to Better Herd Health

Kenneth Meyer, Purdue University
LeRoy Biehl, University of Illinois
David Reeves, University of Georgia

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

     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


     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-

     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 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.
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:

                 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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