Presentation given at Future Harvest CASA Conference in College Park, Maryland. January 13, 2023.

1. Minimizing drug
use
in small
ruminants
Susan Schoenian | Sheep & Goat Specialist Emeritus | University of Maryland Extension

2. Drugs commonly used in small ruminant production
Anthelmintics
(Dewormers)
Albendazole
Fenbendazole
Ivermectin
Moxidectin
Levamisole
Morantel
Vaccines
Abortions
Caseous lymphadenitis
CDT | Covexin-8
Mastitis
Pneumonia
Rabies
Soremouth
Other drugs
Anti-inflammatories
Anti-diarrheal
Anti-fungal
Antiseptics
Coccidiostats **
Hormones
Topicals
Antibiotics
Florfenicol
Gamithromycin
Ionophores **
Penicillin
Spectinomycin
Sulfa drugs
Tetracyclines
Tylosin
- - +
-
- -

3. Antibiotics (= anti-lifeGreek)
• Medicines that fight bacterial infections in
people and animals.
• Kill bacteria or make it hard for bacteria to
grow and multiply
• Can help treat, control, and prevent
bacterial diseases in livestock.
• Vital to animal health and welfare but should
only be used when necessary.

4. Antibiotic resistance
• Antibiotic resistance is a global threat.
• Any time antibiotics are used, they can
contribute to microbial resistance.
• Link between animal health and human
health: One Health
• Starting in the 1970s, there have been
many attempts to regulate antibiotic usage
in the livestock industry.
• Preservation of Antibiotics for Medical
Treatment Act seeks to bring all medically-
important antibiotics under veterinary
oversight.

5. January 1, 2017
Veterinary Feed Directive (VFD)
 Antibiotics put in the feed were converted
from over-the-counter status to veterinary
feed directive status (VFD).
 Antibiotics put in the water were converted
from over-the-counter status to prescription
status (Rx).
 Feeding antibiotics to promote growth or
performance was banned.
 NO Extra-label use of VFD drugs.

6. What did this mean to small
ruminant producers?
• Medically-important antibiotics no longer allowed
in lamb feed to promote growth.
• Only antibiotic FDA-approved to feed sheep is
tetracyclines for prevention of abortion (none
approved for goats, camelids).
• Sulfa drugs (e.g., Di-Methox®), commonly used
to treat coccidiosis in small ruminants, were
converted to prescription status (Rx).
• “Regulatory discretion” with regards to extra-label
drug use in minor species.

7. June 2023
”Medically-important” antibiotics
will no longer be available over-
the-counter (OTC). A veterinary
prescription (Rx) will be required
to purchase and use all antibiotics.
Rx OTC (unaffected)
Cephalosporins Ionophore antibiotics (coccidiostats)
Glycopeptides Bovatec® and Rumensin®
Fluoroquinolones
Macrolides
Penicillins Non-antibiotic coccidia drugs
Quinolones Decoquinate (Deccox®)
Tetracyclines Amprolium (Corid®)
Sulfas
Others

8. Where small ruminants are concerned
. . .
• Most antibiotics require extra-label drug use;
therefore, are already prescription (Rx) only –
even if producers haven’t been following the rules.
Some examples
• LA-200® is not labeled for small ruminants.
• Penicillin is only FDA-approved to treat bacterial
pneumonia in sheep.
• Penicillin is not labeled for goats (or camelids)
• Spectinomycin is not labeled for sheep, goats.
• The longer-acting and more effective
antibiotics are already prescription only.
Some examples
• Nuflor® to treat respiratory
• Excenel® to treat respiratory
• Zactran® to treat footrot

9. Extra Label Drug Use (ELDU)
• Use of a drug in any manner that is not listed on label:
species or class, disease, dosage, route of
administration, interval and duration of treatment, and
withdrawal period.
• Only licensed veterinarians have the legal right to use
or prescribe extra label drugs.
• There are rules that apply to extra label drug use.
• In order for a veterinarian to prescribe drugs extra
label, there must be a valid veterinarian-patient-client
relationship (VCPR).

10. Veterinarian-Client-Patient Relationship
• Veterinarian has assumed responsibility for the health and treatment of
the animal(s).
• Veterinarian has sufficient knowledge of the animal(s) being treated and
is available for follow-up.
• “Timely” visits to the farm are part of a valid VCPR.

11. Vaccinations
• Vaccines are drugs, too.
• Biological preparations that stimulate the
body’s immune system against a specific
disease.
• Usually administered through needle
injections but can also be given in other
ways (e.g., soremouth).
• Given to prevent disease or reduce
incidence of disease.
• Allowed in organic systems.

12. Vaccine toolbox for small
ruminants
UNIVERSALLY-RECOMMENDED
Clostridial diseases
1. 3-way (CDT) toxoid (e.g., Bar-Vac CD/T)
Clostridial perfringins type C & D and clostridial
tetani (tetanus).
2. 7 or 8-way toxoid (e.g., Covexin™-8)
CDT + additional clostridial diseases
3. Anti-toxins
for treatment or immediate, short-term protection
AS NEEDED (risk: benefit)
1. Abortion (sheep)
Chlamydia (Enzootic) + Vibrio (Campylobacter)
2. Caseous lymphadenitis (CL)
(sheep, conditional vaccine for goats)
3. Epididymitis (Brucella ovis) - sheep
4. Footrot (not available in most states)
5. Haemonchus contortus (BarberVax®)
Not available in US (yet?)
6. Mastitis (new goats)
7. Pneumonia
Pasteurella (sheep and goats), PI3 (cattle)
8. Rabies – Vx (not labeled for goats)
9. Soremouth (orf) – live vaccine

13. Some vaccine
do’s and don’t’s
• Always followed labeled instructions
• Give vaccines at proper time and animal
• Booster according to label
• Use clean needles for injections
(appropriate size and gauge)
• Use clean needle for withdrawing vaccine
from bottle.
• Use proper injection technique
• Use appropriate injection site(s)
• Don’t vaccinate wet or dirty animals.
• Store vaccines in refrigerator
• Adhere to withdrawal times

14. Anthelmintics (= anti-wormGreek)
(DEWORMERS)
• Medicines used to destroy parasitic worms
and expel them from the body.
• Different classes of anthelmintics have
different modes of action, e.g., paralyze,
damage, alter metabolism.
• Play an important role in worm control on
small ruminant farms.
• Should be used therapeutically (to treat),
not prophylactically (to prevent).

15. Three classes of anthelmintics for
small ruminants in the US
BENZIMIDAZOLES
1. Albendazole12
Valbazen®
2. Fenbendazole2
Safe-Guard®, Panacur®
3. Oxfendazole
Synanthic®
MACROCYLIC LACTONES
1. Avermectins
Ivermectin (Ivomec®)1
Eprinomectin (Eprinex®)
Doramectin(Dectomax®)
2. Milbemycins
Moxidectin
Cydectin®1, Quest®
IMID/TETR
1. Levamisole1
Prohibit®, Leva-Med®
2. Morantel2
Rumatel®, Positive Pellet®
goat dewormer
1 Labeled for sheep
2 Labeled for goats

16. Anthelmintic (dewormer) resistance
• Dewormer resistance is a world-wide problem and growing.
• Worms have developed resistance to all classes of anthelmintics
(resistance=less than 95% reduction in FEC).
• Resistance varies by farm and geographic region and is a result of
past dewormer use.
• There are no new dewormers in the pipeline.
• Need to use best management practices to preserve what efficacy
we have left in our dewormers.

17. Refugia
An important concept/strategy
• Worms in “refuge.”
Worms that have not been exposed to
dewormers; therefore, remain
susceptible to anthelmintic treatment.
• Farms need to dilute resistant worm
populations with susceptible worms.
• Increase refugia by deworming less
often and always leaving some animals
untreated.

18. Keeping small
ruminants
healthy
without drugs.
Keeping small ruminants healthy without using a lot of drugs.

19. Preventing enterotoxemias
(Overeating disease, Clostridium perfringins)
1. Vaccination
Vaccinate (booster) females in late pregnancy.
Vaccinate lambs/kids at 6-8 and 10-12 weeks of age
Vaccinate feeder lambs/kids, youth project animals
Vaccinate (booster) bucks and wethers annually.
2. Management and nutrition
Don’t allow animals to overconsume feed.
Avoid sudden changes in diet.
Provide plenty of feeder space.
Include long-stem forage in diet.
Mostly a risk with
animals fed grain.

20. Preventing respiratory
disease
• Keep animals in a stress-free, sanitary,
uncrowded environment.
• Provide shelter during weather extremes
(hot/cold)
• Proper ventilation in housing: fresh air
• Dry and draft-free
• Don’t feed dusty feeds
• Use proper drenching technique to prevent
aspiration pneumonia.
• Good nutrition, including colostrum intake
• Carefully monitor animals after transport
• Vaccination, if there is enough risk.

21. Preventing footrot
1. Biosecurity
Do not introduce footrot to your farm!
Maintain a closed flock/herd.
Quarantine all new arrivals
2. Management
Dry, hygienic conditions
Preventative foot bathing
Walk-through baths or dry boxes.
Avoid overzealous hoof trimming.
3. Genetics
Cull animals with abnormal or excessive hoof
growth.
Cull animals that fail to respond to treatment or
get re-infected.
Black hooves healthier (?)

22. Prevent infectious abortion
1. Biosecurity
Maintain a closed flock/herd.
Quarantine all new arrivals.
Separate purchased females
Remove placentas and other products
of pregnancy.
Clean lambing/kidding jugs (pens)
Control bird, rodent, and cat populations.
2. Management
Separate pre- and post-partum females.
Keep animals in a stress-free, sanitary, uncrowded
environment.
Feed a coccidiostat during late pregnancy
Isolate aborting females
Necropsy excess losses
3. Vaccination
Chlamydia-Vibrio (prior to breeding), if there is
sufficient risk.

23. Preventing mastitis
1. Management and nutrition
Keep animals in a stress-free, sanitary (dry),
uncrowded environment.
Good nutrition
Prevent respiratory disease in lambs/kids.
Keep soremouth out
Proper management at (early) weaning time to
properly dry-up females.
2. Genetics
Cull females with teat and udder defects.
Cull females with hard lumps in their udders
(previous mastitis).
3. Vaccinate
New vaccine for mastitis in goats
Vaccinate for soremouth, if you have it on your
farm (otherwise: don’t vaccinate!).

24. Controlling internal
parasites
1. Management (mostly)
Grazing and pasture management
Manage periparturient egg rise
Genetics
Other management practices
2. Drugs (minimally)
Targeted selective treatment (TST)
Combination treatments
Proper use of anthelmintics

25. Pasture and grazing
management
• “Rotational grazing”
Pasture rest and rotation
Less than 4-day rotation -
followed by a 60-day rest period
• Graze forages with condensed tannins
e.g., sericea lespedeza, chicory
• Graze annual forages
• Graze mixed swards
• Browse or graze taller forages
• Maintain minimum grazing heights
• Utilize clean pastures
• Multi or mixed species grazing
• Avoid “hot spots” on pasture
• Supplement with protein and/or energy when needed.

26. Manage periparturient
egg rise (PPER)
Temporary reduction in immunity around time of
parturition (2 weeks prior to 8 weeks after), resulting in
increased fecal egg counts (major source of pasture
contamination for lambs/kids).
1. Keep ewes/does off-pasture during periparturient period.
2. Lamb/kid when parasites are less active.
3. Feed a higher protein ration, esp. by-pass protein to
ewes/does in late gestation.
4. Selectively deworm ewes/does prior to parturition: e.g.,
FAMACHA© > 4, BCS < 2, bottle jaw, 3 or more offspring,
heavy milk producers, first-timers.

27. Genetic control
1. Raise or cross with a more resistant breed
Sheep more resistant than goats
Hair sheep more resistant than wooled sheep
Texel most resistant terminal sire
Southeast “Natives” most resistant wooled breeds
Kiko and Myotonic more resistant than Boer
2. Selection
Select males that shed fewer eggs (resistant) and/or
don’t require deworming (resilient).
Cull females that are higher egg shedders (not-
resistant) and/or require frequent deworming
(susceptible).
70:30 rule
30% of animals shed 70% of eggs
70% of animals shed 30% of eggs

28. Some other ways to
control parasites
• Quarantine drenching (combination treatment) to prevent
introduction of resistant worms.
• Raise sheep/goats in confinement or drylot
• Raise more susceptible kids/lambs in confinement or drylot (or
sell at weaning).
• Lamb/kid when parasites are less active (winter and fall).
• Wean pasture-reared lambs/kids later (~120 days or natural
weaning).
• Good nutrition: protein, energy, minerals and vitamins
• Give copper oxide wire particles (COWP) to help control barber
pole worm infections.
• Feed BioWorma® to reduce pasture contamination [?].

29. Targeted selective
treatment (TST)
(or non-treatment)
1. FAMACHA© eye anemia system
Color of inner, lower eyelid
2. Five Point Check©
Five checkpoints on animal’s body:
1) eye; 2) jaw; 3) back; 4) tail; and 5) nose.
3. Performance criteria
ADG, number of offspring, milk production

30. Fecal egg counts (FEC)
eggs per gram of feces (EPG)
• Do before and after fecal egg counts to determine
treatment efficacy (1 animal) or level of drug
resistance (10 or more animals).
• Use fecal egg counts to monitor pasture
contamination.
• Use fecal egg counts to identify resistant (and
susceptible) animals.
• Combine with other information to make deworming
decisions, but do not use as the sole criteria for
making deworming decisions.
Examples
Poor body condition (<2)+ fecal egg count
FAMACHA© score (>3) + fecal egg count

31. Combination
treatments
To prolong (maybe increase) efficacy of
anthelmintics.
• Give more than one dewormer at the
same time to get an additive effect and
kill as many worms as possible.
• Give most potent drug from each drug
class, usually albendazole + moxidectin
+ levamisole.
• Give full doses, one after the other
• Separate syringes: do not mix!
• Observe withdrawal period of drug with
longest withdrawal
• Extra label for goats and camelids
• Selectively treat!!!!
2/3/20XX 31

32. Proper use of
anthelmintics
• Follow labeled directions
• Oral dosing with drench formulations
• Dose based on accurate weight
• Give accurate dose
• Avoid underdosing
• Use proper drenching technique
• Observe withdrawal periods
• Proper storage and disposal of products

33. Preventing coccidiosis
• Clean environment
• Dry bedding
• Avoid overcrowding
• Prevent/control other diseases
• Good nutrition, including colostrum intake
• Minimize stress, esp. at weaning
• Don’t mix lambs/kids of different ages
• Feed sericea lespedeza pellets
• Coccidiostats in feed, mineral, or water.

34. Maintain healthy
flocks/herds with good
husbandry
• Strict biosecurity
• Good nutrition: energy, protein, minerals, vitamins
• Hygienic conditions: clean, dry, draft free
• Fresh air
• Fresh, clean water
• Minimize stress
• Vaccination, as appropriate
• Good genetics: get rid of animals that don’t fit your
system.
• Crossbreed, if you don’t have a reason to raise purebreds
(hybrid vigor!).
• Proper and judicious use of animal health products

35. Be observant
Know what a healthy animal is
Know how a healthy animal acts
Watch them eat/graze
Learn their behavior(s)
Catch problems early
Learn the subtle signs
Sheep/goats tend to hide problems
Don’t always jump to give an antibiotic
Keep a thermometer handy
Keep good records
2/3/20XX 35

36. sheepandgoat.com Resources Articles
What about
natural
treatments?
• Many testimonials
• Mostly unproven
• Use with caution
• Continue to monitor for
signs of disease
• Give drug(s) if/when
necessary to protect
health and welfare of
animal.

37. Thank You. Comments. Questions?
SUSAN SCHOENIAN
sschoen@umd.edu
sheepandgoat.com
sheep101.info
wormx.info