Presented at Maryland Small Ruminant Pasture, Grazing, and Browsing Conference. October 19, 2019. Keedysville, MD

1. How do I keep them healthy?
Worms and other potential problems on pasture
SUSAN SCHOENIAN
Sheep & Goat Specialist
University of Maryland Extension
sschoen@umd.edu
sheepandgoat.com | wormx.info

2. Three health risks
1. Bloat
2. Plant toxicities
Fescue toxicosis
3. Gastrointestinal
nematodes (worms)

3. Pasture bloat
Build up of gas in the rumen
◈ Occurs when gas production in
the rumen exceeds the
animal’s ability to expel it by
fermentation (burping).
◈ When the gas cannot be
released, severe distension
occurs, compressing the lungs.
◈ Can be fatal. 

4. Symptoms of (frothy) bloat
◈ Swollen left abdomen
◈ Discomfort
◈ Depression
◈ Breathing difficulty
◈ Sudden death
◈ Bloat is also a common
post-mortem change.

5. Frothy bloat
◈ Caused by (over) consumption
of rapidly growing forages,
especially legumes.
◈ Frost, due, or rain increases
likelihood of bloat.
◈ Most commonly seen in spring
and autumn when grass
growth is at its highest.

6. Bloat risk
Bloat causing Low risk Safe*
Alfalfa
Sweet clover
Red clover
White clover
Alsike clover
Winter wheat
Arrowleaf clover
Spring wheat
Oats
Rape (canola)
Perennial ryegrass
Berseem clover
Persian clover
Sainfoin
Birdsfoot trefoil
Cicer milkvetch
Crownvetch
Lespedeza
Fall rye
Most perennial grasses
Source: Forage-induced animal disorders
*If not overly lush or immature
Bloat can occur on any lush forage that is low in fiber and highly digestible.

7. Treatment of bloat
◈ Reduce froth
Administer antifoaming
agents such as vegetable
oil, mineral oil, baking soda,
or anti-bloat medication.
◈ Insert stomach tube to
relieve pressure.
◈ Puncture rumen to relieve
gas (as a last resort).
Moresevere

8. Bloat prevention
◈ Dilution: reduce amount of legume in
pasture (usually < 50%).
◈ Plant non-bloating legumes
◈ Feed coarse hay before grazing legumes
or lush pasture.
◈ Turn animals out in afternoon instead of
morning.
◈ Don’t graze until plants are more mature.
◈ Feed ionophores or poloxalene
◈ Free choice baking soda

9. Fescue toxicosis
◈ KY31 tall fescue is a hardy, cool-
season bunchgrass that grows
throughout the eastern US and on
most Maryland farms.
◈ It is estimated that 90% of tall
fescue pastures are infected with
an endophyte.
◈ The endophyte produces ergot
alkaloids (type of mycotoxin), which
can cause toxicosis in grazing
animals.

10. Signs of fescue toxicosis
◈ Vary by livestock species
○ Vasoconstriction
■ “Fescue foot”
○ Prolactin regulation
■ Rough hair coats
■ Heat stress
■ Depressed appetite
■ Sub-clinical
● Lower growth
● Lower reproduction

11. Fescue toxicosis in small ruminants
◈ Mostly reduced weight gain due to
reduced consumption and
digestibility.
◈ Symptoms of reduced health and
well-being have not been observed
in small ruminants (or they go
undetected).
◈ Fewer studies with sheep and
especially goats have been
conducted.

12. Fescue toxicosis in small ruminants
◈ Not known if endophyte in
fescue adversely affects
fertility.
◈ There are producer
anecdotal reports of kidding
difficulties, similar to those
experienced with mares.
◈ Goats may be more
sensitive than sheep.

13. Management options
◈ Dilute endophyte-infected fescue with
other forages, especially legumes.
◈ Replace endophyte-infected fescue with
other forage, including novel endophyte
fescues.
◈ Increase stocking rates to prevent plant
maturation and seed head formation.
◈ Avoid summer grazing: instead,
stockpile for fall-winter grazing.
◈ Provide supplemental feed to reduce
amounts of ergot alkaloid consumed by
animals.

14. Gastrointestinal nematodes (worms)
Haemonchus contortus (barber pole worm) is primary species.
◈ Primary health problem affecting
sheep and especially goats that
graze.
◈ Few dewormers are FDA-
approved for goats.
◈ There is growing and widespread
resistance to dewormers, making
parasite management even more
challenging.


15. Integrated Parasite Management (IPM)
PRIMARY
Management
◈ Immunity
◈ Animal management
◈ Pasture management
◈ Grazing management
◈ Bioactive forages
◈ Biological control
◈ Alternative dewormers
◈ Nutrition
◈ Genetics
◈ Zero grazing
SECONDARY
Medicine
◈ Targeted selective treatment (TST)
○ FAMACHA© system
○ Five Point Check©
○ Performance indicators
◈ Proper use of dewormers
○ Test for resistance
○ Combination treatments
○ Best management practices

16. Immunity
Body’s natural defense
◈ Young animals lack immunity and
develop resistance to parasites with
age and (continuous) exposure.
◈ Females suffer a temporary loss of
immunity around the time of parturition.
◈ Goats don’t develop immunity as fully
as sheep.
◈ Immunity is compromised by poor
nutrition and other diseases and can be
overcome by high challenge.

17. Animal management
◈ Hygiene
Feed, water, hot spots
◈ Lambing/kidding
when, where?
◈ Weaning management
age, nutrition
◈ Other diseases
pneumonia, soremouth, footrot

18. Pasture management
◈ Good fertility
◈ Mixed swards
◈ Forbs and legumes
◈ Annuals
◈ Taller forages
◈ Browse
◈ Bioactive forages
◈ Tillage
◈ Remove a hay crop
Forage chicory

19. Grazing management
◈ Rotational grazing
○ Short duration grazing
○ Long rest periods
◈ Creep grazing
◈ Multi-species grazing
◈ Low stocking rates
◈ Minimum grazing height
◈ Avoid “hot spots” on pasture
◈ Sacrifice area(s)

20. Bioactive forages
Contain secondary compounds that are anti-parasitic
◈ Consumption of forages
containing condensed tannins
(CT) has been shown to be
effective at reducing parasite
levels in sheep and goats.
○ Sericea lespedeza
○ Chicory
○ Birdsfoot trefoil
○ Sainfoin

21. Sericea lespedeza
◈ Non-bloating, warm season legume
that grows in sub-optimal conditions.
◈ Sericea-fed animals have been shown
to have reduced fecal egg and coccidia
oocyst counts.
◈ The anti-parasitic effects of sericea
lespedeza have been demonstrated in
fresh forage, hay, silage, and leaf meal
pellets.

22. Using sericea lespedeza
◈ A minimum of 25% of the diet is required
to have an impact on parasites; has been
grazed satisfactory as sole forage.
◈ Long term use of SL may depress growth
rates in lambs/kids, due possibly to
mineral imbalance.
◈ Best to graze in rotation to minimize
nutritional impact and to maintain stand.
◈ Provide free choice minerals
◈ Combine with other parasite management
strategies.
◈ Feed pellets two
weeks prior and 4-6
weeks after period of
stress, usually
weaning.
◈ Combine with other
parasite management
strategies.
◈ Simms Brothers only
supplier of SL pellets.

23. Biological control
◈ Feed-through product for grazing
livestock (no effect in animal).
◈ Fungus kills (round) worm larvae in
manure (reduces pasture contamination).
◈ Feed daily (?) during risk period(s) and to
most susceptible animals.
◈ Two products: BioWorma® - Rx
Livamol® with BioWorma® - OTC
◈ ~50¢ per day to feed 100-lb. animalAvailable from Premier 1 (Iowa) and
Sheepman Supply (Maryland)
Duddingtonia flagrans
Nematode-trapping fungus

24. Alternative dewormers
◈ Copper oxide wire particles
◈ Diatomaceous earth
◈ Copper sulfate
◈ Pumpkin seeds
◈ Herbs
◈ Essential oils
◈ Tobacco
◈ Magical mixes
Ineffective
Unproven
Potentially
toxic

25. Copper oxide wire particles (COWP)
◈ Tiny metal rods of copper
oxide (CuO).
◈ Slow release form of copper
◈ Sold as copper supplements
for cattle (12.5, 25 g) and
goats (2, 4 g).
◈ Can repackage into smaller
doses (gel caps) for
deworming sheep and goats.

26. Copper oxide wire particles (COWP)
◈ Recommended to give smallest
effective dose
○ 0.5-1 g lambs/kids
○ 1-2 g mature animals
◈ Targeted selective treatment
◈ Can use in combination with dewormer.
◈ Assess copper status of flock before
using, especially with sheep.

27. Nutritional management
◈ Graze plants when they are in a
vegetative (more nutritious) state.
◈ Supplement pasture diet with most
limiting nutrient, usually energy.
◈ Protein, especially by-pass protein,
may mitigate effects of parasites.
◈ Vitamin and mineral supplementation
◈ Monitor body condition to help you
make management decisions.

28. Genetic control
◈ Raise more resistant breed(s).
◈ Cross with more resistant breed(s).
◈ Use males that don’t require
deworming and/or have lower fecal
egg counts.
◈ Cull females that require frequent
deworming and/or have higher
fecal egg counts.
◈ Don’t keep offspring from
susceptible parents. “Stop selecting sissy sheep (or goats)”

29. Targeted selective treatment (TST)
◈ Deworm only those animals that
require or would benefit from
treatment (vs. whole-flock or
calendar-based treatments).
◈ TST reduces deworming frequency
and increases refugia (worms not
exposed to dewormers; thus, still
susceptible to treatment).
◈ Identify susceptible (cull) and
resistant (keep) animals.

30. Decision-making tools for TST
1. FAMACHA© eye
anemia system (1-5)
2. Five Point Check©
eye, jaw, back, tail, nose
3. Performance
indicators
gain, milk production

31. FAMACHA© System
◈ Estimates anemia (blood loss)
in animal by comparing color of
lower eyelid (membranes) to
color on card.
◈ Five treatment categories and
recommendations.
◈ Only works for barber pole
worm (blood feeding parasites)
◈ Training required; in person or
online.

32. Five Point Check©
◈ Extension of the
FAMACHA© system.
◈ Provides evaluation criteria
for most parasites that
affect small ruminants.
◈ Five check points on
animal’s body: nose, eye,
jaw, back, tail

33. Performance indicators
◈ Happy Factor™
◈ Weight gain
◈ Milk production
◈ Number of offspring
◈ FAMACHA© + gain
◈ FAMACHA© + FEC
◈ Body condition score

34. Proper use of dewormers
◈ Resistance testing
◈ Combination
treatments
◈ Best management
practices

35. Dewormer resistance
◈ Failure of treatment to reduce
fecal egg count by >95%.
◈ Drug is still effective at low levels
of resistance, but becomes less
effective as resistance grows, until
it is no longer effective as sole
treatment.
◈ There is cross-resistance among
drugs in the same class.
SafeGuard®  Valbazen®
Ivomec®  Dectomax®  Eprinomectin®

36. Dewormer resistance in southeastern US
2016 study funded by American Sheep Industry Let’s Grow Committee
0
20
40
60
80
100
Benzimidazoles Ivermectin Moxidectin Levamisole
Maryland Virginia Georgia

37. Test for dewormer resistance
FECRT
Fecal egg count reduction test
◈ Compare before and after
fecal egg counts from same
10-15 animals.
◈ Results from one animal
may show effectiveness of
individual treatment, but not
resistance status of farm.
◈ Need high enough FECs.
DrenchRite®
Larval development assay (LDA)
◈ Determines resistance to
all drugs and classes
simultaneously from single
pooled fecal sample (also
identifies larvae)
◈ University of Georgia
$500 per sample

38. Combination treatments recommended
◈ Use more than one drug active to kill same
kinds of worms; additive effect.
◈ Use most effective drug from each class,
usually Albendazole (Valbazen®) +
moxidectin (Cydectin®) + and levamisole
(Prohibit®, Leva-Med®).
◈ All oral, do not mix drugs; give sequentially.
◈ Can also give copper oxide wire particles
(COWP) in combination with a dewormer.

39. Best management practices for dewormer use
◈ Dose based on accurate weight(s).
◈ All oral dosing with drench (liquid)
formulations.
◈ Proper drenching technique (over the
tongue; no spitting) with oral dosing
syringe with long metal nozzle.
◈ Proper storage of dewormers.
◈ Follow extra label drug laws: VCPR
required for goats and camelids.

40. Integrated parasite management (IPM)
◈ There is no simple way to control
internal parasites.
◈ Every year is different.
◈ Effective control usually requires a
combination of management, along
with prudent use of dewormers.
◈ Deworming should be the last option.
◈ For more info, go to wormx.info

41. Thank you. Comments? Questions?
SUSAN SCHOENIAN
Sheep & Goat Specialist
University of Maryland Extension
sschoen@umd.edu
sheepandgoat.com | wormx.info