Parasite Control and Parasite Control and Rotational GrazingRotational Grazing

Patty Scharko, DVM, MPHPatty Scharko, DVM, MPH

Extension Ruminant Extension Ruminant VeterinarianVeterinarian

Livestock Disease Diagnostic Livestock Disease Diagnostic CenterCenter

Parasite Control External parasites Internal parasites

� Ostertagia

–Brown stomach worm

– Inhibited; arrested in stomach lining

� Haemonchus- goats and sheep

–Barber pole worm

Inhibited Ostertagia

Subclinical parasitism

Decreased dry matter intake

Decreased performance

• weight gain

• conception rate

• milk production

Effect of Strategic Deworming in Grazing

Stocker CattleTrial1 Days of Gain Increase Over

Grazing Controls, lbsLA 155 67VA, 1 120 20VA,2 138 90CA 109 24

Agri-Practice, Vol 13, No. 1, Jan. 1992Agri-Practice, Vol 13, No. 1, Jan. 1992 111Controls treated at trial initiation111Controls treated at trial initiation

Effect of Strategic Deworming in Grazing

CattleTrial WW over Pregnancy/ Calving

Control, lbs over Controls, %

FL 20 10 (C)

GA 19 22.5 (C)

MN,1 39 11 (P)

MN,2 27 12 (P)

Agri-Practice, Vol 13, No. 1, Jan. 1992Agri-Practice, Vol 13, No. 1, Jan. 1992

Where are the worms?

5-10% in animal

90-95% on pasture

Rotational GrazingLarval Counts

Long rotations (4-6 mo.) reduce

pasture larval counts, waste forage

Intensive rotations increase larval

loads

Worm counts in treated & control heifers under

continuous or rotational grazing

Grazing System

Treated

Control

Rotational

3,500

11,300

Continuous

3,100

2,200

Am. J. Vet. Res. 49:724, 1988Am. J. Vet. Res. 49:724, 1988

Worm Immunity Cattle develop immunity to internal

parasites as they mature.

Calves have no immunity and show the most problems when exposed to worms.

Goal is low exposure to worms early in life by keeping pasture levels low.

Dewormers (Anthelmintics) Short Action

InhibitedInhibitedOstertagiaOstertagia IntestinalIntestinal

Panacur/Safeguard + + +* + + + +

Synantic + + + + + + +Valbazen + + + + + + +Levasole/

Tramisol + + + + Rumatel - + + + +

* Dose at 10 mg/kg body weight* Dose at 10 mg/kg body weight

DewormersLong Action/ Endectocide

InhibitedInhibitedOstertagiaOstertagia IntestinalIntestinal

Cydectin + + + + + + + +Dectomax + + + + + + + +Eprinex* + + + + + + + +Ivomec + + + + + + + +

Endectocide DosageWeather

ProofMeat Withdrawal

Time (days)Cydectin Pour-On 5 ml per 110 lbs Yes 0

Dectomax Pour-On 5 ml per 110 lbs Yes 45

Ivomec Eprinex Pour-On

5 ml per 110 lbs Yes- wet or dry

0

Ivomec Pour-On generic ivermectin PO

5 ml per 110 lbs“

No* 48

Cydectin Injectable 1 ml per 110 lbs - 21

Dectomax Injectable 1 ml per 110 lbs - 35

Ivomec 1% Injection 1 ml per 110 lbs - 35

•Need at least 4 hours before rain, best 24 hours

Parasite Transmission Patterns in

Southern Cow /Calf Herds

0

20

40

60

80

100

120

140

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

50

100

150

200

250

Egg counts of cows

Pasture larvae

Egg counts of calves

Eggs per gram of feces Larvae/kg forage

WeaningMonths

When to deworm?SPRING (strategic)

DewormingDeworm 4 weeks after start grazing OPTIONS:

1. Long actionLong action (Ivomec, Cydectin, Dectomax, Eprinex)

2 treatments: 6 weeks apart

2. Short actionShort action( Safeguard, Synantic, Valbazen, Levamisol, Rumatel)

3 treatments: 3 weeks apart

Stockers- deworm every 90 days

SPRING (strategic) Deworming

0

20

40

60

80

100

120

140

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

50

100

150

200

250

Egg counts of calves

Pasture larvae

Egg counts of cows

Deworm

Eggs per gram of feces Larvae/kg forage

WeanlingMonths

SUMMER (tactical) Deworming

June 15 – July 15:� “Preventive Deworming”� Spring calving: cows & calves� Fall calving: cows

Weaning:� Spring calving- calves (FEC)

� Fall calving- do calves in March

“It depends”� Weather- moisture

Summer (tactical) Deworming

0

20

40

60

80

100

120

140

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

50

100

150

200

250

Egg counts of cows

Pasture larvae

Egg counts of calves

Eggs per gram of feces Larvae/kg forage

WeanlingMonths

DewormDeworm

Classes of DewormersClasses of DewormersGoats/ SheepGoats/ Sheep

Benzimidazole Imidazole/ Pyrimidine

Macrolide

Safeguard/ PanacurSynathic/

BenzelminValbazen*

Levasole/ TramisolRumatel

StrongidT

IvomecDectomaxEprinex

Cydectin**

*Do not use in first trimester pregnancy** Use sparingly

Tra

de

Nam

esT

rad

e N

ames

Dru

g C

lass

Dru

g C

lass

Avermectin Resistance Evaluation Study in Cattle

Farm 1 Farm 2

Ivomec Pour-on 54 % 86 %

Safeguard 100% 99 %

Ivomec PO &

Safeguard

92 % 100%

Month tested

Fecal Egg

Counts

August

13 FEC

November

240 FEC

Hay Fields Hay production removes many

larvae in the grass and opens up

the plant to UV light and heat.

Dragging pastures

Do in summer

Do on NON-grazing pastures

Return on investment?

Combine with clipping?

When to deworm?Fecal Examination

To monitor current deworming programs thru fecal egg counts and parasite identification

Do before deworming

Can recheck after deworming to evaluate effectiveness

Caution about sampling cows- spring is best

Calves can be checked thruout the year

Parasite Transmission Patterns in

Southern Cow /Calf Herds

0

20

40

60

80

100

120

140

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

50

100

150

200

250

Egg counts of cows

Pasture larvae

Egg counts of calves

Eggs per gram of feces Larvae/kg forage

WeaningMonths

Oklahoma State University Stocker Cattle

DewormControl

Control

Deworm

Deworm

Feedlot

Pasture

Control

Strategic Pasture Deworming with Safeguard (FBZ) and

Stocker GainTreatment Control Deworm

Head 371 363

Int. Wt., lbs 627 632

Final Wt., lbs 737 790

ADG, lbs 0.93 1.34

Effect of Deworming with Safeguard (FBZ) and Feedlot

Health

Pasture Treatment Control Deworm

Feedlot Control Deworm Control Deworm

Treatment

Morbidity % 13.8 8.1 3.8 2.5

Effect of Deworming Treatment with Safeguard (FBZ) and Feedlot Health

Pasture Control Deworm

Feedlot Control Deworm Control Deworm

ADG 3.85 4.56 4.22 4.46

DDMI 21.75 23.24 23.24 23.91

% Ch 29 52 44.6 55.2

% Std5.9 0.6 1.9 0.6

Cattle Parasite Control

“Some diseases are not easily eradicated,

but can be managed to minimize their

economic effects. These include internal

parasites (thru deworming and

monitoring.)”

Ray Schultz

Goat Parasite Control

Rotate every 3 days

Consider deworming 10 days after a good rain

during dry conditions

Beware of coccidia if goats can get indoors

Consider FAMACHA training & “smart

drenching”

21 days2 days to 3 months

Coccidia