Basics of Sheep Health Care

NAHMS Sheep Producer Surveys

Veterinary consultation as a diagnostic service: 40-53%

46% of surveyed producers consulted a veterinarian in 2000

NAHMS 1996, 2001

Veterinary services & sheep production

Sheep practice: smallest fraction (4%) of total US food animal veterinary service market

Wise, JAVMA, 1987

What are the veterinarian’s goals for serving western range flocks?

To assist the producer in increasing the number of lambs born, the uniformity of the lamb crop, and the number that survive to weaning.

How can this be accomplished?

• Ram fertility testing

• Brucella ovis eradication

• Ultrasonographic confirmation of pregnancy

• Neonatal lamb managment

Late summer / early fall

Last spring’s lambs have been sold, except for replacement ewe lambs

1. Ewe cull; prepare ewes for upcoming breeding season

2. Ram test; prepare rams for same.

Prebreeding Ewe Cull

Body ConditionScore (target: 2-3)

Low BCS (< 2 out of 5):

Poor nutrition

Parasites

Footrot

OtherDiseases

Broken mouth /Gummer

“Bag Check”

Status of udder will influence ewe’s

ability to raise twins, triplets

Mastitis:

Bacterial: Staphylococcus

Viral: Ovine progressive pneumonia virus (OPP)

Those that pass BCS, teeth, and bag check:

Deworm (anthelmintic medicine)

Vaccinate

What vaccines do sheep need?

Enterotoxemia and tetanus – ALL sheep

• Clostridium perfringens type C• Clostridium perfringens type D• Clostridium tetani

Can give now or pre-lambing

Prebreeding vaccinations vs. infectious causes of abortion

Vibrio (Campylobacter fetusfetus) bacterin

Enzootic abortion of ewes (Chlamydophila abortus) bacterin

2 doses: 1 prebreeding, second 2-4 weeks later

When to use?

•Owner preference•Contact w/ other flocks during pregnancy•Flock history of abortion storms•New introductions into flock -

Keep away from pregnant flock!

Cats and Toxoplasmosis

Parasite shed in cat fecesEsp. young catsAbortion, stillbirth, weak

lambs

Ensuring Ram Fertility

ShearShadeSandSalt and waterSemen testSerologic test

Watch crude protein level in feed!

Ulcerative posthitis (“pizzle rot”): Excessive protein in ram feed

Pathogenesis

High protein feeds(greater than16 % crude protein)induce high[urea] in the urine

Bacteria (Corynebacteriumrenale) proliferates onsheath, cleaves ureato ammonia

Chemical dermatitis results, other bacteria invade secondarily

Pain and reluctance to breed

Can scar down and limit capacity to breed

Treatment

Critical step: Remove high protein diet

Systemic antibiotic therapy and/or topical therapy

Ram Breeding Soundness Examination (BSE)

Ram fertility has a profound impact on flock economic performance: size and uniformity of lamb crop; reduced ram #s; lambing labor.

Demonstrable economic results

Breeding season

Conception Lambing

~ 5 month gestation

Breeding season

FERTILE RAMS

Breeding season

SUBFERTILE & INFERTILE RAMS

The S’s of Late Summer Ram Management

ShearShade and SandSalt and water

Semen test Serology (Brucella ovis)

Sperm that they use on a given day were made ~ 50-55 days ago

Ram Breeding Soundness Exam (BSE)

RBSE is a systematic, objective assessment of potential for a ram to impregnate a defined number of ewes through natural service.

Goal: “Identify the duds, keep the studs.” ID and remove subfertilerams.

Fertility influenced byevents prior to breeding season

Ram Breeding Soundness Examination

Brucella ovis infection

Venereal disease: Can spread to involve most or all of the rams in a flock

• reduced lamb crop, non-uniform lamb crop from repeat breedings

• abortion (rare)

• more rams purchased to cover ewes

What is the cost of B. ovis infection?

15-30% reduction in lamb crop

Loss incurred through reduced lamb crop:$487 per 100 ewes

- fewer lambs than what could have been born

Loss incurred through extended lambing season:$182 per 100 ewes

- These losses often go unseen

Kimberling, 1988

Bulgin, 1990

Producer Survey - 1998Kansas State University

B. ovis ELISA performed on 58 rams

Origin: 13 Kansas flocks Results: 5 positive on ELISA

4 suspect on ELISA, all 4 suspects retested and found to be positive

9/58 = 15.5% of tested rams were positive0 of 13 owners thought they had the disease beforehand

Van Metre & Kennedy, unpublished data, 1998

What is the cost of B. ovis infection?

Loss incurred through reduced lamb crop:$487 per 100 ewes

Loss incurred through non-uniform lamb crop:

$182 per 100 ewes

- These losses often go unseen

Kimberling, 1988

Detection of B. ovis infection in a ram:How is it done?

1. “Feel the epididymis”14% of 408 infected rams had palpable abnormalities of the epididymis Kimberling, 1988

2. Attempt to culture the bacteria from ram semen?

Expensive and inaccurate … these bacteria are difficult to culture in the lab

3. Examine semen for white cells?

White cells appear intermittently in semen samples, particularly if the infection is longstanding

Clumped white cells

Sperm cells (dark)

4. Serologic testing: ELISA test (best method for finding infected rams)

Takes 2-4 weeks from the time of infection until antibodies appear

Gall et al, 2003

2429 rams tested for B. ovis

241 (9.9%) tested positive

Of those positive for B. ovis:~ 50% would have otherwise passed their breeding soundness exam…their sperm sample can appear normal!

CSU Ram Testing Study, 2000-2007

Economic justification

Comparison of lamb crops in two flocks:

One with rams that passed BSE and were B. ovis seronegative

vs.

One with random source, untested rams

Kimberling & Schweitzer, 1989

In flock w / tested rams:

Economic advantage of $12 per ewe for larger lamb crop alone

Besides lamb crop:

-Reduced expenditure on additional ram power

-Shorter lambing season

-More lambs born early in the lambing season

-Increased size and uniformity of lamb crop

$12 per ewe (1989 dollars)

Other aspects of the ram test:

granuloma

Approximately 1 in 7 infected ramswill have abnormal epididymides or testes

How do you detect infection?

Serologic testing: Detection of antibodies to B. ovis in an infected ram’s blood, using a test called an ELISA

Takes 2+ weeks from the time of infection until antibodies appear

Almost all infected rams develop detectable antibodies within 6 weeks of exposure

Serologic test all incoming rams

Part of a routine breeding soundness test of rams

Colorado study, 1989

Comparison of lamb crops in two flocks:

One with rams that passed BSE and were free from B. ovis

vs.

One with random source, untested rams

Results: It pays.

Increased lamb crop in flock w / tested rams:

Economic advantage of $12 / ewe

Besides lamb crop:

-Reduced expenditure on additional ram power

-Shorter lambing season

-More lambs born early in the lambing season

-Increased size and uniformity of lamb crop

Kimberling & Schweitzer, 1989

Breeding season

FERTILE RAMS

CSU Ram Test Data, 2000-2007

14,763 exams

Satisfactory: 71%

Questionable: 10.8%

Unsatisfactory: 18.1%

Reasons for unsatisfactory / questionable classification of rams (4,252 failed exams)

Reasons for failure % of failed exams

Sperm morphology or motility 43.2

Physical abnormalities(including low scrotal circumference and emaciated or obese)

30.8

Inflammatory causes 20.0(Epididymitis / WBC in semen / seropos. for B. ovis)

Ulcerative posthitis (pizzle rot) 4.6

Other 1.4

Summary Points on Ram Testing

Infertile and subfertile rams are an economic burden to the producer and may serve as a source of ovine brucellosis.

Optimizing ram fertility has been demonstrated to have tangible, positive economic results.

Ovine brucellosis is commonly subclinical and must be detected through serology.

Ultrasound examination for pregnancy

~ 5 weeks after last ram contact

Benefits of ultrasound exam

1. Serves as early indicator of infertile ram. An entire lamb crop can be missed if the ram is infertile.

2. Allows one to cull open ewes. This provides savings on winter feed costs…~$70 (1990 $US) to feed a ewe over the winter.

3. Can sell open ewe lambs.

Recall that these were born the previous spring. If sold in the fall, they will sell as lamb. If you keep these until the spring, they will be classified as mutton.

4. Allows for sorting of ewes according to stage of pregnancy or by # of fetuses

- fetal counting easiest at day 50-60 of gestation (40-80 if you’re really good)

Can group into early and late lambers

>1 fetus: fed more grain to limit risk of pregnancy toxemia

Winter / Spring

First lambs may arrive at the end of this month

+/- Clostridium perfringens C&D, tetanus toxoids to boost colostral titers, if not given prebreeding.

colostrum supply

Lamb Mortality Benchmarks

NAHMS Sheep 1996:Preweaning Mortality, all regions:

9.4% (out of lambs born alive)NAHMS Sheep 2001:

Preweaning Mortality, all regions:10.0%

Willingham et al, 1986: Preweaning mortality, TX study:13.6%

Primary Causes of Mortality

© WB Saunders Co, 1990.

Lamb losses: Most occur early in life

“Clip, dip, and strip”Clip umbilical cord to length of 2”

Dip umbilicus in iodine or novalsan

Strip out udder of ewe - removes plug, allows for detection of mastitis

Lambing

Colostrum – first milkContains antibodies vs. infectious agents

Critical for lamb survival

Tube feeding warmed colostrum:

10-15 I.U. oxytocin IM to ewe, wait 3 min., milk out

Milk into urine cup, collect in larger cup away from ewe

Triplets / dystocia lambs: may want to “jump start”

60 ml colostrum via tube to each

Repeat 1-2 times in first 24 hours

Summary Points

Ultrasonographic confirmation of pregnancy prevents $ loss from overwinter feeding of barren ewes

Most lamb losses occur in the first week of life

Ensuring colostrum intake is vital to lamb health

Questions?