The General Practitioner’s Guide to Small Ruminants and Camelids

Small ruminants, specifically sheep and goats, were among the first animals to be domesticated. Sheep and goats are primarily used as a source of meat, milk, and fiber, yet they are small and versatile enough to also be considered pets.¹ Nonetheless, in terms of veterinary care for sheep and goats, these species are considered food animals and should be treated as such in accordance with veterinary law.

Camelids (e.g., llamas, alpacas, vicuñas) are considered pseudoruminants because of their 3-chamber stomach that is different from the 4-chamber stomach of ruminants. Their classification as food animals is less clear because they typically do not enter the food chain in the United States. It is the veterinarian’s responsibility to ensure proper guidelines for drug administration are followed.

Few products are labeled for small ruminants and camelids, further complicating the decision-making process (TABLES 1 AND 2). For example, in the United States, the only injectable antimicrobials currently approved by the U.S. Food and Drug Administration for use in small ruminants are penicillin G procaine (approved for use in sheep but at an inadequate dose), ceftiofur sodium (for sheep and goats), and tilmicosin (for sheep). The Animal Medicinal Drug Use Clarification Act of 1994 and extra-label drug use regulations for these species describe requirements for veterinarians who work with them.⁵

Husbandry Practices

Husbandry practices for small ruminants, specifically sheep and goats, vary widely according to the client’s goals and animal’s purpose (i.e., pet or production animal).

Vaccination

Standard vaccine recommendations for sheep, goats, and camelids are an initial booster vaccine series as lambs/kids/crias, followed by an annual booster for protection against Clostridium perfringens types C and D and Clostridium tetani (often referred to as a combination “CD/T” vaccine). A newborn birthed from a dam with an unknown or no vaccination history should receive an initial vaccine or antitoxin at 2 to 3 days of age, then a booster vaccine 3 to 4 weeks later; a third booster 3 to 4 weeks later can also be considered. The initial series should be followed by an annual booster for all adults.

For breeding females, consider administering the annual vaccine booster 4 to 6 weeks before parturition. If the dam is vaccinated before parturition, lambs/kids/crias can receive an initial vaccine at 4 to 6 weeks of age, a booster vaccine 3 to 4 weeks later, then an annual booster vaccine. Rabies vaccines are often recommended for camelids, depending on their likelihood of exposure.

Numerous other vaccines may be given to sheep, goats, and camelids but are not broadly recommended unless certain risk factors are present. Those risk factors are associated with the likelihood of flock/herd exposure and if a disease is endemic to that region or known to be present within a flock/herd. Many vaccines are not approved for use in these species; thus, extra-label administration must be utilized.

Hoof Trimming

Sheep, goats, and camelids should undergo regular hoof trimming; frequency is influenced by genetics, diet, and environment. A routine hoof trim is recommended at least 1 to 2 times per year, and more often for those with lameness or pathology.

Diet

Nutrition is a complex point of consideration for sheep, goats, and camelids. The most reliable source for guidance on feeding small ruminants is the most recent version of Nutrient Requirements of Small Ruminants by the National Research Council.⁶ All 3 species are primarily foragers, yet other nutritional and mineral requirements are determined by life stage.

Production animals require specific diets that must be adjusted during phases of growth, reproduction, and lactation. Alternatively, pets require less intensive dietary management because production phases do not apply. Pets can generally be fed a basic maintenance diet.

Trace minerals should be supplemented according to species-specific needs. Sheep and camelids are sensitive to excess copper; therefore, dietary copper supplementation should not exceed toxic levels.⁷

Water, which is commonly overlooked, is the most essential nutrient. Water intake should be adjusted according to an animal’s dry matter intake and life stage. Maintenance requirements for water intake increase with pregnancy, lactation, growth, and heat stress.⁶

Dental Health

Dental health of sheep and goats is not routinely evaluated. However, for camelids, routine dental examinations are advised to detect and prevent dental disease. Note that the routine floating of sharp enamel points that is recommended for equids is not advised for camelids.⁸ The primary pathology of dental disease in camelids, specifically tooth root abscesses, often occurs at the cheek teeth and, to a lesser extent, the incisors and canine teeth.⁹

Common Health Challenges

Obesity

Obesity is a common problem in pet sheep and goats, and owners should be educated about diet and appropriate body condition. Body condition score (BCS) can be used to monitor an animal’s body reserves and track changes over time. BCS of sheep and goats is measured on a 5-point scale with 0.25, 0.5, and 0.75 being used between whole numbers. An emaciated animal has a BCS of 1, and an obese animal has a BCS of 5. An ideal BCS ranges from 2.75 to 3.5, depending on an animal’s life stage and energy demands. BCS should not be determined solely by visualization; it should be determined by visualization and palpation of the dorsal lumbar region to assess fat and muscle deposition along the animal’s topline.

Obesity is also a problem in camelids and can lead to excess fat infiltration of the liver. Conversely, camelids are predisposed to hepatic lipidosis after extreme or chronic weight loss.

Gastrointestinal Parasitism and Anemia

Gastrointestinal parasitism is the most significant health issue in small ruminants with its inestimable effects on production through treatment costs (including additional necessary treatment for anthelmintic resistance), ill thrift (poor doers), and fatalities. The most effective way to assess gastrointestinal parasites is to run a modified McMaster fecal egg count (FEC), which identifies and quantifies parasite burden.¹⁰ Treatment effectiveness can be monitored with a fecal egg count reduction test (FECRT) 10 to 14 days after anthelmintic administration.¹⁰ More information about conducting a modified McMaster FEC is available at go.navc.com/3WXZrKK.

Pathogenic Nematodes

The most important clinical disorder of sheep and goats is anemia, of which gastrointestinal parasitism with Haemonchus contortus worms is the most common cause.¹¹ Anemia can be presumed if the animal has pale mucous membranes, specifically the conjunctiva. Conjunctiva color is evaluated by using the Faffa Malan Chart (FAMACHA) scoring system (go.navc.com/4cmFkKP).^12,13 In addition to conjunctiva pallor, signs of anemia include weakness, lethargy, tachycardia, and tachypnea.¹²

The FAMACHA scoring system has been used for camelids as well. Their clinical signs and scores seem to mirror those of sheep and goats; however, FAMACHA scoring for camelids is much more challenging because of difficulties handling the animals and differences in mucous membrane pigmentation.¹³

Regularly scheduled assessments of FAMACHA scores, ideally every 2 to 4 weeks, are recommended for sheep, goats, and camelids. Records should document FAMACHA scores as well as any clinical findings.

Protozoa

Eimeria infections, especially in camelids, can be a major problem. Gastrointestinal parasitism with Eimeria species, also known as coccidiosis, can cause anemia in addition to hypoproteinemia and failure of young or immunocompromised animals to thrive.

Coccidiosis can be classified as either clinical or subclinical. Clinical signs range from none (in acute cases) to severe diarrhea, weight loss, and lethargy. A diagnosis of coccidiosis can be made with an FEC. Prompt treatment is critical to ensure that the animal’s intestinal lining is not permanently damaged.

Treatment

Extensive multidrug anthelmintic resistance worldwide necessitates proper and judicious use of anthelmintics. Determining which anthelmintic is appropriate must be done at the individual farm/ranch level through routine use of FECRTs. In the United States, the most commonly used anthelmintics belong to 1 of 3 classes: benzimidazoles, membrane depolarizers, or macrocyclic lactones. Rotational use of anthelmintic products is no longer recommended and will upregulate the development of resistance. Targeted treatment strategies are critical for maintaining refugia within a population.¹⁴

The decision to deworm an animal should be based on its FAMACHA score, FEC, and clinical signs of anemia. Small ruminants should not receive anthelmintics via injection; these products should be administered via the oral route only (TABLE 2). The American Consortium for Small Ruminant Parasite Control (wormx.info) has recommendations for small ruminant parasite management.

Typically, anticoccidial drugs for small ruminants are administered as a 5-day treatment regimen of sulfadimethoxine (Albon; Zoetis, zoetisus.com) or amprolium (Corid; Huvepharma, huvepharma.us). It is important to note that amprolium contains a thiaminase, which can induce polioencephalomalacia if the animal is slightly deficient in thiamine (vitamin B₁). Therefore, precautionary thiamine administration should be considered before treatment.

Treatment of anemia should focus on the primary cause, yet a whole-blood transfusion may also be indicated for patients with a hematocrit of 12% or lower. More than 1 transfusion may be necessary because the half-life of transfused red bloods cells ranges from 5 to 20 days, depending on the source of red blood cells.¹⁵

Other management strategies for mitigation of parasite load include appropriate pasture management and rotation, feeding tannin-rich forages, and maintaining records of necessary data to make management decisions.

Urolithiasis

Urolithiasis is a common health problem in sheep and goats and primarily affects males.¹⁶ The stone composition is predominately calcium apatite or calcium phosphate, yet struvite calculi are common as well.¹⁷ An obstruction secondary to calculi can form in the urethra of castrated and intact males, typically at the urethral process and/or sigmoid flexure.¹⁸

Many factors influence the development of urolithiasis, including diet, age, sex, breed, and water intake.¹⁹ A common predisposing factor is consumption of grain, followed by excess urinary phosphorus excretion. Another common predisposing factor in pet sheep and goats is obesity.

When calculi form in the urinary bladder, the animal often remains asymptomatic; however, when calculi migrate to the urethra, they can cause partial or complete obstruction of urinary flow.²⁰ Clinical signs are variable and tend to progress as the severity of obstruction intensifies and include those of discomfort (e.g., vocalizing, restlessness, frequent posturing or straining to urinate). An animal may exhibit nonspecific signs such as poor appetite and lethargy. Obstruction can result in rupture of the bladder or urethra.

Numerous factors determine the available treatment options, such as the clinician’s expertise, the client’s goals and finances, and the patient’s response to treatment. Initial evaluation should include physical examination, basic laboratory testing (i.e., complete blood count and chemistry), intravenous catheter placement, fluid therapy as indicated, diagnostic imaging, and cystocentesis or temporary percutaneous urinary bladder catheterization.²⁰ Often the first treatment effort to resolve the obstruction is urethral process amputation, which can be performed in the field. If urethral process amputation does not resolve the obstruction, further evaluation and surgical intervention may be performed either by the general practitioner or at a referral hospital.

Urolithiasis cases are often expensive and unrewarding. Thus, clients should be informed of the value of preventing and need to prevent urinary calculi. Paramount is minimizing grain concentrate and maximizing forage intake for male small ruminants. To limit phosphorus availability, the calcium:phosphorus ratio of the ration should be maintained from 1:1 through 2:1. Management strategies to maximize water intake also help prevent urolithiasis.

Summary

The variability in management practices and veterinary care of small ruminants and camelids is extensive. Many more management considerations and health challenges exist than are discussed in this article. Client education on conscientious husbandry and management techniques is immeasurably beneficial. Extra-label drug use is necessary for most patients, with attention to withdrawal periods for food animal species. The popularity of small ruminants and camelids is increasing and, along with it, the need for general practice veterinarians to be familiar with their husbandry and treatment.