Emus are large, flightless birds indigenous to mainland Australia. They have small wings and lack the powerful pectoral muscles necessary for flight. People interested in alternative livestock are raising emus for their meat (low cholesterol red meat), leather, feathers, emu oil (touted for many medical uses), to supply the breeder market with chicks or for other uses (green-belting land, as a novelty pet, for zoos, etc.). As an avian vet, or one who sees exotic pets in practice, you may be called upon to examine, diagnose and treat emus.
While it is fairly easy for an owner to bring in an emu chick, or even a clutch, into a veterinary clinic for examination, it can be difficult and even dangerous to transport an adult emu to an office. If at all possible, it is recommended that you travel to the emu facility to examine and treat emus. There are several reasons for this: it is much easier to watch an emu ambulate in its own pen, you will be able to see the bird in its own environment, not having been transported (and stressed) to a clinic, and you will be able to evaluate the facility, as well, which is very important. Due to the novelty of these birds, there is always a risk of danger to other clients and their pets in an animal hospital that may be curious about, and may approach, an emu.
In addition to learning about the anatomy and physiology of these birds, it is very important for the vet who will be treating them to learn as much as possible about husbandry, nutrition and preventative medicine in order to best advise owners properly. I feel that you are doing an emu patient a disservice if you are unable to actually go out and evaluate the emu facility as you are only getting half the picture.
Before you actually begin seeing emus in practice, it is always best if you can learn as much about bird anatomy as possible, and the specifics about emus. Emus are the second largest members of the ratite family. They are rather hardy three-toed birds that adapt quite well to many environments. Emus appear, to this author, to be the most intelligent and docile of the ratites. While they have a powerful kick and very sharp toenails, they rarely use them offensively. They can kick forward and backwards, and are able so swing their legs laterally, as well. They are good swimmers. Their tiny, useless wings have interesting vestigial claws.
Males have a protrusible phallus, however, determining the sex of chicks cloacally is often difficult, so many breeders may request DNA sexing as chicks (requiring venipuncture, usually), or they may wait until the birds reach maturity, to determine male or female. Emus possess a diverticulum in the trachea, about 6-8 cm. long, leading to a tracheal sac. This is visually obvious in an adult hen as a pouch of loose skin at the base of the neck. This poses special problems when an emu needs to be intubated and inhalation anesthesia needs to be administered. To prevent anesthetic problems, it is advisable to loosely wrap the distal neck to partially occlude the tracheal sac. Adult hens "boom" and adult males "grunt." The lungs and air sacs are anatomically similar to those of other avian species. Adult emus reach up to six feet in height and weigh up to 125-130 pounds. Mature emu hens lay clutches of ten to 40 eggs that are a beautiful dark bluish-green color. Emus have a lifespan of up to 30 years.
Emus have a four-chambered heart. They have a renal-portal system that is similar to that in other birds and reptiles. Unlike many other species of birds, emus do not have an ingluvies (crop). The proventriculus is quite large with the function of mixing food with digestive fluid prior to the ingesta being propelled into the ventriculus (the gizzard) where grinding occurs. The emus possess paired ceca, which are relatively short, and a short colon. The cloaca houses the Bursa of Fabricius, which is the primary lymphatic organ of the bird, and plays a critical role in the development of immunity. The bursa involutes by age three or four. If a young emu dies, and histopathology is to be performed, it should be standard practice to include the bursa in the tissues being examined, as it is usually extremely important diagnostically.
Emus have callosities on the skin at the points where the body contacts the ground when the bird is sternal. The sternum of the emu does not have a keel (carina) for attachment of flight muscles.
In areas where equine encephalitis is prevalent, a bivalent vaccine for EEE and WEE, eastern and western equine encephalitis, using a killed vaccine, should be administered every six months. A full one cc dose should be given intramuscularly in the thigh muscle. Vaccines for horses used should not contain tetanus toxoid or any other additives available for horses. Fecals should be checked every six months for both parasitic worm eggs and protozoa. Testing for Chlamydophila, Salmonella, and other organisms should be performed periodically. Prior to breeding season, birds should undergo a complete CBC and chemistry panel. The right jugular vein is easily accessible and much larger than the left one. The vein can be occluded in a similar manner to that of other species, however it is advisable to not stand directly in front of the bird when performing venipuncture, as they kick straight forward and can injure the phlebotomist. For small blood samples, the wing vein can be cannulated. For chicks or recumbent birds, the medial metatarsal vein can also be used, which runs along the medial side of the hock.
Optimally, chicks should be microchipped for identification purposes soon after hatching. The chip is placed in the muscularis complexus, also known as the hatching or pipping muscle at the nape of the neck. It is a simple procedure to place the microchip in the large complexus muscle. Within a week after hatching, this muscle begins to decrease in size, effectively securing the chip in the tissues. The chip may be placed in other locations in older birds, however, it is important to keep in mind that if the emu is destined for slaughter for meat, the chip may cause problems if it is lodged in muscle. For this reason, chips should not be placed in the dorsal epaxial musculature or thigh muscle. The muscle of the tail may be used as an alternate site and some breeders choose to place the chip in the left wing.
Chicks should receive their first vaccination for EEE/WEE at six weeks of age, using a full one cc dose. Chicks should then be boostered for EEE/WEE three to four weeks later, then every six months. They should also begin receiving 1% cattle ivermectin SQ, every three weeks at a dosage of 1 cc per 110 pounds of body weight, beginning when they are first placed outdoors (in areas where grackles are indigenous). The ivermectin prevents migration of Chandlerella quiscali, a filarid nematode that has the natural host of the grackle and is transmitted by the Culicoides gnats. Other parasitic problems are the raccoon roundworm, Baylisascaris procyonis, which can cause verminous encephalitis, both in adults and chicks from ingestion of eggs. Coccidiosis is common in chicks and may also be observed occasionally in adults. Large numbers of coccidia may cause some intestinal problems, including diarrhea, but the birds seem to develop a resistance and tolerance to these parasites as they age, similar to what we see in companion animal species. Emus are also susceptible to ascarids, other types of intestinal worms, tracheal and lung worms, and protozoa.
Emu chicks should be fed a commercial ratite diet, with protein in the range of 17-22%, and they may be offered finely chopped greens as well. Water should be offered to chicks when they are 2-3 days old, however most chicks will not begin eating and drinking for three to five days after hatching. Until that time, they are utilizing the nutrients in the yolk sac. Adult emus should be fed a commercial ratite diet and have fresh water available at all times. Emus love water and some breeders have set up sprinkler systems to mist their birds during the heat of the day. Emus need shade, and this can be provided by natural trees, shade cloth or appropriately sized sheds.
Adult emus should be housed in pairs. Juveniles may be housed in a group, but must be separated when they reach seven to eight months of age, as they will often begin fighting at that age. Pens should be as large and long as possible. Minimally, they should be 20 feet by 100 feet, but if possible, the larger the better. It is beneficial to use shadecloth as a visual barrier between emu breeder pens, as some emus will spend an inordinate amount of time displaying for neighboring emus.
Emus are inquisitive so pens should be free of metal debris, glass or other objects that could be dangerous if ingested. Pen substrate should be closely cropped grass preferably. Some breeders use shade cloth as a ground cover for chicks, which precludes them from ingesting anything on the ground (preventing impactions), however it must be cleaned frequently. All pens, for both chicks and adults, should be raked and cleared of debris and droppings daily.
During the initial visit to a ratite facility, you should carefully go over the diets being offered to chicks and adults. You should recommend a prophylactic program of vaccination and administration of ivermectin to prevent migration of Chandlerella quiscali, the filarid nematode. A protocol should be set up to microchip hatchlings, as well. Pen size, design and substrate should be discussed. Water delivery systems should be evaluated. You should also evaluate the incubation system, hatchers and brooders for newly hatched chicks.
It will be impossible for you to advise and assist emu breeders unless you have a thorough understanding about their breeding habits. Birds usually begin breeding when they are two years old, although those that hatch late in the season may not breed until they are three years of age. For this reason, early season hatch chicks are more desirable to the investor looking to purchase young birds for future breeding stock. Likewise, chicks from high-producing hens are also coveted for their future breeding potential.
Emus breed during decreasing daylight hours in North America, from October through April or May. Males incubate the eggs and rear the chicks in the wild. Emus scrape and dig out a shallow nest in the dirt, sometimes arranging twigs and leaves around the nest and covering the eggs. In captivity, most emu breeders retrieve each egg as it is laid (usually at dusk) for artificial incubation. Older hens tend to lay more eggs than first year layers and young hens.
Eggs cannot be candled by conventional methods to ascertain fertility. There are several ways to determine fertility, and embryo development can be monitored by egg weight loss during incubation. Eggs hatch after 46 to 50 days of incubation. An incubator temperature of 97.5 degrees F is often used, with a humidity of between 24 to 35 %. There are several incubators developed for ratite artificial incubation. Eggs should be turned frequently during incubation. When eggs are within a day of hatching, they are placed in the hatcher, which no longer turns the eggs, and has higher humidity.
Chicks are quite hardy and do best when allowed outdoors in large pens that allow them plenty of exercise. Chicks may suffer from leg deformities, the cause of which is usually multifactorial. Splay leg may occur in chicks, and is usually easily corrected if detected early and hobbles are applied to the legs.
Because emus are so inquisitive, they will inspect everything in their pens, usually pecking at anything that interests them. For this reason, pen maintenance is extremely important. Loose nails will often be ingested and may result in a perforation in the GI tract. Ingestion of metal scraps may result in lead, zinc or copper toxicosis. Larger objects may result in obstruction or perforation. Surgery is often required in these cases. A fiber-optics endoscope may be employed in some cases to retrieve foreign-bodies. Surgical approach may vary depending on the location of the FB or obstruction. Performing a celiotomy is similar to those performed on smaller birds.
The anesthetic most commonly used is isoflurane, and it is usually quite simple to intubate an emu. As previously mentioned, it is best to loosely wrap the distal trachea in hens to prevent gas build-up in the dead space created by the tracheal sac. If an emu must be sedated in the field, ketamine or tiletamine/zolazepam may be given by injection. However, without an accurate means of weighing an emu in the field, it is possible that the vet may inadvertently give the incorrect dose of injectable medications. Anesthetic recovery is a critical time, and care must be taken to ensure that the bird does not injure itself until recovery has occurred. Keeping the recovering emu in a dark location will greatly facilitate a smooth recovery.
Injuries commonly occur. Skin lacerations are usually easy to suture or staple, however, using local anesthetic is not recommended. The LD50 for drugs in the lidocaine group is quite low for avian species, and while emus are large birds, it is safest to avoid their use, if possible. Often, absorbable sutures are used to prevent the stress of recapture for suture removal.
Wing fractures may occur if the bird is restrained using the vestigial wings during procedures. Unless the fracture is compound, most wings will heal without intervention. Leg fractures are always serious and may result in the decision to euthanize a bird. Many papers have been written on methods of fracture repair.
Lameness, accompanied by swollen joints, may be a sign of mycoplasmosis. Conjunctivitis, respiratory signs and biliverdinuria may be signs of infection with Chlamydophila sp. These may also be signs of bacterial infections.
Diarrhea may have many causes. Salmonellosis can be one cause, which has serious implications for the birds (which cannot then be used for meat, chick production, or other products).
In addition to bacterial, mycoplasmal, chlamydophilial and parasitic infections, emus are also susceptible to fungal infections (most commonly aspergillosis) if raised on wet, moldy hay or contaminated feed. Immunosuppression, bacterial infection and over-use of antibiotics may predispose a bird to aspergillosis. Occasionally, candidiasis may cause problems, especially in chicks. Some viral infections are also significant in emus, which were previously discussed.
Reproductive problems with hens may occur, resulting in egg-binding or dystocia. There can be many causes, including hypocalcemia, oviductal infection and ruptured oviduct. Peritoneal hernias may occur, egg peritonitis may also occur and a hen may lay internally (passing a yolk/ovum into the celoem instead of the infundibulum). Surgery may be required to correct reproductive problems in hens.
Developmental deformities in chicks may be simple or complex. Splay-leg is usually easily corrected by hobbling the bird and placing it on an appropriate substrate. Occasionally, other types of deformities of the musculoskeletal system or beak may occur. Chicks may hatch with a large, externalized yolk, which usually requires surgery. Hernias may be corrected surgically, if large, yet some umbilical hernias will close spontaneously.
Sick emus should be cared for as you would other avian species. Heat, a stress-free environment and appropriate support care are essential. An esophagostomy tube may be placed in order to force-feed emus. Some antibiotics can be administered in the drinking water if the bird is not clinically ill. Tablets and capsules may be given orally. Injections may be given IM or IV. Parenteral fluids may be given via indwelling IV catheters. IV catheters should be placed in the upper half of the right jugular vein to prevent the bird from plucking at it and should be replaced every 24-36 hours.
Emus are fascinating ratites. The meat they produce is a low-cholesterol red meat that is tasty and healthier than beef. With the emergence of bovine spongiform encephalitis, health-conscious families may seek alternatives to beef, and emu and ostrich may yet be the new red meats of the future. Their hides make excellent leather products and emu oil may prove to have several uses in the health and beauty fields. So these birds may prove to offer the future farmers of America an alternative to cattle.
Copyright © 2006 Margaret A. Wissman, D.V.M., D.A.B.V.P.
All Rights Reserved
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