Latest BOLOs

New World Screwworm

Issued: July 2025

New World Screwworm (NWS) flies can be devastating to livestock and other mammals because of the growth cycle of their larvae. Screwworm fly larvae, or maggots, burrow into the flesh of living animals causing serious, and even deadly, damage to the animal. Adult screwworm flies are about the size of a common housefly (or slightly larger) with orange eyes, a metallic blue or green body, and three dark stripes along their backs.

Toic Plant: Common Cocklebur

Issued: 2025

Toxic plant pigweed (also known as rough cocklebur, cockleburr), scientifically known as Xanthium strumarium, is a native, annual, invasive plant that grows one to three feed tall. It grows in disturbed areas, sandy soils, and in wet areas like washes and creeks. Leaves can grow large and are triangular in shape. The seed is football shaped with spiny burrs that stick to clothing, animal fur and skin. 

Toxic Plant: Pigweed (Amaranthus spp.)

Issued: 2025

Toxic plant pigweed (also known as red root, red root amaranth, parelessweed, palmers amaranth, wild amaranth) is an annual in the amaranth and goosefoot family that ranges in height from 1 to 6 feet. All classes of livestock, including llamas and alpacas are negatively impacted. Avoid grazing areas during early growth and/or after sudden temperature changes as that is when the plant is the most toxic to livestock. However, toxicity can occur at any time of the plant's growth.

Toxic Plant: Puncturevine (Goathead)

Issued: 2025

Toxic plant puncturevine (also known as  caltrop, goathead, cat's-head, devil's thorn, tackweed) is a low growing annual that grows mainly in disturbed areas and sandy soils. It also occurs heavily in overgrazed pastures. All classes of livestock including are negatively impacted. The plant contains toxic saponins which may contribute to animal bloat. The wilted plant is the most toxic. Additionally, the plant can carry fungal toxins which cause photosensitivity skin damage and in the case of sheep, swelling of the head. Lameness and/or infection can also occur in the feet or mouth from seeds that become embedded in the skin of the animal.

Toxic Plant: Common Snakeweed (Guttierezia species)

Issued: 2025

Common snakeweed (also known as snakeweed, broomweed, broom snakeweed, matchweed, threadleaf) is a short-lived, native, perennial shrub or subshrub that grows from 8 to 28 inches in height. Cattle, sheep and goats are all impacted. The toxic agent is saponin, and is considered a secondary absorber of selenium which is toxic. Toxin is soluble in milk so nursing calves may be the first to show signs or symptoms.

Dairy Cattle: Highly Pathogenic Avian Influenza (HPAI)

Issued: April 2024

Highly Pathogenic Avian Influenza, or avian flu or bird flu, is a disease caused by infection with avian Type A viruses. This virus spreads naturally among wild aquatic birds via the fecal-oral route, but it can infect other birds, such as poultry and other animals. While HPAI can infect humans via direct contact (e.g., touching eyes, mouth, etc., with contaminated hands) and/or the respiratory route, it is rare. Clinical signs that have been seen include a drop in milk production, thickened or colostrum-like milk, appetite loss, manure inconsistencies, or a low-grade fever. Cows that are infected typically display symptoms for a period ranging from 7 to 10 days before experiencing a recovery. 

Poultry Disease: Avian Flu (Avian Influenza)

Issued: June 2022

Avian Flu is impacting domestic poultry (including Geese, Quail, Chickens, Ducks, Pheasants and Turkeys) throughout the entire state of Arizona. Avian Influenza is a naturally occurring virus in wild (non-domestic) birds that can be transmitted to domesticated poultry. The virus can be found in the feces, nasal secretions or saliva of infected birds. People can spread the virus from bird to bird or flock by poor bio-security habits. 

Toxic Plant: Rocky Mountain Iris (Iris missouriensis)

Issued: June 2022

Rocky Mountain Iris is a toxic plant impacting cattle (especially calved) in southern Navajo and Apache Counties and Northern Greenlee County. The plant is a wild Iris that grows up to 12 inches tall. Flower is blue to purple with a yellow stripe on the petals. The leaves look similar to grass until plant is full grown. It is usually found in high altitude ponderosa pine or spruce-fir forests, and in heavily grazed areas with seasonally moist meadows.

Toxic Plant: Locoweed

Issued: March 2022

Toxic plant locoweed (many species in genera Astragalus and Oxytropis) impacting cattle, horses and sheep in Pima, Santa Cruz and Cochise counties. Symptoms can vary, but poisoning from locoweeds is a chronic process, animals must consume the plant regularly over a period of weeks. Signs of toxicity include odd or erratic behavior, extreme nervousness, a slow, staggering gait, staring, depression, weight loss, and lack of coordination. 

Horse Disease: Strangles

Issued: February 2022

Strangles is a bacteria that impacts equine (horses, donkeys and mules). These can vary from horse to horse. Early signs include early onset of fever (over 100.5 F in adults, over 101.5 F in foals), mild cough, sluggish, reduced appetite and clear nasal discharge. More advanced signs include wheezing and coughing, thicker nasal discharge that is white or yellow, difficulty swallowing from inflammation of the throat, swelling (externally) from abscesses (internally) forming in the lymph nodes (throatlatch and below the jaw).

Horse Disease: West Nile Virus

Issued: January 2022

West Nile Virus (WNV), also known as West Nile Encephalitis is a virus that impacts horses and humans. Signs can vary from horse to horse. Most signs will be neurological and can get progressively worse. Early signs include depression, increased sensitivity to external stimuli, occasional fever, head drooping, incoordination, excessive chewing motions, muscle twitching (muzzle, ears, and fine muscles), and aggression.