Exam II: Organic Synthetic Herbicides, Fungicides, Feed/Water Toxicants, Metals and Minerals

Question 1

Which species is most sensitive to the toxic effects of

phenoxy acids?

Answer 1

Dogs

(acute oral LD50 = 100 mg/kg)

Question 2

_________ of urine enhances renal excretion

of phenoxy acids

Answer 2

Alkalization

Question 3

Rumen stasis with ingested food

is a characteristic finding of toxicosis by this agent

Answer 3

Phenoxy acids

Question 4

You have a farm with cows and pigs. You also have farm dogs that roam about.

All of a sudden, you notice that all of your animals

have diarrhea and are showing signs of muscle weakness

(the dog is mainly ataxic on the hindlimbs).

The dog’s diarrhea is bloody and both the dogs and the pigs are vomiting.

The cow has some ulcers in its mouth. Despite all of these neuro signs,

none of the animals are convulsing.

Elevated AP, LDH, and CPK are reported in blood samples.

What is your primary ddx?

Answer 4

Phenoxy acid toxicosis

Question 5

This agent alters the metabolism of plants which increases

their toxicity by increasing accumulation of either nitrite or cyanide

Answer 5

phenoxy acids

Question 6

The main mechanism for metabolism of phenoxy acids is

Answer 6

Hydrolysis

Question 7

Paraquat and Diquat are __________ herbicides

Answer 7

Dipyridyl

Question 8

T/F: Solutions of Dipyridyl herbicides are destroyed in acidic conditions

Answer 8

FALSE!

They are destroyed in ALKALINE conditions

Question 9

What are 3 ways that Paraquat (dipyridyl) toxicity can be enhanced

Answer 9

Selenium/Vit E deficiency

Depletion of tissue Glutathione

Oxygen therapy

Question 10

The toxicity of which agent can be increased by

supplementing oxygen

Answer 10

Paraquat (dipyridyl) herbicide

Question 11

Paraquat binds strongly to ______

Answer 11

soil

Question 12

T/F: Paraquat (dipyridly) herbicides are best absorbed via GIT and skin

Answer 12

FALSE!

Paraquat is poorly absorbed through GIT and skin!

Question 13

This agent achieves highest concentration in the lungs, an

astonishing 10X the concentration of the rest of the body

Answer 13

Paraquat (dipyridyl)

Question 14

The respiratory signs seen in subacute/chronic toxicosis

by Paraquat are due to ______________ and include:

Dyspnea, Tachypnea

Harsh respiratory sounds

Cyanosis

Reduced pulmonary compliance

Answer 14

progressive pulmonary fibrosis

Question 15

At a puppy mill, several dogs present with dyspnea and tachypnea.

Some are cyanotic, and some are having seizures. A couple have ulcers on their

tongues. After treating one dog with fluids and oxygen, it died

and upon necropsy, you find significant

pulmonary congestion and hemorrhagic edema of the lungs.

The liver, kidneys, and spleen are all congested and enlarged.

What is your primary ddx?

Answer 15

PARAQUAT (Dipyridyl)

Oxygen therapy is CONTRAINDICATED…

you should not have given that dog oxygen!

Question 16

T/F: Dermal exposure to the fungicide pentachlorophenol is the most

toxic route of exposure

Answer 16

TRUE

Question 17

This agent can give off toxic vapors in toxic concentrations,

especially at high ambient temperatures

Answer 17

Pentachlorophenol (Fungicide)

Question 18

Why is Pentachlorophenol (Fungicide)

not persistent in water, sewage, or soil?

Answer 18

Due to bacterial decomposition

Question 19

Hyperthyroidism is a factor that can increase toxicity of this agent

Answer 19

Pentachlorophenol (Fungicide)

Question 20

T/F: Antithyroid drugs can decrease toxicity of Paraquat

Answer 20

FALSE! Antithyroid drugs can decrease toxicity of

Pentachlorophenol (Fungicide)!

Question 21

How is Pentachlorophenol (Fungicide) metabolized?

Answer 21

Via conjugation to glucoronic acid

Question 22

In the hottest part of the summer, you decide to tear down an old barn on your property by the cow field in order to make room for the new “milkatorium”.

The next morning, you wake up to a HORRIFYING scene.

Some of your cows are dead, many of the others are in

respiratory distress and are overheated (have a fever).

You observe one cow die and rapidly go into rigor mortis.

You decide to draw blood and notice it is extremely dark in color.

What is your primary ddx?

Answer 22

Pentachlorophenol (Fungicide)

Question 23

In the hottest part of the summer, you decide to tear down an old barn on your property by the cow field in order to make room for the new “milkatorium”.

The next morning, you wake up to a HORRIFYING scene.

Some of your cows are dead, many of the others are in

respiratory distress and are overheated (have a fever).

You observe one cow die and rapidly go into rigor mortis.

You decide to draw blood and notice it is extremely dark in color.

You rule out Nitrite toxicosis…Why?

Answer 23

Nitrite toxicosis also causes brown (dark) blood,

but there is no hyperthermia seen with nitrite toxicosis

Question 24

Hyperkeratosis of the skin and

villous-like hyperplasia of the urinary bladder mucosa

are clinical signs associated with chronic toxicosis via this agent

Answer 24

Pentachlorophenol (fungicide)

Question 25

T/F: Urea is very acidic

Answer 25

FALSE! Urea is BASIC

Question 26

The species most susceptible to urea toxicosis

Answer 26

Ruminants

Question 27

What is the most toxic of all non-protein nitrogen compounds?

Answer 27

Urea

Question 28

Which is most sensitive to urea toxicosis? 3 year old bull 9 month old calf 3 week old calf

Answer 28

9 month old calf! Very young ruminants are TOLERANT to urea toxicosis!

Question 29

Toxicity of urea can be increased by urease. What is an example of a feed rich in urease?

Answer 29

Soybeans

Question 30

What is the normal rumen pH of ruminants?

Answer 30

5.0 - 6.5

Question 31

T/F: At an increased urine pH (due to ingestion of excess urea), ammonia is in the ionized form and is absorbed

Answer 31

FALSE Ammonia is in the NON-IONIZED form and is absorbed

Question 32

T/F: In urea toxicosis, non-ionized ammonia cross the BBB and placental barrier

Answer 32

TRUE

Question 33

Urea ________ the pH of the rumen causing ammonia to exist in its non-ionized form which can then be absorbed into circulation

Answer 33

_increases_ | (more basic)

Question 34

In urea toxicosis, the rumen pH is \_\_\_\_\_\_\_\_ while systemic pH is \_\_\_\_\_\_\_\_

Answer 34

In urea toxicosis, rumen pH is _increased_ while systemic pH is _decreased_ (systemic acidosis via ammonia!)

Question 35

What 3 fluids can ammonia be found in for lab dx of urea toxicosis?

Answer 35

Whole blood Rumen fluid Vitreous fluid

Question 36

A farmer puts his herd of cows on a new feed supplement. No more than 2 hours later, the cows are acting crazy! Some are being **aggressive, salivating,** and **grinding their teeth**, while others are in **sternal recumbency while standing on their hind limbs**! One is **convulsing** and one has died. The dead cow is **extremely bloated**. Despite all of this, there is **no** sign of **diarrhea**, and the newborn calves seem unaffected. **_What is your primary ddx?_**

Answer 36

Urea Toxicosis

Question 37

Which is the most common ionophore?

Answer 37

Monensin

Question 38

Which species is most sensitive to the toxic effects of ionophores?

Answer 38

Horses!

Question 39

This agent is absorbed 50% in ruminants and 100% in monogastrics

Answer 39

Monensin (Ionophore)

Question 40

This agent does NOT accumulate in tissues when given in HIGH doses

Answer 40

Monensin (Ionophore)

Question 41

How is monensin (ionophore) metabolized?

Answer 41

Rapidly by P-450 oxidative demethylation enyzymes in the liver (Which is why HORSES are most sensitive...they have the lowest oxidative demethylases of all the animals!)

Question 42

The main targest of monensin (ionophore) are

Answer 42

The mitochondria of highly energetic tissues: Myocardium Skeletal mm. Kidney Neurons Smooth mm.

Question 43

Skeletal and cardiac muscle lesions are one of the most important clinical signs associated with toxicosis by this agent

Answer 43

Monensin (ionophore)

Question 44

The best sample to send to a lab if ionophore (monensin) toxicity is suspected is

Answer 44

Sample of the FEED!

Question 45

What abnormalities do you expect to see on blood work/biochem of an animal with monensin (ionophore) toxicosis?

Answer 45

Elevated CPK, AST, LDH and ALP Decreased serum Ca and K (first 12 hours) Increased PCV NO change in Na!

Question 46

What are the normal Na levels in the plasma and CSF?

Answer 46

1. Plasma = 135 – 145 mEq/L 2. CSF = 130 – 140 mEq/L

Question 47

Eosinophilic meningoencephalitis is pathognomonic for this toxicity in PIGS

Answer 47

Water deprivation/sodium toxicosis

Question 48

On a dairy farm in the **cold** of winter in Wisconsin, cows in a field present with **circling** and **head-pressing**, **intermittent convulsive seizures**, **blindness**, **deafness**, and **metabolic acidosis**. Upon necropsy of a dead cow, gastric inflammation and **pinpoint ulcers** are seen, along with prominent **cerebral edema**. **_What is your primary ddx?_**

Answer 48

Water deprivation/sodium ion toxicosis

Question 49

On a dairy farm in the cold of winter in Wisconsin, cows in a field present with circling and head-pressing, intermittent convulsive seizures, blindness, deafness, and metabolic acidosis. Upon necropsy of a dead cow, gastric inflammation and pinpoint ulcers are seen, along with prominent cerebral edema. **_How would you treat these animals?_**

Answer 49

Small amounts of fresh water GRADUALLY over 2 – 3 days (large amounts of water aggravate cerebral edema and can cause death) This is water deprivation/sodium ion toxicosis

Question 50

What is the most toxic oxidative state of inorganic arsenic?

Answer 50

Trivalent (Arsenite)

Question 51

Which species is the most susceptible to inorganic arsenic toxicosis?

Answer 51

Herbivores

Question 52

Which entity is the most sensitive to damage by the toxic effects of inorganic arsenic toxicosis?

Answer 52

Capillary endothelial cells

Question 53

Several cows in Farmer Ben's herd present with the following: Salivation, staggering, and depression. A few have hemorrhagic diarrhea and mucosal shreds are seen in the diarrhea too. Some of the cows seem to be paralyzed (just their hind limbs). Microscopic evaluation shows capillary degeneration. What is your primary ddx?

Answer 53

Inorganic arsenic toxicosis

Question 54

How is inorganic arsenic toxicosis treated? (other than emeergency and supportive treatement and decontamination)

Answer 54

Demulcents (to coat gastric mucosa) and CHELATION therapy (**Kaolin-pectate** is the demulcent of choice) (**Dimercaprol** is the chelator of choice!)

Question 55

What are the 2 main purposes for organic arsenic as a feed additive?

Answer 55

To improve weight gain and control enteric infections in swine and poultry

Question 56

What type of organic arsenic is used to control enteric infections in pigs? In poultry?

Answer 56

1. Arsanilic acid – swine 2. Roxarsone – poultry

Question 57

Toxicity of organic arsenic is enhanced by what 2 mechanisms?

Answer 57

Dehydration/Water deprivation Renal insufficiency

Question 58

What is the MOA of organic arsenic?

Answer 58

Peripheral nerve demyelination and axonal damage

Question 59

Blindness is a clinical sign seen with this organic arsenic agent

Answer 59

Only with **Arsanilic acid** _{(not Roxarsone)}

Question 60

The following clinical signs are caused by \_\_\_\_\_\_\_\_. Erythema in light-skinned pigs Muscle atrophy Microscopically, peripheral and optic nerves degeneration, demyelination, & gliosis

Answer 60

ORGANIC arsenic toxicosis

Question 61

What are the 3 sources of copper toxicosis (chronic) in sheep?

Answer 61

Excess copper Molybdenum deficiency Sulfate deficiency

Question 62

Normally, **molybdate** (MoO42‐) binds to **copper** (Cu2+) in tissues At a ratio of \_\_\_\_:\_\_\_\_ To form copper molybdate (CuMoO4) that is readily excreted in urine

Answer 62

**4:3** **molybdate:copper**

Question 63

What is the normal copper to molybdenum ratio?

Answer 63

Normal copper:molybdenum ratio = **6:1**

Question 64

Accumulation of copper in the liver is due to imbalances between

Answer 64

copper, molybdenum, and sulfate

Question 65

Copper oxidizes hemoglobin in blood resulting in

Answer 65

Methemoglobinemia

Question 66

A sheep presents at necropsy. The cause of death is unknown. The only history we have is that the sheep was transported from one farm to another recently. The findings from the necropsy are as follows: Kidneys- enlarged, hemorrhagic, bluish-dark, friable Spleen- blackish in color and enlarged Liver- Enlarged, yellow, and friable **_What is your primary ddx?_**

Answer 66

Copper toxicosis precipitated by the stress of being transported! GUNMETAL KIDNEYS and BLACKBERRY JAM SPLEEN

Question 67

Sudden onset of hemoglobinuria, jaundice, and signs of shock and respiratory insufficiency in a sheep is most likely caused by

Answer 67

Cooper toxicosis!

Question 68

Ammonium tetrathiomolybate and D‐penicillamine can be used to treat and prevent

Answer 68

Copper toxicosis in sheep

Question 69

What breed of dog is most susceptible to chronic copper toxicosis due to an autosomal recessive disorder at 2 - 6 years old?

Answer 69

Bedlington Terriers

Question 70

Elevated molybdenum can cause ________ deficiency

Answer 70

copper

Question 71

What species is most susceptible to molybdenum toxicosis?

Answer 71

Cattle

Question 72

In molybdenum toxocosis High levels of dietary sulfate\_\_\_\_\_\_\_ toxicity High levels of dietary copper *\_\_\_\_\_\_\_* toxicity

Answer 72

High levels of dietary sulfate *increases* toxicity Dietary copper *decreases* toxicity

Question 73

The following clinical signs result from _______ toxicosis: Severe diarrhea (Greenish, with fluids and gas bubbles) Rough hair coat and depigmentation (Achromotrichia), especially around the eyes (“spectacled” appearance) Loss of weight, anemia Osteoporosis and Lameness Pica Decreased libido in bulls Infertility in cows

Answer 73

MOLYBDENUM toxicosis!

Question 74

The 6 Selenium deficiency diseases include:

Answer 74

White muscle disease (lambs) Nutritional muscle dystrophy (lambs) Hepatosis dietica (young pigs) Exudative diathesis (chicks) Nutritional pancreatic atrophy (chickens) Porcine Stress Syndrome

Question 75

What are the 4 genus of plants that are considered seleniferous **obligate** accumulators?

Answer 75

* Astralagus* (locoweed, milk vetch) * Stanleya* (prince's plume) * Oonopsis* (golden wood) * Xylorrhiza* (woody aster)

Question 76

What are the 3 genus of plants that are considered seleniferous **facultative** accumulators?

Answer 76

* Aster* * Atriplex* (saltbush) * Castilleja* (paintbrush)

Question 77

\_\_\_\_\_\_\_\_\_ acts as antioxidant by prevention of peroxide accumulation through reduction of glutathione

Answer 77

Selenium

Question 78

What is the most toxic form of selenium?

Answer 78

Organic selenium in plants

Question 79

T/F: Selenium is teratogenic and is excreted in milk

Answer 79

TRUE