Teratology 2

Question 1

Using drugs in pregnant animals

Answer 1

Most drugs will have disclaimers stating that they should not be used
-off label use for drugs that don’t say they are safe for pregnant animals are therefore risky

Question 2

Potential chemicals and drugs teratogens

Answer 2

1. Vitamin A toxicity
2. Albendazole
3. Organophosphate insecticides
4. organochlorine insecticides (DDT, lindane)
5. Griseofulvin

Question 3

Vitamin A toxicity

Answer 3

Essential vitamin; and often used in skin issues
-interferes with neural crest cell migration
-results in fetal resorption, cleft palate, micropthalmia, spina bifida, heart/GI.urogenital defects

Question 4

Albendazole

Answer 4

-Inhibits microtubule formation
-not a super toxic antihelminthic but is teratogenic
-results in spina bifida, bond and kidney defects

Question 5

Organophosphate insecticides

Answer 5

-both embryotoxic and fetotoxic
-results in CNS issues (learning impairment and behavioural change)

Question 6

Organochlorine insecticides (DDT, lindane)

Answer 6

Estrogenic effects
-prevents implantation
- Resorption
-reduced CL formation
-reduced progesterone
-reduced sperm

**many herbicides, fungicides, pesticides are not well tested; not necessarily teratogenic but cause clinical signs

Question 7

Griseofulvin

Answer 7

Antifungal drug
-not species specific
-reduced microtubule and mitotic spindle function
-results in abortion, resorption, bone, neural tube, cyclopia, anopthalmia

Question 8

Cyanide

Answer 8

Plant origin
-effects energy and oxygen utilization
-can result in arthrogryposis

Question 9

Nitrates

Answer 9

Plant origin
-results in methemoglobin formation and anoxia in the fetus
-causes abortion (herd problem) and sudden death of adults
**feeding high nitrate diets to adult cattle can lead to adaptation and ability to survive it

Question 10

What are some teratogenic mycotoxins?

Answer 10

**mg/kg toxic range (very small amounts)
-Zearalenone
-alfatoxin
-fumonisins
-Trichothecences
-Dicoumarol
-Ergot

Question 11

Zearalenone

Answer 11

-estrogenic, infertility, and potentially abortion
-pigs more susceptible than cattle
-rapidly eliminated

Question 12

Aflatoxin

Answer 12

Liver toxin
-targets rapidly dividing cells hence embryos= abortion
-carcinogenic
-rapidly eliminated so won’t be able to detect later
-not an issue in Canada unless importing feed from USA

Question 13

Fumonisins

Answer 13

-target rapidly dividing cells hence embryos= abortion and resorption of fetuses
-also targets lungs, and livers
-most common in horses and pigs **
-rapidly eliminated

Question 14

Trichothecences

Answer 14

DON, DAS, T-2 toxin, HT2
-Very toxic
-rapidly eliminated
-target rapidly divided cells
-common occurrence in swine rations

Question 15

Dicoumarol

Answer 15

-causes abortion and bleeding
-fetus 3x more susceptible
-common in sweet clover bails… mold inside converts into dicoumarol
-cattle most susceptible because least protein bound, sheep and horses most resistance because it is highly protein bound

Question 16

Ergot

Answer 16

Results in abortion and vasoconstriction
-rapidly eliminated
-number 1 issue in W. Canada
-Horses most affected, then pigs and sheep, then cattle
-will see impaired milk production (prolactin inhibited); growth retardation in 3rd trimester