ICAR AICE-JRF/SRF (PhD) · India · NTA for ICAR
Original practice questions written to the published syllabus · not past papersPoisoning by metals, plants, mycotoxins, pesticides, non-protein nitrogen, venoms and pollutants, with residues in food and the antidotes used.
In the exams: AVE Paper 1 toxicology at least 3; SAVC toxicology 10 (plus southern African plant poisonings); ICAR AIEEA-PG 13 Unit IV (poisonous plants, agro-chemicals); ICAR AICE-JRF core group 07
ICAR AICE-JRF/SRF core group 07
Mechanisms at molecular level (VKOR, cytochrome oxidase, AChE aging, thiomolybdate chemistry, bioactivation of aflatoxin), toxicokinetics and species differences, ecotoxicology (diclofenac and vultures), residues, ADI and MRL derivation.
How our questions for ICAR AICE-JRF/SRF spread across the units of Veterinary Toxicology. Difficulty: 0 easy, 17 medium, 13 hard.
| Ecotoxicology and residues | 4 | |
| Metal toxicity: lead, arsenic and mercury | 3 | |
| Mycotoxins and aflatoxicosis | 3 | |
| Copper, molybdenum, fluorine and selenium toxicity | 2 | |
| Cyanogenic plants | 2 | |
| Nitrate and nitrite poisoning | 2 | |
| Organophosphate and carbamate poisoning | 2 | |
| Organochlorine and pyrethroid poisoning | 2 | |
| Urea and non-protein nitrogen toxicity | 2 | |
| Radiation hazards | 2 | |
| Antidotes | 2 | |
| Corrosives and irritants | 1 | |
| Oxalate, lantana and bracken poisoning | 1 | |
| Rodenticide poisoning | 1 | |
| Water-borne toxicities | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
A forage contains 1% potassium nitrate (KNO3) on a dry-matter basis. What is its nitrate (NO3) content?
B. About 0.61%
NO3 is 62.0 of KNO3's 101.1 g/mol, i.e. 61.3%; 1% × 0.613 ≈ 0.61% NO3. 1.64% inverts the factor; 0.14% would be nitrate-N in KNO3.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
Equine leukoencephalomalacia, liquefactive necrosis of cerebral white matter in horses, is caused by
C. Fumonisins from Fusarium verticillioides
Fumonisins disrupt sphingolipid metabolism and cause ELEM in horses and pulmonary oedema in pigs. Lolitrem B causes ryegrass staggers.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
Why are organochlorine insecticides such as DDT restricted internationally?
D. They persist, are stored in fat and biomagnify up food chains
Lipophilic, persistent organochlorines bioaccumulate and biomagnify; the Stockholm Convention restricts them. Their low water solubility is the opposite of rapid leaching into groundwater.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
Urea contains 46.6% nitrogen. What is its crude protein equivalent?
B. About 291%
Crude protein = N × 6.25; 46.6 × 6.25 = 291%, so 1 kg urea supplies the nitrogen of about 2.9 kg crude protein. 46.6% is the nitrogen content, not protein; 7.5% divides by 6.25 instead of multiplying, and 746% multiplies by 16 (the N content of protein) instead of 6.25.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
Why is the calcium salt of EDTA used for lead poisoning, not disodium EDTA?
C. Disodium EDTA chelates blood calcium and causes hypocalcaemic tetany
Calcium disodium EDTA exchanges its calcium for lead; disodium EDTA would strip calcium from the blood.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
Sodium nitrite is used in cyanide poisoning because
B. Its methaemoglobin binds cyanide as cyanmethaemoglobin, freeing cytochrome oxidase
Methaemoglobin's ferric iron has high affinity for cyanide, drawing it off cytochrome oxidase; thiosulfate then allows rhodanese to form thiocyanate.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
Ten here, 30 in the app. The Laisha app has every practice question we have written to ICAR AICE-JRF/SRF in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
Free for ten days, then one subscription of US$10 a month. We would rather say so here than have you find it later.
An AI operating system for agriculture: free guides, manuals and tools written for every country.