ICAR AICE-JRF/SRF (PhD) · India · NTA for ICAR
Original practice questions written to the published syllabus · not past papersGrowing, conserving and grazing the forage that feeds ruminants: fodder crops, hay and silage, pasture management and toxic plants.
In the exams: ICAR AICE-JRF core group 05 (LPM and Nutrition units)
ICAR AICE-JRF/SRF (PhD) — core group 05
Botanical names and features of fodder crops, ensiling biochemistry and silage quality indices, grazing systems and carrying capacity, Van Soest fibre fractions and in vitro digestibility, and the toxic principles of pasture plants (HCN, nitrate, oxalate, mimosine, endophyte alkaloids).
How our questions for ICAR AICE-JRF/SRF spread across the units of Fodder Production & Grassland Management. Difficulty: 0 easy, 15 medium, 24 hard.
| Legume fodder crops | 5 | |
| Fodder cropping systems | 5 | |
| Silage making | 5 | |
| Grassland management | 5 | |
| Fodder yield and nutritive value | 5 | |
| Pasture management | 4 | |
| Hay making | 3 | |
| Toxic plants in pasture | 3 | |
| Cereal fodder crops | 2 | |
| Fodder grasses | 2 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
A farmer will sow lucerne for the first time on land where it has never grown. What should be done with the seed?
A. Inoculate it with the Rhizobium strain specific to lucerne before sowing
Rhizobium inoculants are grouped by host; lucerne needs its own strain (the Sinorhizobium meliloti group). Cowpea inoculant does not nodulate lucerne; nodulation matters for forage legumes as much as grain legumes; relying on fertiliser nitrogen wastes the legume's main advantage.
Further reading: Barnes et al., Forages: The Science of Grassland Agriculture
Goats fed leucaena as about 60% of their diet develop alopecia, excess salivation and goitre. Which intervention addresses the underlying cause?
D. Establish DHP-degrading rumen bacteria from adapted animals in the goats
Mimosine is converted in the rumen to DHP, which is goitrogenic; animals lacking DHP-degrading bacteria are poisoned, and transfer of such bacteria from adapted animals is the recognised solution, along with limiting leucaena in the diet. Buffers do not neutralise mimosine; leucaena has no thiaminase; seeds are rich in mimosine.
Further reading: Barnes et al., Forages: The Science of Grassland Agriculture
Why do condensed tannins in a forage legume reduce the risk of frothy bloat?
B. They bind soluble leaf protein in the rumen, so less stable foam forms
Frothy bloat arises when rapidly released soluble leaf proteins (with saponins) form a stable foam that traps gas. Moderate condensed tannins precipitate these proteins and reduce foam. Tannins do not push rumen pH above neutral, protozoa are not the only gas source, and blocking eructation would worsen bloat.
Further reading: Barnes et al., Forages: The Science of Grassland Agriculture
What is the 'overlapping cropping system' developed for year-round fodder on irrigated land?
A. A perennial grass such as hybrid Napier in wide rows, with seasonal legumes sown between them
The overlapping system pairs a perennial grass with seasonal legumes (berseem in winter, cowpea in summer) between its rows, giving a near-continuous cereal-legume supply. Sowing into a standing crop is relay cropping; the other descriptions are not this system.
Further reading: ICAR-IGFRI technical bulletins; ICAR Handbook of Animal Husbandry
In the East African 'push-pull' system, maize is intercropped with Desmodium and bordered by Napier or Brachiaria grass. Besides fodder, what does the system control?
C. Stem borers and Striga weed
Desmodium repels stem-borer moths and suppresses Striga, while the grass border attracts and traps the moths; both supply fodder. The system has no effect on foot-and-mouth disease, ticks, aflatoxin, bloat or tetany.
Further reading: Barnes et al., Forages: The Science of Grassland Agriculture
Why are legume hay crops such as lucerne raked and baled while the leaves are still slightly moist, often in the early morning?
C. Dry legume leaves become brittle and shatter, and the leaves hold most of the protein
Legume leaves dry quickly and shatter during raking and baling; since leaves carry most of the protein, handling them slightly moist limits loss. Hay is not preserved by fermentation, dew does not remove bloat risk, and 40% moisture is far too wet for hay.
Further reading: Barnes et al., Forages: The Science of Grassland Agriculture
A 20 ha pasture produces 6,000 kg DM/ha/year and 50% may be safely utilised. How many 450 kg cows, each eating 2.5% of body weight as DM daily, can it carry for a year?
B. About 14.6 cows
Usable DM = 20 x 6,000 x 0.5 = 60,000 kg. Intake = 450 x 0.025 = 11.25 kg/day x 365 = 4,106 kg/year. Cows = 60,000 / 4,106 = 14.6. 29.2 ignores the 50% utilisation; 7.3 halves twice; 146 is a decimal slip.
Further reading: Holechek, Pieper and Herbel, Range Management
A 500 ha range produces 800 kg DM/ha in the grazing season. Utilisation is set at 40% and one animal unit month (AUM) is taken as 350 kg DM. How many animal units can graze it for a 6-month season?
B. About 76 AU
Usable DM = 500 x 800 x 0.40 = 160,000 kg. AUMs = 160,000 / 350 = 457. For 6 months: 457 / 6 = 76 AU. 190 ignores the 40% utilisation; 457 is the number of AUMs, not AU over 6 months; 1,143 ignores both the utilisation and the 6-month season.
Further reading: Holechek, Pieper and Herbel, Range Management
Why does the proximate (Weende) system describe forages poorly?
A. Crude fibre misses part of the lignin and hemicellulose, which then sits in the NFE
In the Weende scheme acid and alkali digestion dissolve some lignin and hemicellulose, which then appear in nitrogen-free extract (calculated by difference), overstating the 'soluble' fraction. CP is N x 6.25, not amino acid analysis; ether extract does not contain cellulose; ash is measured directly and NFE is the difference.
Further reading: McDonald et al., Animal Nutrition
A forage test reports 0.5% nitrate-nitrogen (NO3-N) in DM. A guideline you are using is written as nitrate (NO3). What is the equivalent nitrate value?
B. About 2.2% NO3
NO3 = NO3-N x 62/14 = 0.5 x 4.43 = 2.2%. 0.11% multiplies by 14/62 instead of dividing; 3.6% converts to potassium nitrate (x 101/14), a different basis; 0.5% ignores the conversion.
Further reading: Constable et al., Veterinary Medicine (plant toxins); Gupta, Veterinary Toxicology
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