Animal Nutrition MCQs Set 3
51. Energy feeds generally contain crude protein less than:
A. 10%
B. 15%
C. 18%
D. 20%
Correct Answer: D. 20%
Explanation: Energy feeds, also known as carbonaceous concentrates (like maize, wheat, and barley), are primarily high in starch. In animal nutrition, they are defined as having less than 20% crude protein and less than 18% crude fiber.
52. Dry matter requirement of lactating sheep is approximately:
A. 2% of body weight
B. 3% of body weight
C. 4% of body weight
D. 5% of body weight
Correct Answer: C. 4% of body weight
Explanation: Lactation is the most nutritionally demanding phase. While a maintenance diet is lower, a lactating ewe requires about 4% of her body weight in dry matter to support milk production and maintain her own health.
53. Concentrate requirement for buffalo milk production is:
A. 1 kg per 1 kg milk
B. 1 kg per 2 kg milk
C. 1 kg per 2.5 kg milk
D. 1 kg per 3 kg milk
Correct Answer: B. 1 kg per 2 kg milk
Explanation: Buffalo milk has a higher fat content (7–8%) compared to cow milk. Consequently, they require more energy-dense feed. The standard thumb rule is 1 kg of concentrate for every 2 kg of milk produced.
54. During last trimester of pregnancy, concentrate allowance for buffalo is:
A. 1.0 kg
B. 1.25 kg
C. 1.5 kg
D. 1.75 kg
Correct Answer: D. 1.75 kg
Explanation: The fetus grows rapidly in the final trimester. To support fetal development and prepare the buffalo for lactation, a “challenge feeding” or pregnancy allowance of 1.75 kg of extra concentrate is recommended.
55. Water, protein, and ash ratio in fat-free animal body is:
A. 10:5:1
B. 15:4:1
C. 19:5:1
D. 25:6:2
Correct Answer: C. 19:5:1
Explanation: In a mature, fat-free body, the chemical components are remarkably stable. The ratio of Water to Protein to Ash is consistently found to be approximately 19:5:1 (roughly 75% water, 20% protein, and 5% ash).
56. Total mineral content of animal body is approximately:
A. 1%
B. 2%
C. 3%
D. 5%
Correct Answer: C. 3%
Explanation: Minerals, collectively termed “ash,” make up a small portion of the total body. In living animals, minerals account for roughly 3% of the total body weight, primarily stored in the skeleton.
57. Weende system of proximate analysis was proposed in:
A. 1855
B. 1865
C. 1875
D. 1885
Correct Answer: B. 1865
Explanation: The Weende System was developed at the Weende Experiment Station in Germany in 1865. It is the most common method used to chemically describe feed samples.
58. Which proximate principle cannot be determined by direct analysis?
A. Crude fiber
B. Ether extract
C. Ash
D. Nitrogen free extract
Correct Answer: D. Nitrogen free extract (NFE)
Explanation: NFE represents the soluble carbohydrates. It is calculated by difference rather than direct measurement: NFE = 100 – ({Moisture} + {Ash} + {Crude Protein} + {Ether Extract} + {Crude Fiber}).
59. Factor used to convert nitrogen into crude protein is:
A. 5.25
B. 6.00
C. 6.25
D. 6.50
Correct Answer: C. 6.25
Explanation: Most proteins contain approximately 16% nitrogen. Therefore, to find the protein content, you multiply the measured nitrogen by 6.25 (100/16 = 6.25).
60. Digestible energy value of 1 kg TDN is:
A. 3.0 Mcal
B. 3.6 Mcal
C. 4.0 Mcal
D. 4.4 Mcal
Correct Answer: D. 4.4 Mcal
Explanation: Total Digestible Nutrients (TDN) is a measure of energy. By standard conversion, 1 kg of TDN is equivalent to 4.4 Mcal of Digestible Energy (DE).
61. Straw is particularly deficient in:
A. Silica
B. Fiber
C. Minerals and protein
D. Carbohydrates
Correct Answer: C. Minerals and protein
Explanation: Crop residues like wheat or rice straw are high in lignified fiber but extremely low in digestible protein and essential minerals, making them “poor-quality roughage” without treatment.
62. Optimal water to urea ratio during urea treatment of straw is:
A. 5:1
B. 8:1
C. 10:1
D. 12:1
Correct Answer: C. 10:1
Explanation: When treating straw, 4 kg of urea is usually dissolved in 40 liters of water for 100 kg of straw. This creates the optimal 10:1 water to urea ratio for proper hydrolysis and moisture distribution.
63. Nitrogen content of pure urea is approximately:
A. 28%
B. 35%
C. 40%
D. 46.6%
Correct Answer: D. 46.6%
Explanation: Urea (NH2CONH2) is a highly concentrated nitrogen source. Pure urea contains 46.6% nitrogen, which gives it a Crude Protein equivalent of about 291% (46.6 \times 6.25).
64. Urea should NEVER be fed to:
A. Adult cattle
B. Lactating buffalo
C. Sheep
D. Young calves and monogastrics
Correct Answer: D. Young calves and monogastrics
Explanation: Monogastric animals (like pigs and humans) cannot utilize urea. Young calves with undeveloped rumens also cannot use it; in both cases, it can cause lethal ammonia toxicity.
65. Adaptation period of rumen microbes to urea feeding is:
A. 3–5 days
B. 1 week
C. 2–4 weeks
D. 6–8 weeks
Correct Answer: C. 2–4 weeks
Explanation: The rumen microbial population needs time to adjust to urea. A slow introduction over 2 to 4 weeks is required to develop enough urease-producing bacteria to safely handle the ammonia release.
66. Rumen ammonia concentration causing urea toxicity is above:
A. 20 mg/100 ml
B. 40 mg/100 ml
C. 60 mg/100 ml
D. 80 mg/100 ml
Correct Answer: D. 80 mg/100 ml
Explanation: Normal rumen ammonia is 5–20 mg/100 ml. Toxicity occurs when the rate of ammonia release exceeds the liver’s ability to detoxify it, which typically happens when levels cross 80 mg/100 ml.
67. Immediate treatment of urea toxicity includes drenching with:
A. Warm water
B. Glucose solution
C. Cold water
D. Saline
Correct Answer: C. Cold water
Explanation: Drenching with cold water (often mixed with vinegar or acetic acid) lowers the rumen temperature to slow down the urease enzyme and dilutes the ammonia while the acid neutralizes it.
68. ATP yield from aerobic oxidation of palmitic acid is:
A. 96
B. 108
C. 129
D. 146
Correct Answer: C. 129
Explanation: Through \beta-oxidation and the subsequent TCA cycle, one 16-carbon molecule of palmitic acid yields a net of 129 ATP molecules.
69. Volatile fatty acid responsible for gluconeogenesis is:
A. Acetate
B. Propionate
C. Butyrate
D. Lactate
Correct Answer: B. Propionate
Explanation: In ruminants, propionate is the only major Volatile Fatty Acid (VFA) that can be converted into glucose in the liver. It is the primary source of blood sugar for the animal.
70. Defaunation refers to removal of:
A. Bacteria
B. Fungi
C. Protozoa
D. Viruses
Correct Answer: C. Protozoa
Explanation: Defaunation is the selective removal of protozoa from the rumen. This is sometimes done to reduce the breakdown of bacterial protein and improve nitrogen utilization.
71. High milk fat percentage in ruminants is associated with increased production of:
A. Propionate
B. Butyrate
C. Lactate
D. Acetate
Correct Answer: D. Acetate
Explanation: Acetate is the primary precursor for the synthesis of short-chain fatty acids in the mammary gland. Diets high in fiber promote acetate production, leading to higher milk fat.
72. High concentrate diets mainly increase which volatile fatty acid?
A. Acetate
B. Propionate
C. Butyrate
D. Valerate
Correct Answer: B. Propionate
Explanation: Starchy feeds (concentrates) favor the growth of amylolytic bacteria, which produce propionate. This shift reduces milk fat but increases the energy available for growth and weight gain.
73. Indicator used internally for digestibility trials includes:
A. Chromic oxide
B. Ferric oxide
C. Lignin
D. Cerium
Correct Answer: C. Lignin
Explanation: An internal indicator is a substance naturally present in the feed that is completely indigestible. Lignin and acid-insoluble ash are commonly used in this method.
74. Chromic oxide is classified as:
A. Internal indicator
B. External indicator
C. Biological marker
D. Enzymatic tracer
Correct Answer: B. External indicator
Explanation: An external indicator is an inert, indigestible substance added to the feed (like chromic oxide). It is used to measure fecal output without having to collect all feces manually.
75. Adjustment period for digestibility trial in ruminants is:
A. 5–7 days
B. 7–9 days
C. 10–12 days
D. 15–20 days
Correct Answer: C. 10–12 days
Explanation: Before the actual collection period of a digestibility trial, an adjustment period of 10–12 days is necessary to ensure that the previously fed material has cleared the digestive tract.