• Assertion (A) is Correct: Individual (Mass) Selection based solely on an animal's own phenotype is the simplest and most effective selection method for traits with high heritability ($h^2 \gt 0.30$), yielding rapid genetic gain per generation ($\Delta G = i h^2 \sigma_P$).
• Reason (R) is Correct: Individual selection cannot be used to select males for sex-limited traits that are expressed only in females (e.g., milk yield, egg production, litter size), necessitating pedigree or progeny testing.
• Relationship: While both statements are correct, (R) describes a specific limitation for sex-limited traits rather than explaining why individual selection produces faster genetic progress for highly heritable general traits.

• Total Digestible Nutrients (TDN) Equation: TDN measures the total energy content of a feedstuff expressed in terms of carbohydrate equivalence:

where:

• $\text{DCP}$: Digestible Crude Protein
• $\text{DCF}$: Digestible Crude Fibre
• $\text{DNFE}$: Digestible Nitrogen-Free Extract
• $\text{DEE}$: Digestible Ether Extract (multiplied by $2.25$ because fat has $2.25$ times higher gross energy density than carbohydrates, $9.45 / 4.15$).

Correct option: (2) DCP+DCF+DNFE+ 2. 25DEE

• BIS Specifications for Compounded Cattle Feeds (IS: 2052):
• Type I Feed (High performance / high yield): Minimum $22\%$ Crude Protein, minimum $3.0\%$ Ether Extract, maximum $7.0\%$ Crude Fibre, maximum $3.0\%$ Acid Insoluble Ash.
• Type II Feed (Maintenance / medium yield):
• Crude Protein: Minimum $20.0\%$
• Ether Extract: Minimum $2.5\%$
• Crude Fibre: Maximum $12.0\%$
• Acid Insoluble Ash: Maximum $4.0\%$

Correct option: (2) Minimum 2.5 % ether extract