Question

Find the correct answer based on following statements:
Statement (I): On an average, the body weight of crossbred heifers at first service should be 300 to 350 kg.
Statement (II): Attainment of proper body size and maturity is mainly controlled by nutritional regimen adopted.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Remember the general rule for dairy heifers: "Breed based on weight, not on age." For crossbred heifers in India, the target weight at first service is 250-270 kg, which they should reach by 15-18 months of age under good nutrition.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Heifer management focuses on rearing young female dairy animals to reach puberty and sexual maturity at an early age. This ensures a lower age at first calving, which improves lifetime productivity.

Step 2: Detailed Explanation:
Let us analyze both statements:

Statement (I): Heifers should be bred (first service) when they reach approximately 60% to 65% of their mature adult body weight.
For exotic dairy breeds (like Holstein Friesian), the mature body weight is 550-600 kg, so their breeding weight is 300-350 kg.
However, for Indian crossbred heifers (such as Karan Swiss, Karan Fries, or Frieswal), the mature body weight is lower, and the standard recommended body weight at first service is250 to 280 kg.
A target of 300 to 350 kg is too high for average Indian crossbreds and would delay their first service unnecessarily. Thus, Statement (I) isincorrect.

Statement (II): The age at which a heifer reaches puberty and sexual maturity is determined primarily by her growth rate and body size, not her chronological age.
The growth rate is directly controlled by the level of nutrition (protein, energy, and minerals) supplied in her diet.
A high-plane nutritional regimen allows heifers to grow faster and reach the target breeding weight (maturity) at an earlier age, whereas poor nutrition delays puberty. Thus, Statement (II) iscorrect.
Therefore, Statement (I) is incorrect but Statement (II) is correct.

Step 3: Final Answer:
The correct option is (D).