What percentage of a heifer's genetic makeup comes from the last three bulls used in her pedigree?

In livestock breeding, it is important to understand how genetics are inherited from ancestors. A heifer, being a female calf that has not yet borne a calf herself, inherits her genetic material from both sides of her pedigree: her sire (father) and her dam (mother).

When considering the contribution from her pedigree, the last three bulls can be analyzed through the concept of genetic contribution. The paternal lineage contributes a significant portion of the genetic makeup. Each parent contributes 50% of the genetic material to the offspring, and we can break this down further through generations.

Looking specifically at the contribution from the last three bulls:

• The first bull (the sire) contributes 50% of the heifer's genetic makeup.

• The second bull (the grandsire) contributes 25% of the genetic makeup (as the genetic contribution halves with each generation).

• The third bull (the great-grandsire) contributes 12.5%.

Adding these contributions together gives:

• 50% (from the sire) + 25% (from the grandsire) + 12.5% (from the great-grandsire) = 87.5%.

Therefore, the correct answer reflects the cumulative genetic contribution from the last three bulls in her