Find the odd zoological term (gendered noun vs species term): Pick the option that is not a specifically gendered animal term.

Introduction / Context:
Verbal classification frequently uses parts of speech or semantic subtypes. In zoology, some common nouns explicitly encode gender, while others are generic species or kind terms. Identifying which words are gendered creates a clean separation for odd-one-out selection.

Given Data / Assumptions:

• Bitch: female dog; explicitly gendered female term.
• Cow: female of cattle; explicitly gendered female term.
• Vixen: female fox; explicitly gendered female term.
• Horse: general species/common name without built-in gender marking.

Concept / Approach:
Group options by whether the noun denotes a gendered form. Three choices encode the female sex of a specific species, whereas one is the species term itself without gender information.

Step-by-Step Solution:

Verification / Alternative check:
Consider male counterparts: dog vs bitch, bull vs cow, dog-fox vs vixen. Horse requires stallion or mare to indicate gender, confirming its generic status.

Why Other Options Are Wrong:
They each specify a female animal and thus share the same semantic subtype.

Common Pitfalls:
Avoid mixing taxonomy with husbandry uses; the test relies on lexical gender marking within the noun.

Final Answer:
Horse