Concept:Semen collection for artificial insemination is done through controlled techniques, not by allowing free natural mating.
Explanation:The massage method is a recognized collection technique in which the reproductive organs are manually stimulated to obtain semen.
The electro-ejaculation method is another recognized technique that uses a mild electric stimulus to collect semen.
Herd mating simply allows animals to mate naturally within a group.
This natural process does not provide a directed way of collecting the ejaculate for use in artificial insemination.
Because artificial insemination requires semen to be collected directly by a controlled method, herd mating is not suitable for this purpose.
Therefore, herd mating is not used in collecting semen for artificial insemination.
Answer:C. Herd mating of the animals