Castration
What happens if I wait longer — until after puberty — to castrate?
Unlike horses, all llamas castrated after puberty retain some sexual interest and behavior — enough to make management and handling more difficult, interactions notably less enjoyable, and to cause frustration for the llama at times.
Llamas castrated after puberty (referred to as "late geldings") will attempt to breed females — even if they themselves were never allowed to breed — and, often, late geldings will also eventually attempt to breed (and can seriously injure or actually kill) immature males.
Late geldings can not be trusted serve as livestock guardians because most will attempt to breed (and in the process, injure) their charges. Despite many cases in which it initally appeared that a guard gelding was not bothering his charges, eventually it happens ... even after many years. Although sheep, ewes in particular, are reported to be particularly vulnerable, no small animal that lies down is immune from innocently triggering a late-gelded llama's instructions for sexual desire (and becoming a tortilla).
Late geldings fight more seriously and more often. This means that they must be housed and handled similarly to studs.
Llamas castrated after puberty retain some problematic stud behaviors in their interactions with humans. These behaviors and attitudes are most noticably during training, but also spill over into routine handling and pasture interactions.
Llamas castrated after puberty will erupt fighting teeth (canines) around 28 months. These teeth must be first blunted and later cut at least twice if the llama is to be safely handled or housed with other llamas. Older llamas who fighting teeth were allowed to grow quite large prior to cutting are believed to have an increased risk of subsequent canine root infection.
Most importantly, llamas who have had the opportunity to develop and practice any abnormal, difficult or problem behavior(s) due to delayed castration will retain those behaviors and thus require rehabilitation. This situation is not at all desirable — whether you intend to keep the llama in question or to sell him.
An ounce of prevention is worth a pound of cure.