When I tried to use Google now (OK Google) and told them "Send message via telegram to Home" (Home is my telegram bot name). Google didn't find bot contact name (see picture). When I use regular contact it worked well. I tried creating contact with a bot name but it also didn't work ... Maybe someone can help?
It's not possible out of the box. When you tell Google to send a message via some app, it looks for the contacts in your contacts list - where bots doesn't exist.
 Maybe it's possible with some extensions, such as those apps that let you set more voice commands for some actions. Haven't tried it.