I came upon this interesting article today. I didn’t even know there there were cattle brands for California’s Spanish missions, although it certainly makes sense. Perhaps there were some for Spanish missions in other parts of the Southwest as well.
http://wcreynolds.com/images/writings/CC_CAMission_outwest_1-1.pdf
The California missions were more than religious outposts in the wilderness. They were, like many religious houses in Europe, also major economic operations to generate the money to support their religious activities and defensive needs. In many if not most cases, this included large cattle herds for meat, hides and tallow, as well as olive groves, vineyards etc.