Thank you for sharing about the beef in your classroom. Below are links to many resources that can help you with lessons about raising cattle and beef.
On the Farm STEM provides teacher toolkits that help you easy deploy lessons on many beef topics.
Ag in the Classroom has many great lessons on beef that are fun for kids of all ages.
The AFBF has lesson plans for many subjects across several areas of ag.
Powered by the American Farm Bureau Foundation for Ag, the Ag Lit Catalog allows you to search by topic, grade level and resource type (video, lesson, book) and find good info about all aspects of ag.