Cali State-Line Inspectors always ask: Any fruits, nuts or plants in your vehicle. They also MUST inspect all livestock for proper brands and ownership.
It is illegal to transport any livestock without proper brands, tags or bill of sale.
There's an agricultural check point in Yermo, Ca on 15 freeway, just above Barstow. I think that's the only way to get from Nevada to Ontario, Ca so they will have to stop there. FYI