Teachers, please give me some advice.

I have a cow, gave birth for 2 months, one day suddenly do not eat, may be eating too much, hungry two meals, and reduced concentrate, now eat not enough, feeding key stomach medicine effect is not obvious, nasal mirror less sweat. Rumination is normal. It doesn't get any better with the addition of concentrate. There is no fever and the amount of milk is reduced. I'm depressed. Ask the teachers to guide one or two. (1) forestomach relaxation caused by rumen accumulation; (2) detection of ketone body content; (3) examination of whether there is true stomach displacement. Once the milk production of cows under external stress decreases, it is difficult to rise again. You now give priority to solving the problem of cow feeding. Can you feed some cooking oil to the cow and try it?