I am sorry to hear about Tishka.
My name is Rebecca. I am a veterinarian, and will do my best to help.
Low appetite can mean many things: pain, being hot, nausea, internal disease.
Some dogs, when they become fully grown and mature, may start to eat less than when they were growing. However, at age 2, he has probably been finished growing for awhile.
If his temperature is normal ( can you take his rectal temperature? Normal is between 101 and 102) and he is not losing weight, I would not be too worried.
Some dogs just eat less in summer, when it is hot and they may be less active.
If he vomits, starts to lose weight, or if he is drinking more water than usual, then I would be concerned.
If you are concerned, the place to start is a good physical exam: feeling internal organs, checking anal glands, taking his temp, listening to heart and lungs, feeling pulses.
Is it just his food he is eating less of? Would he eat table food or treats like usual?
I am not seeing responses from you. This chat format does not work for everyone, and for all devices. I can try to connect with you another way, if I do not hear from you soon.
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Why do you give him Nutrical?
Is he eating any of his Royal Canin?
If he is not losing weight, he must be getting enough calories through the day.
At 15 pounds, he does not need much food to maintain his body weight.
What was his temp?
Nutrical is very calorie dense, so depending on how much you give him, he may be getting a significant number of calories from that and his dental treats.
If you can't see his ribs, if they are not sticking out or visible, he is getting enough to eat.
How much of the Royal Canin does he eat in a day now that his appetite is less?
You are very helpfull. His temp is 101.5, he eats only one greeny dental treat per day, nutry cal was suggested by his vet long time ago, but he hets only pinky nail size amt of nutry cal at AM, he is eating Royal canine usually once or twice a day about 3/4 of a cup. I can feel his ribs on palpation
I apologize, mistype, I ment 0.3 of a cup. Do you think I should stop nutrical? He also becomes hyper around 7-8 PM alpost daily.
Really appreciate your help. You are unbelievable. Thank you so much.