Hello I am Dr. Joey. Thanks for trusting me to help you and your pet today. I am a licensed veterinarian with over 16 years of experience. I look forward to working with you.
This poor thing. First we must remember constipation is a problem that occurs secondary to dehdyration. It is highly unusual to be simply due to a food change. Most food changes cause the opposite (diarrhea)- so if she is straining to go to the bathroom please be certain she is not having diarrhea (from a distance the straining can look the same). If you are certain she has not gone at all in over a week, at her age I worry this might not just be food causing to be constipated, especially if she is eating/drinking well but just not defecating. If she is not eating/drinking well, then this may be why she is not defecating (they must eat for it to come out), and it suggests something else more significant is going on. In a dog of her age/size constipation is unusual and if and when it occurs, the dog usually has a problem such as kidney disease or something else that leads to profound dehydration or the dog eats something sandy that binds her up.
So, what to do? If she is acting normally with a great appetite and drinking well, then you could try this weekend to give her a bit of increased fiber. Pumpkin is great but I would increase this to 1 to 2 tablespoonfuls with each meal. And, focus on getting her to drink lots since this problem has to do with dehydration. You might need to feed canned food to increase her water content in her diet. Or, switch her off dry food and cook her boiled chicken and white rice for a few days. You could try also adding 1/8th tsp of miralax to her food twice daily. No more than that. No other over-the-counter stool softener products are safe in dogs.
However, if she is having symptoms other than constipation such as not eating well, lethargic, vomiting, etc, then you should have her seen on emergency today. This cannot wait another 3 days.
I am at a point I need to know what questions you have. I hope that the information I provided has been helpful.
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