Cat straining after switching to dry food

Straining in the litter box after switching from wet to dry food is a classic and genuinely worrying pattern — especially in a male cat. Dry food drastically reduces water intake, which concentrates urine and can trigger crystals or inflammation almost immediately in cats prone to urinary issues. Male cats are at higher risk because their urethra is narrow, and a blockage can become life-threatening within 24–48 hours. Is he producing any urine at all when he strains, or does nothing come out? And has he seen a vet yet for this episode?

Blood in the urine alongside straining puts this firmly in the 'see a vet today' category — I want to be straightforward with you about that. Even if he's passing some urine, a partial blockage or cystitis can escalate quickly in male cats. Please call your vet this morning. While you're doing that — how long ago did you make the switch to dry food, and what dry food is he currently on?

James Wellbeloved is a decent food — the issue isn't the brand, it's the format. Cats evolved as desert animals and get most of their hydration from prey, not from drinking. Wet food is typically 75–80% water; dry food is around 10%. That drop in moisture intake can be enough to tip a predisposed cat into urinary trouble within weeks, which is exactly what you're seeing. Once your vet has assessed him and ruled out a blockage or infection, the single most effective long-term change you can make is going back to wet food — ideally one specifically formulated for urinary health.

For a male cat with a confirmed history of urinary symptoms, I'd recommend Royal Canin Urinary Care wet food in gravy pouches. It's formulated to dilute urine by encouraging water intake through the food itself, and it controls the mineral levels — particularly magnesium and phosphorus — that contribute to crystal formation. It's widely available on Amazon UK, your vet will recognise it, and it's one of the most evidence-backed options for exactly this situation. Once his acute symptoms have been assessed and treated, transitioning fully back to this wet food is the most practical protective step you can take.

For a male Siamese who's already shown he reacts to dry food, I'd stay on wet food as his primary diet. If you want the convenience of dry occasionally, some owners use a small amount of urinary-formula dry as a topper or treat — Royal Canin also do a dry Urinary Care version — but the bulk of his diet should be wet. Hydration is really the cornerstone of prevention here. Good luck at the vet — you're doing the right thing moving quickly on this.