my bitch fudge had a litter yesterday ending around 5pm, this evening she has started to pant. she is eating and looking after the pups. should I be worried?

If you are really worried call your vet..... Have you taken her temperature?

Certainly panting in the days after whelping is normal. 

One reason is discomfort caused by the uterus contracting, and also if the pups are being kept warm the bitch can get too hot for her comfort.

Bitches vary, but I've certainly had bitches continue to pant for over a week.

Remember that her body is working overtime now.

I find bitches can find pups suckling very hot, but if you at all concerned contact your vet

if she is just panting because shes hot and has others have said then theres no worries ,but have you be checking her when she goes out for a wee or poo ,does it look like she could be straining abit? i had 1 bitch that had 2 very large litter and she would do this after having pups i had to get her to the vets she had a pup retained with both litters ,now i get my vet out when my girls look like shes finished for a oxitosin jab just to make sure! has we lost the ones that were stuck.