
I agree and I would cut her food by about a third and see how she is after a week or so, as chances are after her being spayed the food will need about a 25% cut to stop her gaining weight, certainly have found that to be the case in everyone of my girls.
Also she is likely to drop all her coat in about 6 weeks or so, it is something people are often surprised at following spaying an adult bitch, it can be quite dramatic depending on breed..