My cat wont lactate

Question
My cat gave birth at around 9am this morning to 2 kittys, its now 7pm and she still is not lactating, i've been feeding them kitten formula out of a bottle now, how long will it be till she starts lactating, or will i have to bring her to the vet to get a shot?

Answer
Sara, I am so sorry it has taken so long to get back to you.  I hope by now she is feeding her babies.  Are you feeding her a kitten food.  This helps provide more calories and energy.  Continue to try to put the kittens on her nipples and hold them there until you know they are sucking.  Usually this is all it takes to get the milk flowing.  If not, take her to the Vet for help.  Hope all is well.