The only thing you want to be cautious about with adding puppy food prior to whelping is that you do not want to supplement calcium as supplementing calcium can cause the body to stop producing its own, and it is critical during whelping in order to stimulate and sustain contractions. If the body is unable to produce calcium during whelping it can lead to things like uterine inertia, eclampsia, etc. I never ever add puppy food until after whelping for this reason. I personally, would go with a higher quality adult/all stages food, Diamond is an ok brand but does have a lot of fillers. If you are budget conscious the Kirkland (Costco) brand is very good quality and very cheap. Petfoodadvisor.com has lots of info if you want to compare brands. I would go with something 4 stars or higher...
a good large breed puppy food isn't going to be high in calcium as too much calcium is a HUGE no-no for them. You have to do research on the food and see what the calcium level is.
arabian, dogfoodadvisor.com or dogfoodanalysis.com look up your food brand and see how it rates.
http://www.dogfoodanalysis.com/dog_food_reviews/showproduct.php?product=1486&cat=all
here is diamond naturals large breed puppy review -
The first two ingredients in the food are named meat products. The second of these is in meal form and the sole significant meat product in the food. The first is chicken - inclusive of its water content. Once this is removed, as it must be to make a dry food, the ingredient will weigh around 20% of its wet weight. It is thus unlikely that it is the true first ingredient in the food, and it is likely to be more accurately placed much further down the ingredient list and is unlikely to make any significant contribution to the overall meat content of the food. There is a further meat meal ingredient 12th on the ingredient list. This is a fish meal, however, and we fail to find any assurance on the manufacturer's website that the ingredient is not treated with Ethoxyquin. Ethoxyquin is a chemical preservative, banned or heavily regulated in human food, and believed to be carcinogenic (and is commonly added to fish meal ingredients).
Egg product is the third ingredient, though we would prefer to see the use of whole eggs.The main grains in the food are barley, millet and rice, all of which are decent quality. Potato protein adds to the protein content of the food, but this is very low quality protein compared to that obtained from meat. Further carbohydrate sources are oatmeal and potatoes. Tomato pomace is primarily filler.
Overall, this product appears better than some produced under the Diamond label, although the ingredients overall are of mixed quality and we have limited confidence in the meat content of the food.
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In the end, the best way to know would be to talk to her breeder. Things like this, just like with humans, run in families. If you know that Mom and grandma lost a lot of weight when whelping, then you know that she is going to as well.
