Dear Ariel,

Shalom and thanks for your question.

In general one may not prepare food on Yom Tov if he does not plan on eating it (or in some cases, at least some of it) on Yom Tov. Our case, however, is an exception to the rule. The Mishnah Berurah 498:34 explains that since in this case there technically is time to eat a Kezayis of meat during Yom Tov, although he does not intend to do so, we apply the rule of "Ho'il" (since). This means that since if guests who had not yet eaten would show up, he could feed the meat to them, therefore there is no Torah prohibition to slaughter the animal, since potentially the slaughtering can be for the sake of eating it on Yom Tov. Despite applying "Ho'il" it remains an Isur mid-Rabanan, but they did not apply their prohibition in the case of a monetary loss, as in our case. Thus in our case, all that's required is ample time to eat the Kezayis, but no need to actually eat it.

Kol tuv.

Y. Landy