Causative verb derivations mostly have the object in the same case form as for the base verb. For example, we can say Minna korjasi tietokoneen (Minna repaired the computer) and Jukka korjautti tietokoneen (Jukka had the computer repaired). In both sentences, tietokoneen is the object, but in the latter sentence, Jukka did not fix it but had someone else fix it. If we would like to mention in the latter sentence who actually fixed it, we would use the adessive (-llA case): Jukka korjautti tietokoneen Minnalla (Jukka had Minna repair the computer).
However, for some causative verbs, the allative (-lle case) is used instead of the adessive. This applies to verbs like syöttää and juottaa, from syödä (eat) and juoda (drink). Thus, we would say Liisa juotti hevoselle vettä (Liisa gave the horse water). We do not say hevosella here, as we do not think of a horse as an agent of drinking but rather the recipient of water.
We can also say Liisa juotti hevosen (Liisa let the horse drink, i.e. watered the horse).