The Talmud states (Berakhot 40a, Gitin 62a) that it is prohibited to taste food before feeding one’s animals. In latter halakhic sources, though, two changes are found in the formulation of this rule: a) although the Talmud says “prohibited”, the Rambam (Hil. Avadim 9:8) implies it is meritorious behavior, a change questioned by commentators (see Even HaEzel, and others); and b) although the Talmud [in Gittin] uses the word “taste”, the Taz (O.C. 167:7) understands from the formulation of the Shulchan Arukh that tasting food before feeding animals is actually not prohibited, only actually eating. The Chayei Adam (Nishmat Adam, klak 5, 11:11) acknowledges the possibility of variant texts [as Berakhot uses the word “to eat”], but suggests that a reconciliation is nonetheless possible: if one is only tasting, and not beginning a set meal, this is permitted before feeding the animals; however, if one is beginning a formal meal, even tasting from that meal before feeding the animals is wrong. (See also Birkei Yosef, 167:5, and Resp. Sh’vut Ya’akov, III, 13.)

Further, the Magen Avraham (O.C. 167:18), citing the Sefer Chasidim, asserts that only eating is prohibited, but drinking is permited. He proves this from the case of Rivka’s encounter with Eliezer, in which she proved her worthiness by giving his camels water to drink, but only after she gave Eliezer first. R. Tzvi Pesach Frank (Resp. Har Tzvi, O.C. 90) suggests two reasons for this distinction: a) the anguish involved in abstaining from drink is greater than in abstaining from food; thus, to wait until after feeding animals to be permitted to drink is more of a burden than can be expected from, or is imposed upon, humans; b) the reason for the prohibition is to ensure that the owner of the animals [or anyone with the responsibility of feeding, even if not the owner – see Resp. Chatam Sofer, Y.D. 314] does not forget to feed the animals. Thus, just as regarding the prohibition of eating before prayer, distinction is made between eating and drinking, so too here, as drinking is unlikely to lead to forgetting the responsibility. If R. Frank’s second reason is accepted, the distinction of the Chayei Adam noted above can likewise be understood.

R. Ya’akov Emden (Resp. Sh’eilat Ya’avetz, 17) discusses whether this prohibition applies to pet cats and dogs. In doing so, he considers questions such as whether or not cats and dogs are included in the term “behaimah” used in the Talmud, and whether these animals provide services for humans, under the assumption that that would be relevant to this rule. He concludes by noting that these issues may not be relevant, as this rule is rooted in the concern not to be cruel to animals, and in recognition that animals that are dependant upon an individual will starve if that individual does not prioritize their welfare. (Similarly, the Har Tzvi and the Sh’vut Ya’akov, in the above-cited responsa, rule no distinction is to be made between different types of animals). R. Emden further notes that it emerges from this rule that anyone who has not yet fed his animals is forbidden to eat even if he is in a different house.