Tosefta sobre Deuteronómio 15:20

All consecrated [animals] that become consecrated in the womb, and are born by caesarian section (lit., "from the side"), consecration is imbued upon it. [As to] a first-born and [an animal subject to] cattle-tithe, consecration is not imbued upon them. All sanctified animals about which it is written, "year after year" (Deut. 15:20), as soon as their year has passed, behold, they are disqualified. A first-born and a cattle-tithe, even [after there have passed] two or three years, behold, they are valid.