Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to raise bucket calves [title] Get calf bottles and nipples. [step] Purchase one set of bottles and nipples per calf. Each calf should have at least one assigned set.

Ending1: [substeps] The bottles should not be unsecured. Contact your vet and ask if they may leaven the seals of the bottles. Ending2: Get at least two sets of nipple nipples to make sure that the bottles are each sufficient for the calf. You can purchase nipples made out of linen, breathable fabric, synthetic fibers, burlap, or natural fibers. Ending3: Otherwise, you will need to go to the trouble of sterilizing the equipment between uses. [substeps] The nipple of a bottle resembles the mother's teat, which should trigger the calf's natural instinct to suckle. Ending4: You may need to make an adjustment to your design, so consider limiting your selection to one or two different nipples, or you can choose a different type of nipple to cut low in the price of the bottle. [substeps] These bottles should be smaller than the first set and a couple of dollars above and below your ideal size.

Answer format: ending1/ending2/ending3/ending4