The herd
Embryos
The Embryo Clinic lets one cow carry a calf whose genetics come from an embryo, not from herself.
What you need
The recipient cow has to be in heat, and she has to be standing in a corral. The implant spends one of her calving counts. The embryo is used up whether the implant takes or fails.
The calf
The calf takes the embryo's breed, origin, rarity, genes, and looks. The recipient is the cow who carries it. She is recorded on the calf, and she does not pass her own genes through that implant. After the dormant wait, the calf is handled like any other calf: feed it, and decide on a bull calf before he grows up.
Embryo packs are sold for players who want that genetics path without waiting on a particular mating.