Reference for Ketubot 186:5

ליפלוג וליתני בדידיה במד"א בשור לחרישה ועומד לחרישה אבל בשור לחרישה ועומד לטביחה זה נוטל לפי מעותיו וזה נוטל לפי מעותיו

let it draw a distinction in the very same case, “When was this stated? Only when an ox was bought for ploughing and was used for ploughing, but when an ox was bought for ploughing and was used for slaughter each partner receives a share in proportion to his capital”?

Jastrow