Heifer Spaying

Kimberly Rupp Method

Abstract

But spaying has been a common procedure in the western states for years. It started in Wyoming and it was a management program. When controlled weight studies were conducted, spayed nonimplanted heifers failed to gain up with the intact nonimplanted. Rupp and Kimberly, in reviewing a lot of the trials, reporting 22 of 27 in the early trials intact heifers average daily gain didn't keep up. Intacts had higher AGs than the spayed mates. Including grazing growing and finishing trials, the intact averaged 7.9% higher and this just follows the experience I was having at that time. Then in 15 trials comparing implanted spays and implanted intacts 13 of 15 showed better gain, average of 1.8 improvement, meant that they picked up the 7.9 plus the 1.8 gain. So implanted reporting to have quite a profound effect on the spayed.