Wethers vs. short-scrotum vs. entire rams

A comparison of wethers (WTH), short scrotum (SSC), and rams (RAM) was made on 552 crossbred Romney lambs in New Zealand. A short scrotum is a ram whose testicles have been pushed into the body and had its scrotum removed. It is also called a cryptorchid.

The experiment began when the lambs were five weeks old. They were grazed on ryegrass/white clover pastures in New Zealand's hill country. The lambs were weighed at day 0, 81, 120, 154, and 192 and slaughtered when they weighed approximately 36 kg (79.2 lbs.).

WTH lambs grew slower than SSC and RAM lambs. Due to higher dressing percentages, WTH and SSC lambs had heavier carcasses than RAM lambs. The carcasses of WTH lambs were fatter than the carcasses of SSC and RAM lambs.

Due to fatter carcasses and extra costs of feeding and drenching (deworming), researchers deemed the WTH lambs to be less profitable than SCR and RAM lambs. They found no difference in growth, carcass, and value traits for SSC and RAM lambs.

Read full article from 2007 Proceedings of the New Zealand Society of Animal Science | Read abstract only