Winning the entire debate
Leaving lambs uncastrated is a win-win situation
In mid-season prime lamb production, the objective is to achieve high levels of lamb performance in a cost-effective way. High levels of lamb performance result in early drafting, ensuring all lambs are sold by the end of the grazing season. In Ireland, 73pc of all lambs are sold between early May and late December.
As the lambing season progresses, an imminent question to face is whether or not to castrate male lambs.
There is a lot of evidence that finishing male animals entire increases their performance. However, there is a perception among industry commentators, producer groups, processors and marketers that leaving male lambs entire may have a negative impact on meat-eating quality. So what are the facts about the effects of castration on male lamb performance and subsequent meat quality?
Rearing males entire aids performance
In beef production, finishing male cattle entire (as bulls) and which are slaughtered at 24 months boosts carcass weight by 41kg, carcass conformation classifications (on a five-point scale) by 0.4 points and decreases carcass fat classification (on a five-point scale) by 0.7 points.
A study was completed at Athenry which evaluated the effects of castrating male lambs on subsequent performance and carcass characteristics. This study was undertaken using 157 all-male litters in mid-season prime lamb production systems.
In each of the all-male twins, one lamb was chosen at random and castrated shortly after birth, while its sibling was left uncastrated. The effects of castration on animal performance are in table 1.
Leaving the male lambs entire increased weaning weight by 1.8kg, reduced age at slaughter by 16 days and resulted in leaner carcasses.