Pros and cons of leaving male lambs entire

Are there any advantages of leaving male lambs entire? The answer is certainly, yes, but producers who consider reaping the benefits must also be aware of the management challenges it creates.

Ram lambs bred in commercial ewe flocks and left entire will finish faster, have better conformation and produce leaner carcasses compared with lambs that are castrated.

These advantages have been proven repeatedly in trials over many years, but for most sheep producers who intend to market their lamb crop in late summer, the idea of leaving ram lambs entire is seen as putting undue pressure on the way they have to manage their flock.

If lambs aren’t castrated there are savings, albeit small, in the time and cost of applying rubber rings, but entire lambs can also pose a risk of producing meat that has a stronger flavour or carries taint. 

See also: Read more technical articles on lamb production and sheep management

So what are the other pros and cons of this vexed issue?


Growth rates

The fact that entire lambs grow faster has most recently been proved yet again in trials conducted by Teagasc in Northern Ireland, where results showed lambs left entire achieved superior growth rates and weighed an average 1.8kg more at weaning compared with castrated lambs in the trial.

Entire lambs were also slaughtered 16 days ahead of the castrated lambs and produced leaner carcasses.

The average weight of entire lambs was 31.7kg compared with 29.9kg for the castrated lambs. The carcass weight comparison was 18.1kg for the entires compared with 18.2kg for the castrates. However, the killing out percentage was almost the same.

Katie Brian of Eblex admits entire males do have superior performance, increased growth rates, improved feed efficiency and often higher meat yields than castrated males.

“The main reason commercial sheep producers castrate male lambs is for management purposes, but if they decide to leave them entire they must be separated from the rest of the flock by 20 weeks to avoid the risk of unwanted pregnancies.

“Entire males often are leaner so they can be finished to a heavier weight without becoming over fat,” says Miss Brian.

Niche markets

A few niche markets have developed over the last few years where entire ram lambs have been in demand for religious festivals such as Ramadan.

“In these situations having a supply of suitable lambs available can pay dividends,” says Michael Gottstein, who conducted the Teagasc trial.

But because the meat produced by entire lambs can have a stronger flavour it’s important to notify any conventional outlets prior to lambs being offered.

Early finishing

Early lambing maturing breeds such as Hampshire Down, Dorset, Suffolk, Charollais, Vendeen or Texel-cross, have good early growth rate, which can be exploited when male lambs are left entire.

The male and female lambs can be run together as one flock from birth without problems when the slaughter age is well under 20 weeks.

There can also be advantages to early spring lambing flocks by leaving all singles entire as well as the best twin-ram lambs born during the first three weeks of lambing.

This allows them to be finished faster and sold first, relieving pressure on stocking rates and exploiting the higher growth rate.

But flocks that decide to leave male lambs entire must have the appropriate management in place when later finishing is involved.

Entire male lambs run separately can be safely reared to about one year of age – when the broad teeth start to erupt – with no detriment to lamb meat quality or flavour.

Trial work undertaken by Signet showed that no taint was discovered by taste panel assessments when male lambs were kept up to 388 days before being slaughtered and fed hay and concentrates or grass.

But producers must ensure later finished, entire male lambs are acceptable to the market being aimed for.

There is also anecdotal evidence reported by Signet that suggests ram lambs kept isolated from female sheep outdoors on grass had more tender meat than rams kept with female sheep.

Some spring lambing hill flocks prefer to leave ram lambs entire to benefit from higher growth rates where early season marketing for export is the preferred option.


Increased management time

Separating the sexes not only involves some additional labour, but also means increased management, because there are more groups of animals to monitor and manage.

Rearing all lambs together is easier for management reasons and by castrating ram lambs it means aggressive male behaviour is eliminated.

The chance of injury is reduced compared with running large groups of entire male lambs which have to be handled regularly.

Risk of injury

MIss Brian says even her own family’s flock, which markets lambs by 17 weeks, always castrates its male lambs.

“I suppose you could say why do we bother to do it, but we don’t want entire male lambs wasting their energy riding each other or potentially getting bruised or injured,” she says.

Buyer concerns

Miss Brian adds that even though some early lambing flocks may see leaving lambs entire as potentially improving growth rates, buyers can be less enthusiastic if they have experience of entires being harder to skin on the slaughter line.

Whether lambs are easier to slaughter because more effort is required to remove the skin from entire ram lambs. Any slight taint to meat from entire ram lambs also means there’s a risk of a discounted price.

Need for distance

If entire ram lambs aren’t run separately, the benefits of the extra growth rate are quickly foregone as the ram lambs spend most of their time chasing ewe lambs.

Only lambs that are likely to make it to slaughter by late August are potential candidates for being left entire.

Entire male lambs remaining on pasture after weaning certainly benefit from having no females in their surrounding environment, which means there must be at least one field between the sexes.

Measurements using pedometers have shown entire lambs kept near female sheep will walk further than other lambs. This may result in weight and condition loss.

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