3 tips for broody hens Why drench­ing preg­nant ewes

just be­fore lamb­ing isn’t the an­swer

NZ Lifestyle Block - - Notebook -

If you’d like to try rais­ing a clutch of chicks, a broody hen who re­fuses to get out of her nest for days at a time is your nat­u­ral-born in­cu­ba­tor. How­ever, dur­ing the time she is sit­ting, she won’t be lay­ing eggs for you. • Don’t put your most valu­able fer­tile eggs un­der an untested broody – you need to make sure she’s re­li­able be­fore you en­trust her with valu­able eggs. • You can buy fer­tile eggs (these are posted in the mail, quite safely) and this gives you the op­tion of get­ting her­itage breeds, or you can have a rooster. • If you are rais­ing a clutch, re­mem­ber you will be get­ting a 50-50 mix (or there­abouts) of males to fe­males – are you pre­pared to keep the boys or raise them for meat, or to sell or eu­thanise them? Dump­ing birds is cruel and not per­mit­ted un­der the An­i­mal Wel­fare Act.

Drench­ing preg­nant ewes just be­fore lamb­ing is a long-held, pop­u­lar be­lief. The the­ory is any sheep that are thin and not do­ing as well as others in the flock are suf­fer­ing from par­a­sites, and so pre-lamb­ing drench­ing is a must.

That seemed to be backed up by re­search over the last 50 years, but sci­en­tists at Agre­search have now found that isn’t the case and that there are other is­sues far more likely to be the cause of thin ewes in late preg­nancy.

It has just fin­ished a re­view of all the on-farm tri­als con­ducted in New Zealand since the 1960s and dis­cov­ered some­thing in­ter­est­ing: there is no con­sis­tent ben­e­fit from drench­ing ewes around lamb­ing time, no mat­ter what method you use.

“That means that some­times there is a mea­sur­able ben­e­fit and some­times there isn’t,” says Agre­search par­a­sitol­o­gist Dr Dave Leath­wick. “But it’s a bit more com­pli­cated than that, be­cause many of the tri­als didn’t ac­tu­ally mea­sure all the vari­ables nec­es­sary to make a proper de­ci­sion on the ben­e­fits of treat­ment.”

His find­ings showed that over the pe­riod from pre-lamb­ing to wean­ing, some ewes in­crease in con­di­tion, some lose con­di­tion and some stay the same.

“The pro­por­tions fol­low­ing this pat­tern were ex­actly the same whether the ewes were drenched or not, and the type of drench was ir­rel­e­vant. We in­ter­pret these data as telling us that low body con­di­tion in ewes at this time of year is un­likely to be caused by worms. Even when skinny ewes are given a long-act­ing drench, many of them don’t im­prove in con­di­tion, and some lose con­di­tion.”

Work by Massey Univer­sity sug­gests that thin ewes are more likely to be suf­fer­ing from sub­clin­i­cal pneu­mo­nia and/or the long-term ef­fects of fa­cial eczema.

“While the causes of ill-thrift re­main un­cer­tain, it does ap­pear worms are not im­por­tant,” says Dr Leath­wick. “If you try and solve an ill-thrift prob­lem in your ewes by drench­ing you will prob­a­bly fail.”

The best recipe to hav­ing healthy ewes at lamb­ing? Get as many as pos­si­ble to con­di­tion score 3 be­fore lamb­ing starts.

If you try to solve an illthrift prob­lem in your ewes by drench­ing, you will prob­a­bly fail.

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