Ewe feeding can affect progeny

Breeding ewe nutrition has the potential to affect not just the performance of the ewe, but also her lambs and their future progeny, too, according to researchers speaking at an SAC Sheep Nutrition workshop last week.

While it is well known that better feeding just before mating improves lambing percentage, few realise the responsiveness of the ovary to that feeding may depend on the nutrition the ewe received as an embryo. This knowledge has the potential to improve sheep productivity, health and welfare.

Many progressive sheep farmers had realised there was no one-size-fits-all approach to nutrition, said SAC sheep specialist John Vipond. “In future they would like to know their replacements have been fed to a scientific blueprint designed to maximise their full genetic potential for breeding.

Ewe nutrition could affect not only their own breeding performance, but also that of the progeny.

“But many lambs never make it this far, the latest research shows some prolific breeds can easily be overfed at mating. This can lead to the liver removing hormones which are important for the survival of newly-produced eggs,” said Dr Vipond.

“Recent work on lambs shows that those underweight at weaning due to feed restriction or worms may not express their full genetic potential for breeding.”

Likewise, other trace element deficiencies could affect the number of potential eggs in the ovary and muscle development, too, he said. Cobalt deficiency could even affect behaviour at lambing. Embryo transfer work showed that the cobalt status of ewes before they ovulated could affect how the subsequent lamb produced grew, its immunity and even its blood pressure later in life.

“Breeders are used to the idea of selling lifetime productivity, as they have statistics like EBVs to measure this. But they are less aware of the lifetime effects of their feeding regimes. Potentially there are benefits for both them and their clients if they get it right.

“Similarly, the feed industry is used to breeders using feed to bring animals out for sale looking their best. But the new research shows how there can be much more permanent and beneficial effects from proper nutrition,” said Dr Vipond.

As a result of the workshop new guidance will be issued in the form of a booklet incorporating many of the new messages identified by recent research.