Poor ewe nutrition affecting a lifetime of wool

A lamb's lifetime of wool production is affected by its mother's nutrition during pregnancy


Wool
Research shows there are big flow-on effects of proper ewe nutrition, not just on lamb survival, but their lifetime wool production.

Research shows there are big flow-on effects of proper ewe nutrition, not just on lamb survival, but their lifetime wool production.

Aa

Poor nutrition during a ewe's pregnancy will have adverse effects on her progeny's entire lifetime of wool production.

Aa

While the impacts of poor nutrition on a ewe's own fleece quality and quantity are well known, a lamb's entire lifetime of wool production is also significantly affected by its mother's nutrition during pregnancy according to sheep industry consultant, Geoff Duddy of Sheep Solutions.

"For twin-born lambs in particular there are big flow-on affects in terms of lamb survival and their lifetime wool production," Mr Duddy said.

"It is important to consider the nutrition of the ewe prior to joining in terms of improving conception rates and from mid-pregnancy on in particular especially when sheep meat and wool prices are so good at the moment."

He said when ewes loose condition, they themselves will potentially cut less wool.

"If they lose up to half a body condition score from pregnancy to lambing, you run the risk of losing about half a kilo of the ewe's fleece weight as well as producing tender fleeces," Mr Duddy said.

"But the other big factor to consider is the lamb in utero."

Lack of nutrition during a ewe's pregnancy will have an adverse effect on their progeny's fibre diameter and fleece weight, lamb birth weights and survival, even the future development of muscle fibres and ewe progeny ovaries/follicles.

Inadequate nutrition can impact negatively on the development of the placenta which provides nutrients to the developing foetus.

Primary follicles (broad fibres) develop in the growing foetus from around day 60 of pregnancy and are completed by about 90 days after conception.

Secondary follicles (fine fibres) develop from around day 90 to birth, with some follicle maturation occurring in the first month of the lamb's life.

Secondary follicles are the most important part of the wool-producing skin, having a direct influence on the density and fineness of the fleece for the entire life of the animal.

Mr Duddy said if twin bearing ewes foetuses are underfed in utero, and they survive, they will come out and cut broader and less wool over their lifetime.

A reduction in nutrient supply to the developing foetus at the time of secondary follicle development, either because of poor nutrition or because there are multiple foetuses competing for nutrients, will lead to less secondary fibres, resulting in broader fibre diameter and lower fleece weight.

Mr Duddy said these effects are permanent throughout the lifetime of the progeny and can't be compensated for by improved nutrition after birth.

"There are definite relationships between changes in ewe condition and the amount and quality of wool produced by single and twin lambs," Mr Duddy said.

"But there are tools producers can use to assist the ewes in getting the correct amount of feed, especially twin bearers."

He said from the point of scanning, separate the twin bearing ewes and consider feeding energy rich supplements that also provide high rates of bypass protein.

"Meals and pulses are probably preferred in terms of a low grain poisoning risk while providing higher rates of ‘bypass’ protein," Mr Duddy said.  

"Protein and energy that bypasses rumen breakdown can supply upwards of 40 per cent more 'bang for your buck'.

"By doing this the ewe is getting more protein into the system and developing the placenta that then ensures twin foetuses are going to be well fed.

"In turn, they are then less likely to come out 'woody' and broader in the wool."

Studies shows fleeces from under-nourished twin foetuses produce 0.3kg less wool that is 0.3-micron broader than single foetuses.

Over their lifetime these relatively small differences can add up.

Ewes that lose 0.5 condition score in early to mid-pregnancy increases the progeny fibre diameter by 0.2-micron in both single and twin lambs.

But ewes that lose 0.5 condition score and then regain this condition by lambing produce progeny that will cut the same amount and fibre diameter of wool as those from ewes that maintain condition score throughout pregnancy.

On the opposite end of the scale, an increase of more than one condition score of the ewe results in an increase of 0.2kg in clean fleece weight and reduction of 0.4 micron in fibre diameter in the progeny.

Mr Duddy said the Merino ewe can be a good mother if fed well.

"We are fortunate that fertility is only lowly heritable. We have underfed the Merino for over 200 years, focusing more on wool cut than fertility and reproductive traits – if we feed her though she can be a good mum,” he said.

"If we strategically feed twin bearing ewes not only will their lambs have a greater chance of survival but they’ll produce better quality wool, they will cut more wool and you will improve your flock fertility."

Aa

From the front page

Sponsored by