Drought proofing breeding ewes

Top tools to help flock's fertility when joining this autumn


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NSW Department of Primary Industries livestock researcher,  Dr Gordon Refshauge, says condition scoring and pregnancy scanning are the two top tools to help ensure sheep and wool producers get the best outcomes this breeding season.

NSW Department of Primary Industries livestock researcher, Dr Gordon Refshauge, says condition scoring and pregnancy scanning are the two top tools to help ensure sheep and wool producers get the best outcomes this breeding season.

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Drought, feed and heat stress will have major impacts on 2019 autumn, winter and spring lambing.

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Drought-impacted producers preparing to join their flocks for a winter or spring lambing need to carefully plan for their flock's nutritional needs according to industry experts. 

NSW Department of Primary Industries (DPI) livestock researcher, Gordon Refshauge said it was crucial producers condition score ewes before joining and pregnancy scan after joining.

A condition score of at least 2.5 prior to joining is optimal, he said, with a less likely instance of conception if the ewe is in poorer condition. 

“Two weeks on improved feed prior to joining for ewes scoring less than 2.5 will lift fertility and ovulation rates for those leaner ewes," Dr Refshauge said.

David Trengove, Elders Livestock Cowra, said more and more producers were starting to tailor their feeding programs, especially in tougher times. 

"When producers enter into expensive feeding programs, they really need to tailor their programs accordingly," Mr Trengove said.

"If they are down in condition, producers can separate those ewes and feed them to requirement."

He said sheep were like humans, all different shapes and sizes, therefore one size wouldn't fit all when feeding stock. 

"People are now realising that once they get that condition score right pre-joining, that has a flow on effect right through to scanning," Mr Trengove said. 

People are now realising that once they get that condition score right pre-joining, that has a flow on effect right through to scanning - David Trengove

John and Kylie Wood, Maroo, halfway between Cowra and Boorowa in NSW, join 6000 Merino ewes to Poll Dorset rams. 

Out of those 6000 ewes, 4500 are run through a drought lot. 

The couple introduced a three-phase body condition scoring program after a run of bad seasons and having to join in a drought lot, which meant full feed as opposed to feeding only on grass. 

"The condition scoring is a flow-on from the drought lot as we already had full control of what we feed them," Mr Wood said. 

"By giving them full feed, we needed to be doing that as efficiently as possible, tailoring their intake according to their condition score.  

"We obviously want our ewes in the best possible condition to join to give us the return on the feed that we are injecting into them." 

Phase one is condition scoring at five weeks out from joining.

Phase two is condition scoring at joining and phase three is carried out at scanning. 

After phase one, ewes were drafted up on their condition score and fed tailored rations depending on their condition to get them up to joinable status. 

The second lot of condition scoring, or phase two, has only been completed a week ago, but already Mr Wood recorded a marked improvement in his ewes.

"They picked up between .8 to 1 condition score in the five weeks leading up to joining," Mr Wood said. 

"Hopefully our scanning results and then flowing on to lambing are not back from last year and hopefully up, if anything."

Mr Wood said once scanned, the ewes will be split into twin-bearing, singles and dry's.

"On from that, if there is a twin-bearer that is at 2.5 condition score, she needs to be at 3.5 by lambing to give those two lambs the best possible opportunity in life," he said. 

"That ewe will be put with other ewes that are around the 2.5 condition score and they will be feed a full feedlot ration to get them up to that 3.5 mark by lambing. 

"Whereas is there is another ewe that is 3.5 already, all she needs is maintenance to get her through to the point of lambing."

Scanning benefits

The ideal time to scan is 75 to 100 days after joining commenced to identify dry, single and twin-bearing ewes.

"Scanning identifies stock which can be sold, allowing producers to target feed to single and twin-bearing ewes, which require different levels of feeding during mid and late pregnancy," Dr Refshauge said. 

“The sooner ewes can be scanned the better, as feed can be matched to suit single and twin-bearing ewes.

"There may also still be time to rejoin dry ewes - shortening day lengths give ewes a natural lift in fertility and ovulation rates.”

He said late spring and early summer rains can deliver pasture growth, which will lead to an increased ovulation rate, higher pregnancy rates and more twins.

Twin-bearing ewes which conceived in low body condition will need improved nutrition from mid-pregnancy or the health of the ewe and lamb production can be impaired.

Dr Refshauge said high temperatures will also impact on the ability of sheep to produce lambs.

“Ewes experiencing nine hours of 41°C temperatures lose 100 per cent of embryos up to three days old,” he said.

“The highest risk conditions are hot days coupled with hot nights as sheep cannot lose heat from the body.”

Low pregnancy rates may be due to rams suffering from ovine brucellosis or in low condition, which will impair sperm count and sperm quality. 

The future efficiency of EIDs

Mr Trengove said as the use of Electronic Identification (EIDs) in sheep becomes more wide-spread, more data will be on-hand for producers.

"Scanning used in conjunction with EIDs is becoming a lot more powerful," Mr Trentgrove said. 

"People are using it for pregnancy scanning and separating twins and preferentially feeding those to requirements.

"But the next step is when EIDs become a lot more common place, we can collect a lot more data and one of those data points is around pregnancy status. 

"Scanning will capture whether or not a particular ewe is dry, has one or two or more lambs, which can then be repeated year in, year out, allowing producers to build up a profile of that ewe and make concise management decisions going forward."  

The story Drought proofing breeding ewes first appeared on Farm Online.

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