Ewe nutrition vital through late pregnancy

Dr Sean McGrath, from Millicent & Kingston SE Veterinary Clinics, gave presentations on ewe nutrition in late gestation at the field days in Lucindale, inspired by recent weather conditions.

"With the way the season has panned out, we anticipate paddock feed is running out quicker than most years," he said.

This threw up a number of issues, but Dr McGrath used his talk to focus on preventing ewe mortality and improving lamb survival by "getting the feeding right"

"It's all about energy," he said.

"Especially as ewes get into late pregnancy."

Dr McGrath said this was when ewe energy levels ramped up and between 15 and 17 megajoules of energy a day was needed.

"Feed needs to be monitored at the moment, as pastures have got little energy left in them," he said.

"If sheep aren't getting enough energy, then they start to mobilise their body reserves and you will get changes in body condition scores."

Dr McGrath delved into how body condition scores affected ewes in terms of production, including lamb survivability, ewe mortality and production of the progeny.

Body condition scoring assesses the amount of soft tissue over the short ribs and backbone, on a scale of 1-5, with 1 being very skinny, and 5 being over-fat.

"As condition score goes down, ewe mortality goes up because they can get things like pregnancy toxemia," Dr McGrath said.

"But if condition score gets over four, mortality rates can also go up a little bit as well, potentially due to lambs being too big and having troubles lambing."

Dr McGrath recommended a body condition score of about 3 for single-bearing ewes, and a score of 3.3-3.5 for twin-bearing ewes.

"Changes in condition score can affect lamb survival," he said.

"If you move from a two to a three, you can increase lamb survival by 10 per cent to 15pc, especially in twins.

"And then the progeny of those ewes - for wool-producing sheep, if we lose condition score through late pregnancy, when the progeny is developing their wool-producing cells, that affects the amount of and the type of follicle that are produced.

"So those lambs will produce less fleece weight and have broader fiber diameter for their lifetime, so they'll be less productive as wool sheep."

Dr McGrath said this information was all provided as part of the popular Lifetime Ewe Management Training Course, which included body condition score training.

"Lots of producers have done the course, but there's always a new crop of people that haven't," he said.

"And in our field, we see producers that haven't frequently.

"That's why we want people to be aware of the differences between what's in the pastures, what sheep need, and then making sure that they know that they need to supply more energy to meet those ewe requirements."

Dr McGrath said scanning pregnant ewes would help to better address the feed needs in late gestation.

"It's important to have accurate scanning so you are doing the sums for the twins correctly versus the singles and feeding them differently," he said.

"It also helps to refine feed budgets - as keeping costs down is a priority.

"People need to be aware of what feeding out is costing them and are they getting a return for that investment."

Dr McGrath said he was asked - "how much grain should I feed?"

"It's not a question you can answer until you sit down and work it all out with what you have on-farm," he said.

"We spoke a bit about what made up good paddock feed and what didn't.

"And if it's not meeting the energy requirements, then most people will do some supplementary feeding in the forms of hay, silage or grains.

"But there are things that can go wrong doing that, especially with grain feeding, so there are a few things to keep in mind to do grain feeding right."

Dr McGrath again stressed that these sorts of calculations are taught in the Lifetime Ewe Management Course, or an advisor could help work out feed budgets.

"I think doing some business analysis and financial business benchmarking helps work out if you have to feed heavily every year, and whether that's something that is going to be profitable long-term."