With most sheep producers forced to hand-feed over the past few years, there has been a spotlight cast on the relationship between feed intake and returns.
So, should producers be putting more value on feed efficiency?
The topic created interest on Twitter recently when prime lamb seedstock producer, Tom Bull, Holbrook, raised the question of whether seedstock producers should apply fine tuned management techniques to their ewes or whether they should instead aim to produce sheep that can be managed with less feed and labour?
"It's all about collecting data in the same environment the progeny of these animals are going to be living in," Mr Bull said.
"If we put our sheep in show sheds, they're not going to get any exposure to worms, the weather. It creates an artificial environment."
Mr Bull said efficiency for their business was ewes who had two lambs that could be turned off quickly.
"Firstly, you have one ewe feeding who is producing two lambs, not one," Mr Bull said.
"Secondly, if those lambs grow quickly and are able to be produced off green grass when there's abundant feed, you don't incur the feed and labour costs of a slow growing lamb which you might have to feed grain to all summer to try and get to a slaughter weight."
EFFICIENCY THROUGH STORING FAT
He said as well as selecting for fast growth rates, they selected for high fat Australian Sheep Breeding Values (ASBVs).
"That means the sheep are storing more fat, their energy, in spring when feed is abundant, then they draw on it in autumn when the feed isn't abundant," Mr Bull said.
"That's incredibly feed efficient for us, because in a normal year we can't eat all the spring grass anyway, we have feed utilisation issues, the sheep can store that on their back and draw down that when things get tight."
Mr Bull argued that the composition of the sheep should be valued more than its weight.
"If we took a lot of fat off our sheep, they would weigh lighter but we'd actually have to feed them more because they would have no energy stored," Mr Bull said.
He said because most of their lambs were sold at domestic weights, adding fat to their ewes did not have a significant impact on their carcases.
"We don't specialise in heavy, export lambs where that extra fat could consolidate, we aim for 23kg at 12 to 15mm of fat," Mr Bull said.
BALANCING GROWTH RATES WITH FRAME SIZE
Dubbo's Nutrien Ag Solutions Merino specialist Brad Wilson said feed efficiency was becoming a discussion point with some commercial Merino producers, particularly after the past few years.
"Their main focus is finding that balance where they can turn a wether lamb off quickly without getting breeding ewes too big," Mr Wilson said.
He said due to the season over the last three years, studs and commercial producers alike, had been forced to run more efficient operations.
"There's been no feed in the paddocks, so containment lots and early weaning strategies have been developed," he said.
Tony Armour operates a self-replacing fine-wool Merino flock south of Bookham and has been a long-term entrant in the Bookham Flock Ewe competition.
Mr Armour said he was concerned about the increasing size of ewes across the industry and wondered whether they were really efficient converters of feed.
He said that although he didn't mind feeding sheep through a drought, he did not want to have to feed them to get the most performance from them.
"They have to be able to convert the available pasture without any supplementation," Mr Armour said.
TRANSPARENCY ON RAM SALE PREP
He said he understood the need for seed stock producers to present their rams in good condition for sale, but as a commercial ram buyer, he was looking for balance in his sheep and questioned the need to have them over prepared, where the biggest is the best.
"Perhaps we could have the studmaster or auctioneer prior to sale let everyone know how the rams have been fed through the year, it could be a good selling point," Mr Armour said.
Leading sheep consultant Geoff Duddy thought the ability for sheep to cope with environmental conditions, like heat stress, was key for producing efficient animals.
"Two to three years ago, heat stress particularly in relation to conception and loss of embryos, was a very big issue," Mr Duddy said.
He said there were several studs focused on breeding sheep that would survive and thrive in harsh environments, with the ability for sheep to store fat a benefit if animals were able to draw on those resources during periodic droughts.
HUGE VARIABILITY IN FEED CONVERSION
Mr Duddy said although it was difficult for feed conversion to be measured in the paddock, "we don't actually know what each sheep is eating," when sheep were put into confinement it became clear that it was profitable to understand the genetics of the sheep you were buying.
"Studies have found there can be a large variability in feed conversion," he said.
One of the studies he cited was by Nick Linden of Agriculture Victoria, who found that lambs from his trial's top sire could put on 1kg of live weight for every 3kg of feed, while lambs from the bottom performing sires needed 14kg of feed to put on 1kg of live weight.
Mr Linden said they would find groups of lambs that had all put on 15kg in liveweight during a finishing phase, but they would still see a massive variation in feed intake between those lambs.
"Looking at measures, like growth rate, you would say they're both really efficient lambs and they're both putting on a heap of weight.
"But the reality is one would make you a lot of money and one would be just a break-even at best."
He said it was important that producers understood the maturity patterns of their sheep's genetics.
"If you're a spring lamber that wants every lamb gone by Christmas, it's a different genetic package to if you're a spring lamber who wants to carry lambs on stubble over summer and then feed them to target an Easter turn off.
"You have to know your production system and genetics, because it's really important that the two line up - you've got to feed the lambs when they are going to give you the greatest return."
He said improving the efficiency of ewes was also an important consideration.
"They are the ones that are staying on the farm the longest, so they need to be efficient," Mr Linden said.
ASBV FOR FEED EFFICIENCY?
Mr Linden's colleague at Agriculture Victoria, Dr Stephanie Muir has looked at whether feed efficiency changes over the lifetime of the ewe, assessing the animals as weaners, hoggets and adults to find out if a more efficient weaner became a more efficient ewe.
She said there was a low to moderate correlation in feed efficiency observed between age groups, which suggests that while some animals continue to be more efficient as they grow, there is likely to be some changes in ranking as animals mature.
Dr Muir said ideally they would like to see enough interest in feed efficiency from the sheep industry to back development of an ASBV or genomic test that measures the trait.
"The dairy industry has a genomic breeding value for feed efficiency called 'feed saved' that indicates the amount of feed saved for a given level of milk production," Dr Muir said.
Meanwhile, the NSW Department of Primary Industries is leading a Meat and Livestock Australia-funded project which aims to give producers the tools to select sheep which will improve the overall feed efficiency by 15 per cent.
In uncovering what makes some sheep more feed efficient than others the 'better doers' project is investigating nutrient uptake and metabolism in the rumen and the processes controlling energy expenditure and metabolic efficiency in the animal's skeletal muscle.
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