Irish farmers spend approximately €3m annually on mineral supplements for their sheep.
When ranking the factors that influence lamb performance, minerals are third after grassland management and parasitic burden.
Minerals are often blamed for poor thrive in lambs, fertility issues in ewes and regularly linked with lameness.
At Teagasc Athenry, final year PhD student Daniel Hession has been researching the effects of mineral supplementation on the performance of ewes and lambs.
A survey of Irish sheep farmers found that 69% supplement with either minerals or vitamins.
Of those who supplemented, 22% said their decision to do so was based on lab analysis of a blood sample, a herbage sample or a soil sample. A further 13% did so based on advice from their vet.
Speaking at a farm walk in Teagasc Athenry, organised for international sheep farmers taking part in the Europe-wide knowledge transfer programme SheepNet, Daniel said the biggest concern was those supplementing without evidence-based reasons to do so.
“What stood out to me was 20% supplemented based on tradition and 13% on experience. So if you combine those two, you’ve a third there. A third of those who supplement do so simply because they’ve always supplemented or their father/mother before them did,” he said.
Daniel said there was evidence of over-supplementation and that this was an extra cost to the farm not only from the products themselves but also the labour and time to administer them. He advised farmers to only supplement where evidence showed it was required.
Key minerals
The three key minerals in an Irish context are cobalt, copper and selenium. Cobalt is required by the rumen microbes to produce vitamin B12 which is important for thrive and fertility. Selenium is important for muscle function and copper has a role in the production of enzymes.
Approximately 73% of Irish farms are deficient in cobalt. \ David Ruffles
Based on herbage analysis from 56 farms across Ireland, Daniel estimates that over 70% of Irish farms are deficient in cobalt.
This means ewe and lamb requirements are not being met. A further 27% were marginal, which meant lamb requirements were met but ewes were not.
For copper, almost 100% of the farms surveyed were sufficient. The majority of farms (80%) were marginal for selenium and the remainder (20%) were deficient.
Ewe performance
As cobalt is the most commonly deficient mineral on sheep farms, a study was undertaken over two years in Teagasc Athenry to determine the effects of its supplementation on ewe performance. Some 34% of farms supplement ewes pre-breeding, so the trial ran from six-weeks before rams joined the flock to seven weeks before lambing.
The international SheepNet group made up of researchers, farmers and industry visited the Teagasc Mellows Campus in Athenry. \ Philip Doyle
Both cobalt drench and boluses were examined and it was found that there was no effect from either supplementation programme on ewe performance. Litter size and lamb birth weight both remained unchanged in the region of two lambs per ewe and a birth weight of 5.1kg.
For the farm in Athenry, which is classed as deficient in cobalt, supplementation or the method in which it was administered had no effect on ewe performance.
Daniel said there was evidence from New Zealand that the current estimated requirement for ewes may be too high. He again advised farmers to only supplement based on evidence.
Lamb performance
The effect of mineral supplementation on lamb performance at Athenry was also examined. Post-weaning, lambs were managed in three different ways – no supplementation, a cobalt-only drench and a drench containing cobalt, selenium and vitamin B12.
The study found that the effects of supplementation increased further into the autumn. While all three groups had the same performance for the first 45 days, the control group fell further and further behind as time progressed.
Liveweight gain was initially 175g/day but from day 45 until day 73, performance in supplemented lambs increased beyond 200g/day, while those not supplemented fell below 170g/day. All groups took a hit in performance from day 73 until day 115 but while the supplemented group performance fell by just 80g/day, the control fell by almost 120g/day.
\ David Ruffles
Lamb performance and drafting rate were increased as a result of supplementing, with day 157 being the final one in the trial.
Lambs that were supplemented were slaughtered at an average of 47.4kg for cobalt only and 47.8kg for the mineral/vitamin drench.
Their carcase weights were 20.4kg and 20.6kg respectively, giving a kill-out percentage of 43%.
Those lambs that were not supplemented were slaughtered at an average of 45.5kg and had a carcase weight of 19.1kg, giving a kill-out percentage of 41%.
While the trial showed the benefits of supplementing later in the season, it did not find a benefit in the inclusion of selenium or vitamin B12 in the drench.
Approaching the end of June, Daniel said many mid-season lambing flocks would be in the process of weaning lambs.
He said: “It is no harm to give mineral supplementation but again going back to evidence, the key things are your grass quality and then your parasite control.
"After that, focus on your mineral supply, but your key is always grass. Enough of grass and quality grass and then your parasites.”
Read more
Sheep Welfare Scheme tasks refresher course
Managing the lambing ewe to improve lamb survival
Irish farmers spend approximately €3m annually on mineral supplements for their sheep.
When ranking the factors that influence lamb performance, minerals are third after grassland management and parasitic burden.
Minerals are often blamed for poor thrive in lambs, fertility issues in ewes and regularly linked with lameness.
At Teagasc Athenry, final year PhD student Daniel Hession has been researching the effects of mineral supplementation on the performance of ewes and lambs.
A survey of Irish sheep farmers found that 69% supplement with either minerals or vitamins.
Of those who supplemented, 22% said their decision to do so was based on lab analysis of a blood sample, a herbage sample or a soil sample. A further 13% did so based on advice from their vet.
Speaking at a farm walk in Teagasc Athenry, organised for international sheep farmers taking part in the Europe-wide knowledge transfer programme SheepNet, Daniel said the biggest concern was those supplementing without evidence-based reasons to do so.
“What stood out to me was 20% supplemented based on tradition and 13% on experience. So if you combine those two, you’ve a third there. A third of those who supplement do so simply because they’ve always supplemented or their father/mother before them did,” he said.
Daniel said there was evidence of over-supplementation and that this was an extra cost to the farm not only from the products themselves but also the labour and time to administer them. He advised farmers to only supplement where evidence showed it was required.
Key minerals
The three key minerals in an Irish context are cobalt, copper and selenium. Cobalt is required by the rumen microbes to produce vitamin B12 which is important for thrive and fertility. Selenium is important for muscle function and copper has a role in the production of enzymes.
Approximately 73% of Irish farms are deficient in cobalt. \ David Ruffles
Based on herbage analysis from 56 farms across Ireland, Daniel estimates that over 70% of Irish farms are deficient in cobalt.
This means ewe and lamb requirements are not being met. A further 27% were marginal, which meant lamb requirements were met but ewes were not.
For copper, almost 100% of the farms surveyed were sufficient. The majority of farms (80%) were marginal for selenium and the remainder (20%) were deficient.
Ewe performance
As cobalt is the most commonly deficient mineral on sheep farms, a study was undertaken over two years in Teagasc Athenry to determine the effects of its supplementation on ewe performance. Some 34% of farms supplement ewes pre-breeding, so the trial ran from six-weeks before rams joined the flock to seven weeks before lambing.
The international SheepNet group made up of researchers, farmers and industry visited the Teagasc Mellows Campus in Athenry. \ Philip Doyle
Both cobalt drench and boluses were examined and it was found that there was no effect from either supplementation programme on ewe performance. Litter size and lamb birth weight both remained unchanged in the region of two lambs per ewe and a birth weight of 5.1kg.
For the farm in Athenry, which is classed as deficient in cobalt, supplementation or the method in which it was administered had no effect on ewe performance.
Daniel said there was evidence from New Zealand that the current estimated requirement for ewes may be too high. He again advised farmers to only supplement based on evidence.
Lamb performance
The effect of mineral supplementation on lamb performance at Athenry was also examined. Post-weaning, lambs were managed in three different ways – no supplementation, a cobalt-only drench and a drench containing cobalt, selenium and vitamin B12.
The study found that the effects of supplementation increased further into the autumn. While all three groups had the same performance for the first 45 days, the control group fell further and further behind as time progressed.
Liveweight gain was initially 175g/day but from day 45 until day 73, performance in supplemented lambs increased beyond 200g/day, while those not supplemented fell below 170g/day. All groups took a hit in performance from day 73 until day 115 but while the supplemented group performance fell by just 80g/day, the control fell by almost 120g/day.
\ David Ruffles
Lamb performance and drafting rate were increased as a result of supplementing, with day 157 being the final one in the trial.
Lambs that were supplemented were slaughtered at an average of 47.4kg for cobalt only and 47.8kg for the mineral/vitamin drench.
Their carcase weights were 20.4kg and 20.6kg respectively, giving a kill-out percentage of 43%.
Those lambs that were not supplemented were slaughtered at an average of 45.5kg and had a carcase weight of 19.1kg, giving a kill-out percentage of 41%.
While the trial showed the benefits of supplementing later in the season, it did not find a benefit in the inclusion of selenium or vitamin B12 in the drench.
Approaching the end of June, Daniel said many mid-season lambing flocks would be in the process of weaning lambs.
He said: “It is no harm to give mineral supplementation but again going back to evidence, the key things are your grass quality and then your parasite control.
"After that, focus on your mineral supply, but your key is always grass. Enough of grass and quality grass and then your parasites.”
Read more
Sheep Welfare Scheme tasks refresher course
Managing the lambing ewe to improve lamb survival
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