Brothers Karol and Peter McCaughan hosted a webinar last week, detailing the management of the 650-ewe flock on their 340ha hill farm outside Ballycastle, Co Antrim.
While all aspects of flock management were outlined, the evening focused on animal health in particular, with ovine pulmonary adenocarcinoma (OPA), also known as Jaagsiekte, discussed in detail.
The flock primarily consists of Lanark-type Scottish Blackface ewes, which lamb in April. Improved upland grazing carries around 130 Mule- and Texel-cross ewes, along with 130 Lleyn-sired ewes.
Rams used to mate hill ewes include Scottish Blackface and Lleyn. Suffolk and Texel rams run with crossbred ewes, along with a Cambridge ram introduced to the flock last year.
The Cambridge ram is a composite breed, containing Finnish Landrace genetics that drive prolificacy and maternal traits. The aim is to keep female progeny sired by this ram as future flock replacements.
Peter and Karol McCaughan getting ready for a visit by the sheep vet on their farm outside Ballycastle Co. Antrim. \ Houston Green
High replacement rate
When the McCaughan brothers joined the NI Sheep Programme, a review of the farm’s financial and physical performance was undertaken to establish baseline information for the farm.
On the sheep side, the review highlighted flock fertility and replacement rates as areas that needed immediate action.
“We had far too many ewes scanning empty, which meant we had a high culling rate. To maintain breeding numbers, we had to keep extra ewe lambs, which meant fewer lambs for sale,” said Peter.
Flock output
In 2019, scanning rates for the crossbred ewes were 141%, with hill ewes on 121%, yet weaning rates were 0.83 lambs/ewe.
“We knew that something needed to be done on ewe fertility. Ewes were blood sampled for trace elements, but nothing of note showed up to cause the problem,” said Peter.
Animals were also checked for resistance to anthelmintic products with faecal egg counts (FEC). Again, there was nothing to suggest an underlying problem impacting flock output.
Sheep that died were sent for post-mortem, as were any lambs aborted. Toxoplasmosis was a problem, but after vaccinating ewes, there was little improvement in barren rates. The final step was to consider OPA as the underlying problem in the flock.
Scanning
Ultrasonic scanning of ewes was carried out during the summer of 2019 which found that across the entire flock, 8% of mature animals were affected by the disease.
Across 650 ewes, this equates to just over 50 animals. OPA is an incurable and highly contagious disease, which causes tumours to develop in the animals’ lungs.
“We culled hard after the scanning results last year to remove confirmed cases as quickly as possible.
“Ewe lambs bred from OPA-positive ewes are also sold on, with replacements only kept from animals scanning free of the disease,” said Karol.
Improvements
Scanning was repeated this year during August and the good news is that decisive action is being rewarded.
Across the flock, the incidence of OPA-positive sheep was reduced by 50%, with 4% of breeding females affected. Again, these animals were culled from the flock.
Cost benefit
“For us, the benefits of OPA scanning and hard culling outweigh the costs incurred. It costs around £2/ewe to scan, which across the flock is around £1,300.
“But this year, we had an extra 25 ewes in lamb. Just by selling one extra lamb from these 25 ewes, at a modest store price of £60/head, means we have an extra £1,500 in sales.
“This more than covers the scanning costs. Factoring in twin-bearing ewes increases sales further.
“OPA-positive ewes would also die during winter when they came under nutritional stress, giving us no cull value for these animals. Scanning early and culling 25 ewes at £50/head is worth another £1,250.
“For some, OPA scanning may seem unnecessary and expensive, but, in the long run, it is cheap and worthwhile,” said Karol.
Future plans
OPA scanning is an aspect of flock management across all 10 farms involved in the NI Sheep Programme.
Karol and Peter intend to continue scanning their flock annually to drive down the percentage of animals affected by the disease.
This will be combined with a flock recording package that will link in with EID tagging. All lambs are now tagged at birth and problem animals and lamb weights are being recorded manually.
Having such data will come in useful when making breeding decisions every autumn.
Added health benefits
Like any disease, OPA suppresses the animal’s immune system. This leaves sheep open to secondary infections, which are much easier to diagnose and often cited as the cause of mortality in flocks.
By addressing the OPA challenge in their flock, the McCaughans are seeing fewer health problems, as animals are less immuno-suppressed.
Lamb performance
Combined with a concentrated effort to improve grazing management, lamb performance in particular has excelled during 2020.
The farm traditionally sold lambs in the store ring. But this year, a number of crossbred lambs have been finished off grass due to increased thrive.
“We have been weighing lambs with greater regularity this summer and were surprised by how well animals have performed.
“While store lamb prices are strong, we thought that the best crossbred lambs could be finished off grass at little cost. Finishing lambs would add value with a higher sale price.
“We finished 40 lambs and sold 330 lambs as stores, with 180 ewe lambs kept as breeding replacements.
“Lambs are being rotationally grazed and by splitting fields to manage swards better, there is scope to put more lambs away fat, rather than through the store ring in future years,” said Karol.
Read more
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This week in photos: sheepdog trials and feeding cattle and flocks
Brothers Karol and Peter McCaughan hosted a webinar last week, detailing the management of the 650-ewe flock on their 340ha hill farm outside Ballycastle, Co Antrim.
While all aspects of flock management were outlined, the evening focused on animal health in particular, with ovine pulmonary adenocarcinoma (OPA), also known as Jaagsiekte, discussed in detail.
The flock primarily consists of Lanark-type Scottish Blackface ewes, which lamb in April. Improved upland grazing carries around 130 Mule- and Texel-cross ewes, along with 130 Lleyn-sired ewes.
Rams used to mate hill ewes include Scottish Blackface and Lleyn. Suffolk and Texel rams run with crossbred ewes, along with a Cambridge ram introduced to the flock last year.
The Cambridge ram is a composite breed, containing Finnish Landrace genetics that drive prolificacy and maternal traits. The aim is to keep female progeny sired by this ram as future flock replacements.
Peter and Karol McCaughan getting ready for a visit by the sheep vet on their farm outside Ballycastle Co. Antrim. \ Houston Green
High replacement rate
When the McCaughan brothers joined the NI Sheep Programme, a review of the farm’s financial and physical performance was undertaken to establish baseline information for the farm.
On the sheep side, the review highlighted flock fertility and replacement rates as areas that needed immediate action.
“We had far too many ewes scanning empty, which meant we had a high culling rate. To maintain breeding numbers, we had to keep extra ewe lambs, which meant fewer lambs for sale,” said Peter.
Flock output
In 2019, scanning rates for the crossbred ewes were 141%, with hill ewes on 121%, yet weaning rates were 0.83 lambs/ewe.
“We knew that something needed to be done on ewe fertility. Ewes were blood sampled for trace elements, but nothing of note showed up to cause the problem,” said Peter.
Animals were also checked for resistance to anthelmintic products with faecal egg counts (FEC). Again, there was nothing to suggest an underlying problem impacting flock output.
Sheep that died were sent for post-mortem, as were any lambs aborted. Toxoplasmosis was a problem, but after vaccinating ewes, there was little improvement in barren rates. The final step was to consider OPA as the underlying problem in the flock.
Scanning
Ultrasonic scanning of ewes was carried out during the summer of 2019 which found that across the entire flock, 8% of mature animals were affected by the disease.
Across 650 ewes, this equates to just over 50 animals. OPA is an incurable and highly contagious disease, which causes tumours to develop in the animals’ lungs.
“We culled hard after the scanning results last year to remove confirmed cases as quickly as possible.
“Ewe lambs bred from OPA-positive ewes are also sold on, with replacements only kept from animals scanning free of the disease,” said Karol.
Improvements
Scanning was repeated this year during August and the good news is that decisive action is being rewarded.
Across the flock, the incidence of OPA-positive sheep was reduced by 50%, with 4% of breeding females affected. Again, these animals were culled from the flock.
Cost benefit
“For us, the benefits of OPA scanning and hard culling outweigh the costs incurred. It costs around £2/ewe to scan, which across the flock is around £1,300.
“But this year, we had an extra 25 ewes in lamb. Just by selling one extra lamb from these 25 ewes, at a modest store price of £60/head, means we have an extra £1,500 in sales.
“This more than covers the scanning costs. Factoring in twin-bearing ewes increases sales further.
“OPA-positive ewes would also die during winter when they came under nutritional stress, giving us no cull value for these animals. Scanning early and culling 25 ewes at £50/head is worth another £1,250.
“For some, OPA scanning may seem unnecessary and expensive, but, in the long run, it is cheap and worthwhile,” said Karol.
Future plans
OPA scanning is an aspect of flock management across all 10 farms involved in the NI Sheep Programme.
Karol and Peter intend to continue scanning their flock annually to drive down the percentage of animals affected by the disease.
This will be combined with a flock recording package that will link in with EID tagging. All lambs are now tagged at birth and problem animals and lamb weights are being recorded manually.
Having such data will come in useful when making breeding decisions every autumn.
Added health benefits
Like any disease, OPA suppresses the animal’s immune system. This leaves sheep open to secondary infections, which are much easier to diagnose and often cited as the cause of mortality in flocks.
By addressing the OPA challenge in their flock, the McCaughans are seeing fewer health problems, as animals are less immuno-suppressed.
Lamb performance
Combined with a concentrated effort to improve grazing management, lamb performance in particular has excelled during 2020.
The farm traditionally sold lambs in the store ring. But this year, a number of crossbred lambs have been finished off grass due to increased thrive.
“We have been weighing lambs with greater regularity this summer and were surprised by how well animals have performed.
“While store lamb prices are strong, we thought that the best crossbred lambs could be finished off grass at little cost. Finishing lambs would add value with a higher sale price.
“We finished 40 lambs and sold 330 lambs as stores, with 180 ewe lambs kept as breeding replacements.
“Lambs are being rotationally grazed and by splitting fields to manage swards better, there is scope to put more lambs away fat, rather than through the store ring in future years,” said Karol.
Read more
Lamb drafting pattern coming back on track on Tullamore Farm
This week in photos: sheepdog trials and feeding cattle and flocks
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