Sheep Management: cobalt supplementation, selecting replacements and event dates

This week’s Northern Ireland Sheep Programme feature touches on the importance of cobalt supplementation, where required. Research has shown that herbage on most Irish farms is typically deficient in cobalt. A Teagasc study in mineral supplementation found that 73% of samples analysed were deficient for cobalt, with the remaining 27% classified as marginal.

Symptoms of a deficiency include loss of condition, poor fleece quality, ears becoming dry and scaly (photosensitisation), a loss of appetite, runny eyes with tear staining on the animal’s face and possibly raised worm counts due to suppression of the animal’s natural immune response.

The Teagasc Athenry study led by Tim Keady showed lambs which received cobalt or a cobalt, B12 and selenium drench delivered 1.3kg and 1.5kg heavier carcases, along with reaching slaughter weight much quicker. There was no significant benefit found from supplementing lambs in July and early August in the Athenry study and no benefit from including B12 and selenium.

The requirements and timelines for supplementation vary between farms and it is important to be aware of this. The study advises that producers could better match mineral supplementation strategies with information on pasture herbage mineral concentrations to allow for targeted supplementation.

In the Athenry trial, lambs received a cobalt drench every two weeks, with this viewed as the optimum timeframe under the conditions there to satisfy cobalt requirements.

The strength of the cull ewe trade is providing an excellent opportunity to cull problem breeders at a low or negligible cost to the system. Where retaining homebred replacements, it is important to select potential replacements early. It is useful to initially select a higher number than required to allow for further assessment as the season progresses. The same applies to purchased replacements.

Selecting replacements early is critical where lambs are destined to be mated as ewe lambs. Research has continually shown the potential for ewe lambs to produce an average of over a lamb per ewe mated is strongly influenced by liveweight at mating. The heavier lambs are (at least 60% of mature weight at mating), the better breeding performance will be.

It is also useful to assess the performance of yearlings rearing lambs and considering early weaning if hoggets are in any way under pressure to provide a longer recovery time.

Sheep Ireland, in conjunction with the EU project Smarter, is holding a breeding conference and farm walk on 12 July. The conference in the Anner Hotel, Thurles, Co Tipperary, starts at 9.30am. Topics include an overview of the UK sheep breeding programme, how the Sheep Ireland genetic evaluations work and challenges and solutions for the sheep industry in meeting greenhouse gas emissions targets. The afternoon farm walk takes place on the farm of John Large who is a central progeny test flock. Attendance is free but attendees must register at www.tickettailor.com.

Registration has also opened for the Tullamore Farm beef and sheep open day on Tuesday 26 July from 10am to 5pm. The event will include farm tours, workshops, exhibitors and demonstrations. Attendance is free and pre-registration is required at www.ifj.ie/tullamorefarm.