Optimum weaning tips for your lambs
The optimum age to wean lambs at is 100 days or 14 weeks of age. Leaving the lambs suckling the ewes for longer than this will have a negative effect as ewes will be competing with lambs for grass.
But if ewes are thin, grass height is below 4cm or lambs are growing less than 150 grams/day early weaning is beneficial. As the next breeding season is approaching ewes need a break from lambs to allow them to recuperate and regain body weight.
Good grassland management is key in getting ewes back into correct body condition score at mating, and allowing weaned lambs to continue to thrive in the absence of their mothers.
To reduce stress at weaning, farmers should prepare ewes and lambs several days prior to the planned weaning date. Cutting out meal feeding and grazing poorer quality pastures while allowing lambs use creep gates to access leafy grass will reduce ewe’s milk production.
Lambs should have all their vaccinations prior to weaning, avoid stressful jobs such as castration/tagging and watch closely for signs of health problems for several weeks after weaning. Ewes should also be observed for signs of mastitis.
The target weaning weight for lambs sired by terminal sire breeds is 34kgs. If lambs are significantly below this target at 14 weeks of age the reasons for poor performance must be identified. Look at areas such as disease or parasites, poor ewe condition at or post lambing, grassland management or poor genetics in ewe/ram.
Once you have identified the probable causes a plan must be put in place to rectify any issues for next year e.g. discuss flock health plan with VET or soil sampling to ensure your spreading the right type of fertiliser to improve grass growth and yield.
Once lambs are weaned the farmer should implement an effective parasite control regime and graze swards down to 6 cm to improve lamb performance. If lamb performance continues to fail to impress, the focus should be on trace element (Mineral) deficiency.
In Ireland the main trace elements of concern include cobalt, selenium, copper and iodine with cobalt deficiency being most common. Trace element deficiencies can be caused by low concentrations in the soil or uptake restricted by another trace element. These deficiencies may be expressed either in a clinical (symptoms Present) or sub clinical form (no obvious symptoms).
Cobalt is required by animals in the synthesis of vitamin B12 which is essential for the metabolism of a rumen volatile fatty acid which is an important energy source to ruminants. Symptoms of cobalt deficiency include loss of condition, poor fleece quality, ears become dry and scaly, loss of appetite, runny eyes and higher worm count.
The uptake of cobalt by plants from the soil can be restricted by high concentrations of manganese and by high soil pH. As cobalt is not stored in the lambs body and is needed in the rumen, a continuous supply is required throughout the grazing season for vitamin B12 production. If a trace element deficiency is suspected on symptoms present, it needs to be identified by blood samples and tissue samples.
A study undertaken recently by Athenry Research Centre concluded that supplementation with cobalt increased lamb performance and that the benefit to supplementation was greater later in the season.