Silage analysis will improve pre-lambing ewe feeding

5 January 2018

Getting silage for pregnant sheep analysed will help ensure pre-lambing ewes get the appropriate nutrients in the most cost-effective diets.

SheepRosie Miller, Ruminant Specialist with Trouw Nutrition GB stresses that managing ewe nutrition in the run up to lambing is an important step toward a successful lamb crop, but adds that without a representative silage analysis it will be impossible to ensure ewes are fed correctly.

“The starting point of any ration is good quality forage, with compound feed or straights fed alongside. But to develop an effective diet you have to know how good the forage is so that the other feeds supplement it correctly to meet the total requirements of the ewe.

“Forage is an important part of pre-lambing diets at what is a crucial stage for the ewe and the lamb crop,” she continues. “Assuming an average analysis as the basis for supplementation decisions could result in ewes being either over-fed or underfed.”
Ms Miller says the consequence of over-feeding will be higher feed costs, an increased risk of twin lamb disease and prolapse and increased feed intakes post-lambing. Underfeeding means ewes may lose excess body condition, have poorer colostrum quality and yields, reduced milk yields, low lamb birth weights and increased mortality. Early lamb growth will also be compromised.

She says the variation is silage quality can be significant. From a review of grass silages produced for sheep in the winter of 2016/17 she says the average energy content was 9.8MJ/kgDM while the top forages had an energy content of 10.8MJ/kgDM.

“This difference will have a marked impact on performance and possible costs. With improving quality, forage intakes will increase and farmers can take advantage by maintaining a high forage to concentrate ratio in the diet to help avoid issues such as acidosis. Conversely, intake of poorer quality forage will be compromised, which could result in a lower energy supply than anticipated. So one aim should be to maximise the quality of grass silage made on sheep farms. However, for this season the forage is made and so it is key to utilise forage analysis so ewes can be rationed accurately.

“A 70kg twin bearing ewe requires 15.3MJ per day at three weeks pre-lambing. Ewes fed the average sheep silage last year would require 0.6kg/day of an 11.8MJ compound feed to meet requirements, but if they were on the best silage this would drop to 0.43kg/day. Without a silage analysis it is impossible to balance the forage correctly.

“Using our example, if the farmer assumed he was using average quality silage and supplemented accordingly but actually had the better quality feed, ewes would be being over fed by 170g/day. For a 350 ewe flock this is 60kg of concentrates per day that is being fed unnecessarily at a cost of around £13 per day. As well as pushing up costs, there is a risk of overweight lambs and more problems at lambing.”

Ms Miller says samples can be analysed and back on farm in a few days meaning diets can be reviewed and fine-tuned to improve performance and control costs. Trouw Nutrition GB now produce a special analysis report especially for sheep farmers which provides the information they require, and is available through the farm’s feed supplier. To ensure they get the correct analysis, farmers should write ’sheep’ on the analysis request form.

“Investing time in getting silage analysed could make a big difference to performance and margins this winter,” Ms Miller observes.

For further information, please contact our Ruminant Team.