Sheep Farm Management Notes: 16/03/2010

Current Sheep Issues

Michael Gottstein

Grass Growth

As I write (Thursday) the cold spell is still with us and even though the days are somewhat milder we are still getting hard frost at night. Soil temperatures according to Met Eireann are hovering between 1.6 and 4.7°C depending on location (for the period 4th March – 10th March). These figures are still below the 6°C required for growth and are back about 3°C from where they would normally be for this time of year.

I think at this stage where fertiliser has not yet been applied a chance may have to be taken that the weather will at some stage have to turn for the good. Certainly having the fertiliser in the yard and the spreading equipment at the ready is important so that you can jump when the opportunity arises.

Meal Feeding

Until grass growth kicks off and ewes suckling lambs get access to good quality grass, meals will have to be fed to make up the shortfall. I have already covered this issue in detail in my article two weeks ago (Tuesday 2nd March) but lets recap. The levels of meal that will be required per ewe per day will depend on how much grass is available, the quality of the grass, the body condition of the ewe and how many lambs the ewe is rearing. I suggest that the minimum supplementation rate on most lowland farms will be 1kg per head per day until grass heights reach 4cm of good grass (as opposed to dead material that has been sitting there over the winter). In situations where there is little or no roughage available then this level may have to be increased to double that figure.

When lactating ewes are being supplemented at grass aim to supplement them with ‘fibre based’ concentrates rather than ‘starchy’ ones. Suitable ingredients are Oats, Citrus Pulp, Beet Pulp, Distillers, Soyabean meal, Rapeseed, Gluten, and Soya Hulls. The last three ingredients are low in energy and should therefore not be included at high rates.

Fodder Shortage

If winter forage stocks are running low and there is insufficient grass available to turn out consider feeding adlib meals. All categories of sheep can be fed adlib meal providing that it is balanced to meet their nutritional requirements.

Dry ewes or weaned ewes will require 0.8 of ufl in energy terms plus 100grams of protein per day. 0.9kg of an 11% protein ration will achieve this and provided that there is at least 7% fibre in the ration there will be no requirement for roughage. Take care when introducing the ration and build the sheep up to the 0.9kg level gradually. It should be fed in two feeds at least eight hours apart.

Lactating ewes require 2.5 ufl’s of energy and 400grams of crude protein per day in the first six weeks of lactation. This can be achieved by feeding 2.7kg of a 15% C. Protein ration. Again crude fibre levels should be kept above 7%.

Grass Tetany

Grass tetany is one of the big killers of lactating ewes. It is essentially a lack of blood magnesium which is exacerbated when the animal is stressed due to bad weather or lack of nutrition. Treatment of affected animals can be successful if they are detected early and treated with a solution of magnesium sulphate. The dose rate is 100cc of 25% solution given under the skin at 5 – 6 different places.

However preventing the condition in the first place is a much better option than trying to save affected animals afterwards. There are a number of different options available to prevent cases from happening in the first place. The following are some of the measures that may be considered;

Meal feeding and incorporating Cal-Mag into the meal. Aim to achieve an intake of 5 grams of magnesium per head per day. If using cal mag that means that 10g of cal mag (50% magnesium) needs to be fed.
Pasture dusting with Cal – Mag (Note: the granular form of Cal-Mag is not suitable for pasture dusting use the powder form only) at a rate of 17kg / ha every week for paddock system and double that amount every 2 weeks for set stocking system. For this to work the paddock being dusted needs to have at least 10cm (4inches) of grass for the Magnesium dust to stick to, so it is unlikely to an option on sheep farms this spring.
High mag buckets/blocks – are generally successful but some ewes will not eat sufficient to ensure protection. Do not use blocks designed for dairy/suckler cows as they will have copper levels that can be toxic to sheep.
Magnesium bullets – purchase ones that deliver 4-5 grams of magnesium per day. These bullets are also quiet expensive and may have to be repeated every 30 days. Some sheep will regurgitate the bullets and these will not be protected.
Treating the drinking water with magnesium is not a reliable control method for sheep.