Prioritising mobs, strategic feeding and mid pregnancy shearing are amongst the management tools farmers could consider implementing to maintain ewe productivity in a challenging season.
Speaking at a recent Beef + Lamb New Zealand Farming for Profit field day in Marlborough, Professor Paul Kenyon from Massey University’s School of Agriculture and Environment gave an overview of the nutritional requirements of the ewe flock and some management tools that can be used to make the best use of limited feed resources.
He encouraged farmers to determine the amount of feed they have on-hand now and try and predict what would be available in late pregnancy and early lactation.
If there was likely to be a feed deficit, a plan can be developed around which mobs should be prioristised, sold or sent away and what supplement, if any, could be used.
Winter rotation
Professor Kenyon suggests farmers think about which their best lambing paddocks are from a survival perspective, and these should be grazed early in the winter rotation. This allows covers to be built in time for set-stocking.
These paddocks will be needed for set-stocking the most vulnerable ewes (and lambs).
Prioritising mobs
Scanning is a good time to identify the ewes that need the most nutrition in late pregnancy. Poor condition multiple-bearing ewes, especially those bred in the first cycle, need to be the priority group for feeding in mid to late pregnancy. These ewes should have their feed allowance increased to above their pregnancy requirements to enable them to gain condition.
The balance of the mob can be fed to meet their pregnancy requirements which, where possible, may mean splitting into single and multiple-bearing ewes.
Nutritional requirements from day 70
From day 70, single-bearing ewes should be offered an allowance of 1.5-1.8kg/DM/ewe/day with post-grazing covers of around 800kg DM/ha (a sward height of 2cm). For multiple-bearing ewes, post-grazing covers should be around 900/1000 kg DM/ha (2.5-3cm sward height).
If winter crops are being used, ewes need a similar daily DM allocation, but feed utilisation should be considered.
Professor Kenyon says poor condition multiples should be offered higher post-grazing masses so they can gain condition. This condition will act as a buffer in late pregnancy.
Mid pregnancy shearing
Professor Kenyon says shearing ewes between days 40 and 100 days of pregnancy with a cover comb can increase placental and foetal growth. This leads to a larger lamb at birth and can improve survival by 3-5% in multiples.
Other potential advantages include reduced ewe casting, lambs having easier access to teats, improved wool quality and improved lamb weaning weights by up to 1-2kg.
This management tool will only work if the ewes are at between days 40-100 of pregnancy, they are at a Body Condition Score (BCS) of at least 2.5 and are being fed to at least pregnancy maintenance levels.
“Farmers don’t need to shear the whole mature ewe flock, they can target those most likely to respond in terms of positive impacts on lamb survival.”
The impacts of under-feeding ewes
Malnourished ewes tend to have sub-optimal levels of colostrum production, delayed milk let down, they produce less milk overall and have lower peak milk production. Their lambs ae lighter at birth, the ewes have a poorly developed maternal instinct and are at a greater risk of developing metabolic diseases and dying. All of which lead to lower lamb survival and lamb weaning weight.
Nutritional requirements 50 days before lambing
During days 100-126 of pregnancy, individual ewes should be grazed so that pasture masses don’t get below 900 kg DM/ha.
Three weeks out from lambing, ewes should be offered 2-4 kg DM/ewe/day and post-grazing residuals lifted to 1000-1100 kg DM/ha.
If there is not enough feed to meet these nutritional requirements, priority should be given to poor condition, multiple-bearing early lambing ewes and then the remainder of the first cycle multiple-bearing ewes.
After these comes the second cycle multiple-bearing ewes, then the single-bearing early lambing ewes and finally the late, single-bearing ewes.
Professor Kenyon reminded farmers that those breeding over to three cycles have a range of 34-51 days in expected lambing dates.
This makes it more feasible to target the mobs that need it most while holding the others back.
Late pregnancy nutritional requirements
After day 133 of pregnancy, intake should not be restricted, although often ewes cannot physically eat enough at that stage of pregnancy to meet their theoretical demand. That’s why multiple-bearing ewes should be in good condition going into late pregnancy and lactation. Ideally, individual ewes should not be allowed to graze pastures below 1200 kg DM/ha (or 4cm) and multiple-bearing ewes should be given an allowance of 3-4 kg DM/day.
There is no advantage to grazing above 1800 kg DM/ha from an intake point of view.
Set-stocking
Ideally, individual paddocks should be set-stocked so covers never go below 1200 kg DM/ha during lactation.
Late lambing ewes can be set-stocked later and on lower covers (as grass will be growing) to help save feed.
Single-bearing ewes can also be set-stocked on lower pasture covers as there will be less impact on their performance.
Related resources
For information about pregnant ewe management go to: