Feeding ewes on a budget
19 Dec 2022
Jill Hunter, Beef & Sheep Nutritionist
When it comes to ewe feed, you generally get what you pay for and in a year where feed costs are high, finding value for money while also maintaining performance can be a challenge.
Pre-lambing nutrition can be separated into four key focus areas; Supporting the ewe, get up and go of newborn lambs, quality of colostrum and subsequent milk and future lamb growth.
Supporting the ewe
First consideration has to be Body Condition Score (BCS) with different breeds and production systems having different targets. An upland, twin-bearing ewe will tup at BCS 3 which will naturally drop off to around 2.5 at the point of lambing, as grass quality deteriorates through the winter.
It can be tempting to withhold feed from fit ewes, however ewes carrying extra body condition and lean ewes alike, find it difficult to mobilise body fat reserves and will be more likely to go down with twin lamb disease. Choosing a feed bucket which will supply propylene glycol as the main source of energy coupled with no added vegetable oil, will be key to supporting these girls.
Coming into the last 6 weeks before lambing, keep in mind 70% of lamb and liquid growth now happens. This results in a huge increase in nutrient demand, including energy and protein. Not only is energy demand increasing, the physical size of the rumen is being constricted by the growing lambs. This means feed must be high energy, well balanced and encourage rumen function. There is often a lot talk a lot about providing by-pass protein pre-lambing, which is important for colostrum quality, but it is equally as important to feed rumen degradable protein, to stimulate rumen function and ensure ewes get as much out the forage as possible.
Finally, it is important to consider water supply. Demand for water more than doubles from pre-lambing to having lambs at foot. Consider putting ewes in a shed; do they know where the water is, can they reach it, are they bullied away from it, is it clean and is it defrosted? Drinking cold water requires energy to bring up to body temperature.
Once ewes are successfully lambed, supporting the ewe to ensure she repairs any tissue damage and can produce milk, adequate enough to grow her lambs is essential. As a rule, continue to supplement ewes until grass sward height is over 4cm. Under 4cm, the compound complements the grass, but over 4cm, compound feed is simply replacing grass intake, which is not cost effective. Ewe nutrition and body condition in the first few weeks post-lambing is linked to the number of lambs she has next year. Therefore, cutting feed this year will not only impact lamb viability this year, but for seasons to come.
Mastitis is a huge problem after lambing and we know genetics, management, hygiene and nutrition all have their role to play. Recent studies have shown up to 5% of ewes have acute mastitis and of them, around 50% die and of the ones left, most lose the affected side. Additionally, a further 20-30% suffer sub-clinical cases. Roughly a quarter of these cases can be put down to poor nutrition during pregnancy and lactation, leading to poorer immunity and poor milk yield, meaning lambs are constantly suckling so the udder is never rested. With the industry under increasing pressure to reduce antibiotic use and a key focus area in this reduction identified as mastitis treatment, supplementing ewes post lambing can help significantly help in working towards this goal.
Lamb get up and go
Shivering accounts for 50% of heat production in newborn lambs and brown fat, which is the layer of fat a lamb is born with, accounts for a further 30%. Alongside other supplements, selenium is essential for muscle function, which allows the newborn to shiver and is needed to release energy stored in brown fat. This means it is essential to supplement ewes with selenium. Traditional sources of selenium can be poor quality and not well utilised by the animal. This is why Sel-plex is used across species in Harbro products. Sel-plex is an organic, yeast-based selenium, which is readily absorbed and utilised, with trials showing more lambs weaned, heavier, and grew quicker than those not fed Sel-plex.
Additionally, gestation length has an effect on birth weight, as well as the time it takes to stand and suckle. Of course, the quicker a lamb stands and suckles, the quicker it reaps the benefit of the quality colostrum waiting for it. Omega 3 has been shown in trial work to increase gestation length and birth weight and decrease time to stand and suckle, making it essential in top quality ewe feeds.
The science and advice behind colostrum supply has not changed, although that does not negate the importance of getting it right. Concentrate on getting a big belly full, as quickly as possible. If in doubt, tube the lamb with colostrum from its own mother or another ewe. Quality can be influenced by ensuring a proportion of the pre-lambing diet contains by-pass protein. Traditionally this would have been fish meal, more recently soya bean meal and as we move towards a more carbon neutral target, there are a growing range of equally cost effective options which have the same benefit on colostrum quality.
The first step towards optimising lamb growth is rumen function and whether finishing lambs on grass or compound feed, feeding creep is the best way to develop the rumen well and to set the lamb up for the rest of life. When finishing lambs, feed conversion is the most important consideration, rather than cost per tonne of feed and this can be easily calculated with your feed advisor.
To help producers keep track of performance in a very practical way, Harbro has created a benchmarking group in conjunction with Glasgow Vet School. Open to all customers, the system is being utilised by producers to ensure management decisions are fact based and cost-effective.
To summarise, getting ewe nutrition right pre-lambing pays dividends for ewe health, lamb vitality, survivability and subsequent growth. Good management coupled with quality, cost effective nutrition will ensure productive and profitable sheep enterprises in the coming months and years.