Estimated reading time: 6 minutes
Producers widely acknowledge that the success of any sheep enterprise depends heavily on the potential and management of the farm’s female animals.
Nutrition plays a key role: How ewes are fed has a direct influence on the quality of the lamb crop destined for the feedlot or retained as replacements. Consistent, well-planned ewe nutrition is therefore vital as even short-term mistakes can have long-term consequences.
Mating and early gestation
The ewe’s nutritional cycle begins at mating. Flush feeding typically commences three to four weeks before the breeding season, depending on the ewes’ condition, and continues while the rams run with the flock. The goal is to improve the ewes’ body condition so that they can achieve a score of at least 3,5 out of 5 at mating.
Primary follicle development can commence as far back as six months before mating, meaning that some immature eggs in the ovaries have already started maturing in preparation for ovulation.
Good nutrition during the six to five months leading up to mating is therefore essential. However, by the time mating commences, nutrition no longer has an impact on the number of mature follicles that can release an egg. It can, however, significantly affect the ovulation rate, or the number of viable eggs released, as well as the successful implantation of fertilised eggs in the uterus.
Supplements used as flush feed should provide high levels of energy and protein, in the correct amounts, as well as adequate amounts of essential minerals and vitamins. The composition of the lick and the quantity consumed should be adjusted according to the ewes’ body condition and the prevailing grazing conditions.
After mating, it is important to maintain the condition achieved before and during the breeding period. A maintenance lick is generally sufficient, as the placenta develops rapidly only from mid-gestation onwards, while most foetal growth occurs during late gestation.
Fat ewes are more prone to dystocia, while ewes in good condition can be given fewer supplements supported by good-quality, palatable roughage.
As the name implies, the purpose of a maintenance lick is simply to preserve the ewe’s current condition. In other words, ewes should not lose condition while receiving a maintenance lick. The lick should supplement any nutritional gaps in the pasture (energy, protein, and macro- and trace minerals) while also supporting rumen microbes so they can digest forage as efficiently as possible (energy, nitrogen, and sulphur).
Mid-gestation
Most placental growth takes place during mid-gestation. Sub-par nutrition at this stage has a significant effect on foetal development because inadequate intake of feed impedes placental development, reducing the placenta’s ability to transfer nutrients from the ewe to the foetus. When ewes’ maintenance requirements are not met during mid-gestation, placental growth is delayed and blood flow to the foetus is restricted.
This reduced blood flow limits nutrient supply and prevents the foetus from developing optimally.
Placental development also establishes the foundation for udder growth later in pregnancy, as well as for the foetus’s muscle cell and primary wool follicle development. By the end of mid-pregnancy, all foetal muscle cells have formed; from this point on, they can only enlarge, not multiply. Sub-par nutrition during this period can permanently reduce a lamb’s production potential through impaired placental development.
It is therefore essential to meet ewes’ maintenance requirements during early – and especially mid – pregnancy. These requirements vary across production stages (dry, early, mid, and late gestation) and depend on the number of foetuses carried.
Late pregnancy
Nutrition should be increased during mid- to late pregnancy, as 70% of lamb growth occurs in this period. The ewe’s nutrition directly influences lambs’ birthweight, which is linked to survival. Ideal birthweights range between 3,5 and 6kg, depending on the number of lambs.
Lambs grow rapidly and the ewe’s rumen capacity decreases due to limited abdominal space, particularly when carrying multiples. For this reason, supplements need to contain more protein and energy. Be careful with high-moisture or lush cultivated pastures, as ewes cannot consume enough dry matter from these forages; the high water content fills the rumen before the nutrient requirements are met. Ewes carrying only one lamb can usually be maintained with a good lick, whereas ewes carrying multiples have higher nutritional demands and therefore require more substantial supplementation during late gestation.
Proteins and trace minerals
A common misconception is that bypass proteins – typically supplied by protein sources such as oilcake – are the only important protein source for ewes during late pregnancy and early lactation. This is not the case. Ewes remain ruminants, and their rumen microbes also require proper nutrition. Adequate rumen-available protein, often supplied as urea, is essential for efficient roughage digestion. Importantly, rumen-degradable protein should always be paired with an easily fermentable energy source such as maize, to ensure effective utilisation by microbes.
Bypass proteins can be safely included in ewe diets and play a significant role in foetal growth, milk flow, and overall milk production (udder development), particularly during late pregnancy and lactation. High-quality bypass proteins also support optimal colostrum production.
Ewes’ body condition should be assessed before supplying supplements. Fat ewes are more prone to dystocia, while ewes in good condition can be given fewer supplements supported by good-quality, palatable roughage.
When ewes lamb in pens, it is essential to adapt them to the complete lambing ration provided there. Proper adaptation helps prevent metabolic disorders such as acidosis, which can compromise ewe health and milk production potential.
Trace minerals should not be supplemented individually. Because trace minerals interact in complex ways, supplementation must be carefully balanced. Adding a single trace mineral without the guidance of a nutritionist can easily disrupt this balance and cause unexpected issues.
Post-lambing nutrition
Ensure that newborn lambs consume enough high-quality colostrum immediately after birth. Colostrum provides essential immunity and the energy required for the production of heat.
Its quality is largely determined by the ewe’s nutrition in the pre-lambing period.
After lambing, ewes should be given high-quality feed to prevent excessive condition loss and support optimal milk production. The goal is to help the ewe reach peak milk production by around 21 days post-lambing and maintain it as long as possible. Approximately ten days after this peak, milk production naturally begins to decline, and the ewe’s nutritional requirements gradually decrease.
Throughout this period, ewes should maintain good condition while still having capacity to gain weight in preparation for the upcoming flush period.
Ewes rearing multiple lambs require nutritional attention, as the demand for milk is substantially higher. Without adequate support, these ewes may struggle to regain weight, which can negatively affect their future health and fertility.
Consult your nearest Feedtek nutritionist to develop a balanced, complete, and sustainable nutrition programme for your ewes. It is one of the most valuable investments a sheep producer can make. – Carina le Roux
For more information, contact the author at 082 824 1753.
