Ewe Nutrition Special
"Recent Advances in Feeding the Ewe." with Rowan Boardley, Technical Sales Advisor
Recent research and reviews highlight the importance of Body Condition Scoring ewes throughout the production cycle, as well as setting, monitoring and reaching targets.
A recent review in ewe nutrition highlights the importance of Body Condition Scoring (BCS) throughout the production cycle of the ewe, and its long term influence on productivity. It has been shown that reaching target BCS at key points can influence long term productivity in terms of:
• Ovulation rate and subsequent scanning percentage
• Colostrum and milk production
• Lamb birth weights and growth rates
• Lamb age at finishing
• Replacement costs
Assessing ewes allows accurate allocation of grazing or feed. The most under-conditioned ewes should be offered the best quality feed in order to regain condition.
It is important to remember that 1 BCS unit is equivalent to around 10% of body weight and consists of both fat and muscle tissues (7kg for a 70kg ewe). In this instance, to gain 1 BCS over 70 days, an ME intake of 18.4MJ/d would be required. Assuming a grass or forage quality of 10MJ/kg DM, intakes would need to be at 1.84kg/day just for BCS gain alone, before maintenance and other factors such as lactation.
This highlights the importance of early weaning of lambs off thin ewes in order for her to partition energy towards BCS gain before the next production cycle. If a high percentage of the flock are below the target BCS, it is important to consider other factors such as lameness, poor teeth or diseases including Johne’s or Maedi Visna etc.
It is common knowledge that achieving target BCS by tupping influences ovulation rate and subsequent scanning results, but recent research suggests longer term nutrition can also influence ovulation rate. Ewes that are considerably under condition up to as much as six months before tupping can have reduced ovulation rates due to the negative impact on the maturation cycle in the ewes’ ovary throughout this period.
In the 8 weeks pre and post lambing, accurate nutrition is essential in order to match the requirements of the ewe and the lamb. Feeding under or over requirements can result in problems.
• Low lamb birth weight
• Reduced lamb survival
• Weak ewe and lamb bond
• Delayed lactation with low colostrum and milk yield
• Reduced lamb growth rates and poor ewe performance
• Dystocia from over-sized lambs (particularly singles)
• Weak ewe and lamb bond
• Lambing difficulties
• Impact on future performance of ewe
Twin lamb disease, or pregnancy toxaemia can result from under or over feeding, as well as incorrect rationing. In the last few weeks pre-lambing, the demands of the lamb increase significantly and when the demands of the ewe and lamb are not met this can lead to pregnancy toxaemia.
In addition to sufficient energy, the ewe’s diet must supply plenty of protein. This should be in line with the ewe’s BCS and expected lamb numbers. Insufficient protein can result in loss of protein and fat from the carcase with subsequent reduction in BCS, lamb birth weights and overall productivity.
The Metabolisable Protein requirement of the ewe rises seven weeks pre-lambing, with a significant increase in the last three weeks. The demand for protein rises by 60% between weeks seven and one pre-lambing for a 70kg twin-bearing ewe.
As well as being in sufficient supply, the type of protein is also important. Enhancing bypass protein, or DUP, supply can improve ewe live weight and condition pre-lambing as well as colostrum yield, beneficial for subsequent lamb survival. Bypass protein is highly available in sources such as soya bean meal or Amino Pro.
METABOLISABLE ENERGY REQUIREMENT (MJ/DAY) FOR HOUSED PREGNANT EWES
For outdoor lowland ewes, add 0.11MJ for 10kg increase in body weight and for upland ewes outdoors, add 0.24MJ for each 10kg bodyweight.
EXAMPLE RATION FOR TWIN BEARING 70KG EWE, 3 WEEKS PRE-LAMBING
The ewe has a requirement for 15.3MJ ME (see table).
Her Dry Matter Intake from forage is around 1.6% body weight (70kg * 0.014 = 0.98kg forage DM/d).
Assuming a forage ME of 10MJ/kg DM, and 30% DM, the forage fresh weight would be 3.27kg/day.
With a DMI of 0.98kg/day and ME of 10MJ/kg DM, ME from forage would be 9.8MJ/day.
This leaves a deficit of 5.5MJ to be provided from supplementation.
In order for a 12.5ME concentrate to provide 5.5MJ, 0.44kg DM would be required.
This is equivalent to 0.5kg fresh weight of a 12.5ME concentrate.
FEEDING A HIGHER ENERGY CONCENTRATE CAN SAVE MONEY. FOR EXAMPLE:
• Ewenique costs from 76p/ewe/week based on £222/t and feed rate of 0.49kg/day
• To meet the same total energy requirement, 0.51kg/day of the lower energy Prime Ewe Nuts would need to be fed.
At £217/t this results in a cost of 77.5p/ewe/week.
The cheapest solution is not always the most economic.
For information about the DN range of sheep feed, please click here, or alternatively you can call your local DN Representative.