More money in your pocket and better productivity comes down to a balanced diet and maintaining ewe Body Condition Score (BCS) in late winter. Losing body condition between scanning to pre-lamb vaccinations directly impacts lamb survival, especially in triplet ewe or ewes more than five years old. Losing even one BCS in this period saw a 10 percent decrease in survival in mixed aged ewes. Five-year-old ewes saw even greater losses, with survival rates dropping from 70 to 66 percent. That is a lot of lambs.
Body Condition Score losses affect more than survival, they impact foetal growth, too. Three-fourths of growth occurs in the last six weeks of pregnancy, so meeting the increased energy and protein demand to prevent any loss of BCS is a good investment. If your flock’s BCS is quite variable during pre-lamb vaccinating — more than 30 percent having lost half to one BCS from scanning to vaccinating— then it may be time to examine your winter feeding system. Running short of feed prior to lambing has major financial impacts.
Diet imbalances such as too little protein, minerals, or amino acids, can be just as limiting as not having enough food. Protein deficiencies can drive farm production down by some 15 percent. Demand for protein during the final six weeks rises to support foetal growth. Bulb crops are unlikely to provide the crude protein needed of twin and triplet ewes during the last six weeks of pregnancy. This leads to a reduction in foetal growth and impacts colostrum quality. Though protein supplements, like baleage versus grass straw, are more expensive, the monetary rewards are significant. Feeding a green crop, like kale, provides adequate protein balance, as can wintering on grass and silage.
There is no one system that needs to be followed. The only requirement is a well-balanced diet, particularly in older ewes and those with twin and triplet pregnancies.
TECH TIPS
- If you are happy with scanning, but disappointed with lambing percentage, examining your winter feed programme is a good starting point to make improvements.
- BCS ewes at scanning as you still have a small window to regain this body condition.
- BCS ewes pre-lamb to know what is happening on your farm.
- Older ewes and triplets are most vulnerable to feed shortages.
- High-yielding bulb crops are likely a protein deficient diet in late pregnancy for in-lamb hoggets, multiple bearing, and older ewes.
- Impacts of winter crop choice and ewe body condition score change on whole farm profitability and production Anna Taylor, David R. Stevens and Sue A. McCoard
- Impact of change in body condition score in mid-late pregnancy in ewes fed a mixed diet on lamb survival and performance. Susan McCoard, Shen-Yan HEA, Catherine McKenzie, Kirsty Hammond and Tim Smith
