
A shortage of protein in a ewe's diet in late pregnancy is a recipie for disaster. Ewes will have little or no colostrum. Lambs will be lost as a result. They will produce less milk as mammary tissues for milk production do not develop fully. The result – slow growing lambs.
It is the last three weeks of pregnancy that protein becomes crucial. When questioned about protein; most farmers refer to the percentage in the ration e.g. 16% or 18%. But this is only part of the story. To get the full story you should know the answer to five questions
What is protein % of your ration?
How much meal are you feeding?
What is protein % of your hay/silage?
How much are they eating?
What type protein are you feeding?
Knowing these tells how much protein the ewe is eating – this is the real measure.
200 grammes/day
In the last three weeks of pregnancy a ewe requires 200 grammes each day, in mid pregnancy only 100 grammes/day is needed. All feeds that the ewe eats contributes to this daily requirement.
For example, one kg of a purchased ration (18%CP) will supply 180 grammes of protein, therefore feeding a ewe 0.8 kg get about 140 grammes. This ewe will eat about 4kg of fresh silage (0.8kg Dry Matter, 14% CP), which supplies about 110 grammes.
Total protein intake is 250 grammes. This is adequate but it assumes that silage is 14%, if it was 10% then the ewe would have barley enough. Similarly, if less meal was fed there could be problems.
It highlights the importance of knowing what type roughage you are feeding.