Feeding Sheep Whole or Processed Grains
What is the proper way to feed grain - whole or processed?. It depends on many factors such as the age (or weight) of the animal, the grain source and overall diet. Before getting to some useable rules of thumb, here is some background on why processing matters, and some general theory.
What is processing?
'Processing' means milling or rolling grain. It is also inferred by cracking, grinding, hammer-milling and so on. Generally, it can be assumed that processing adds about $10 per tonne to the diet cost, due to labour, power use and machinery upkeep.
Sheep are ruminant animals; they are designed to eat forages, fermenting them in the first of four stomach compartments known as the rumen. The rumen is not an acidic stomach as is ours. It uses bacterial fermentation and requires a neutral pH, or a balance between acidity and alkalinity. To accomplish this, sheep excrete a buffer, (bicarbonate) from the salivary glands while chewing their cud. Thus, cud-chewing (rumination) promotes saliva production and rumen health. Chewing is good! So, coarser grains are better in most cases, as this promotes rumination and extends the amount of starch available over a longer period. This helps prevent acidosis - a condition to be avoided, where the rumen becomes acidic. In sheep, whole grains are sufficiently large to be ruminated and chewed, so they do not require processing, except in the following cases;
- In small lambs(creep feed). Processing grains stimulates intake, as the smaller particle size is more palatable to lambs. For lambs less than 20 lbs. live weight, process all grains. For lambs less than 50-60 lbs, corn should be processed. Once they exceed this weight, all grains can be feed whole without compromising intake, and reaping the benefits of whole grain.
- When energy needs to be available quickly in the rumen. For the rumen to use the soluble nitrogen in silages (especially alfalfa haylage), grains can be processed to speed the availability of energy to the rumen microbes so that they might utilize the silage nitrogen for protein production. There is debate as to whether this is necessary, but the approach has been used 'successfully' by dairy farmers in the past, and by some shepherds. Consult with your flock nutritionist before proceeding with this approach, as it is intentionally contrary to the above guidelines, and useful only in specific cases!
Recent research from University of British Columbia (Dr. Steve Mason, Livestock Nutritionist) indicates that growth rate and feed efficiency were improved when whole grain was fed to lambs compared to pelleted or mash feeds.
Much of the advantages came from higher dry matter intake and overall feed "acceptance" by the lambs. Feeding whole grain offers the following advantages:
- Feed intake may increase by 25% while feed utilization remains similar for whole and pelleted grain.
- Growth rate is up to 20% faster with whole grain.
- Feed conversion is improved by up to 10%.
- Whole grain produced a firmer and more desirable fat finish on the carcass.
- Whole grain does not cause damage to the rumen.
- When feeding whole grain, there is less probability of off feed problems caused by acidosis.
When forage is fed with the grain, additional evidence shows that whole grain is preferable to pellets. Feed intake is again higher, and the utilization of the forage is improved. The choice of grain will vary by location and in most northern regions, mixed grain or barley is probably the best for lamb feeding.
As always, review your feeding program with a nutritionist and make feed changes slowly. Evaluation of the protein content and quality is also important.
What's the Bottom line?
Avoid processing unless required. For most cases, this means processing only lamb rations. You don't need a mill to feed sheep, and feeding whole grains actually improves rumen health in your flock as compared to processed feeds.
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