Feed mixes for early weaners

As discussed in other articles, the rumen of young calves is undeveloped and as such, the diet provided to these animals needs to be adjusted accordingly to prevent illness.

In rations, rates of ingredients are described as ‘percentages by weight’. That is, the percentages of all the ingredients in a mix must add up to 100.

For all dry ingredients, the process is quite straight forward, however feeds like molasses are often measured by volume rather than weight.

For ration calculation, volumes need to be converted to weights.

1 litre molasses weighs approximately 1.4kg; 1 gallon = 4.54 litres, therefore 1 gallon of molasses weighs approximately 6.56kg.

The younger the weaner, the better quality the ration should be — particularly the energy and protein content.

For very young weaners (e.g. less than 10 weeks of age), the mix should preferably have no urea, although some commercial products will contain low levels of urea at a safe rate, e.g. 0.5%.

Vegetable protein meal included at 15–25% of the ration will generally supply the required protein content.

Key components of a good early weaner grain mix will include:

  • grain (higher energy and better responses from barley and wheat than sorghum)
  • maximum of 4–5% tallow or vegetable oil will increase energy content without reducing intake (optional)
  • preferably no urea (for weaners less than 10 weeks)
  • 15–25% vegetable protein meal (depends on which meal and required protein level)
  • 5–10% roughage
  • 2% bentonite or 1% bicarb soda
  • mineral/vitamin premix with Rumensin (or equivalent coccidiostat)
  • limestone, salt and perhaps a potassium source, if added calcium, sodium and potassium are not included in the premix.

For more information about dietary components, including definitions and examples, click here.

Molasses alone provides energy only (but is not as good as grain on an as-fed basis), i.e. it effectively has no protein.

In the absence of urea, the challenge with molasses mixes is to achieve reasonable protein levels by mixing in vegetable protein meals.

Whether mixing by hand or mechanical mixer, there is a limitation to how much dry material can be mixed in. Adding grain will replace some of the molasses with a higher starch-based energy source that typically has at least 10% crude protein (CP).

From a nutritional perspective, the more protein meal (and perhaps also grain) that can be mixed in, the better.

Suggested mixes include:

  1. minimum of 15% of a high protein, vegetable protein meal (e.g. cottonseed meal or soy bean meal) + 85% molasses, (20-30% protein meal would be preferred).
  2. 20% vegetable protein meal + 10% grain +70% molasses

Variations of these mixes can be used.

If a mechanical mixer is available, low levels (1–3%) of urea could be added to the mix, for weaners greater than 100–120kg. However, in trials in North Queensland, weaners averaging 100kg have been fed a molasses mix with 3% urea with no ill effects. As the rumens of young weaners develop, they are better able to both utilise urea and to avoid toxic effects.

The presence of a mechanical mixer also provides the option of adding a coccidiostat such as Rumensin, most likely as a part of a mineral/vitamin premix.

A mineral/vitamin premix for molasses would preferably not include added calcium (as for a grain mix). Extra phosphorus may be desirable. Where it is too difficult to mix in the required amount of protein meal and/or grain, an option is to feed additional protein meal separately.

For more information about dietary components, including definitions and examples, click here.

Points to note

The level of vegetable protein meal (examples include cottonseed meal, soybean meal, sunflower meal, linseed meal, peanut meal, copra meal, or palm kernel) in the grain and molasses based diets may need to be varied slightly depending on the crude protein content of the vegetable protein meal used, the age/weight of the weaners and the level of performance required. Suggested levels of feeding are typically aimed at higher levels of performance.

 

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