Rearing healthier more productive calves

By Dr Simone Hoskin,  PhD (Animal Nutrition)

Fibre is absolutely essential in the calf shed for rumen development.  Ruminants require quality fibre in the diet to maximise production and maintain health by sustaining a stable environment within the rumen.  The focus of calf rearing should be to rear a calf to perform on pasture.  If the calves you are rearing need to achieve maximum milk or beef production from pasture, then setting the rumen up for life with quality fibre early cannot be overemphasised.  But both fibre quality and form are paramount.

Poor quality fibres like straw and hay, especially if long stemmed, are indigestible in a young calf.  These bulky fibres remain in the rumen until the calf can ruminate (chew cud) enough to grind it down.  This takes up valuable space needed for the high energy and high protein feeds that fuel calf growth, especially when milk is restricted.  Even when chopped, these fibre types provide a limited nutrient supply for rumen microbial fermentation, and chopping or chaffing can create short, sharp fibres that can damage the mouth, oesophagus or stomachs.

There is no doubt that only forage fibre can stretch and strengthen the rumen wall and build the musculature required for effective stomach contractions.  But why bulk the rumen with filler, when highly nutritional fibre can build the rumen as well as grow the calf?

Rumen development starts when the first mouthful of solid feed is eaten.  Rumen development is completed when the weaned calf is sustaining optimum growth rates on pasture.  Fiber Fresh research has shown, if only quality fibre (FiberStart®: 20% crude protein, 12.2 MJ metabolisable energy/ kg dry matter) is available from day one, rumen development will be accelerated and calves will be grass-ready in seven weeks.  It takes about 6 weeks on a forage diet for adequate rumen development to support calf growth from forage.  So if quality fibre is withheld from calves for 3 to 6 weeks, then it will take an additional 6 weeks from the point that quality forage is introduced before the rumen is sufficiently developed.

The form of fibre is key to calf intake and hence calf growth.  Nutrient-rich fibre is preferred such as the fresh harvested and preserved forage fibre feeds from Fiber Fresh® at 40-55% dry matter where nutrient intakes are maximised.  Fresh pasture in spring or autumn is usually only 10-20% dry matter.  So if pasture is the only fibre source, calves are mostly taking in water.  Most pastures contain less than 10% clover, but like most ruminants, calves prefer legume (Lucerne) to grass-based forage.  Fiber Fresh Feeds base their FiberStart® and FiberGain® on lucerne.  Maximum intakes of the total solid diet required for maximum growth occur when lollipopping FiberStart® and blending FiberStart® with starter meal, which increases intake of the meal.

A common issue associated with grain only feeding is rumen acidosis and this is caused by the rapid fermentation of starch to acids.  So if calves are reared on grain-based starter meal, muesli or pellets, additional high nutritional fibre such as FiberStart® will prevent acidosis.  Ideally this is blended with the starter at the time of feeding to stimulate saliva to buffer/ neutralise acids produced by rumen fermentation of carbohydrates, and slow the rate of carbohydrate fermentation to provide a more constant supply of energy.

If rumen pH gets too low and acidosis develops, then microbial growth and digestibility suffer and feed intake drops.  Another reason to avoid acidosis in calves is because right from the start, rumen development requires correct rumen pH for microbial growth and VFA production.

Veterinarians recommending Fiber Fresh have described it as a starter meal in forage form without the health risks because it’s right up there with meal in quality.  It simply cannot be compared to any other fibre used in the calf shed and its natural alkaline forage nature prevents rumen acidosis.