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Find nutrient balance in calf diets

Mark Hill and Dale Carr Published on 27 April 2010

About 10 years ago in a research trial, calves were fed a 29 percent CP, 19 percent fat milk replacer powder at different rates. Calves were not fed starter. The trial ended when calves reached 230 pounds of bodyweight and the researchers observed that the calves responded to feeding rate with rather dramatic weight gains and efficiency of gain.

This research from Cornell University challenged the way that calves had been fed in the U.S. for decades. Subsequent research from the University of Illinois showed that calves fed milk replacer (again no starter was fed) respond to protein in the diet but that the response is also dependent upon the amount of energy consumed by the calves.

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Figure 1

Similar research published that same year showed that feeding more than one pound (about 4 quarts of liquid milk replacer daily) of a 20 percent CP, 20 percent fat milk replacer powder (the age-old U.S. standard for milk replacers) did not affect calf weight gain like higher protein milk powders did. As you can see in Figure 1 , when 1.5 pounds of powder were fed daily (about 6 quarts of liquid milk replacer daily), a higher protein powder than 20 percent protein was needed to increase weight gain.

Figure 2

Again, that same year, more research better defined the protein and fat concentrations needed in a milk powder fed at moderate rates of 1.5 pounds daily (about 6 quarts of liquid milk replacer daily). Figures 2 and 3 reflect those trial results. A 26 percent protein and 17 percent fat powder maximized weight gains in those trials where calves were fed starter and weaned at 6 weeks of age.

Figure 3

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More recent research has further defined protein and energy ratios in baby calf diets. That research reported the greatest bodyweight gains in calves fed 1.25 pounds of milk replacer powder daily (approximately 5 quarts of liquid milk replacer) was supported with a 24 percent protein powder (see

Figure 4

Figure 4 ). Also, the greatest bodyweight gains in calves fed 1.5 pounds of milk replacer powder daily (approximately 6 quarts of liquid milk replacer) was supported with a 26 percent protein powder (see Figure 4 ).

While in the above trials the rates of milk replacer were moderate at 1.5 pounds of powder daily (approximately 6 quarts of liquid), much higher rates of liquid diets are sometimes fed to calves. The response in published research is that feeding more liquid in the first few weeks of life resulted in more weight gain. However, calves fed 2 or more pounds of high-protein milk replacer powder have not weighed more than calves fed 1.5 pounds of high-protein milk replacer powder by 3 months of age in any of the trials. There were several reasons for this and they included less starter intake, less digestion of starter, and less digestion of the milk replacer fed at the high rates.

Finally, the discussion has focused heavily on protein. However, calves really have requirements for and utilize amino acids, not protein. In Figure 5 , Figure 5

milk replacers of similar protein concentrations but formulated with and without amino acid requirement in mind were fed to calves. Calves fed diets formulated for amino acid requirements gained approximately 15 percent more weight than calves without amino acid consideration. In fact, calves fed the 24 percent protein diet with amino acid formulation gained as much weight as calves fed the 28 percent protein diet without amino acid formulation.

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The take-home message is that 1 pound or 4 quarts of a 20 percent protein milk replacer is too little to feed Holstein calves. Approximately 1.5 pounds or 6 quarts is more appropriate. That milk replacer powder should contain 26 percent protein with amino acid formulation. Nurture your calves – do not just keep them alive. PD

References omitted due to space but are available upon request by sending an email to .

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