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How nutrients consumed impacts growth of neonatal calves

H. Gale Bateman and Mark Hill Published on 16 September 2010

An analysis was made from 993 individual calves used in 20 trials published in two U.S. peer-reviewed journals. Results of this analysis were presented at the Joint Annual Meetings of ADSA and ASAS, held recently in Denver, Colorado.

Each trial used Holstein calves that were initially 2 to 3 days old and on trial for eight weeks. All calves in these trials were housed and cared for individually in an unheated nursery in Ohio.

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The variables that were measured and evaluated for influencing average daily gain in these calves included: concentration of fat and protein in the milk replacer powder, intake of milk replacer powder and intake of dry starter feed. These variables were used in regression analysis to determine which had influence on predicting the average daily gain (ADG) of calves over the first eight weeks of life.

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Within this dataset, intake of starter feed was the largest predictor of calf average daily gain ( see Figure 1 ). This was not surprising. Most calves will consume their entire allotment of milk replacer.

Therefore, differences in starter intake within an individual trial will account for the majority of differences in nutrient intake.

Additionally, another large predictor of ADG was milk replacer intake.

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As milk replacer intake increased, ADG increased. ( See Figure 2. )


However, as calves consumed more milk replacer powder, their intake of starter feed declined. ( See Figure 3. )

Note in Figure 2, when intake of milk replacer reached the maximum amounts fed in these trials, ADG did not continue to increase. This is the impact of high milk replacer intake – reducing starter intake and offsetting ADG.

Protein and fat content of the milk replacer also affected calf ADG. There was a positive relationship between protein content of the milk replacer and ADG. As protein content increased, ADG increased.

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There was a small but significant negative relationship between milk replacer powder fat content and ADG in these calves. As fat increased, ADG slightly decreased. Other published research has shown that as fat content of milk replacer powders increased, starter feed intake decreased.

While increasing milk replacer fed increased calf ADG, increasing the protein content while increasing milk replacer fed was needed to realize more calf growth.

Increasing fat content of milk replacer from 17 to 22 percent fat reduced calf growth slightly. Feeding too much milk replacer resulted in reduced starter intake and reduced ADG. Starter intake was the largest factor predicting calf growth in this analysis of 20 trials.

Within this dataset, increasing total feed intake or increasing nutrient intake without compromising total feed intake improved ADG of the calves.

The regression analysis confirmed that it is possible for some nutrient contents to increase, but result in offsetting depressions in other nutrient intakes, thus reducing ADG of the calves. Because calves will almost entirely consume milk or milk replacers, anything that reduces starter intake should be avoided to allow for maximal ADG. PD


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