An alternative to weaning by age, which is common
in our industry, is the traditional concentrate- or starter-dependent
weaning strategy. Optimal preweaning
starter intake before step down (>0.5 kg/d) is essential
for postweaning intake and gain and is influenced
by the nutrient content of the milk replacer and calf
starter (Stamey et al., 2012; Kertz and Loften, 2013).
Greenwood et al. (1997) demonstrated that calves fed
low planes of nutrition could be successfully weaned
when starter intake reaches 1% of BW. It was also
determined that postweaning growth did not differ
between calves that were weaned when starter intake
reached 1.5 and 2.0% of BW (Greenwood et al., 1997).
In the current study, weaning was based on age, and
reduction of milk resulted in an increase in starter intake.
This finding opposes the concentrate-dependent
method, in which the level of starter intake prompts the
milk reduction. In the current trial, calves weighed 66.5
kg when weaned at 6 wk and 83.5 kg when weaned at
8 wk, thereby requiring starter intakes of 0.67 and 0.84
kg/d, respectively, to reach 1% of BW. This target was
easily achieved for 8WW calves, which consumed 1.38%
of BW the week before weaning. However, this target
was not met for 6WW calves, which consumed only
0.6% of BW the week before weaning. Ultimately, this
finding indicates that when feeding 1.2 kg/d of MR,
weaning at 6 wk is too early when calves are weaned
according to the concentrate intake as a percentage of
BW (Greenwood et al., 1997). Calves weaned at 6 wk
could not achieve optimal starter intake during stepdown
and weaning, which had a longstanding effect
on gastrointestinal development and growth. However,
calves weaned at 8 wk had higher starter intake preweaning
and were more able to maintain adequate ME
intake postweaning, possibly due to gastrointestinal
and metabolic development from higher levels of solid
feed intake preweaning
An alternative to weaning by age, which is commonin our industry, is the traditional concentrate- or starter-dependentweaning strategy. Optimal preweaningstarter intake before step down (>0.5 kg/d) is essentialfor postweaning intake and gain and is influencedby the nutrient content of the milk replacer and calfstarter (Stamey et al., 2012; Kertz and Loften, 2013).Greenwood et al. (1997) demonstrated that calves fedlow planes of nutrition could be successfully weanedwhen starter intake reaches 1% of BW. It was alsodetermined that postweaning growth did not differbetween calves that were weaned when starter intakereached 1.5 and 2.0% of BW (Greenwood et al., 1997).In the current study, weaning was based on age, andreduction of milk resulted in an increase in starter intake.This finding opposes the concentrate-dependentmethod, in which the level of starter intake prompts themilk reduction. In the current trial, calves weighed 66.5kg when weaned at 6 wk and 83.5 kg when weaned at8 wk, thereby requiring starter intakes of 0.67 and 0.84kg/d, respectively, to reach 1% of BW. This target waseasily achieved for 8WW calves, which consumed 1.38%of BW the week before weaning. However, this targetwas not met for 6WW calves, which consumed only0.6% of BW the week before weaning. Ultimately, thisfinding indicates that when feeding 1.2 kg/d of MR,weaning at 6 wk is too early when calves are weanedaccording to the concentrate intake as a percentage ofBW (Greenwood et al., 1997). Calves weaned at 6 wkcould not achieve optimal starter intake during stepdownand weaning, which had a longstanding effecton gastrointestinal development and growth. However,calves weaned at 8 wk had higher starter intake preweaningand were more able to maintain adequate MEintake postweaning, possibly due to gastrointestinaland metabolic development from higher levels of solidfeed intake preweaning
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