Monday, September 7, 2015

Gradual vs. Abrupt Weaning: 
The Case for a Step-Down Strategy

A research trial compared rates of gain both during and after weaning for dairy calves that were abruptly weaned at 48 days with those calves weaned gradually (35 to 48 days) (N=55).

On one hand, the gradually weaned calves gained more slowly during the weaning period than calves left on full feed until 48 days of age.

Gradually weaned (days 35-48) - gained  1 pound per day (0.48kg).
Left on full milk (days 35-48) - gained 2.2 pounds per day (1.0kg).

I estimated the cumulative difference in gain between the two feeding treatments over the 14 day period between 35 and 48 days as slightly above 15 pounds (7kg).

On the other hand, the gradually weaned calves gained more rapidly after full weaning period than the calves that were weaned abruptly at 48 days.

Gradually weaned calves post-weaning gain was 1.9 pounds per day (0.86kg).
Abruptly weaned calves post-weaning gain was 0.3 pounds per day (0.15kg). Basically, flat lined!

I estimated the cumulative difference in gain between the two feeding treatments for the first 14 days after full weaning as slightly below 22 pounds (10kg).

Thus, the net effect in terms of gain at two weeks post-weaning (62 days) was plus 6.6 pounds (3kg) in favor of the gradually-weaned calves. 

And, the chemical composition of the rumen fluids was much more favorable for the gradually-weaned calves on the day of full weaning compared to the abrupt-weaned calves (volatile fatty acids were measured). This partially explains why the gradually-weaned calves did not suffer from the transition-calf growth slump observed in the abrupt-weaned calves.

For a checklist of best management practices for weaning dairy calves click HERE or go to www.calffacts.com and click on "Weaning calves: A Checklist."

[M. A. Steele, "Gradual weaning affects pre- and postweaning feed intake, growth, and gastrointestinal development in Holstein calves fed an elevated plane of nutrition during the pre-weaning stage." Journal of Dairy Science, 98 Suppl 2, page 242, abstract 158.]

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