Friday, March 22, 2019

Starter grain intake among intensive milk-fed calves

As part of an experimental design testing fat levels  in calf starter grains intakes were collected on regular 18% c.p. starter. The calves were fed a 23-19 milk replacer  at the rates of :
     Week 1 = 6.3 qts/day @ 12.5% solids or 1.6# of powder
     Weeks 2-7 = 6.3 qts/day @ 15% solids or 2# of powder
     Week 8 = one-half of previous week or 1# of powder daily
All calves had free-choice water, calf starter and chopped straw.

Some of the calves were fed conventional starter grain. So, looking at just these calves what did they find?

What about calf starter intake? (average pounds per day) (volume estimates based on 1 quart equals roughly one pound)

Week one = almost none
Week two = just more than none
Week three = 0.2#/day or 0.8 cups - small handful
Week four = 0.4#/day or 1.6 cups
Week five = 0.8#/day or between 3 and 4 cups
Week six = 1.2#/day or well over 1 quart
Week seven = 1.8#/day or nearly  2 quarts
Week eight (on half milk ration this week) = 3.3# or over 3 quarts
Then, 4 weeks after weaning:
Week 12  (no hay, grain only) = just over 8#/day

What does this tell us about rumen development?
1. By 28 days calves were consuming enough grain to begin the rumen development process. We can begin counting the 21 days required for enough papillae development to support maintenance and growth.

2. By 42 days (week 6) calves are starting to eat enough starter grain to significantly supplement their milk ration. Rumen development is progressing well and lots of fermentation-based protein is supplementing the milk proteins.

3. At 49 days milk is cut to one-half per day - now, the calves need lots of energy and protein from grain. It has been 21 days since significant starter intake began - plenty of papillae surface now present to absorb the energy needed for growth.

4. By 56-60 days the calf is beginning to eat enough grain to support maintenance and between one and two pounds of growth per day. As long as she does not over-eat on hay this ration will soon support 2 to 2.5#/day growth.

5. They followed these calves out to 12 weeks of age - by then they were eating an average of 8+ pounds of starter grain per day (enough to support around 2.5#/day gain).

If I had a preference on the weaning for calves like this I would have set up the one-half milk ration to extend for 10 to 14 days rather than just 7 days. In an ideal situation maybe the 7 day period would work well - but remember Murphy's Law [If any can go wrong, it well], the longer step-down interval accommodates the wide variation among calves in rumen development rates so we get a more uniform accommodation to full weaning.

Reference: Berends, H. and Others "Effect of fat inclusion on starter feeds for dairy calves by mixing increasing levels of a high-fat extruded pellet with a conventional highly fermentable pellet." Journal of Dairy Science 101:10962-10972 (December, 2018).

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