Thursday, June 29, 2017

Gradual compared to Abrupt Weaning

I was reading a report involving 18 dairy farms in western Canada. Among the data were facts about weaning practices followed by these farms. Thirty-nine percent of them abruptly weaned calves with the remaining 61 percent following "gradual" weaning procedures. Why do so many farms continue to abruptly wean dairy calves?

Then I recalled work done in 2010 that compared different weaning strategies (abrupt, 4 days, 10 days and 22 days). They found that the 10-day weaning period resulted in the minimum growth check post-weaning. That is, the calves weaned this way had the lowest decrease in their rate of gain. In sharp contrast, abruptly weaned calves lost weight initially post-weaning.

My consulting experience with health problems among "just-weaned" calves include many farms experiencing high respiratory treatment rates among these abruptly weaned calves. What else would we expect among calves that are experiencing high levels of stress?

That transferred my attention to a June 2017 Journal of Dairy Science article, "Abrupt weaning reduces postweaning growth and is associated with alterations in gastrointestinal markers of development in dairy calve fed an elevated plane of nutrition during the preweaning period." [underline added by me]. They compared 0 step-down with a 12 day gradual weaning protocol.

If one uses only average daily gain as measure of successful weaning their data show that both groups of calves had about the same rate of gain at the end of the full 54 days of the study.

BUT, during the post-weaning period (days 49 - 54) the gradually-weaned calves consumed 2.9 pounds (1.32kg) of starter grain daily compared to the abruptly-weaned calves considerably lower consumption rate of 2.2 lbs. (0.991kg).

Further, the average daily gain among the abruptly-weaned calves dropped from 2.2 pounds daily pre-weaning to 0.5 during the week post-weaning - a huge growth check. These are the high-risk calves for respiratory illness.

As an aside, I recommend that farms feeding milk/milk replacer at an intensive level (that is, 8 or more quarts per day) not depend on calf starter grain intake for coccidiosis control. In my experience calves that I started to wean around 35 days (5 weeks) were eating far to little starter to provide coccidosis control. With my step-down program (eliminate one full feeding a day when the calf is regularly eating one full pound of starter daily for three days in a row) I depended on amprolium in the milk for coccidiosis control. Most of my calves increased their daily starter intake by 56 days to roughly 4.5-5.0 pounds (about 2kg). At that age they were moved into small group pens (N=5) and continued to be offered ad lib a 16%cp heifer pellet. Coccidiosis breaks were few and far between.

References: Sweeney, B. C. "Duration of weaning, starter intake, and weight gain of dairy calves fed large amounts of milk." Journal of Dairy Science 93:148-1525 2010. Atkinson, D. J., and Others, "Benchmarking passive transfer of immunity and growth in dairy calves." Journal of Dairy Science 100:3773-3782 April 2017. Steele, M.A. and Others, as above Journal of Dairy Science 100:5390-5399 June 2017. 

1 comment: