Insights that Come from Walking in Calf Barns
Dr. Mark Thomas, Dairy Health Management, made a presentation on group housing at the Discover conference last week. He has walked in quite a number of preweaned group pens the past couple of years. His insight was that when calves are fed ad lib. or free-choice milk or milk replacer (or rates of 8 liters or more a day with an automatic computer feeder) the pens require much more bedding than calves fed on more restricted milk rations. Rationale? More liquid in results in lots more urine out!
So, if you have group pens for preweaned calves that are on an intensive milk/milk replacer feeding program be aware that these pens will require more than the usual amount of bedding in order to keep the calves dry.
Second insight. Dr. Ken Nordland , University of Wisconsin, made a presentation on ventilation of calf barns. In the course of his work on this subject he is in many calf barns. Sometimes he observes bedding procedures that fill the barn with dust - either from chopped straw or sawdust. When asked about problems that might result from exposure to this kind of organic particulates he explained that the endotoxins attached to bacteria cell surfaces (these are part of the "dust") are highly inflammatory. This exposure, therefore, often leads to significant imbalances between pro- and anti-inflammatory responses in calves - this leads to supression of immunological defenses.
So, if your bedding procedures are regularly exposing calves to these kinds of organic "dust" and you have an issue with treating too many calves for pneumonia maybe it is time to think about some other way to get bedding into the calf pens.
Insights that are food for thought.