Wednesday, June 18, 2014

Pooling Colostrum

Standing behind the rotary milking unit I watched a milker shove the partly full milker bucket from one milking stall to the next. He proceeded to milk a second fresh cow into the milker bucket. This is pooling colostrum. Since the average amount of colostrum for Holstein cows is about twenty-five pounds (three gallons) there is plenty of space in the big plastic 80 pound milker buckets for at least two cows.

Where else does pooling happen? Some farms mix fresh colostrum with a supply held in a refrigerator - dump the warm into the cold. Or, dump colostrum from all the fresh cows milked at one time into a series of five-gallon pails.

Advantages?
Less time when milking: Just slide the 80-pound milker can over to the next cow and keep milking. Or, even when milking into a separate milker bucket it's quicker just to dump the contents into a common five-gallon plastic pail than into separate buckets. 

Not as many buckets and pails to clean. And, no testing and record keeping - colostrum is just colostrum.

Disadvantages?

One best colostrum management practice is to assess the concentration of antibodies before feeding. This allows the calf care person to feed the highest quality colostrum available as the first feeding for heifer calves. Reliable on-farm technology for quality assessment is available both as a Colostrometer (click HERE for colostrometer resource) and Brix refractometer (click HERE for Brix resource). 

If you do not maintain separate lots of colostrum at least until it is quality tested there is no way to sort out the best to feed first. In a national (USA) study of colostrum quality approximately thirty percent of the samples were below the recognized threshold for acceptable concentration of antibodies for feeding newborn calves. [Morrill, et al. "Nationwide evaluation of quality and composition of colostrum on dairy farms in the United States" Journal of Dairy Science, 95: 3997-4005 July 2012] 

So, poor quality colostrum does exist. Heifers had lower quality colostrum compared to second lactation and greater cows. Dairies that test colostrum have a much higher potential for passive transfer success compared to dairies that do not test and pool colostrum. 

The dairy where I observed the milking with the rotary unit routinely collects fecal samples from all cows at dryoff. Thus, Johnes status of fresh cows is know for all cows and their colostrum is discarded.

But, what if not testing is done? And, colostrum is pooled? Then if a heavy shedding cow's colostrum is pooled with colostrum from other cows many calves can be exposed to the Johnes organism. Each dairy has to assess the level of risk and decide if pooling is acceptable.

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