Friday, July 11, 2014

Milk Yield at Second Milking

How good is your memory? Have you milked many fresh cows for their first three or four milkings? How much milk did you collect at second milkings compared to first milkings?

I milked all the fresh cows for a 800-cow dairy for about eight years. My memory for cows (compared to heifers) is that second milking yields were substantially less than yields at first milking. What, however, does a recent study say?

Study: 39 Holstein cows, milk weights recorded for first 10 milkings. [Kessler, E. C. and Others, "Milk production during the colostral period is not related to the later lactation performance in dairy cows." Journal of Dairy Science 97:2186-2192 April 2014]

  • As expected, lots of variation among cows in first milking (colostrum) yields varying from about 2 quarts and 21 quarts (about 46 pounds). Fully 75 percent gave at least 5 quarts.
  • The variation in first milking yield for cows second lactation and greater was not related to the amount of time between calving and first milking and was only weakly related to previous lactation performance. 
  • Average colostrum (first milking) yield was between 16 and 17 pounds.
  • Second milking for cows averaged nearly 14 pounds. Compared to first milking yield that is 82 percent.
Yes, that number at second milking was 82 percent. I fear that my memories from 20 years ago are not very accurate - if I had to make a guess based on my recall I would have come up with 50 percent yield at second milking compared to first.

Could I have a problem with selective memory? I recall very well the cases where the cow gave 20 plus pounds first milking and 10 or less pounds at second milking? All the cows that yielded 3/4 or more of first milking at their second milking all blurred together and I don't really remember them? 

True that these results are based on only 39 cows. However, these data are much more definite than my recall. I will keep watching for another study. 

BTW, the title of the article reflects the study's main findings, milk production during the first 10 days in milk is not a good predictor of later production performance.

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