Monday, June 19, 2017

Variation in Colostrum Yields

In response to a recent question about variations in colostrum yields I pulled together data from two studies published in the Journal of Dairy Science in 2016 and 2017. All cows were second lactation and greater.

The first study was with Holstein breed cows from 9 farms with a total of 111 first milkings. They averaged 17 pounds of colostrum at first milking. However, the overall variation was from 1 pound to 87 pounds! Two-thirds of the samples (N=74) fell between 2 and 33 pounds.

The second study was with Jersey breed cows from one 3,500 cow dairy in California. They collected data on 134 first milkings. The average yield was 9 pounds. The overall variation was from less than 1 pound to 30 pounds. Two-thirds of the samples (N=90) fell between 3 and 15 pounds.

The answer to the question "How much variation in volume of colostrum production is 'normal'?" is:

1. Widely varying amounts among cows for any given lactation, length of dry period, dry-cow ration and season of the year are "normal." Further, predicting this variation based on production in previous lactation is not very reliable.

2. If we plan on feeding about 17 pounds (4 quarts) of colostrum for newborn calves during the first 4 hours of life (Jersey calves = 13 pounds or 3 quarts) then we need to be prepared to supplement the dam's yield for many of our calves.

3. Having a provision to store excess colostrum while minimizing bacteria contamination is a best management practice. Remember rapid chilling to 60F (16C) after collection is a cost effective way to maintain high colostrum cleanliness.




References: Cabral, R. G. and Others, " Predicting colostrum quality from performance in the previous lactation and environmental changes." Journal of Dairy Science 99:4048-4055 2016 Silva-del-Rio, N. and Others, "Colostrum immunoglobulin G concentration of multiparous Jersey cows at first and second milking is associated with parity, colostrum yield, and time of first milking, and can be estimated with Brix refractometry." Journal of Dairy Science 100:5774-5781.

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