Monday, June 25, 2018

Is it Okay to Draw Blood After Day 2?

Drawing blood to check on the effectiveness of the colostrum management program is an increasing common best calf management practice. But, when should the blood sample be taken? A small research project drew blood samples daily for up to 10 days to answer that question.

1. Blood samples drawn up to 9 days of age will provide reasonably reliable estimates of passive transfer immunity.

2. Blood samples drawn 24 to 48 after first colostrum feeding do result in slightly more reliable blood serum total protein (BSTP) estimates than those at 8 and 9 days of age.  

3. But, for management purposes the variation between 2 and 9 day samples is small enough so that we should not hesitate to blood sample the older calves.

I recognize that not every dairy will find it possible to draw blood on all their calves between 24 and 48 hours like I did with my calves. These data support the practice of weekly blood sampling if daily blood draws are not practical. 

Alternatively, with a small herd with monthly or quarterly assessment of colostrum management blood sampling between days 2 and 9 may allow including enough heifer calves to give useful information. 

Just for Reminders:
A. Remember that blood samples are fragile - careful handling will result in fewer broken red blood cells and more accurate estimates.
B. Keep a supply of distilled water at hand all the time - it only takes a minute or two to calibrate your refractometer; reliable readings depend on calibrated instruments.
C. Lab practice suggests that blood samples that have been held more than one day may require some extra time in the centrifuge to get full separation of blood serum.
D. If using gravity method of separation, undisturbed samples held at room temperature for approximately 24 hours will have the closest match with samples spun with a centrifuge (i.e., between 95 and 98 percent agreement).

Reference: Wilm, Jensine and Others, "Technical Note: Serum total protein and immunoglobulin G concentration in neonatal dairy calves over the first 10 days of age." Journal of Dairy Science 101:6430-6436 June 2018

Friday, June 22, 2018

Exploring Low Colostrum Yields

Colostrum yield data were collected from Jersey cows in a Texas herd. There were 1,143 first-lactation cows and 752 second-lactation cows and 1,003 cows of third lactation and greater (total records = 2,988)

Fact #1. Huge variation in colostrum volume among cows of all lactations
     1st lactation varied from 0 to 30.6 lbs. [17.5kg] (est. 18 quarts)
     2nd lactation varied from 0 to 53.2 lbs. [24.2kg] (est. 25 quarts)
     3rd & greater lactation varied from 0 to 58.5 lbs. [26.6kg] (est. 27 quarts)

Fact #2. No colostrum at all
     1st lactation - 3 out of 1,143 had no colostrum (0.3%)
     2nd and greater lactation - 105 out of 1,755 had no colostrum (6%)

Fact #3. Strong seasonal influence - December being the lowest volume month. Research  team suggests maybe a photoperiod influence. June-July yields were the highest.

Fact #4. Factors influencing volume but only a small amount included calving age, gender of calf, previous lactation 305ME, dry period length. Environmental factors (e.g., THI) and predigree had minor influence on volume. Note that this was only one herd in a Texas environment (2,988 Jersey cows).


1. Expect and prepare for wide variations among animals. Don't beat yourself up over the small percentage of cows with zero yields - they are going to happen. Adopt best management practices for calm and gentle animal handling to promote optimum let-down at first milking. 

2. Be prepared to take advantage of high-yielding cows - adopt best management practices for collection and storage of colostrum in excess of immediate needs. 

3. Remember that we continue to get the biggest bang for our buck when we feed enough high quality CLEAN colostrum ASAP after birth. When available and practical, second and third small feedings of colostrum in the first 24 hours do boost blood IgG levels.

4. If practical, calves benefit from feeding transition milk (that is, 2nd, 3rd and 4th milkings) - this milk can help us avoid treatments with antibiotics during the critical first two weeks of life.

Reference: Gavin, K. and Others, " Low colostrum yield in Jersey cattle and potential risk factors."
Journal of Dairy Science 101:6388-6398 June 2018.

Tuesday, June 19, 2018

Good Colostrum Quality from 2nd Milking

Is  it worth your time to check second milking from mature cows for antibody concentration? YES.

Dr. Noelia Silva-del-Rio, UC Davis Veterinary Medicine Extension specialist in Tulare CA, measured first and second milking from third or greater lactation Jersey cows. She had 134 first-milking samples and 68 second-milking samples.

43% of the second-milking samples contained IgG concentrations of 50g/L  (the industry standard for acceptable quality for first feeding).  

Given a shortage of first milking colostrum, Dr. Silva-del-Rio encourages producers to collect and test 2nd milking. 

I agree. These data suggest that nearly one-half of the time the 2nd milking will be suitable for the first feeding of newborn calves. 

Reference: California Dairy Magazine, May 2018, p16.

Tuesday, June 5, 2018

Feeding Hay with Calf Starter Grain

The June 2018 issue of the calf management newsletter, "Feeding Hay with Calf Starter Grain," is now available at or click HERE.

The summary bullet points are:
  • Achieve better outcomes feeding a mix of grain and hay compared to grain only.
  • If a “little” is good, would “more” be better? No!
  • Practical alternatives for including 5 percent chopped hay.
  • What if no chopped hay?