Current Progressive Dairy digital edition

New research confirms the two most important hours on a dairy

Stephen Hayes Published on 29 August 2012


There are many things dairy producers do every day to keep cows healthy and productive, but there may be nothing more important than focusing on the first two hours when a calf is born.



A recent article in the Journal of Dairy Science evaluated factors affecting passive transfer in heifer calves and how this related to the time of first insemination. Their findings continue to tell us how important colostrum and the transfer of immunity is to a calf’s life.

Calf immunoglobulin levels
A calf is born with little to no immunoglobulins (Ig) in its bloodstream. The transfer of maternal Ig to the newborn calf occurs via the consumption of high-quality, clean colostrum shortly after birth.

If the transfer of maternal antibodies is successful, the calf has successful passive transfer (SPT). Researchers usually define SPT as having a level of 10 g per L (or higher) Ig in calf serum after 24 hours old. Is 10 g per L adequate or could even higher levels be of benefit?

This article looked at calves based on their level of passive transfer as follows:
• Group 1 – Serum Ig levels < 5 g per L (failure of passive transfer or FPT)
• Group 2 – Serum Ig levels 5 to 10 g per L (partial failure of passive transfer or pFPT)
• Group 3 – Serum Ig levels 10-15 g/ L (successful passive transfer with good protection or SPT)
• Group 4 – Serum Ig levels >15 g/ L (successful passive transfer with very good protection)

They found that calves in Groups 1 and 2 (failure or partial failure of passive transfer) were more likely to be fed poor-quality colostrum. Poor quality was defined as having infection present in the colostrum and/or poor-smelling material that should have been discarded but was fed to calves.


Poor-quality colostrum was also more likely to be lowest in density of immunoglobulin levels. In addition, calves with failure of passive transfer (Group 1) received less total colostrum than the other calves.

Dystocia and its impact on passive transfer
In addition, calves in groups 1 and 2 were more likely to have human assistance at calving (most likely from dystocia) when compared to the calves in Groups 3 and 4. It is interesting that pFPT calves (Group 2) were fed a similar level of colostrum as groups 3 and 4 but with a higher level of dystocia – the calves in Group 2 had less passive transfer. This data tells us that dystocia plays a role in determining passive transfer rates of calves.


Passive transfer in calves at birth and Ig levels at 3-4 weeks of age
The researchers looked at blood Ig levels at 2 days old and again when calves were between 3 and 4 weeks old.

They then calculated an index by dividing the older blood values by the newborn blood Ig blood values. ( See Table 1. )

They found that calves in Group 1 had a significantly higher index because this was the only group of calves that had higher Ig levels in blood at 3 to 4 weeks old than they had at 48 hours of life.


Colostrum research will tell us that blood values for passively transferred Ig are highest at 24 to 48 hours after birth and then they will decline over time. This concept holds true except for the calves in Group 1 which actually had higher blood Ig levels at 3 to 4 weeks than what they had at 48 hours old.

These calves needed to make their own Ig in response to pathogens not being controlled by colostrum Ig. The very young calf is capable of creating immunoglobulins if the passive transfer rates are not at a level to control disease. Could the young calf pay a price for this immune stimulation early in life?

Passive transfer and the age of first insemination
Group 1 calves took 30 days longer to get to first insemination when compared to Group 4 calves. Calves with FPT grew slower than calves in Group 4, giving us additional data to support future calf performance based on colostrum and passive transfer rates. Thirty days of faster growth to first insemination based only on passive transfer rates is worth repeating.

Passive transfer and health
Calves in Group 1 had over 80 percent of the calves showing either respiratory or GI disease. Calves in Group 4 had only 26 percent of the calves show disease. In addition, calves in Group 4 showed no respiratory disease. This research further confirms the positive interaction of passive transfer rates on calf health.

This study found the following benefits to a higher level of passive transfer in newborn calves.

1. Less disease including the finding of no respiratory disease in calves with passive transfer rates greater than 15 g per L.

2. Earlier age at first insemination for calves with the highest rate of passive transfer.

3. Achieving levels of passive transfer greater than 15 g per L is worth striving for instead of just shooting for the industry standard of 10 g per L that is commonly recommended.

It is clear that if we:
• Feed more high-quality, clean colostrum to calves that are two hours old or less
• Develop successful maternity pen protocols for trouble-free calvings

We will maximize passive transfer and the benefits that come from such activity. The long-term benefits of a good calving and colostrum program will far outweigh the costs of time and effort expended. If you want healthy and productive cows, remember to focus on the first two hours of the calf’s life. PD

References omitted due to space but are available upon request. Click here to email an editor.

Stephen Hayes is a veterinary consultant with Day 1 Technology , based in Winona, Minnesota.