Born with very little natural immunity, a calf’s odds are stacked against it from the moment it hits the ground. The calf depends heavily on passive transfer of antibodies from its mother in the first feeding. Jorge Botero, MV, Wet Calf Health and Nutrition Consultant, Dairy Tech, Inc. detailed the importance of passive transfer – improving the level of IgG in serum – during a Knowledge Nook session on opening day of World Dairy Expo.
Botero said new standards show that it’s important to improve passive transfer, citing this as the most important factor for survivability. While it’s hard to measure the level of IgG in serum, let alone what the calf actually absorbs in a feeding, there are several practices that promote high levels of passive transfer.
Time of feeding
Botero referenced several studies pointing to time as a critical factor in the first feeding. One study showed a 28 percent reduction in serum IgG if the colostrum is fed at six hours. The same study showed a reduction in epimural bacteria in the colon when the feeding is delayed up to 12 hours. He said you can count on a three percent per hour reduction in absorption rate.
He added, “New calves like to run around and lick things, and that exposes them to a lot of pathogens and bacteria. If we can get them that first feeding right away, they’ll lie down and go to sleep, and that’s what we want. Good colostrum can’t change if a calf has been allowed to explore and lick things.”
Heat treatment
Botero encouraged care and caution when storing and heating colostrum, noting that temperatures over 142° Fahrenheit will destroy 10 percent of IgG. In addition, setting the colostrum in boiling water will denature the protein. Proper heating and thawing to preserve the highest levels of IgG takes time.
Second colostrum feeding within first 12 hours of life
“More colostrum is better,” Botero said. “Calves fed four quarts of colostrum compared to two see a 20 percent lower cull rate, produce more milk and have fewer vet expenses.”
Producers should also note that the second milk from a fresh cow has more value to the calf than its components have to the bulk tank. The second feeding can improve IgG serum concentration by 25 percent.
Colostrum and milk pasteurization
If possible, Botero said pasteurized colostrum is the most ideal. He cited a study showing morbidity and mortality rates cut nearly in half when feeding pasteurized colostrum as opposed to raw. Pasteurized colostrum leads to greater absorption, and it kills many of the bacteria that a calf isn’t ready to fight yet, including salmonella, e-coli and listeria.
In summary, Botero stressed the importance of timing as much as quality and quantity in many of the factors that influence passive transfer. Feeding colostrum as soon as possible gives the good bacteria a chance to colonize in the gut before bad bacteria is ever introduced.
