Scours prevention and colostrum
Research shows scours can cause up to 18% of calf mortality, making it the number one calf killer. A calf’s best defense against scours is colostrum, which carries antibodies that help provide immunity against scours-causing pathogens.
“To get the highest levels of colostrum antibodies, you need to start with a quality nutritional program for the mother cows during gestation,” says Jon Seeger, DVM, Pfizer Animal Health. “Colostrum develops during late gestation at the same time major fetal growth occurs. These activities require significant quantities of energy and protein. Cow management should focus on quality nutrition to support this colostrum development.”
According to Seeger, colostrum management should also focus on enhancing antibody levels in the colostrum. Vaccinating a dam with a scours vaccine helps produce high levels of antibodies in the dam’s blood stream. The antibodies are then transferred to the calf through colostrum, eventually entering the calf’s blood stream through the GI track.
Cows transfer antibodies from their blood into colostrum two to five weeks prior to calving. Vaccinating against scours before this time helps build up the highest level of antibodies in the cow’s blood during the period that the antibodies are being transferred to the colostrum.
“Vaccination timing is really important because all antibody transfer from the dam to calf is done through the colostrum,” Seeger explains. “If the vaccination isn’t done at the right time to help build a high level of antibodies in the cow’s blood stream??—?? and in the colostrum??—??the calf won’t get the best protection possible.”
Advise producers to make sure calves nurse early and properly to get an adequate quantity of colostrum within two hours of birth. Seeger recommends 4 quarts of colostrum within the first 12 hours of birth and an additional 4 to 6 quarts in the first 24 hours after birth.
Temp and WBC of postpartum cows
Research by Sarah Wagner, DVM, PhD, Dan Schimek, MS and Fu-Chih Cheng, PhD, North Dakota State University, provides evidence that healthy dairy cows in the postpartum period have higher rectal temperatures and white blood cell (WBC) counts than would be considered normal for cows in mid-lactation. Cows that remained healthy in the first 10 days after calving frequently had rectal temperatures greater than 103.1° F and 103.5° F, values which had previously been described as indicative of illness.
The use of rectal temperature alone to diagnose illness in postpartum dairy cows, in the absence of other clinical signs, will result in significant over-diagnosis of illness in cows that are healthy. Increased rectal temperature may be most useful in combination with daily milk production as a tool to indicate which postpartum cows should be given a full physical examination for the presence of other clinical signs. Future investigation may focus on the sensitivity and specificity of these combined factors for early diagnosis of sick postpartum dairy cows.
Cows that remained healthy had significantly higher neutrophil counts in the first three days after calving when compared with cows that became ill, and their neutrophil counts exceeded normal reference ranges for several days after calving. WBC counts in cows that became ill remained within reference ranges and neutrophil counts in such cows dropped into normal range by the second day after calving. This finding suggests that “normal” hematologic values in postpartum dairy cows are higher than what is considered normal in other cattle. The explanation for this phenomenon may be that an increase in the number of circulating neutrophils enables cows that remain healthy to meet the immune challenges encountered around the time of parturition.
This tip excerpted from the Spring 2008 Bovine Practitioner.