Early intervention helps ensure dairy calves reach their genetic potential
GREEN BAY – Colostrum management is the single most important factor in determining calf health and survival, according to Dr. Chelsea Holschbach University of Wisconsin School of Veterinary Medicine.
Holschbach, a large animal veterinarian and board-certified internist, working as a clinical instructor at the University of Wisconsin-Madison School of Veterinary Medicine, recently spoke to more than 150 dairy producers and other ag industry professionals.
She says the keys to setting up dairy calves for success are to “feed colostrum, prevent disease, identify and treat sick calves promptly and you’ll wean healthy calves.”
Holschbach stressed that calves are born without a fully functional immune system, and only through colostrum absorption (passive transfer) will they obtain immunoglobulins necessary to prevent disease.
Colostrum quality, quantity
“We’ve upped the ante on what constitutes adequate passive transfer. Proposed levels of immunoglobulin (G) and equivalent total proteins are: lgG excellent 25%; good 18-24-9% and fair 10-17-9%,” she said. “Equivalent serum Brix levels: excellent 9.4%; Good 8.9-9.3%; fair 8.1-8.8%.”
Holschbach recommends feeding colostrum totaling 10% to 12% of the calf’s bodyweight within 2 hours after birth, approximately 4 liters for an 80-pound Holstein calf.
For colostrum replacer products, she recommends feeding 150-200 grams lgG. “Read the package because not all colostrum replacer products are created equal. Read mixing instruction closely; with a packet weight of 225 grams, lgG content is 60 grams. You would need to feed 3 packages to hit the target of 150-200 g/gG.”
Holschbach says force-feeding excessive volumes of colostrum at a single feeding can lead to delayed abomasal emptying bloat, ulceration and death. “Consider a second feeding of colostrum within 12 hours to further increase passive transfer," she advised.
There are reported health and growth benefits from supplementing the milk diet with colostrum or transition milk for the first 14 days of life.
“Producers feeding pasteurized whole milk are encouraged to add transition milk to the pool,” Holschbach suggested. “Proceed with caution, monitor total solids if combining colostrum replacers and milk replacer products.”
Preventing diseases such as Bovine Respiratory Disease (BRD) and Salmonella Dublin are keys to keeping calves healthy, Holschbach stressed.
“BRD is a leading cause of morbidity and mortality in pre-weaned dairy calves, with 12% of pre-weaned calves affected and 24% of pre-weaned deaths are attributed to BRD,” she said. “But 95% of BRD-affected calves can be treated with antibiotics.”
She noted that BRD is important because calves with clinical signs of BRD at 120 days of age are 1.62 to 4.98 times more likely to leave the herd prior to calving. Calves with lung consolidation identified on a lung ultrasound in the first 8 weeks of life will likely have a 1,155-pound reduction in milk production during their first lactation.
Heifers with lung consolidation at weaning also likely will be older at first calving and have a lower pregnancy rate at first service.
Calves that develop Salmonella Dublin run the risk of a life-long infection. “It is spread through fecal and oral transmission from livestock, rodents, birds, feed, water. It most commonly affects calves 6-8 weeks old, and manifests as septicemia, respiratory disease, joint infections and diarrhea, has a high mortality rate and is resistant to many drugs,” Holschbach said. “Carrier animals are often asymptomatic but the disease can also cause serious illness in people.”
To help prevent Salmonella Dublin, Holschbach advises farmers to maintain a closed herd. “If purchasing cattle, ensure a negative serologic test or a bulk tank milk sample from the herd of origin,” she said. “ Also isolate new purchases and those returning from calf/heifer raisers.”
Holschbach says some of the best disease prevention is to make cleaning pens and disinfecting equipment a top priority, and avoiding common-use equipment for feed and manure handling. “Remove calves from maternity pens before they make their first attempt to stand,” she stressed.
She noted that non-clinical signs of BRD include reduced appetite, depression and fever. “Respiratory tract clinical signs include nasal/ocular discharge, cough, ear droop or head tilt and rapid breathing.” Lung ultrasound also can be used to rapidly screen calves for pneumonia.
Summing up, Holschbach said, “When calves don’t wean clean, we fail them twice. We may let her get pneumonia and fail to treat her effectively which may result from late detection, poor innate immunity, incorrect antibiotic doses and antimicrobial resistance.”
She stressed that events occurring in the first 24 hours of a calf’s life will impact its future health and productivity. “There is often a disconnect between clinical signs and pulmonary manifestation of BRD in pre-weaned calves, and the opportunity exists to use lung ultrasound not only for early detection of pneumonia but also to define recovery from BRD.”