While many conversations surrounding judicious antibiotic use on the dairy start with mastitis treatments, a key time frame to consider evaluating antibiotic usage is also during weaning, according to a specialist at Boehringer Ingelheim. During the weaning period, calves are at a high risk of developing respiratory disease, which often requires antibiotics to be treated successfully, the company said.
“Antibiotics should only be used as a supplement to well-planned and -executed management protocols leading up to and during the weaning period,” Boehringer Ingelheim veterinarian Dr. Mark van der List said.
A good preventive health program can reduce the number of calves that succumb to bovine respiratory disease (BRD), lessen the severity of clinical signs and decrease the number of animals that develop complications, he added.
Van der List encouraged dairy producers to take a close look at their current weaning protocols and identify any areas that could be changed to further mitigate antibiotic use on their operation.
He also suggested that producers consider talking through the following questions with a herd veterinarian:
1. What environmental stressors are present on your operation, and how are you working to offset them? In the cattle industry, there are a number of built-in stressors such as weaning, shipping, commingling and dehorning. Even seemingly minor environmental events -- like changes in temperature, dust, poor ventilation and moisture -- can be factors.
“Judicious use of antibiotics starts with identifying ways in which stressors that cause disease can be minimized in your herd,” van der List said.
2. Do your dry cow protocols contribute to quality colostrum production? A nationwide evaluation of colostrum on dairy farms in the U.S. showed that 60% of maternal colostrum fed to newborn dairy calves is inadequate, causing many calves to be at risk for failure of passive transfer.
When calves don’t receive enough high-quality antibodies from colostrum, they do not acquire necessary protection against the most common viral and bacterial infections found within their environment, van der List said. They’re also more likely to develop scours or pneumonia and are at greater risk of death.
Colostrum quality starts with healthy cows. The management of cows during the last 60 days of pregnancy — proper nutrition, ensuring cow comfort and reducing stress — will optimize cow health and good colostrum development.
Safely administering vaccines at appropriate times within the dry cow period also helps keep the dam healthy and enhance antibody levels in colostrum, van der List said. Cows vaccinated during the dry period are more likely to enter the next lactation with a robust immune system to fight off infectious disease threats.
3. Do you have a calf vaccination program in place to extend immunity? For calves, respiratory vaccines are important to stimulate the acquired immune system, which develops immunological memory. When the animal encounters these respiratory pathogens in the future, this memory response results in a rapid and specific immune response.
Vaccines help protect the individual calf, prevent the spread of infection to other calves and lessen the severity of disease.
Van der List suggested that producers consult with their veterinarian about the use of vaccines prior to weaning to increase immunity against common respiratory pathogens. “The time frame for vaccinating calves will vary from farm to farm, but ideally, the calf will have had time to develop a robust immune response from the vaccine by the time it starts facing the challenges associated with weaning.”
4. Are there ways calf nutrition could be improved? The calf's immune response is influenced strongly by nutrition. When calves switch from a milk-based diet to a solid food, it must be ensured that they are eating enough so they don’t go into an energy-deficit period, van der List said. Working with a local nutritionist can help determine the appropriate amount and type of feed required to transition diets smoothly.
5. How are calves grouped? How quickly are they required to adjust to a larger group?
“We don’t want calves to go into very large groups right after weaning,” van der List said. “They should be introduced into a group of no more than 10 animals in the first week postweaning, and the size of the group should be increased very gradually to minimize stress.”
6. How fast do sick calves receive the necessary treatment? Rapid identification of animals showing signs of BRD with bacterial involvement and administering a fast-acting, effective antibiotic are very important. This not only helps them recover quickly, but it also reduces the likelihood of future complications.
Van der List suggested that producers evaluate the animal’s chance of recovery before administering treatment. “If you have a calf that has been treated multiple times, the calf likely has a very poor chance of recovery,” he said. “When our goal is to reduce antibiotic usage in the dairy herd, we want to be targeting those antibiotic treatments to animals that have a high chance of recovery.”
7. Are you practicing metaphylaxis? Why or why not? In the dairy business, metaphylaxis is not typically recommended as a standard procedure, but there are certain times that it can be used very effectively and contribute to judicious use.
“If you know animals are undergoing more stress than usual or are at a higher risk of developing bacterial respiratory disease, this may be a time to consult your veterinarian and determine if metaphylaxis is warranted,” van der List concluded.