Highlights from Minnesota Dairy Health Conference
Marcia Endres, Extension Dairy Scientist
June 8, 2013
The University of Minnesota recently held its annual Dairy Health Conference. The main audience for this event is dairy veterinarians, but consultants, dairy producers and academics also attend this very good educational program.
Two of the topic areas in particular caught my interest because they were related to animal welfare. Frank Garry (Colorado State University) shared information about cow and calf mortality. On-farm cow mortality in U.S. dairies could be improved, with positive financial results for the farm and welfare of animals. His results confirm what we have seen in our research at the University of Minnesota, with the majority of cows leaving the herd in the first 60 days in milk. He advised veterinarians who were in the audience to perform more necropsies on-farm to improve the knowledge of the main causes of death on each farm. With that information, preventative measures can be implemented that are specific to that farm, resulting in lower involuntary loss of animals, and improved dairy profitability. Garry and colleagues have developed a necropsy manual available online (web search 'Garry and necropsy manual' to find it).
In relation to calf stillbirth and early death loss, Garry emphasized the relationship between calf death and cow dystocia (difficult calving). He uses a simple score for dystocia of 1 (no assistance), 2 (slight problem), and 3 (any assistance needed). Recording of all dystocia cases should be a standard practice on the farm. Fifty percent of stillbirths were a direct result of dystocia. The odds of a heifer calf having any disease event were significantly increased for dystocia scores 2 and 3. Calves born to cows having a severe dystocia had an increased risk of death after 24 hours of age compared to calves born unassisted. In addition, calves having mild dystocia were less likely to survive to 30 days than calves born unassisted. In order to minimize dystocia, he suggested three steps veterinarians and producers can take: 1) Decrease its occurrence, which is not easy to accomplish since it is a complex issue; 2) Decrease the impact of dystocia by good calving management practices, which are not very different than what needs to be done to reduce prevalence of Johnes disease; this requires employee training; 3) Increase the level and quality of newborn calf care; this also requires employee training and can help compromised calves survive and thrive.
Dr. Jan Shearer (Iowa State University) spoke on lameness, specifically digital dermatitis (hairy heel warts). He noted that 70 to 100% of herds have digital dermatitis and 20% of all cows in the U.S. are infected. Eighty to 85% of the time it is the back feet that are affected. It is a very painful condition and, as it progresses, cows become very lame. There has been some possible association of digital dermatitis with udder sores—a problem seen in some dairies in Minnesota. The specific causing microorganism is not yet known for sure, but spirochetes are found on lesions, especially more chronic lesions. Current research using advanced identification techniques will possibly help us identify the causing agent and hopefully cure this disease.
The disease can be managed by topical treatment of lesions and appropriate use of footbaths. Successful topical treatment includes antibiotic solution sprayed directly onto the lesion after cleaning with water, waiting a minute, then applying it again, and doing it for 5 consecutive days. Antibiotic sprays are less effective when lesions exist in the cleft between the toes. In those cases, immersing the affected foot in a treatment solution may be most effective. Footbaths also are used to control digital dermatitis and other infectious lesions on the farm. Shearer recommended a footbath that is 12 feet in length, so it is long enough to allow for two dunks for each of the animal's feet (as recommended by Nigel Cook, UW-Madison). The most effective treatment is a 3% to 5% solution of formalin (be careful not to burn skin, it should be diluted), but copper or zinc sulfate is also used in footbaths. Large dairies need to have more than one bath to get all cows treated.
Activity sensors are being used to detect lame cows. In that case, once a cow is tagged by the system, feet could be examined more closely by a hoof trimmer, and paste antibiotic applied to the lesion, hopefully at earlier lesion stages.
I also suggest that the use of precision dairy tools, such as rumination, activity and temperature sensors (as I discussed in my previous Dairy Star article) could help us identify cows at risk earlier, and then intervene as soon as possible to prevent early loss of those animals. Plan to attend the Precision Dairy 2013 Conference and Expo on June 26-27 in Rochester, Minnesota, to learn more about these precision tools (details about the event can be found at precisiondairy.umn.edu).