Keena Mullen, Claire McPhee, Leslie Gentry, Roberta Lyman, Steve Washburn, and Kevin Anderson.
Added April 5, 2011. The College of Veterinary Medicine and the College of Agriculture and Life Sciences at North Carolina State University (NCSU) have been investigating alternative udder health management strategies for dairy cattle. This work is being done in partnership with the
pasture-based dairy unit at the Center for Environmental Farming Systems (CEFS) in Goldsboro, North Carolina and with cooperating pasture-based and organic farms in the state.
This study compared an organic botanical intramammary product (Phyto-Mast™, Penn Dutch Cow Care) to either no treatment or to conventional dry treatment (Quartermaster + Orbeseal, Pfizer Animal Health). A total of 150 Holstein, Jersey and crossbred pasture-based dairy cattle at CEFS were assigned to the three treatments, with 40 cows and 10 late-gestation heifers receiving each treatment. Milk samples were taken directly before treatment at dry off and three days post-calving. Milk was cultured at dry off and again at freshening to determine the effect of treatment. The focus was on measuring the cure rate of existing bacterial infections or preventing new infections during the dry period (or both). First test date milk production and somatic cell scores were also measured, but no significant difference was observed between treatments for either milk production or somatic cell score.
Milk samples which were missing or contaminated at collection were removed from the analyses, thereby lowering the total numbers of quarters available for paired comparisons at dry off and at freshening. The percentage of quarters that were cured between dry off and freshening was significantly higher for those treated conventionally (18.5%) whereas cure rates for quarters treated with Phyto-Mast™ (7.2%) did not differ from untreated controls (9.7%). Percentages of new infections present at freshening were lowest (6.6%) for conventionallytreated quarters and highest (20.1%) for untreated quarters whereas
the rate of new infections (13.7%) was intermediate for quarters receiving Phyto-Mast™ treatment. Phyto-Mast™ was not as effective as the conventional treatment at curing existing infections or in preventing new dry period infections.
Though the herbal therapy was similar to untreated controls for curing existing infections over the dry period, Phyto-Mast™ was promising as a dry treatment in reducing the rate of new infections compared to untreated controls.
In the dry-treatment study described above, the combination of an intramammary antibiotic and a teat sealant may have provided the conventional treatment an advantage over the Phyto-Mast™ treatment. Currently, another dry treatment study is in progress to compare 5
treatments: 1. conventional (Quartermaster + Orbeseal) treatment; 2. no treatment; 3. treatment with Phyto-Mast™; 4. treatment with Essential Cinnatube™ (New AgriTech Enterprises); and 5. treatment with Phyto-Mast™ and Cinnatube™. Cinnatube™ is an herbal intramammary product that acts as a teat sealant. All treatments will be tested in the CEFS herd. Three organic dairies in North Carolina are also participating in the study, evaluating every treatment except the conventional treatment. The results of this study are expected in late 2011.
The summer of 2010 was one of the hottest on record for North Carolina, but that did not deter veterinary student, Leslie Gentry, and graduate student, Keena Mullen, from collecting milk samples and somatic cell count information from 14 dairies (7 organic, 7 pasturebased
conventional) for microbiological comparison. A total of 4988 quarter milk samples (2608 conventional, 2380 organic) were collected from 1247 cows (652 conventional, 595 organic).
Results from this study will be presented at the American Dairy Science Association 2011 meeting in July, but here's a sneak peek: the proportion of cows with some type of bacteria present in the milk samples did not differ between organic (56.1%) and conventional (52.9%) dairies. Conventional herds had a lower proportion of infected quarters (27.0% versus 36.3%), but somatic cell scores (SCS) did not differ between organic and conventional herds (3.0 +/- 0.1). Despite differences in herd management, milk culture results and SCS measurements were remarkably similar between organic and conventional NC dairies compared for this study.
Despite the recent growth of the organic dairy industry, organic producers and veterinarians have limited information when choosing mastitis treatments for animals in organic dairy production. Organic producers commonly administer homeopathic or other plant-based products without research showing that they are effective. These products do not have known withholding times, even though they may contain components that could get into the milk. At the North Carolina State University College of Veterinary Medicine, we performed a study to identify the active chemicals in Phyto-Mast™, and to measure the residues in milk and blood samples following intra-mammary infusion.
A method was developed to detect thymol, the active chemical component of Thymus vulgaris (garden thyme)—one of the active ingredients in Phyto-Mast™ in milk and blood samples. As a model for dairy cows, five, healthy, lactating alpine dairy goats were dosed with 5 mL in each
teat. Following this infusion, thymol residues were measured in the milk and blood samples in the laboratory. Thymol was detected in the blood for about 4 hours, and for 12 hours in the milk. There was no inflammation in the udder after infusing Phyto-Mast™, and the goats did not show any signs of systemic illness.
At the dosage used in dairy goats, thymol was eliminated in a relatively short time, but residue information for other Phyto-Mast™ ingredients was not investigated. In future work, we would like to repeat this study using dairy cows, and also look for residues of the other ingredients. This type of research will ensure the safety of organic milk in the future.
This summer, Keena Mullen plans to test commonly used herbal extracts, like those included in the formulation of Phyto-Mast™ and Cinnatube™, against specific mastitis-causing bacteria in the laboratory. This research will specify which extracts have strong activity against specific pathogens, helping strengthen the ability of intramammary treatments to combat infection.
Use of antibiotics is not an option for treating or preventing udder infections in organic dairy production. Therefore, many organic dairy producers have interest in having access to effective alternatives to antibiotics to use as needed. At NCSU, we are investigating some of the available alternative products to determine their efficacy in controlled studies under applied conditions. There is potential, especially with the current concern over antibiotic resistance, for
the dairy industry as a whole to start using effective alternatives to antibiotics to treat mastitis. To that end, organic dairy producers collaborating in such studies on alternative therapies will be truly leading the way to reduce the chance of antibiotic resistance. Quantification of the efficacy under farm situations can be established by cooperating with university researchers and may lead to more industry-wide use of some "organic" practices. We really appreciate the staff at CEFS and the dairy producers involved in our studies for their cooperation.
Keena Mullen is a second-year PhD student at NCSU with a BS in Animal Science from Washington State University. Working under the guidance of Dr. Steve Washburn and Dr. Kevin Anderson, she is interested in evaluating the efficacy of alternatives to antibiotics both on-farm and in the laboratory.
Claire McPhee grew up in Iowa, has a BA from Wesleyan University, MSPH in Epidemiology from UNC-Chapel Hill and currently is a third year veterinary student at NCSU. She plans to become a dairy veterinarian, and is interested in working with organic and pasturebased clients. Her major interests in the dairy industry are udder health and cow welfare, and she hopes to continue to investigate alternative mastitis treatments.
Leslie Gentry is a third year veterinary student at NCSU after receiving her BS in Animal Science from NCSU.
Roberta Lyman is a Research Technician in the NCSU Mastitis and Milk Quality Laboratory coordinated by Dr. Kevin Anderson.
Dr. Steve Washburn is Extension Specialist and Professor of Animal Science at NCSU. He coordinates research and educational programs associated with the pasture-based dairy system at the Center for Environmental Farming Systems in Goldsboro, NC.
Dr. Kevin Anderson, Professor of Ruminant Health Management, is a dairy veterinarian and researcher at the College of Veterinary Medicine at NCSU. He focuses on mastitis and milk quality and has maintained a Mastitis and Milk Quality Laboratory at the College for over 20 years.
