Improving mastitis management in Asturias, Spain

A recent pilot study in Spain shows that working with differential somatic cell count (DSCC) analysis and the new Udder Health Group concept has great potential for dairy farms, in terms of successfully implementing a mastitis control program. In a recent interview, we caught up with Technical Director, Lara Suárez Escandón from the Interprofessional Dairy and Agri-Food Laboratory of Asturias (LILA ASTURIAS) to talk about the successful implementation of the Differential Somatic Cell Count (DSCC) test for mastitis management in their local region.

LILA ASTURIAS is a professional dairy and agri-food Laboratory, founded in 1991 and one of the first interprofessional laboratories created in Spain. They currently have 19 employees, and their primary services include analysis of dairy herd improvement samples and milk quality payment samples, for dairies and dairy farmers. The laboratory also has a physicochemical and microbiological department, where the composition of dairy products is analyzed for the presence of pathogens and bacteria for quality control. The analytical services provided by the LILA Laboratory have the accreditation and certification of different ISO standards.

“Every year we analyze more than 400,000 DHI samples and more than 250,000 milk quality payment samples. In addition, we carry out identification of mastitis bacteria and antibiograms to assist veterinarians in choosing the most effective antibiotics,” explains Lara Suárez Escandón.

Lila Asturias have a high throughput of samples and a lot of work is put into collecting and controlling them. Using methods that enable a reduction of analysis time is therefore high on their agenda.

“We have a daily sample collection service with two routes and more than 45 stops, an inspection service to attend complaints or inquiries from industries and farmers, carry out controls on collection routes, secure tanks and milk equipment to improve milk quality and the level of mastitis in herds. All this to control and certificate different quality marks, and training courses for the dairy sector.”

A pilot project in four phases

The pilot project lasted approximately one year and was carried out in collaboration with three partners: the government of Principado de Asturias, CAIA RURAL de Asturias, which is a financial institution, and Central Lechera Asturiana which is the main dairy in the region. The project involved nine farms and approximately 1000 Holstein cows in total.

• Phase 1 – Collect DSCC data
  Participating farms were selected to be representative of the whole region and differential somatic cell data was collected to define the Udder Health Groups.
• Phase 2 – Check DSCC data from selected farms
  The DSCC data collected at selected farms were checked using microbiological cultures and CMT and classified into Udder Health Groups.
• Phase 3 – Design a DSCC report
  Meetings were held with milk quality veterinarians and academic lab staff to share the obtained results and design a differential somatic cell report. 
• Phase 4 – Build a communication plan
  Finally, a communication plan was rolled out, to explain the usefulness of the new parameters and the content of the new report to farmers, veterinarians, and their staff. 

Phase 1 - Data collection

In phase 1, the farm selection criteria included the type of milking system, farm size and geographical location. One farm had an automatic milking machine, while the rest used manual milking systems. 

As shown below, two farms with less than 100 animals, four farms with 100-250 animals and two farms with more than 250 cows were selected. 

MM: Milking machine
AMM: Automatic milking machine

In terms of geographical location, the selected farms were situated in the center, east and west of the region. 

Phase 2 – Classification of cows in udder health groups

Once the farms were selected the next step was to collect the data to define the udder health groups. “In October 2021, we started collecting differential somatic cell data from the DHI samples analyzed. In the first month, only 67% of the samples received, were analyzed for differential somatic cells. In the following months, this percentage progressively increased to the current 100%. With this data, the udder health groups were constructed and the percentage of cows in groups ABCD were calculated,” explains Lara.

The established protocol was to analyze the samples from the selected farms first and then classify them into udder health groups according to the criteria indicated by FOSS: 200,000 total somatic cells and 65% DSCC. 

Phase 3 - Integrating the Udder Health Group tool

Once the cows were classified, the laboratory then informed the veterinarians responsible for each farm which animals were in groups B and C. The veterinarians then had ten days to go to the farms and perform a California test on these animals and take a sample for culture in the laboratory.

“The criteria for taking a sample for a positive Californian test were set by the veterinarians. CMT values of two or more are considered positive and then the positive quarter is sampled for the laboratory. In case of a negative CMT, a composite sample is taken for all four quarters,” says Lara.

Back in the laboratory, a microbiological culture of all the received samples received was carried out to identify the presence of bacteria and verify the existence or non-existence of intramammary infection in group B and C cows. “In the cultures from Group B, the presence of major pathogens represents almost 47%, whereas in the culture from group C the percentage of major pathogens rises to 69%,” she continues.

This microbiological culture is considered the gold standard method and is taken as a reference to establish the conclusions. Of the 936 cows analysed, the distribution in the groups A, B, C and D was presented in the report. “About 70% were in group A, 14% in group B almost 40% in group C and 2% in Group D,” Lara explains.

Looking at Group C, complete data is available for 100 cows. When analyzing the results of group B using the DSCC test in the laboratory, the most remarkable fact is that of the 103 animals in this group, positive cultures were detected in 84 cows, whereas the California test only detected 15. “The California test is a very useful tool on the farm, but with low cell counts, it loses sensitivity,” explains Lara. “When selecting animals for treatment and dry therapy, it is vital to choose tests with high sensitivity to detect the greatest number of cows with intramammary infection,” Lara continues.

When the same study was performed on Group C animals - 45 out of 75 cows tested positive for intramammary infection using the Californian test. This means that 30 animals went undetected. “In conclusion, even in Group C, in which the California test already has a higher sensitivity, the DSCC parameter, allows detection of 15% more animals with intramammary infection,” Lara concludes. This shows the importance of the DSCC test as a support tool for the detection of cows with subclinical mastitis. 

The differential somatic cell report

In this example from the differential somatic cell report, that farmers received in October 2022, there are two parts.

First, a table showing the individual data for each cow, from the past 6 months.

“The number in each square indicates the total somatic cell count and the color of the square indicates the udder health group in which it was classified. Green for group A, yellow for group B, red for group C and blue for group D,” explains Lara. This table is useful for both farmers and veterinarians when applying selective dry therapies. 

The second part of the report shows the data at heard level, including the distribution of the percentage of cows in the udder health groups during the last 12 months. At the bottom of the report, a comparison with the regional average in the last quarter is included for reference. 

Phase 4 – Implementation throughout the region 

The last and most time-consuming phase of the pilot project has been the communication plan, explains Lara. Rolling out this project to a large group of stakeholders has required a lot of coordination, meetings and training sessions. These activities have been held in different parts of the regions involved with the participation of farmers, veterinarians and technical staff. In addition to this work, several articles have been published in newspapers, magazines and social networks, to broaden the knowledge to larger industry audience.

There is no doubt that this has been a major project for LILA ASTURIAS, but the payoff is undeniable. According to Lara, the main advantage of the DSCC test is that it has been able to detect almost 67% more animals with intramammary infection compared to the California test. “This makes it a very useful tool for selecting candidate cows for antibiotic treatment in selective dry therapies, increasing the likelihood of success of any dairy farm’s mastitis control program,” Lara says.