SPECIAL REPORT: Strategies to reduce disease during dairy cow transition period
From the 2024 Kemin Intestinal Health Symposium
By Krissa Welshans
There is a huge increase in the metabolic demands on a dairy cow following calving and when lactation is initiated, but it takes time for the animal to be able to cope with the increased demand. During this time, a transition phase occurs, often accompanied by hypoglycemia and a dysregulated immune system, which raises the animal’s susceptibility to diseases, according to Dr. Lautaro Cangiano, speaking at the 2024 Kemin Intestinal Health Symposium.
In the transition phase, 30-50% of a herd is going to have at least one metabolic disorder, such as ketosis, displaced abomasum, mastitis, metritis, etc.
Cangiano, assistant professor in immunology, animal and dairy sciences at the University of Wisconsin-Madison, said the adaptive side of the immune system is really important, because this is where commands from the immune system occur, particularly the T cells. However, very little is currently known about the adaptive side.
“The T cells are kind of like your coach of the immune system. They integrate a lot of signals from the environment, and then they decide what kind of response they are going to command,” Cangiano explained.
The types of T cells vary, but they are all crucial in orchestrating systemic immunity. However, there is limited understanding of how their function is impacted during the transition and how this may contribute to disease vulnerability.
This is one of the main areas of focus for Cangiano’s lab.
One study conducted by the lab started monitoring markers in the blood and gut of 80 cows from a month before calving through the transition period (70 days in milk).
Blood and gut samples both showed an increase in T cell markers, but whether this is a good thing or not remains unknown, Cangiano noted. Additionally, because T cells vary, he said the T cells that increased in number may not necessarily be activating an appropriate immune response. One of the theories currently receiving attention is that changes in the metabolic environment could be shifting the type of response in the cells, making them more pro-inflammatory.
The study also looked at how changes in metabolism may be altering how the group of cells acts. Researchers found that cells switch their metabolism when they become activated.
Another study at the lab explored intestinal permeability and found that it increases after calving. This might contribute to the pro-inflammatory phenotype of the immune system during this period, Cangiano explained.
Particularly noteworthy, one group of cows in the study was fed Saccharomyces cerevisiaeboulardii, a yeast product, from 21 days prior to calving and 60 days in milk. They had reduced intestinal permeability. A decrease in activation markers on the T cells at a systemic level was also observed. This, Cangiano said, suggests there are ways of modulating the intestinal environment to tone down the inflammatory response.
Early immune system critical
Setting an animal up for success begins at birth, Cangiano said, as early colonization of mucosal surfaces in a young animal is key in the process of immune development. It is also a good time to make microbial interventions with probiotics or feed additives, he noted.
“This is probably one of the areas that you can have the greatest impact on the development of the microbiome, because in an adult animal you’re going to have a more established microbial structure, and it’s harder to modify it,” he said.
Cangiano noted that some industry practices are unfortunately hindering the ability to get calves off to a strong start. For example, inadequate colostrum intake early on reduces milk production and cow performance. Calves that receive a second colostrum feeding are proven to perform better throughout their lifetime.
Watch the full presentation from Dr. Cangiano and access all content from the 2024 Kemin Intestinal Health Symposium at kemin.com/symposium.
