We all know replacement heifer health is important. When we think of this topic, we often think of respiratory health, foot and leg health, and other more common, physical health issues. But we also need to watch for heifer mastitis.
You may be asking, “How does a heifer get mastitis before her first calving and lactation?”
During the first pregnancy, the milk-producing tissues in the udder undergo the most development. It is important to protect the mammary gland from any bacteria or coliforms that can cause infection, reducing milk production. According to the University of Wisconsin-Extension, research from New Zealand has shown that Staphylococcus aureus mastitis results in high production losses during the heifer’s first lactation. But, once treated, the infection will still carry over into the subsequent lactation.
Many factors can be a source of infection. According to the UW-Extension, no one knows exactly what to pinpoint as the cause for intramammary infections. However, researchers have discovered four potential risk factors:
- Bacteria found on the udder skin, which can colonize the teat end and enter the teat opening.
- Bacteria that live in the oral cavities of calves and spread through suckling of other calves.
- Bacteria present in the heifers' environment, such as the soil, manure and bedding.
- Bacteria spread from flies that accumulate on teat ends.
Research has shown that treatment during the first, second and third trimester has no effect on calving. According to UW-Extension, the best times to treat are at the convenience of the management practices of a dairy. An example of a timeline of when to best treat the heifers is:
- At the time of artificial insemination
- During routine pregnancy checks
- When moved to the close-up pen
However, remember treatment should not be given after 45 days prior to expected calving date to prevent antibiotic residues at calving. Using a non-lactating cow product is the best treatment for heifers during pregnancy for the following five reasons:
- The cure rate is higher than during lactation.
- There is no milk loss during therapy.
- Antibiotic residuals are minimized.
- Somatic cell count is reduced at calving.
- Milk production increases about 10 percent in successfully treated cows.
Another treatment option is the use of dietary supplementation. According to UW-Extension, a study has been done using selenium and vitamin E supplementation. The dietary supplementation reduced potential infections at calving by 42 percent. Vitamin E and selenium improves overall udder health of heifers and is most evident during calving and early lactation.