Source: Pennsylvania State University
The dry period is an important time for all dairy cows. This critical break allows the cow’s udder to regenerate milk-producing tissue resulting in a productive subsequent lactation. Cows are very susceptible to new intramammary infections during the dry period.
To prevent new cases of mastitis in your dry cows, here are three areas to focus:
1. The dairy cow
It may sound simple, but by taking several steps to manage your dairy animals both during their lactation and dry period, new cases of mastitis can be prevented. The risk of common transition cow disorders such as milk fever, retained placenta, displaced abomasum, and clinical mastitis can be minimized with proper dry cow management.
Cows are most susceptible to new mastitis infections during the first two weeks of the dry period and the two weeks both before and after calving. Susceptibility is increased because the mammary gland is undergoing a transition either from or to a state of active milk synthesis and secretion (Nickerson, 2019). Bred heifers are at greatest risk two weeks before calving while their udder is preparing for lactation.
Research has demonstrated active milk-producing cells need to regress or go into a resting state to prepare for the next lactation (Nickerson, 2019). As calving approaches, these cells become active again, and new milk-producing cells are formed.
During lactation, the teat-end condition should be monitored. A cow with cracked teats has a 1.7 times higher risk of picking up a new infection during the dry period (Dingwell et al., 2003). Monitoring milking equipment and milking practices can ensure good teat end condition at the end of lactation.
Whether you use blanket dry cow treatment for all your cows or selective dry cow therapy, proper administration of the dry cow treatment is essential. Before treatment, pre-dip each teat with a germicidal teat dip and after 30 -45 seconds of contact time, dry the teats using a clean towel. Next, clean each teat end with rubbing alcohol. After the alcohol has dried, administer the treatment according to the label. After treatment, the teats should be dipped with a barrier post-dip.
In addition to a dry cow treatment, an approved teat sealant can be used as an extra barrier to prevent infection. Dry cow treatment usually only lasts for the first 30 days of the dry period, then, cows rely on a natural keratin plug to inhibit bacteria from entering the teat canal. When dry cow housing may not be optimal, teat sealants can add an extra level of protection. A teat sealant, which is typically a bismuth-based paste, acts as the keratin plug (Couture et al., 2019). Teat sealants have been found to reduce the incidence of developing intramammary infections and decrease the incidence of clinical mastitis (Rabiee and Lean, 2013).
2. The dry cow’s environment
The dry cow should be provided with the proper housing. Remember her body may be working to clear up any lingering subclinical mastitis infection. Providing her with a clean and dry environment gives her a better chance to recover and avoid a new infection. Exercise and time off concrete can give dry cows a break during the dry period.
Dry cows need clean, dry bedding to avoid manure transfer to the teat ends. If dry cows are housed on pasture, proper pasture management is also critical. Environmental mastitis pathogens, such as Streptococcus uberis have been isolated from high-traffic areas of pastures and have contributed to mastitis during the dry period (Lopez et al., 2007).
Adequate space is also important as there is a greater risk of bacteria transfer in a crowded pen or pack. Adequate bunk space of at least 30 inches per cow and proper barn ventilation is also important. Keep dry cows cool during hot weather with fans and/or shade. Also, keep areas clean and free of excess mud and manure to prevent flies as they can carry mastitis-causing pathogens.
The week before calving, cows start to produce milk again. It is common for cows to be moved to a calving area or close-up pen around this time. The cleanliness of this area can greatly affect the rate of clinical mastitis. One study found that herd management factors such as less frequent cleaning of the calving area increased the risk of clinical mastitis as a result of increased pathogen exposure from the environment (Green et al., 2007). One way to test the cleanliness of this area is the knee test. To do this, try dropping to your knees in several areas around the pen. If your pants are still clean and dry after 10 – 15 seconds of kneeling on the bedding, then the calving area is sufficient. But if your pants are dirty or damp, more fresh bedding should be added.
3. The dry cow nutrition program
Proper dry cow nutrition can help boost the immune system to aid in preventing new infections during the next lactation.
Many dry cow diets are modified compared to the lactating ration to prevent overfeeding. Work with a nutritionist to ensure the dry cows receive adequate vitamins and minerals. Vitamins E, A, and D are associated with proper immune function (Van Saun, 2022).
By including the recommended amount and type of minerals and vitamins in the dry cow ration, their immune systems are boosted helping their body fight off mastitis-causing pathogens. Proper amounts of energy and protein are also needed for a strong immune system.
When feeding dry cows, they may have a varied feed intake, particularly in overcrowded pens or during times of heat stress. The variation can be up to 5 – 8 pounds per day (Van Saun, 2022). The potential for variation in feed intake corresponds to the importance of providing adequate pen space, feed bunk space, and heat abatement.
Every dairy farm is managed differently, so consult with your veterinarian to develop a comprehensive dry cow program that works for your operation.
By focusing on these areas, you can help reduce new mastitis cases during the dry period. Minimizing physiological and nutritional stressors can give your cows the best chance to have optimal milk production in their next lactation.
Resources
Benavides, M.G., J.H. Williamson, G.D. Pullinger, S.J. Lacy-Hulbert, R.T. Cursons, and J.A. Leigh. 2007. Field observations on the variation of Streptococcus uberis populations in a pasture-based dairy farm. J. Dairy Sci. 90:5558-5566.
Couture, V, Pighetti, G., Krawczel, P., and L. Eckelkamp. 2019. Managing Mastitis in Heifers and Dry Cows. University of Tennessee Publication.
Dingwell, R., L. Timms, J. Sargeant, D. Kelton, Y. Schukken, and K. Leslie. 2003. The association of teat canal closure and other risk factors for new dry period intramammary infections. Pages 298–299 in Proc. Annu. Mtg. National Mastitis Council. National Mastitis Council, Madison, WI.
Green, M.J., A.J. Bradley, G.F. Medley, and W.J. Browne. 2007. Cow, Farm, and Management Factors During the Dry Period that Determine the Rate of Clinical Mastitis After Calving. J. Dairy Sci. 90: 3764-3776.
Nickerson, S. 2019. Importance of Dry Cow Management in the Control of Mastitis. University of Georgia Extension.
Rabiee, A. R., and I. J. Lean. 2013. The effect of internal teat sealant products (Teatseal and Orbeseal) on intramammary infection, clinical mastitis, and somatic cell counts in lactating dairy cows: A meta-analysis. J. Dairy Sci. 96:6915-6931.
Van Saun, R. 2022. Can We Feed to Prevent Mastitis? Penn State Extension.
Author: Daniela Roland, Extension Educator, Dairy
