Udder health starts in dry period

NEW PRAGUE, Minn. — The highest risks for intramammary infections in dairy cattle occur at two peak times: right after dry-off and during calving and immediate postpartum, according to Dr. Marcello Guadagnini.

“It is clear that the dry period and early lactation play a key role in udder health,” Guadagnini said. “We have two spikes due to milk cessation and udder remodeling, and the dysregulated immune system and oxidative stress.”

Guadagnini is the international technical manager for Axiota Animal Health. He spoke about the connection between udder health and trace minerals May 7 in a National Mastitis Council webinar.

Guadagnini said a good way to measure udder health is with somatic cell count or Dairy Herd Improvement Association records.

In a study of 156,000 lactations across 681 farms over two years in Spain, the average occurrence of subclinical mastitis at herd level was 22%, with many farms struggling to stay under the recommended 15% threshold. Guadagnini said that proper dry cow management is needed for healthy udders.

“I like to relate most of these issues to milk production losses or negative consequences into lactation,” Guadagnini said. “You not only get the infection but also the activation of the immune system, which is actually costing energy.”

Guadagnini focused on zinc, manganese, copper and selenium for the discussion. 

Because selenium has received more attention over the last decade, Guadagnini said it is important to realize the importance of zinc as a key for over 300 enzymes in the body. Copper is key to modulating inflammation. Manganese is especially important during heat stress, and all are critical to establish an effective antioxidant system. Of course, selenium is important to the immune system and its resistance.

Because trace minerals are fed orally, there are not clinical signs of deficiency, Guadagnini said.

“We might be tempted to think that just because we feed the trace minerals and supply them orally, the trace mineral status is always optimal,” Guadagnini said. “The reality is that when we start from an optimal trace mineral level, we can see a lot of things that get impaired when we go below that, and the first thing is immunity.”

Guadagnini said producers should not only look for subclinical signs but also think in terms of optimal mineral levels. He described two environments: deficiency or times of specific demand. Deficiency often happens when cows are on pasture, Guadagnini said.

A time of specific demand may occur during an infection or activation of the immune system because there is a higher consumption of trace minerals during those times. This can include transporting cows and vaccinating cows. In the case of replacement animals, rapid growth can also cause a trace mineral deficiency.

Dry off and early lactation are also critical times. The most recent guidelines from the Nutrient Requirements of Dairy Cattle have increased requirements for copper, zinc and manganese in both far-off and close-up cows. Selenium has been kept the same because it has a legal limit, Guadagnini said.

“This increase shows that modern cows really need a lot of trace minerals to have proper immune function and to start the lactation in the best way,” Guadagnini said. “Just because we feed trace minerals, it is not given that the trace mineral level is optimal.”

The trace mineral system is a multi-phase, dynamic process. Trace minerals are exchanged between plasma and where they are needed and used for all structural demands, such as the keratin plug in the teat canal or to produce antioxidants.

Especially when milk production is high at dry off, there is a spike of zinc and plasma concentration. This may be because zinc is needed to remodel the udder as it is a high-replicating tissue and needs to facilitate the migration of neutrophils from the bloodstream to remodel the udder. 

“If we think about when approaching calving, we need to know that part of these trace minerals will be dedicated to be transferred to the fetus to generate mineral storage in the fetal liver,” Guadagnini said. “Especially when we approach calving, we have a significant transfer to colostrum. So, whatever we provide to the last trimester, part of that will transfer to the fetus so it will not be fully available to the cow.”

Moreover, in early postpartum, free radicals are produced due to a fast metabolism. If an efficient antioxidant system is lacking, oxidative stress often occurs, which is a risk factor for post-partum disease and mastitis.

Guadagnini said injectable trace minerals can help cows maintain an optimal level and can be used even when oral trace minerals are fed. The injectable trace minerals from Axiota Animal Health have been shown to be safe when used according to label instructions.

Most importantly, studies in different geographies show that using trace minerals during periods of high demand, such as the dry period, can help reduce mastitis and improve udder health.

“All of our studies have been focused on prevention,” Guadagnini said. “As we saw, once we have mastitis, we have a big loss. What we really want to avoid is getting to the disease.”