Nutrition's Role in Mammary Gland Health
Proper Diet Important for Immune System
The risk that a cow will develop mastitis is largely a function of pathogen load at the teat end, and the cow's ability to prevent a bacterial infection from becoming established in the mammary gland.
Nutrition can have significant effects on the cow's immune system, thereby affecting infection rate and severity of mastitis. The immune system has high requirements for specific nutrients and when these nutrients are not provided in adequate amounts, immune function may suffer.
At this year's NMC Regional Meeting, Dr. Bill Weiss, Ohio State University, reviewed nutritional influences on immune function and mastitis during the periparturient period. Three of his 'take home' messages on how to improve mammary gland health follow:
1. Feed and manage
late-lactation and dry cows to maintain proper body condition.
Avoid a large decrease in feed intake around parturition and a large
loss in body condition score (BCS) during early lactation. Normal, healthy
cows lose 0.25 to 0.5 BCS units in early lactation.
Management and dietary practices that can help reduce excessive body condition loss include:
a) Prevent
cows from becoming too diet based on less digestible feeds so the rumen
gets full before over consuming energy.
b) Avoid a large decrease in dry matter intake (DMI) during the
pre-partum period and provide adequate bunk space and stalls for pre-fresh
cows.
c) Promote a rapid increase in energy intake post-calving, which
usually requires a rapid increase in DMI. Feeding a well-balanced diet
based on highquality forage, which contains moderate fiber (about 30%
NDF) and starch (22%-25%), and <5% total fat improves DMI. Overcrowding
fresh cows also restrcits their intake.
2. Prevent hypocalcemia
via proper mineral nutrition for dry cows.
Cows with milk fever are much more likely to get clinical mastitis than
cows without milk fever. Calcium is needed for muscle contractions --
if experiencing hypocalcemia, cows' teat sphincters may not contract
as quickly or completely, opening up the risk for bacterial invasion.
Cows with milk fever have higher concentrations of plasma cortisol than
normal cows, and cortisol suppresses immune function. In addition, the
calcium status of monocytes is impaired in cows with milk fever, reducing
the ability of the monocyte to function properly.
3. Feed adequate,
but not excessive, amounts of trace minerals and vitamins.
Selenium and vitamin E are especially supplementation during the pre-fresh
period. Other key nutrients include vitamin A, betacarotene, copper,
and zinc.
Source: 2009 NMC Regional Meeting Proceedings, p 44-52 (Weiss)
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