The fresh cows on any dairy are the most profitable cows in the herd as they reach their peak milk production. But this is often the time in which they are experiencing the most stress due to the hormonal changes associated with calving and the excessive demands of milk production. Proper nutrition both pre-calving and post-calving will aid in the prevention of overstressing the immune system. A healthy immune system will help in preventing mastitis. Mastitis is considered to be the most costly disease affecting the dairy industry. One study concluded that 1/3 of all dairy cows will experience mastitis in at least one quarter. Lost milk production was estimated to be over 800 pounds of milk during a lactation.
The costs associated with mastitis go beyond just the loss of milk production and the discarded milk. With the costs of medicine, veterinary costs and extra labor, total costs to a dairy farmer easily tops $200 with today’s prices. Preventing and quickly treating mastitis must always be one of the top management priorities on a dairy.
Mastitis, simply defined, is an infection in the mammary gland. For cows and heifers, bacteria must gain access to the inside of the udder by way of the teat canal and infect the mammary tissue, causing an inflammation.
The milk ducts and tissue surrounding the ducts recognize this infection and respond by bringing white blood cells (also known as somatic cells) to the infection. In the presence of too many antibodies, milk is ruined, no longer fit for human consumption.
Minimizing and curing a mastitis infection is highly dependent upon the health of a cow’s immune system. Her immune system provides the pathway by which somatic cells are activated and sent to an infection site.
If the somatic cells or antibiotics are not able to destroy the mastitis-causing pathogens, mammary tissue is damaged and, if the infection is severe enough, that portion of the udder’s ability to produce milk will be seriously affected. This is where we get our light quarters and three-titters.
This article will focus on nutritional strategies that help bolster a cow’s immune system, enabling her to fight off mastitis challenges. It goes without saying that much of the prevention of mastitis also must be focused on the cleanliness of a cow’s housing environment as well as the all-important cleanliness of the milking parlor and properly maintained milking equipment.
If cows are routinely challenged with manure and dirt on the udder and are subjected to improper milking procedures, they will get mastitis no matter what the plane of nutrition is.
It’s well known that fresh cows are energy-deficient at the time of calving, and energy plays a significant role in immune health. In fact, there are three factors that work together to negatively affect immunity at the time of calving.
1. There is a surge in cortisol, an immunosuppressive chemical found in all mammals.
2. There is a decline in feed intakes which causes a spike in NEFA and ketone levels that can result in ketosis.
3. Calcium metabolism is often affected, resulting in milk fever and other calcium-related metabolic disorders.
Any level of immune response to infections requires more energy from the cow. If dry cow and close-up diets are not supplying enough energy, a fresh cow cannot mount an adequate immune response to an infection.
Cows in a negative energy balance will attempt to compensate for it by mobilizing body fat. Body fat must be converted from its triglyceride form to a usable form of glucose, and this must be done in the liver – again requiring energy. The cow’s liver has a limited capacity to convert a lot of fat and when too much fat is sent to the liver, some of the fat will become ketone bodies which bind with glucose receptors, preventing glucose absorption.
The immune system is suppressed by the onset of ketosis and the lack of energy to the cow’s systems. Calories (mcals) from the diet are critical to keeping fresh cows healthy and productive.
Calcium metabolism is critical to both muscle and cellular function. It’s well known that calcium must be present for muscles to work properly. That’s why a cow can’t stand up when she has a clinical case of milk fever. Subclinical milk fever will impact rumen function and involution of the uterus.
It’s now known, as well, that calcium plays a significant role in the immune function at the cellular level. Therefore, calcium must be mobilized and absorbed in copious amounts at the time of calving and early into lactation.
Calcium mobilization from the bones occurs in the presence of an acidic (anionic) charge in the blood stream. This is accomplished by the feeding of anionic salts in the diet. A negative dietary cationic-anionic difference (DCAD) must be present for proper calcium metabolism.
Dr. Mike Hutjens, a dairy specialist at the University of Illinois, reports a 10-to-1 benefit-to-cost ratio with the use of anionic salts in pre-fresh diets. The cost of anionic salts will range from 40¢ to 75¢ per dry cow per day. He recommends dietary calcium be 100 grams per cow per day during the three-week close-up period.
Ketosis can occur in both underconditioned and overconditioned cows if they are mobilizing body fat too rapidly. Dr. Hutjens recommends the use of rumen-protected choline to manage fatty liver problems.
Rumen-protected choline should be fed at 15 to 30 grams per cow per day up to two months post-calving. Rumen-protected choline offers a benefit-to-cost ratio of 2 to 1 and will cost the dairy farmer about 30¢ per cow per day.
Organically bound and chelated forms of zinc, manganese, copper and cobalt are available and highly recommended to help bolster the immune systems of close-up and fresh cows, enabling them to fight off infections. These products offer greater bio-availability than their sulfate and oxide counterparts.
Selenium and Vitamin E used in combination during transition are well researched in supporting immune function in close-up and fresh cows. Selenium is federally regulated in dairy feeds, so care must be taken in its use. An organic version of selenium is now on the market which is more bio-available to the cow.
The one hundred days that a cow is in transition as a close-up and into early lactation is certainly the most stressful and critical part of her life and lactation. How she is taken care of during that time will determine how healthy and profitable she will be during the current lactation and all the others that follow.
As we seek to improve efficiencies in a volatile dairy economy, a relatively small investment at the time of transition will improve udder health as well as overall health and immune status, greatly reducing mastitis and other metabolic challenges. PD
References omitted due to space but are available upon request to editor@progressivedairy.com .
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John Hibma
- Nutritionist
- Email John Hibma
