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What are the 2 ways to minimize immunosuppression around calving?
- reduce immunosuppressors: ketones and NEFAs are potent immunosuppressors--> prevent ketosis and HypoCa
- promote stronger immune system: adequate vitamins and trace minerals- antioxidants
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Diets that promote high NEFAs cause depressed __(2)__ function; promote high BHBA depresses _________ function; promote hypoCa depresses _________ function.
PMNs and lymphocytes; PMNs; lymphocyte
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The predominant cells in an uninfected mammary gland are __(2)__; the predominant cells in a mastitic mammary gland are _________.
macrophages and lymphocytes; PMNs
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What nutrient affects migration of neutrophils?
- Selenium
- cows with Se deficiency respond much slower to infection (ie. don't fight it off and get clinical mastitis)
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What is oxidative stress?
antioxidant capacity is exceeded by reactive oxygen and nitrogen species (free radicals)--> depressed immune cell function
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If your cows ___________, you will need to supplement Vit E.
are not on pasture
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What are the antioxidant nutrients, and which of these nutrients are most likely to be deficient in a diet? (8)
- Selenium, Vit E, Copper
- Zinc, beta-carotene, Manganese, Iron, Vit C
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Describe how antioxidants are phase specific and which nutrient antioxidant is most important in each phase.
- Water soluble versus fat soluble
- Vit E is the major fat soluble vitamin
- Se and Cu are the most important water-soluble antioxidants
- [technically Vit C is the most important water soluble vitamin, but diets are almost NEVER deficient in Vit C, so we don't worry about ]
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What are the pro-oxidants, and what does this mean?
- Se, Cu, and Fe
- they themselves are not technically antioxidants, but they increase antioxidant enzymes
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What is important to remember about nutrition and immune function?
- you need adequate vitamins and trace minerals
- BUT don't just start throwing them in the feed; too much (Cu, Fe) will cause immune depression
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What is the goal for Vit E in the feed?
- in confinement housing-1000 IU/day
- pre-fresh need 2000-4000IU/day
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What is the goal for Se in a diet?
- all diets 0.3ppm supplemental Se (the Se in the feeds is inert...don't count it)
- this is a legal limit because Se is carcinogenic
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What Se supplements are used in pre-fresh versus lactating cow diets?
- Pre-fresh- Se-yeast
- Lactating- selenite/selenate
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Why are yearly water tests important? What values should we evaluate? (3)
- sulfate/ sulfur: increase S causes Cu deficiency
- iron: increased iron causes immune deficiency
- nitrate: increased nitrate causes oxidant damage
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What is the most toxic trace mineral?
- Copper- do not go overboard!
- ~15ppm TOTAL
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