Lecture50 - Lecture 50: Lecture 50: Minerals Macro Minerals...

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Unformatted text preview: Lecture 50: Lecture 50: Minerals Macro Minerals Macro Minerals S, Na, K, Cl, and Mg Sodium and Chlorine Sodium and Chlorine Common salt 80% of NaCl entering GIT is from internal sources Most likely mineral to be deficient when animals are not supplemented Low in both forages and grains Used in supplementation programs Increase intake of mineral suppl. Limit intakes of energy and protein suppl. NaCl Metabolism NaCl Metabolism Virtually all NaCl absorbed Primary functions in body: Buffer rumen through saliva Maintain acid­base balance Excesses: Some absorption in rumen Majority in upper small intestine Not a problem with ample water supply Prevent urinary calculi Deficiencies: ↓ production ↓ feed intake feed intake Potassium Potassium Concentrations in feeds vary widely Antagonistic to Na Regulation of Na:K Aldosterone and antidiuretic 3rd most abundant mineral in the body Largely intracellular (98%) Absorbed via diffusion in SI Not stored, must be supplied daily Deficiency ↓ feed intake and ↓ milk production feed intake and Magnesium Magnesium Typically higher in forages then grain EXCEPT: early spring forages Leads to grass tetany or hypomagnesemia Females more susceptible Treat with IV or enema Absorption occurs throughout GIT Most in rumen and omasum Toxicity Severity closely related to intensity of diarrhea Sulfur Sulfur Critical to avoid deficiencies in ruminants ↓ bacteria in rumen, changes species bacteria ↓ performance death performance Toxicity Toxicity ↓ both Cu and Zn absorption both Cu and Zn absorption Converts to hydrogen sulfide in rumen Binds with Mo thiomolybdates Form insoluble complexes with Cu in rumen ↓ Cu absorption independently via Cu sulfides May cause polioencephalomalacia (PEM) May polioencephalomalacia ( Trace Minerals Trace Minerals Essential trace minerals Essential trace minerals Necessary in the diet for growth and production These include: Cobalt Copper Iodine Iron Manganese Molybdenum Selenium Zinc Newer trace minerals Newer trace minerals May be necessary in the diet for growth and/or production Discovered since the 1970’s Not as well studied These include: Aluminum, Arsenic, Boron, Bromine, Fluorine, Germanium, Lead, Lithium, Nickel, Rubidium, Silicon, Tin, Vanadium Trace mineral deficiencies Trace mineral deficiencies Primary Animals are consuming inadequate concentrations of the trace mineral Secondary Animals exhibit signs of deficiency even though they are consuming due to an antagonistic effect by another element Trace mineral deficiencies Trace mineral deficiencies Secondary Examples: High [Mo] and [S] induce a Cu deficiency High [S] can produce Cu and Se deficiencies Overcome deficiencies by increasing concentration of trace mineral in the diet Forms of trace minerals Forms of trace minerals Inorganic Can have lower bioavailability, supplement at higher concentration Less expensive i.e. Copper oxide, Zinc sulfate etc. Organic (chelated) Typically better bioavailability Often bound to an amino acid More expensive i.e. Copper lysine, SelPlex Cobalt Cobalt Required by rumen microbes Used to synthesize Vit B12 If deficient: succinate builds up because the microbes can not convert it to propionate Decreased gluconeogenesis Molybdenum and Copper Molybdenum and Copper Mo is readily absorbed while Cu is poorly absorbed In the presence of S, ↑ Mo causes Cu Mo causes Cu deficiency Ruminants ↑ susceptible to Mo­Cu imbalance Low Cu in grazed forages Cu deficiency will cause: Achromotrichia lack of hair/wool pigment Swayback effect on CNS Anemia necessary for hemoglobin syn. Etc. Normal Normal Cu deficient on cti je in u r C te af th on 1 m Selenium Selenium Originally thought to be toxic Linked to many production issues: Narrow range between def. and toxicity Se uptake by plants ↑ on alkaline soils on alkaline soils White muscle disease Retained placentas Metritis uterine inflammation Component of glutathione peroxidase Important antioxidant Leg of lamb with Leg of lamb with lesions on right Heart affect by WMD Zinc Zinc Storage in body low Critical for male fertility in particular Zinc sulfate or zinc oxide Organic more available Also ↓growth and appetite growth and appetite Parakeratosis flaking skin Vit A metabolism mobilization from liver Inorganic forms Deficiency signs < 1 week Zinc methionine Ca is especially antagonistic to Zn Iodine goiter Iodine Trace mineral supplementatio Trace mineral supplementatio Free choice, loose mineral premix for grazing beef cattle Covered mineral feeder Should contain 20­25% NaCl and 8­12% P Many interaction/antagonisms between minerals that affect avail. Most common to overfeed slightly to include a margin of safety ...
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