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1、Vitamins in Ruminants,Organic compounds required in trace amounts for biological processes Vital amine Fat soluble A, D, E, and K Absorbed with lipids Water soluble C, B family,Vitamins,Vitamins,Fat soluble Vitamins A, D, E and K Water soluble Thiamine, niacin, riboflavin, pyridoxine, pantothenic ac
2、id, biotin, folic acid, vitamin B12, vitamin C, choline Water soluble vitamins and vitamin K synthesized in the rumen or in body tissues Dietary requirements: Vitamins A, D, and E,Vitamin Nutrition of Ruminants,Important Some vitamins must be supplemented in the diet Several aspects of vitamin nutri
3、tion unique to ruminants 3. Likely will be more important: As productivity of ruminants is increased With increased confinement of animals References Chapter 7 Dairy NRC 2001 Chapter 6 Beef NRC 1996,Vitamin Requirements of Ruminants,Ruminants require the same vitamins as monogastric animals at cell
4、level Prior to rumen development young ruminants require dietary sources of vitamins Colostrum and milk Concentration of vitamins in colostrum is greater than in milk Calves need to be fed vitamins if they are being fed milk replacers with nonmilk protein,Vitamin Requirements of Ruminants,Mature rum
5、inants have dietary requirement for: Vitamins A, D, and E Vitamin D in feed or from UV exposure B vitamins usually not supplemented in ruminant diets High producing dairy cows sometimes benefit from supplementation with B vitamins Mixtures of biotin, niacin, riboflaven, panothenic acid, thiamin, and
6、 B12,Inadequate Dietary Vitamin Intakes,Low concentrations in feeds Harvesting and agronomic effects Processing and storage effects Humidity, heat, light, pH, minerals, pelleting Reduced feed intake Bioavailability B-vitamins affected more than fat soluble Level of production Increased grain intake,
7、 increased feed intake, increased rate of passage, reduced rumen function Rearing in confinement out of sunlight Stress and disease Decreased feed intake, increased requirement,Factors Influencing Vitamin Stability,+ = stable - = unstable ( ) = tocopheryl acetate,Circumstances Affecting Vitamin Nutr
8、ition,Vitamin antagonists of importance to ruminants Dicumarin (Dicumarol) Found in moldy sweet clover - Blocks the action of vitamin K (Depresses formation of thrombin) Animals can bleed internally Rancid fats Destroys vitamins A, D, and E Thiamin antagonists Thiaminase - may develop in the rumen A
9、mprolium blocks absorption Sulfur may destroy thiamin in the rumen,Situations for Supplementing Vitamins,Vitamin A (Retinol),Vitamin of most practical importance in ruminant feeds. Deficiency most likely: High concentrate feeds (low forage) Large amounts of fermented feeds Mature - drought pastures
10、Long stored feeds Sunlight, air, high temperatures Heavily processed feeds Some destruction of vitamin A in the rumen Increases when concentrates are fed Forage diets 20%Grain diets up to 70%,-Carotene,Provitamin A found in many plants Mostly in the vegetative parts of plants Decreases as plants mat
11、ure Decreases with time in storage Some destruction in the rumen (0 to 35%) Converted to retinol by enzymes in intestinal mucosal cells Some absorption of -carotene Ruminants do not efficiently convert carotene to vitamin A 1 mg carotene = 400 IU vitamin A,Vitamin A,Deficiency Reduced feed intake -
12、slow growth Rough hair coat Edema of joints and brisket Watery eyes Night blindness Retinol needed for synthesis of rhodopsin Low conception Still births Function of immune system,Functions Normal night vision ,Vitamin A,Vitamin A,Requirements Cattle IU/kg feed DM Growing2,200 Pregnant beef cows2,80
13、0 Pregnant dairy cows4,000 Lactating cows3,900 Sheep Growing lambs1,500 Gestating ewes3,300 Lactating ewes2,700,Vitamin A,Requirements Dairy cattle Growing: 80 IU/kg body wt Adult: 110 IU/kg body wt Supplemental Vitamin A (retinol) 1 IU of Vit A activity = 0.344 ug of all-trans retinyl acetate 0.550
14、 ug all-trans retinyl palmitate,Vitamin A When to Supplement?,Carotene content of feeds is variable and usually unknown Cost of supplemental vitamin A is low so usually should supplement Exception is animals grazing green forages Should be consuming adequate carotene Increased exposure to infectious
15、 pathogens Times when immunocompetence may be reduced,Vitamin A Reserves in the Body,Vitamin A stored in the liver when intake of vitamin A or carotene is high Vitamin A in the liver has about 4 week half life Should not depend on more that 2 to 4 months of protection from storage of vitamin A in th
16、e liver Ruminants have a high tolerance for vitamin A Will tolerate 66,000 IU/kg feed,Vitamin D,Ergocalciferol (Vitamin D2) - found in plants Cholecalciferol (Vitamin D3) - found in animals Photochemical conversion in skin: 7-dehydrocholesterolCholecalciferol Liver (Sequesters Vit D3) Vit D3 25-hydr
17、oxy-vit D3 Circulating form of Vit D3 Blood concentrations of 25-hydroxy-vit D3 indication of vitamin D status of the animal Kindney 25-hydroxy-vit D3 1, 25-dihydroxy-vit D3 Active form of vitamin D Active on skeleton and intestine Potentiates action of parathyroid hormone,Vitamin D from UV exposure
18、,Active Vit D3,Vitamin D3,Low blood Ca (or P) increases parathyroid hormone secretion Parathyroid hormone increases production of 1,25-dihydroxy-vit D3 in kidney Increases resorption of bone Ca and P Involved in: Absorption of Ca and P and mobilization of Ca and P from bone Regulation of blood Ca an
19、d P Immune cell function Reproduction of males and females,Vitamin D - Ruminants,Deficiency Rickets in calves Swollen and stiff joints Reduced feed intake Tetany Weak bones Vitamin D can be toxic High blood Ca Calcification of soft tissues Loss of appetite Vitamin D not stored in the body in any qua
20、ntity,Vitamin D - Requirements,Requirement IU/kg Feed DM All beef cattle275 Growing lambs185 Gestating ewes216 Lactating ewes148 Lactating dairy30 IU/kg body wt Dry pregnant cows30 IU/kg body wt Generally recognized as more than required Animals fed sun cured hays and/or kept in sunlight have limite
21、d needs for supplemental vitamin D Dairy NRC does not give credit to feed and sunlight as sources of vitamin D,Vitamin D Toxicity,Safe feeding levels: A few days - 25,000 IU/kg feed 60 days - 2,200 IU/kg feed Toxicity Loss of appetite Weight loss Reduced rumination Depression Widespread calcificatio
22、n of soft tissue Kidneys, heart, pancreas, lymph glands, lung alveoli Inflammation Demineralization of skeletal system,Feeding Mega Doses of Vitamin D,Prevent milk fever 20 million IU/d starting 3 to 5 days before calving continuing through the fist day postpartum Improve tenderness of beef Assumpti
23、on: Increased blood and muscle Ca increases activity of calpains, enzymes in muscle that degrade muscle myofibrils Observations: Blood Ca increased Increased degradation of myofibrils Reduced force to shear muscle,Vitamin E,-tocopherol is the most common form of vitamin E in feeds Vit E content of f
24、eeds is highly variable Vit E decreases in forages with drying and storage Most fresh forages excellent source of Vit E Most grains have low concentrations of Vit E Heat treatment destroys most of the Vit E Supplemental form of vitamin E is DL- -tocopherol The esterified form is more stable than the
25、 alcohol Rumen metabolism is minimal 1 IU = 1 mg DL- -tocopherol,Vitamin E,Functions as an antioxidant and involved in Maintenance of cell membranes Immunity Reproduction Deficiency White muscle disease Weak muscles Retained placenta Reduced reproduction Reduced disease resistance Toxicity not demon
26、strated in ruminants Vitamin E not extensively stored in the body,Vitamin E - Dairy - 2001,1. Dry cows 60 days before calving 80 IU/kg feed DM Based on reduction of mastitis and immune function Higher amounts needed for fetus and to increase concentration in colostrum 2. Lactating cows 20 IU/kg feed
27、 DM Needs to be increased when poor quality forage is fed or if feeds have low Se content Supplement Se if low in soils 3 to 5 mg /d for dry cows 6 to 8 mg/d for lactating cows,Vitamin E - Beef & Sheep,Requirement IU/kg feed DM All beef cattle 15 to 60 Pregnant and lactating cows20 Growing heifers25
28、 All sheep15 Related to adequacy of selenium Vitamin E not transferred across placenta to fetus Dependent on colostrum for dietary source Feedlot cattle Feed 500 IU/day for 100 days. Extend shelf life of beef cuts in the sales case,Vitamin K,Vitamin K is a generic term describing a group of quinone
29、compounds Phylloquinone (vitamin K1) Found in chloroplasts of plants Menaquinone (vitamin K2) Synthesized by rumen bacteria Menadione (vitamin K3) Synthetic form used for supplementing vit K,Vitamin K,Required for synthesis of four blood clotting factors Prothrombin, factors VII, IX, and X Involved
30、in blood clot formation No established supplemental requirement for ruminants Microbial synthesis and vit K in feeds Deficiency limited to: Cattle consuming moldy sweet clover have prolonged clotting of blood - “sweet clover disease” A fungus produces dicoumarol that is a metabolic antagonist of vit
31、amin K Stiffness and lameness Uncontrolled bleeding hematoma of tissues,Other Water Soluble VitaminsNot required in diet of ruminants,Ruminants with functional rumen obtain water soluble vitamins from the digestive tract Niacin- Supplementation may benefit high Biotin - producing animals Folic acid
32、- Vitamin B12 Synthesized in rumen if Co present, not present in feeds Vitamin C - Not synthesized in cattle until about 3 wks Riboflavin Pyridoxine Pantothenic acid Choline,Supplementation of B Vitamins,Prevent overt deficiency symptoms Probably occur only in calves fed milk replacers 2. Prevent su
33、bclinical deficiencies Optimum production Impact of stress on immune system Niacin - May benefit early lactation cows Biotin - May benefit herds with high incidence of hoof lesions Folic acid - Might increase milk production Cobalt - B12 - (methylmalonyl CoA mutase) utilization of propionate, foliat
34、e metabolism, milk yield B-vitamins - immune function of stressed cattle,Thiamin,1. Adequate quantities normally produced by the bacteria in the rumen 2. Inadequate thiamin Thiaminase and thiamin antimetabolites produced in ruminants fed rapidly fermented diets Infrequently polioencephalomalacia (PEM), a disorder of the central nervous system develops Retracted head, weakness, collapse, blindness are symptoms Respond to administration of thiamin,