Influence of high levels of dietary zinc in milk performance and biochemistry of lactating cows

Journal Article · Fri Jan 01 04:00:00 EST 1965 · J. Dairy Sci.; (United States)

DOI:https://doi.org/10.3168/jds.S0022-0302(65)88251-0· OSTI ID:5145523

Miller, W J; Clifton, C M; Fowler, P R; Perkins, H F

Twenty-four lactating dairy cows were fed either a) 0, b) 500, c) 1000, or d) 2000 ppm of supplemental zinc (as ZnO) in the concentrate portion of the diet for 6 wk. Coastal Bermudagrass and Sudan grass silages were fed ad libitum as the only source of forage and constituted 43% of dry matter intake. Average zinc contents of the total dry matter of the four groups were: a) 44, b) 372, c) 692, and d) 1279 ppm. The level of supplemental zinc did not significantly affect milk production; FCM production; fat, SNF, protein, or magnesium content of milk; voluntary forage dry matter intake; body weight changes; blood hemoglobin; packed cell volume; blood serum lactic dehydrogenase; blood scrum alkaline phosphatase; or apparent animal health. The addition of the supplement zinc materially increased the zinc content of the milk. However, the higher levels had progressively less effect with the milk from cows given 1000 ppm supplemental zinc containing as much zinc as those fed 2000 ppm. The average ppm of zinc in the milk of the four groups were: a) 4.2, b) 6.7, c) 8.0, and d) 8.4. Recoveries of zinc in the milk as percentages of dietary zinc were: a) 12.5, b) 2.2, c) 1.6 and d) 0.8 for those fed the four levels of zinc. The blood plasma zinc concentration increased with increasing levels of supplemental zinc. The values were: a) 2.1, b) 3.2, c) 4.0, and d) 7.5 ppm. Thus, the zinc concentrations increased at a much more rapid rate in plasma than in milk. This suggests that the udder is discriminating against zinc at the higher dietary and blood levels. 14 references, 2 tables.

• Research Organization: Univ. of Georgia, Athens
• OSTI ID: 5145523
• Journal Information: J. Dairy Sci.; (United States), Journal Name: J. Dairy Sci.; (United States) Vol. 48; ISSN JDSCA
• Country of Publication: United States
• Language: English

Related Subjects

560305* -- Chemicals Metabolism & Toxicology-- Vertebrates-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE PHOSPHATASE
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL FUNCTIONS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CHEMISTRY
BLOOD PLASMA
BODY
BODY FLUIDS
CATTLE
CHEMICAL COMPOSITION
COWS
DOMESTIC ANIMALS
DOSE-RESPONSE RELATIONSHIPS
ELEMENTS
ENZYMES
ESTERASES
FEEDING
FOOD
FUNCTIONS
GLANDS
HYDROLASES
INGESTION
INTAKE
LACTATION
MAMMALS
MAMMARY GLANDS
MATERIALS
METABOLISM
METALS
MILK
ORGANS
PHOSPHATASES
RUMINANTS
VERTEBRATES
ZINC