$sup 65$Zn metabolism, secretion into milk, and biological half-life in lactating cows

Journal Article · Sat Dec 01 04:00:00 EST 1973 · J. Dairy Sci., v. 56, no. 12, pp. 1526-1530

OSTI ID:4387624

Neathery, M W; Miller, W J; Blackmon, D M; Gentry, R P

Following oral dosing, zinc-65 metabolism was studied in 10 first- lactation Holstein cows during the 5th and 6th wk of an experiment in which a high beet pulp, low-zinc diet (16.6 ppM) was fed without and with (39.5 ppM total zinc) supplemental zinc. For the 14 days after dosing, cows fed low zinc had a much higher net zinc-65 absorption (53.4 versus 34.8%) and consistently secreted far more zinc-65 into milk (14.4 versus 6.3%). The zinc secreted into milk of cows fed low zinc during the 14 days had been in the body a shorter time than in controls, indicating greater dependences on recently consumed zinc for secretion into milk, The biological half-life (in lactating ruminants defined as the time required for one-half of the zinc-65 dose to leave the body via feces and milk) was shorter for the cows fed low zinc. Lactating cows are able to absorb a high percentage of dietary zinc, and lactation is a major factor in zinc metabolism and homeostasis. Major changes in zinc metabolism occur before performance is affected. (auth)

• Research Organization: Univ. of Georgia, Athens
• NSA Number: NSA-29-016070
• OSTI ID: 4387624
• Journal Information: J. Dairy Sci., v. 56, no. 12, pp. 1526-1530, Journal Name: J. Dairy Sci., v. 56, no. 12, pp. 1526-1530; ISSN JDSCA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

*ZINC 65-- METABOLISM
BIOLOGICAL EFFECTS
CATTLE
CONTAMINATION
DIET
HOMEOSTASIS
LACTATION
N48720* --Life Sciences--Nuclide Kinetics & Toxicology-- Animals
SECRETION