title: [The vitamin A requirement and the vitamin A status of growing cattle. 1. Studies of calves].
abstract: Five experiments with 18 to 36 male calves each of the black and white dairy cattle breed (age: 14-21 days, initial live weight: approximately 45 kg per animal) were carried out in order to investigate the influence of various vitamin A supply (0-80,000 IU per 100 kg LW and day) on dry matter intake and weight gain as well as the vitamin A status of liver and blood plasma over 84 days. The calves consumed a diet free of carotene and vitamin A consisting of milk replacer, concentrate and chopped wheat straw. The calves were fed in three experiments for a longer time in order to observe the further vitamin A depletion. Nine animals consumed an unsupplemented ration, nine other one got 10,000 IU vitamin A per 100 kg LW and day. Biopsies of liver and plasma samples were taken from 4 animals per group every four weeks. The various vitamin A supplementation did not significantly influence the dry matter intake (Mean: 1.67; 1.48 to 1.80 kg DM per animal and day) and the weight gain of calves (Mean: 702, 599 to 770 g per animal and day). First vitamin A deficiency symptoms (reduced feed intake, decreased weight gain, diarrhoea etc.) were observed in animals of unsupplemented group after 100 days of experiments. After 84 days the vitamin A concentration of liver of animals of unsupplemented groups decreased to 1.3-32.2% compared with the begin of experiments (60.6-155.7 mumol/kg fresh matter). Up to 51% of initial concentration were found when 10,000 IU vitamin A per 100 kg LW and day were fed. About 25,000 IU vitamin A per 100 kg LW and day were required in order to keep the initial level of vitamin A concentration of liver. The plasma vitamin A concentration is unsuitable for estimation of vitamin A status of calves. The concentration of vitamin A of liver and plasma amounted to 114 mumol per kg and 0.25 mumol per litre at the begin of experiments. The vitamin A concentration of liver of unsupplemented group decreased to 20 mumol per kg, that of plasma increased to 0.28 mumol per 1 at the end. A strong vitamin A deficiency (liver concentration: less than 10 mumol/kg) may cause a decrease of vitamin A concentration of blood.
authors.affiliation: Karl-Marx-Universität Leipzig, Sektion Tierproduktion und Veterinärmedizin, Wissenschaftsbereich Tierernährungschemie.
authors.forename: G
authors.initials: G
authors.lastname: Flachowsky
authors.forename: H
authors.initials: H
authors.lastname: Wilk
authors.forename: H J
authors.initials: HJ
authors.lastname: Löhnert
authors.forename: W I
authors.initials: WI
authors.lastname: Ochrimenko
authors.forename: D
authors.initials: D
authors.lastname: Geinitz
authors.forename: A
authors.initials: A
authors.lastname: Hennig
mesh_terms: D000821:Animal Feed; D000818:Animals; D002417:Cattle / Q000254:growth & development*; D004032:Diet; D004435:Eating; D008099:Liver / Q000032:analysis; D008297:Male; D014801:Vitamin A / Q000008:administration & dosage* / Q000032:analysis / Q000097:blood; D015430:Weight Gain
chemical_list: D014801:Vitamin A
vernacular_title: Untersuchungen zum Vitamin-A-Bedarf und zum Vitamin-A-Status wachsender Rinder. 1. Mitteilung. Untersuchungen an Kälbern.