Zinc deficiency and the zinc requirements of calves and lambs

Abstract

I . The effects of changes in zinc intake on weight gain, plasma Zn concentration and the development of clinical lesions of Zn deficiency have been studied in Zn depletion and repletion studies with calves and lambs.2. A basal diet, the principal components of which are urea, dried egg white, starch, glucose, cellulose and arachis oil has been developed for trace element deficiency studies with ruminants.3. Weight gain ceased abruptly in both calves and lambs when either the unsupplemented basal diet was given or when Zn supplements provided only 0.05 mg Zn/kg live weight per day. Mean plasma Zn concentrations in these animals fell from pre-experiment values of between 0.8 and 1.2 yg Zn/ml to below 0.4 pg Zn/ml after I week on these treatments.4. Supplements providing 0.2 mg Zn/kg live weight per day were sufficient to maintain a good rate of growth but insufficient to prevent a fall in plasma Zn. Growth arrest occurring within z weeks and a rapid fall in plasma Zn occurring withinI week after Zn supplements were withheld from calves and lambs that had previously received 0.7 mg Zn/kg live weight per day for 6 and 14 wceks respectively indicated that these species have only a limited capacity to store Zn in a form that can be utilized during periods of inadequate Zn intake.6. Tentative estimates are presented of the Zn requirements of calves maintained on this type of basal diet and the influence of ration composition on Zn availability is discussed.7. The possible value and the limitations of plasma Zn determination as an aid to the field diagnosis of Zn deficiency are considered.

Grazing Cow and Calf Responses to Zinc Supplementation1

“…However, Zn absorption is not reduced when ruminants are fed diets containing soybean meal and 1.5% Ca (Mills et al, 1967;Kincaid, 1979). Weight gain response to Zn supplementation in the present study was similar when either soybean meal or cottonseed meal was fed (tables 1 and 2).…”

“…The mean plasma Zn values of .81 to .S pg/ml, (table 5) measured in this study are the low end of the range, .8 to 1.2 mg/ml, d cribed by Mills et al (1967). They are slightly lower than median plasma Zn 1ev measured in grazing cattle, some of which h clinical signs of Zn deficiency (Spais Papasteriadis, 1973 (Aug. 20, 1974;Sept.…”

“…Zn deficiency in cattle, especially calves, has been produced experimentally with semipurified or purified diets (Blackmon et al, 1967;Mills et al, 1967). From these studies, research-_ ers concluded that the Zn requirement for young calves was not more than 8 to 12 ppm.…”

Abstracts of Communications

“…Eighteen Border Leicester x Cheviot lambs were weaned when 2 months old on to a semi-synthetic basal diet (Mills, Dalgarno, Williams & Quarterman, 1967) supplemented with 18 ppm Zn. They were randomized by weight into three groups of six.…”

Hepatic copper–and zinc-binding proteins in ruminants

“…Sheep livers were obtained mainly from animals fed on a semi-synthetic ration (Mills, Dalgarno, Williams & Quarterman, 1967) with a Zn content of 40 mg/kg ('normal-Zn', five samples) and < I mg/kg ('Zn-deficient', three samples). The following materials were used: Sephadex (2-75 and blue dextran (Pharmacia Ltd, Uppsala, Sweden), Chelex-100 (Bio-rad Laboratories, Richmond, California).…”