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Effect of zinc from zinc
sulfate on trace mineral concentrations of milk in Varamini
ewes
A. Zali and M. Ganjkhanlou*
Department
of Animal Science, Faculty of Agronomy and Animal Science,
University of Tehran, P.O. Box#3158711167-4111, Karaj, Iran.
*Corresponding author: E-mail:
mganjkhanloo@yahoo.com. Tel.: 09125129045. Fax:
0261-2246752.
Abbreviation: BW, body weight; DMI, dry matter intake.
Accepted
7 September, 2009 |
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This study was conducted to evaluate
the
effect of feeding supplemental zinc (zinc sulfate) in
different levels (15, 30, or 45 mg/kg) on trace mineral
concentrations in milk of ewes. Thirty lactating Varaminni
ewes were assigned to three experimental groups according to
their live body weights, milk production and lambs sex in a
completely randomized design. Ewes were fed a basal diet
containing alfalfa, wheat straw, cottonseed meal, barley
grain, wheat bran, cracked corn and vitamin-mineral
supplements at 3.2% of body weight (BW) to meet NRC
requirements for protein, energy and macro minerals. The
basal diet contained 15 mg/kg Zn and zinc sulfate was added
to the basal diet to supply 30 or 45 mg/kg of dietary zinc.
Daily milk yielded was recorded
at 7
days intervals
and samples of the milk were taken once per week for
determination of milk composition and trace mineral
concentration. Concentrations of Zn, Cu, Mn and Fe in milk
were determined. Dry matter intake (DMI), milk yield and
milk compositions were not affected by supplemental zinc
(P > 0.05).
But zinc
concentrations in milk were affected by supplemental zinc
(P <
0.05).
Other
mineral concentrations were
not affected by supplemental zinc
(P > 0.05).
It suggests
that supplementation of ewes diet with zinc sulfate could be
an effective way to increase zinc concentration in milk when
zinc concentration of basal diets is limited for ewes in
lactation period.
Key
words:
Supplemental zinc, zinc sulfate, Varaminni ewes. |
