Concentrations of plasma copper and zinc and blood selenium in ewes and lambs of Merino, Dohne Merino and SA Mutton Merino sheep

Abstract

Concentrations of plasma copper and zinc as well as blood selenium were determined in single and twin lambs and their dams for a period of 120 days from the birth of the lambs, using Merino, Dohne Merino and SA Mutton Merino sheep. The ewes and their lambs were kept on the same pastures and received the same feed supplementation. Plasma concentrations of copper and zinc were respectively 50% lower and 40% higher in new-born lambs, but both returned to adult concentrations within the next 14 days. Concentrations of blood selenium in lambs throughout the preweaning period were lower than those of the ewes. Blood concentrations of selenium in lambs of all three breeds declined rapidly during the first eight weeks after birth. At the age of six months, Merino ram lambs displayed higher (P ≤ 0,05) plasma copper and blood selenium concentrations but lower (P ≤0,05) concentrations of plasma zinc than did Dohne Merino or SA Mutton Merino ram lambs.

Plasmakoper-, plasmasink- asook bloedseleniumkonsentrasies is by ooie en hul enkel- of tweelinglammers vanaf geboorte tot op 'n ouderdom van 120 dae bepaal. Merino-, Dohne Merino- en SA Vleismerino-skape is gebruik. Ooie en lammers van al drie rasse is op dieselfde tipe weiding met dieselfde aanvullende voeding gehou. By geboorte was die plasmakoperkonsentrasies van die lammers ongeveer 50% laer, en die plasmasinkkonsentrasies ongeveer 40% hoër as dié van die ooie. Hierdie konsentrasies by die lammers het egter binne 14 dae verander tot normale konsentrasies van volwasse skape. Bloedseleniumkonsentrasies van lammers was tydens die voorspeense periode deurgaans laer in vergelyking met dié van ooie. Bloedseleniumkonsentrasies van lammers van al drie rasse het 'n skerp daling tydens die eerste agt weke na geboorte getoon. Merino-ramlammers het op 'n ouderdom van ses maande hoër (P ≤0,05) plasmakoper- en bloedseleniumkonsentrasies, maar laer (P ≤ 0,05) plasmasinkkonsentrasies as Dohne Merino- en SA Vleismerino-ramlammers gehad.

Keywords: Breed, ewes, lactation, lambs, trace elements.