Growth, reproductive performance, and manganese status of heifers fed varying concentrations of manganese1,2

Abstract

An experiment was conducted to examine the effects of dietary Mn on growth, reproductive performance, and Mn status of beef heifers. Eighty Angus (n = 40) and Simmental (n = 40) heifers, averaging 249 kg, were stratified by BW within a breed and randomly assigned to 1 of 4 treatments providing 0 (control), 10, 30, or 50 mg of supplemental Mn/kg of DM from MnSO(4). Heifers were individually fed a diet containing cottonseed hulls, corn gluten feed, citrus pulp, and ground corn, and the control diet contained 15.8 mg of Mn/kg of DM by analysis. Average daily gain, DMI, and G:F for the 196-d period were not affected by Mn supplementation. Control heifers had reduced (P = 0.04) liver Mn when contrasted with the 3 levels of supplemental Mn. Serum cholesterol was greater (P = 0.001) in Angus compared with Simmental heifers over the course of the 196-d experiment but was not affected by treatment. Dietary Mn did not significantly affect measures of reproductive performance. Results of this study indicate that 15.8 mg of Mn/kg of diet DM should be adequate for growth, onset of estrus, and conception of beef heifers.

Blood biochemical profile of Sudanese crossbred repeat breeder cows

“…However, in a more recent study, it is reported that treating heifers with different concentrations of Mn did not affect the serum cholesterol (Hansen et al, 2006). This study indicates that even low serum levels of Mn are sufficient for cholesterol synthesis (Hansen et al, 2006). This result is quite consistent with our data of plasma cholesterol that showed no significant difference between the NC and the RB cows (Table 1).…”

“…The earliest studies demonstrated that a manganese deficiency causes defective ovulation and subfertility of female and male (Tuormaa, 1996). It is suggested that Mn act as a cofactor for mevalonate kinase and farnesyl pyrophosphate synthase; enzymes involved in the production of squalene, a precursor of cholesterol (Davis et al, 1990;Hansen et al, 2006;Hidiroglou, 1979;Tuormaa, 1996;Watts, 1990). However, in a more recent study, it is reported that treating heifers with different concentrations of Mn did not affect the serum cholesterol (Hansen et al, 2006).…”

“…It is suggested that Mn act as a cofactor for mevalonate kinase and farnesyl pyrophosphate synthase; enzymes involved in the production of squalene, a precursor of cholesterol (Davis et al, 1990;Hansen et al, 2006;Hidiroglou, 1979;Tuormaa, 1996;Watts, 1990). However, in a more recent study, it is reported that treating heifers with different concentrations of Mn did not affect the serum cholesterol (Hansen et al, 2006). This study indicates that even low serum levels of Mn are sufficient for cholesterol synthesis (Hansen et al, 2006).…”

“…This result is consistent with other studies (Das et al, 2009;Kalita and Sarmah, 2006). Manganese is involved in all metabolic processes (Davis et al, 1990;Hansen et al, 2006;Watts, 1990). The earliest studies demonstrated that a manganese deficiency causes defective ovulation and subfertility of female and male (Tuormaa, 1996).…”

Repercussions of growth path on carcass characteristics, meat colour and shear force in Alentejana bulls

“…Nutritional status before slaughter can influence collagen content and its solubility and consequently meat tenderness (Thénard et al, 2006). Several studies investigated the effects of growth path and rate on carcass characteristics or meat quality in cattle (Jones et al, 1990;Hornick et al, 1998), but they were restricted to evaluation of the Longissimus muscle, regardless that compensatory growth effects on carcass and meat characteristics may be muscle-dependent (Hansen et al, 2006b). Consequently, results obtained in past studies cannot be extrapolated to the rest of the carcass.…”