Relative bioavailability of organic and hydroxy copper sources in growing steers fed a high antagonist diet1.

To assess relative bioavailability (RBV) of hydroxy and organic Cu sources compared with CuSO4 in steers fed a high Cu antagonist diet, 84 steers were stratified by BW to pens randomly assigned to dietary treatments for 90 d. Steers received a common corn silage-based diet supplemented with Cu antagonists (diet analyzed 0.25% S; 6.

Influence of dietary zinc concentration and supplemental zinc source on nutrient digestibility, zinc absorption, and retention in sheep.

The objective of this study was to assess whether supplemental Zn source or concentration would affect ruminant Zn retention and nutrient digestibility. Thirty-six weaned crossbred Polypay wethers, were sorted by BW to 3 periods and stagger started on a common diet (22 mg Zn/kg DM) for a 52-d depletion period. Day 52 BW was used to assign Zn treatments (3 lambs/treatment/period): no supplemental Zn (CON), or supplemental Zn (40 mg Zn/d) from Zn sulfate (ING; Zinc Nacional, Monterrey, SA, Mexico), Zn methionine (ORG; Zinpro 120; Zinpro, Eden Prairie, MN), or Zn hydroxychloride (HYD; IntelliBond Z; Micronutrients USA LLC, Indianapolis, IN).

Supplemental trace minerals (zinc, copper, and manganese) as sulfates, organic amino acid complexes, or hydroxy trace-mineral sources for shipping-stressed calves.

Crossbred calves (n = 350; average BW 240 ± 1 kg) were obtained from regional livestock auctions. Within each set (block, n = 4), calves were stratified by BW and arrival sex into 1 of 8, 0.42-ha pens (10 to 12 calves per pen).

Effects of monensin and tylosin in finishing diets containing corn wet distillers grains with solubles with differing corn processing methods.

A total of 3,632 crossbred steers were used in 3 separate randomized complete-block designed finishing experiments. Data from Exp. 1 were analyzed separately whereas data were combined for Exp.

Effects of ractopamine and trenbolone acetate implants with or without estradiol on growth performance, carcass characteristics, adipogenic enzyme activity, and blood metabolites in feedlot steers and heifers.

Two experiments were conducted to evaluate effects of ractopamine (RAC) and steroidal implant treatments on performance, carcass traits, blood metabolites, and lipogenic enzyme activity in feedlot cattle. In Exp. 1, yearling steers (n = 486; initial BW = 305 kg) were used in a 3 × 3 factorial arrangement of RAC doses of 0 (R0), 100 (R100), or 200 (R200) mg·steer(-1)·d(-1) fed for 28 d and implant regimens (implant-reimplant) of no implant-no reimplant (NI-NI), 120 mg of trenbolone acetate (TBA) and 24 mg of estradiol-17β (E17B)-no implant (RS-NI), or 80 mg of TBA and 16 mg of E17B followed by 120 mg of TBA and 24 mg of E17B (RI-RS).