Comparison Of Trace Mineral Supplementation Strategies For Beef Cows

Author : Mathew J. Faulkner
Publisher :
ISBN 13 :
Total Pages : 214 pages
Book Rating : 4.:/5 (967 download)

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Download or read book Effects of Trace Mineral Supplementation in Lactating Dairy Cattle written by Mathew J. Faulkner and published by . This book was released on 2016 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments were designed to study the effects of Cu, Zn, and Mn supplementation on production, gene expression of trace mineral transporters expressed in the milk fat globular membrane (MFGM), milk fatty acid (FA) profiles, digestibility, and fecal bacteria relative abundance in lactating dairy cattle. In experiment 1, 30 Holstein cows were fed diets devoid of supplemental Cu, Zn, and Mn (basal diet provided 8, 41, and 41mg/kg, respectively) for 30 d and were then split into three treatment groups: one group remained on the unsupplemented diet; the second and third groups were fed a diet supplemented with Cu, Zn and Mn from sulfates (assayed total dietary concentrations = 17, 60, and 55mg/kg, respectively) or glycinates (assayed total dietary concentrations = 20, 66, and 58mg/kg, respectively) for 30 d. Milk yield (averaged 29.2 kg/d), DMI (averaged 3.55% of BW or 22.5 kg/d) as a percent of BW, and milk components were not affected by treatment. Feeding supplemental minerals decreased iso-15:0, anteiso-15:0, iso-17:0, and 16:1+anteiso-17:0 branched-chain fatty acids (FA) and tended to increase trans-10 18:1 as percentages of total FA in milk fat. Trans-10 18:1 was greater (0.76 vs 0.50%) for cows fed sulfate minerals compared to glycinate sources. Gene expression (via qPCR) of metallothionein (1.51 vs 0.77 2(-delta Ct)) in MFGM were greater for multiparous cows than primiparous. Expression of a zinc transporter, ZIP8, was greater (3.37 vs 2.06 and 2.65 2(-delta Ct)) for cows not fed supplemental minerals compared to cows fed sulfate and glycinate sources, respectively. In experiment 2, Eighteen multiparous cows were used in a split-plot replicated Latin square with two 28 d periods to evaluate the effects of Cu, Zn, and Mn source (sulfates or hydroxy; Micronutrients Inc., Indianapolis, IN) and dietary neutral detergent fiber (NDF) source (forage-based control diet = 26% NDF vs byproduct = 36%) on total-tract nutrient digestibility, mineral balance, and gene expression of trace mineral transporters in the MFGM. During the entire experiment (56 d) cows remained on the same fiber treatment but source of supplemental trace mineral was different for each 28 d period so all cows were exposed to both mineral treatments. During each of the two 28 d periods cows were fed no supplemental Cu, Zn, or Mn for 16 d followed by 12 d of feeding supplemental Cu, Zn, and Mn from either sulfates or hydroxy sources. Basal Cu, Zn, and Mn concentrations for the control diet were 9, 30, and 38mg/kg, respectively; while basal concentrations were 11, 50, and 47mg/kg, respectively for the byproduct diet. Supplemental concentrations of Cu, Zn, and Mn fed were approximately 9, 30, and 30mg/kg, respectively. Treatment had no effect on DMI (averaged 24.2 kg/d) or milk production (34.9 kg/g). No mineral source x fiber interactions were observed for production measures or macronutrient digestibility; however apparent Cu balance and Cu retention was increased for cows fed the control diet with hydroxy minerals compared to the control diet with sulfate minerals (+11 vs -3 mg/d), but retention of Cu was decreased for the byproduct diet when cows were fed hydroxy minerals compared to sulfates (-5 vs +29 mg/d). Cows fed the byproduct diet had decreased DM digestibility (65.9 vs 70.2%), OM digestibility (67.4 vs 71.7%), CP digestibility (58.8 vs 62.1%) and starch intake (4.3 vs 8.8kg), and increased starch digestibility (97.5 vs 96.3%), NDF intake (8.6 vs 6.0kg) and NDF digestibility (50.5 vs 44.4%) compared with cows fed the control treatment. The control diet had increased TDN concentration (70.2 vs 65.3%) compared to the byproduct diet. Measured NDF digestibility and TDN treatment effects were consistent regardless of the method used to determine NDF. Multiple (>12) milk FA concentrations were affected by fiber source and mineral source. In experiment 3, 24 cows were fed diets devoid of supplemental Cu, Zn, and Mn for a 16 d preliminary phase (basal diet provided 9, 29, and 32mg/kg of Cu, Zn, and Mn, respectively), and then were randomly assigned to one of three treatment diets (n=8 cows/treatment): supplemental Cu, Zn, and Mn from sulfate mineral; or glycinate minerals; or Cu and Mn sulfate with glycinate Zn. Assayed total dietary concentrations were approximately 21, 73, and 72 mg/kg for Cu, Zn, and Mn, respectively. Body weight, milk production (averaged 38.8 kg/d), DMI (averaged 25.8 kg/d), and analyzed milk components were not affected by treatment. Fecal DNA was extracted, amplified using the 16S rRNA gene to quantify total bacteria, and microbial populations were sequenced to compare populations between treatments. Relative abundance of phyla Spirochaetes, family Spirochaetaceae, genus Treponema, and uncultured or other treponema species were less abundant for cows fed Cu and Mn sulfate with glycinate Zn compared to those fed sulfates, but were similar to cows fed glycinate mineral sources, and responses for cows fed either exclusive glycinate mineral or sulfate mineral treatments were similar.