Supplementation of Rumen-protected Forms of Methionine, Betaine, and Choline to Early Lactation Holstein Cows

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dc.contributor.advisor Dr. Brinton A. Hopkins, Committee Co-Chair en_US
dc.contributor.advisor Dr. Jack Odle, Committee Co-Chair en_US
dc.contributor.advisor Dr. Lon W. Whitlow, Committee Member en_US
dc.contributor.advisor Dr. Vivek Fellner, Committee Member en_US
dc.contributor.advisor Dr. Cavell Brownie, Committee Member en_US Davidson, Shannon en_US 2010-04-02T18:52:14Z 2010-04-02T18:52:14Z 2006-12-11 en_US
dc.identifier.other etd-08162006-141227 en_US
dc.description.abstract Methionine (Met) is frequently the first limiting amino acid or co-limiting with lysine in dairy rations, and Met metabolism is closely linked to that of betaine and choline. Methionine, betaine, and choline are all degraded by microbes in the rumen, so rumen-protected (RP) forms were used to perform two experiments. The objective of these experiments was to investigate the impact of supplementing RP forms of methionine, betaine, and choline to a Met-limited total mixed ration (TMR) on performance, metabolism and ruminal fermentation in early lactation Holstein cows. Experiment 1 utilized 80 lactating Holstein cows from 21 to 91 days in milk (DIM) that were fed a corn silage-based TMR formulated to meet National Research Council (2001) recommendations, except the Met content was limited (42 g⁄d). One of four supplements was blended into the TMR to produce four dietary treatments: 1.) control, 2.) 20 g⁄d RP-Met, 3.) 45 g⁄d RP-betaine, and 4.) 40 g⁄d RP-choline. Calcium salts of fatty acids were used to protect the RP-betaine and RP-choline supplements and were added to the control and RP-Met supplements so that equal amounts of fat were supplied to all treatments. Consequently, dry matter (DM) intake, body weight, and body condition score were not significantly different among treatments (P > 0.2). The treatment by parity interaction tended to be different (P = 0.06) for milk yield with 44.3 kg⁄d produced in multiparous (MP) cows fed RP-choline compared to MP cows fed all other treatments (37.8, 40.0, and 38.7, respectively) while there were no differences among treatments in primiparous cows. Cows fed RP-met or RP-choline had higher milk crude protein yield than cows fed control or RP-betaine (P = 0.02). However, there were no differences in milk fat yield or milk urea nitrogen (P > 0.2). Experiment 2 utilized 4 dual-flow continuous culture fermentors (700 ml) to determine the effects of supplementation of rumen-protected forms of methionine, betaine, and choline to a Met-limited corn silage-based TMR on microbial metabolism by mixed ruminal cultures. Fermentors were inoculated with rumen fluid and allowed to stabilize for 2 days. Treatments were added for 5 days of adaptation followed by 3 days of sample collection. One of 4 supplements was blended into the TMR to produce 4 dietary treatments with a composition that was similar to those used in Experiment 1. Here, treatments are described as a percent of dietary DM: 1.) control, 2.) RP-Met (0.09% of DM as Met), 3). RP-betaine (0.20% of DM as betaine), or 4.) RP-choline (0.18% of DM as choline). Fat was added to all treatments as in Experiment 1. Four replicates were performed with each fermentor receiving each of the 4 treatments for one replicate. As a result, total volatile fatty acids (VFA) and individual VFA concentrations were not affected by dietary treatment, except for propionate and isobutyrate concentration. Propionate production was significantly lower in RP-choline than in control fermentors (P = 0.05). Isobutyrate production was significantly higher in control fermentors than in the ones supplemented with either RP-Met or RP-betaine, but was not significantly different from RP-choline fermentors (P = 0.05). Methane production and pH were similar across treatments (P > 0.2). Ruminal ammonia concentration was lower for fermentors receiving RP-choline than those receiving control (P = 0.04). There were no significant differences in microbial N %, flow, or efficiency between treatments (P > 0.2). Overall, cows fed RP-choline produced more milk and milk protein than those fed the Met-limited control, and there were no beneficial effects of RP-betaine supplementation to a Met-limited TMR. Also, RP-Met, RP-betaine, and RP-choline affected ruminal fermentation minimally which suggests that they were protected from degradation. en_US
dc.rights I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. en_US
dc.subject methionine en_US
dc.subject choline en_US
dc.subject betaine en_US
dc.subject dairy en_US
dc.title Supplementation of Rumen-protected Forms of Methionine, Betaine, and Choline to Early Lactation Holstein Cows en_US PhD en_US dissertation en_US Nutrition en_US

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