Thesis - Open Access
Master of Science (MS)
Department / School
Cobalt, Cobalt lactate, Dairy Science, essential oil, rumen modifiers
Three studies were conducted to evaluate a commercial blend of essential oils, active dried yeast product and cobalt lactate on production performance, rumen fermentation and nutrient digestibility by cows by using in vivo and in vitro methods. The first study evaluated the lactational performance and nutrient digestibility of lactating Holstein dairy cows fed two commercial supplements: 1) a propriety blend of essential oils and Cobalt lactate (EOC) (Stay Strong, Ralco, Inc., Marshall, MN) and 2) active dried yeast (ADY) (Omnigen AF, Prince Agri Products, Inc., Quincy, IL). The 12-week experiment demonstrated no differences in milk production, milk composition, and feed efficiency. However, cows fed EOC were cooler than cows fed ADY. Both commercial products prevented the growth of Aspergillus fumigatus. Nutrient digestibility (ND) was higher for cows fed ADY than cows fed EOC. This study demonstrated that while milk production and FE were similar, lactating dairy cows fed EOC were cooler during the hot summer/fall season, whereas ND was significantly higher for the cows fed ADY. In the second in vitro study, cobalt carbonate (CoCO3) and cobalt lactate (CoL: CoMax, Ralco, Inc., Marshall, MN) inclusion rates were evaluated for effects on ruminal fermentation and nutrient digestibility when feeding a grass hay as substrate. Treatments included 1) Blank: No feed and no CoCO3; 2) CoCO3 - 0.1 ppm; 3) CoCO3 -3.5 ppm; 4) CoL - 0.11 ppm; 5) CoL - 0.22 ppm; 6) CoL - 0.875 ppm; 7) CoL - 1.75 ppm; and 8) CoL - 3.5 ppm. Rate of gas production was lower (P < 0.05) for 0.1 ppm of CoCO3 compared to 3.5 ppm of CoCO3, and intermediate for 0.11, 0.22, 0.875, and 0.11 ppm of CoL. Total VFA (mmol/L) concentrations were lower (P < 0.05) for 0.22 and 3.5 ppm of CoL compared to remaining treatments. Molar percentage of acetate was lower (P < 0.05) for 1.75 and 3.5 ppm CoL than remaining treatments. Rumen ammonia concentration was similar (P > 0.10) for all treatments. Dry matter digestibility was highest (P < 0.05) for 0.11 ppm of CoL and was intermediate for 0.1, 3.5 ppm of CoCO3, and 0.22 ppm of CoL. Digestibility of NDF was higher (P < 0.05) for 0.11 ppm of CoL, intermediate for 0.1, 3.5 ppm of CoCO3 and 0.22 ppm of CoL and lower (P < 0.05) for 0.875, 1.75, and 3.5 ppm of CoL than other treatments. Results show that lower doses of CoL are more effective for fiber digestion of grass hay than CoCO3. The third in vitro study evaluated CoCO3 and CoL on ruminal fermentation and nutrient digestibility evaluating a 60:40 (DM basis) blend of corn silage and alfala baleage as a typical dairy ration substrate. Treatments included 1) Blank: No feed and no treatment, 2) CoCO3 - 3.5 ppm, 3) CoL - 0.11 ppm, 4) CoL - 0.22 ppm, 5) CoL - 0.875 ppm, 6) CoL - 1.75 ppm, and 7) CoL - 3.5 ppm. Rate of gas production was similar (P > 0.10) among treatments. Total VFA concentrations (mmol/L) were higher (P < 0.05) for 0.11 ppm of CoL, intermediate for 0.22, 0.875, 1.75, and 3.5 ppm of CoL and lowest (P < 0.05) for 3.5 ppm of CoCO3. Acetate molar percentage was higher (P < 0.05) for 3.5 ppm of CoCO3, intermediate for 0.11, 1.75, and 3.5 ppm of CoL and lowest for 0.22 and 0.875 ppm of CoL. Molar propionate concentration was higher (P < 0.05) for all CoL treatments compared to 3.5 ppm CoCO3. Rumen NH3-N and pH were similar (P > 0.10) among the treatments. The DMD was lower (P < 0.05) for 3.5 ppm CoCO3, intermediate for 0.11 and 3.5 ppm of CoL and highest (P < 0.05) for 0.11, 0.22, 0.875, and 1.75 ppm of CoL. Results demonstrate that Cobalt Lactate is more effective than CoCO3 for improving fiber digestion with a corn silage and alfalfa baelage based forage.
Library of Congress Subject Headings
Dairy cattle -- Feeding and feeds
Cobalt in animal nutrition
Essences and essential oils
Includes bibliographical references (pages 85-105)
Number of Pages
South Dakota State University
Poudel, Prakash, "An Evaluation of Rumen Modifiers for Lactational Performance and Nutrient Digestibility by Cows" (2016). Electronic Theses and Dissertations. 1072.