Progress 09/01/07 to 08/31/12
Outputs
OUTPUTS: The primary output from this project last year was data generated from two experiments conducted with dairy cows. In one experiment, we compared three different diets. One diet was a typical Midwestern diet for dairy cows based on corn silage, alfalfa silage, corn grain and soybean meal. The second diet was based extensively on a corn gluten feed byproduct and contained only corn silage, the corn byproduct and supplemental minerals. The third diet was the same as the second diet except it contained supplemental rumen protected methionine and lysine. The hypothesis was that milk yield, milk composition, and feed efficiency would be similar between the control diet and the byproduct diet that included supplemental amino acids but milk protein would be lower in the byproduct diet without amino acids. Based on typical feed costs, the byproduct diet would be least expensive and the control diet would be most expensive. We determined that the byproduct diet without supplemental amino acids was not quite as good as the control diet with respect to milk protein production but that it was much better than the major nutritional models currently in use predicted. Supplemental amino acids increased milk protein yields but the response was less than expected. We found that a diet based almost exclusively on corn silage and a corn milling byproduct was almost as good as a complex diet with multiple ingredients. The simple diet would usually be much less expensive and should improve dairy farm profitability. This project was part of a MS project and that student has graduated and accepted a position in the feed industry. The second experiment evaluated a new corn silage hybrid designed to have improved fiber and starch digestibility. A production trial and a digestibility trial has been conducted. Over the life of this project we determined that a high fiber corn silage hybrid can provide the necessary fiber to a dairy cow without adversely affecting production as long as the hybrid has high in vitro fiber digestibility. We conducted experiments measuring digestible energy of various fat supplements and mixtures of byproducts when fed to lactating cows. Overall, our data on digestibility is being used to improve the prediction of feed energy values. Data from our studies also has been useful in reducing manure excretion and excretion of manure nutrients by dairy cows. We conducted experiments evaluating the bioavailability of magnesium, biotin, selenium, manganese, vitamin E, and methionine. These data have led to improved diet formulation methods and should lower cost by ensuring adequate, but not excessive amounts of available nutrients. Results from all these experiments have been disseminated to scientific audiences via peer-reviewed journal and to practicing nutritionists and veterinarians and to producers via talks and published proceedings for all major feed conferences in the US. Some of the information has also been disseminated via popular press articles. Three MS students and one Ph.D. student conducted experiments under this project and all our currently employed in the feed industry or are working toward obtaining a PhD degree. PARTICIPANTS: William Weiss, Department of Animal Sciences, Ohio State University, Lucien McBeth, 2012 MS student, Henry Paz, former graduate student, Peter Yoder, 2012 MS graduate student, Gonzalo Ferreiro, former graduate student, Donna Wyatt, technician, Dianne Shoemaker, OSU extension, Mike Socha, Zinpro Corp. Alejandro Castillo, California Extension Service, Dale Bauman, Cornell University. TARGET AUDIENCES: Primary target audiences are: dairy producers, dairy nutritionists, dairy veterinarians, graduate students, nutrition scientists, and undergraduate students PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Results from the experiments conducted last year represent a change in knowledge and may result in a change in action. Over a longer term, results from one of the experiments should result in a change in conditions. Complex, multi-ingredient diets for dairy cows are the norm because we thought that multiple ingredients were necessary to ensure that all required nutrients were provided. Results from our study with a corn milling product challenges this concept. A very simple diets with only three ingredients performed almost as well as a much more complex diet. The simple diet is cheaper and will reduce inventory needs on a dairy farm. Both of which should improve profitability. Enhanced performance was observed by adding two important amino acids but the response was much less than expected. This experiment may lead to a change in the approach taken to formulate diets. Many farms with limited land base can grow adequate corn silage but much purchase other feedstuffs. This simple, three ingredient diet approach would be quite beneficial to such producers. Long term this approach could be extended to evaluate the use of other byproducts such as distillers grains and soyhulls in very simple three ingredient diets. Over the life this experiment, major impacts include a reduction in excretion of manure and manure nutrients by dairy farms. Data from this project, if applied will result in cows producing less manure without decreasing milk production. Nitrogen excretion would also be reduced. The method we developed to evaluate methionine availability will also more precise diet formulation with respect to protein. This will reduce feed costs (protein sources are at historically high prices), reduce excretion of nitrogen and improve profitability of dairy farms. The data on manganese, selenium, biotin, and vitamin E should improve cow health by ensuring cows are in optimal trace nutrient status. This will benefit cow welfare and improve dairy farm profitability.
Publications
- Weiss, W.P. 2012. Minerals and vitamins for dairy cows: Magic bullets or just bullets. Proc. Northeast Herd Health and Nutr Conf. Pp 27-36.
- Shoemaker, D.E., W.P. Weiss, and N.R. St-Pierre. 2012. Advantages and disadvantages of homegrown forages. Proc. Tri-State Dairy Nutr. Conf. Pp87-96.
- Weiss, W.P. 2012. Vitamin nutrition for dairy cattle: NRC requirements versus todays reality. Proc. California Animal Nutr. Conf. Pp 9-18.
- Weiss, W.P. 2012. Reducing enteric methane production associated with milk production. Proc. California Animal Nutr. Conf. Pp 81-89.
- Castillo, A.R., N.S. del Rio, N.R. St-Pierre, and W.P. Weiss. 2012. Composition of diets fed to different groups of lactating cows on California Dairies. J. Dairy Sci. 95 (suppl 2):360. (abstract)
- Weiss, W.P., 2012. Use of a corn milling product to alleviate milk fat depression. J. Dairy Sci. 95:2081-2090.
- ODonnell-Megaro, J.L. Capper, W.P. Weiss, and D.E. Bauman. 2012. Effect of linoleic acid and dietary vitamin E supplementation on sustained conjugated linoleic acid production in milk fat from dairy cows. J. Dairy Sci. 95:7299-7307.
- Castillo, A.R., N.S. del Rio, N.R. St-Pierre, and W.P. Weiss. 2012. Effects of total solids in drinking water and milk yield per cow on milk mineral concentrations from California dairy farms. J. Dairy Sci. 95 (suppl 2):127.(abstract)
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: The primary output from this project last year was data generated from two experiments conducted with dairy cows. In one experiment, diets were formulated to have different nitrogen availabilities and then manure from the cows were incubated under laboratory conditions and loss of ammonia was measured. Diets were formulated so that excretion patterns (urine versus feces) of nitrogen would differ among diets. In the short term (days), urinary nitrogen is the primary source of manure ammonia; the different diets used in this experiment were designed to produce a wide range in the production of manure ammonia. This was needed to evaluate a method that may have value in estimating loss of ammonia from manure under farm situations. The measured losses of ammonia from the incubated manures were compared to estimated losses to determine if the on-farm method was accurate. The on-farm method to estimate manure ammonia losses is based on measuring concentrations of ash and specific minerals and nitrogen in feeds and manure and using an equation to calculate loss of nitrogen from manure. This project was part of a master of science research program and that student has graduated and is currently pursuing a Ph.D degree at another university. The second experiment was conducted to evaluate the energy and protein availability of a corn milling product to dairy cows. The corn milling product is a co-product when corn sweetener is produced. Because of its nutrient composition it can be a substantial source of energy, protein, and fiber for dairy cows. This experiment was conducted to determine optimal inclusion rates and whether the product should substitute for concentrate feeds or a mix of concentrate and forages. PARTICIPANTS: In addition to the PI, Henry Paz Master of Science student received training and degree. Industry partners included M. Engstrom and W. Steinburg from DSM and Paul VonBehren from Cargill. Both those companies provided financial support for some of the research. Donna Wyatt worked as the research associate providing technical assistance on all projects. Normand St-Pierre, professor, collaborated on publications. TARGET AUDIENCES: The target audience for the second experiment is dairy cattle nutritionists who can use the data when formulating cost-effective diets. Dairy farmers are a secondary audience for that data because they ultimately are responsible for approving feed purchases. The primary target of the first experiment is scientists because the method we developed needs further evaluation before it is adopted. Potential target audiences will be farmers who are or will be required to monitor ammonia losses from their farms, regulators who will be responsible for monitoring ammonia losses from farms, and nutrient management and crop specialists who will be providing advice on manure management systems and manure application to crops PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The primary output from this project last year was data generated from two experiments conducted with dairy cows. In one experiment, diets were formulated to have different nitrogen availabilities and then manure from the cows were incubated under laboratory conditions and loss of ammonia was measured. Diets were formulated so that excretion patterns (urine versus feces) of nitrogen would differ among diets. In the short term (days), urinary nitrogen is the primary source of manure ammonia; the different diets used in this experiment were designed to produce a wide range in the production of manure ammonia. This was needed to evaluate a method that may have value in estimating loss of ammonia from manure under farm situations. The measured losses of ammonia from the incubated manures were compared to estimated losses to determine if the on-farm method was accurate. The on-farm method to estimate manure ammonia losses is based on measuring concentrations of ash and specific minerals and nitrogen in feeds and manure and using an equation to calculate loss of nitrogen from manure. This project was part of a master of science research program and that student has graduated and is currently pursuing a Ph.D degree at another university. The second experiment was conducted to evaluate the energy and protein availability of a corn milling product to dairy cows. The corn milling product is a co-product when corn sweetener is produced. Because of its nutrient composition it can be a substantial source of energy, protein, and fiber for dairy cows. This experiment was conducted to determine optimal inclusion rates and whether the product should substitute for concentrate feeds or a mix of concentrate and forages.
Publications
- St-Pierre, N. R., and W. P. Weiss. 2011. How do forage quality measurements translate to value to the dairy farmer Proc. 2011 Western Alfalfa and Forage Conference, Las Vegas, NV, Dec 11-13. http://alfalfa.ucdavis.edu .
- Weiss, W.P. 2011. Optimizing and evaluating dry matter intake of dairy cows. Proc 2nd Internat. Symp. Dairy Cow Nutr. and Milk Quality. PP 122-128. Beijing, China.
- Paz, Henry. 2010. Use of ash and nitrogen concentrations in manure to estimate loss of ammonia over time. M.S. Thesis. The Ohio State University, Columbus
- Weiss, W.P. J. M. Pinos-Rodriguez, and D. J. Wyatt. 2011 . The value of different fat supplements as sources of digestible energy for lactating dairy cows. J. Dairy Sci 94:931-939.
- Weiss, W. P., W. Steinberg, and M. Engstrom. 2011. Milk production and nutrient digestibility by dairy cows when fed exogenous amylase with coarsely ground dry corn. J. Dairy Sci. 94:2492-2499.
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: The primary output of this project is data generated from three experiments conducted with dairy cows. In one experiment, different sources of rumen escape methionine were fed to dairy cows and changes in the concentration of milk selenium was measured. When cows are fed selenium yeast, but not selenite, concentrations of selenomethionine in milk increase and is correlated with milk selenium concentrations. When sources of available methionine are fed, the increase in flux of methionine is proportion to the decrease in concentration of milk selenium (i.e., increasing available methionine increases the size of the methionine pool but not the size of the selenomethionine pool). Cows were fed methionine (a negative control), a commonly used commercial rumen protected methionine and two commonly used methionine derivatives (HMB and HMBi). In the second experiment, different fat supplements were fed to dairy cows and the concentration of digestible energy in the diets were measured using total collection of urine and feces method. The fat supplements varied in chemical form (free fatty acids vs. triglycerides), fatty acid saturation, and fatty acid chain length. The third experiment evaluated the use of exogenous amylase on nutrient digestibility when fed in diets with coarsely ground corn. Fine processing of corn increases starch digestibility but adds cost and increases energy use. Amylase has the potential of improving starch digestibility with less processed corn. Some data from these experiments can be directly incorporated into commonly used ration balancing software (e.g., digestible energy values and absorbed methionine values). Overall, more accurate feed and diet information should improve our ability to formulate cost-effective and efficient diets which are the main goals of this project. PARTICIPANTS: In addition to the PI, Donna Wyatt, Research Associate, OSU; Josie Plank, graduate research associate, OSU; Mike Socha, industry partner TARGET AUDIENCES: Target audiences are dairy nutrition scientists, practicing nutritionists and veterinarians and to some extent, dairy farmers. Much of the data we generate is directly applicable to nutritionists and can be incorporated into the software they use to formulate diets. Data are published in scientific journals to reach the science audience. Talks and lay publications are prepared to reach dairy farmers PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
In one experiment different sources of rumen escape methionine was fed to dairy cows and changes in the concentration of milk selenium was measured. Cows were fed methionine, a commercial rumen protected methionine and two methionine derivatives (HMB and HMBi). Only cows fed the rumen protected methionine and HMBi had reduced milk selenium concentrations showing that the two sources increased flux of methionine in dairy cows. The two main impacts of this project was validation of the selenium method to evaluate methionine sources and methionine availability data that can be used in ration formulation software which should leave to more efficient and cost effective diets. In the second experiment, different fat supplements were fed to dairy cows and the concentration of digestible energy in the diets were measured using total collection of urine and feces method. The fat supplements varied in chemical form (free fatty acids vs. triglycerides), fatty acid saturation, and fatty acid chain length. Fatty acid digestibility differed by more than 10 percentage units resulting in significant differences in digestible energy concentrations. Triglyceride was much less digestible than fatty acids and less saturated fats were more digestible than saturated fats. Although digestible energy concentrations differed significantly among treatments, small changes in feed intake negated those effects resulting in equal digestible energy intake among treatments. The main outcomes of this experiment were: 1. energy values for different fat supplements. These values are needed for ration formulation software; and 2. Increased understanding of factors affecting fat digestion in cows. This should help develop better supplements. The third experiment evaluated the use of exogenous amylase on nutrient digestibility when fed in diets with coarsely ground corn. Fine processing of corn increases starch digestibility but adds cost and increases energy use. Amylase has the potential of improving starch digestibility with less processed corn. Starch digestibility measured using total collection was not affected by amylase, however fiber digestibility was enhanced. This may have been caused by increased microbial action within the rumen. The main impact of this experiment was that supplemental amylase will not replace fine grinding of corn but can increase digestibility of fiber. This may result in increased feed efficiency (i.e., less manure per unit of milk produced).
Publications
- Weiss, W.P. 2010. Does nutrition affect immune function and mastitis in dairy cows Proc. Pacific NW Nutr. PP 83-94.
- Lascano, G. J., G. I. Zanton, A. J. Heinrichs, and W. P. Weiss. 2010. Technical note: A noninvasive urine collection device for female cattle: Modification of the urine cup collection method. J. Dairy Sci. 93:2691-2694.
- Plank, J.E., W.P. Weiss., and N.R. St-Pierre. 2010. Determining the difference in the supply of metabolizable methionine to dairy cows fed four methionine supplements using concentrations of selenium in milk. J. Dairy Sci. 93 (suppl. 1):447 (abstract)
- Weiss, W.P. 2010. Feeding in todays economy. Proc. Tri-State Dairy Nutr. Conf. Ft. Wayne, IN, PP 107-113.
- Weiss., W.P. 2010. Refining the net energy system. Advances in Dairy Technology (Proc. Western Canada Dairy Seminar) 22:191-202.
- Weiss, W.P. 2010. Feeding strategies to decrease manure output of dairy cows. Advances in Dairy Technology (Proc. Western Canada Dairy Seminar) 22:229-240.
- Weiss, W. P., J. M. Pinos-Rodriguez, and M. T. Socha. 2010. Effects of feeding supplemental organic iron to late gestation and early lactation dairy cows. J. Dairy Sci. 93:2153-2160.
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: The primary output of this project is data generated from experiments conducted with dairy cows. In one experiment we evaluated the effects of a relatively new commercial form of vitamin E (RRR-tocopheryl acetate) on immune function and vitamin E status of periparturient dairy cows and their newborn calves. Cows were fed either the standard form of vitamin E (all-rac tocopheryl acetate) or RRR tocopheryl acetate and concentrations of tocopherol were measured in blood (dam and her calf), milk, and neutrophils. The phagocytic and killing ability of blood neutrophils were also measured. We developed and evaluated a simple and non-invasive method to evaluate the bioavailability of different methionine sources using the concentration of selenium in milk. Cows are fed selenized yeast which increases the selenium concentration in milk and then are fed different sources of methionine. Sources that have high bioavailability dilute the selenium in milk (i.e., reduce its concentration) in proportion to it availability. We developed and evaluated a method to estimate ammonia-nitrogen losses from dairy manure that should be applicable on farms. The diet and milk are sampled and assayed for ash and nitrogen which allows manure excretion of nitrogen and ash to be estimated. In manure, the mass of ash is constant whereas nitrogen mass decreases as ammonia is lost via volatilization. Changes in the ratio of ash and nitrogen can be used to calculate nitrogen losses. We conducted an experiment to evaluate how the energy value of a fat supplement was affected by different diet formulations. Diets with high and low concentrations of fiber were fed with and without added fat and energy balance of cows was monitored over a 90 day experiment. Data from these experiments were disseminated via peer-reviewed journal papers, proceedings papers for technical conferences and presentations at technical and scientific conferences. The results from the experiment evaluating different types of vitamin E have immediate application in the feed industry. These results have been presented at a major feed industry conference and a bulletin written in language appropriate for practicing nutritionists and dairy farms has been written and distributed. The data from that experiment was also incorporated into another presentation for dairy service industries and extension personnel. The method we developed to evaluate methionine sources was published in a scientific journal so that other scientists can use the method in their experiments (one person has started experiments using this method). PARTICIPANTS: W.P. Weiss (PI) L.B. Willett (CoPI) N.R. St-Pierre (CoPI) Donna Wyatt (technician) Tonya McKelvey (technician) Partner organization ADM Nutrition (financial support for vitamin E experiment), Adissio Inc. and Evonik-Degussa (financial support for methionine experiment), and Milk Specialties (financial support for the fat experiment). Henry Paz. Masters student that was trained under this project. He graduated in fall, 2009. TARGET AUDIENCES: The target audience for this project are dairy veterinarians, feed companies and nutritionists, dairy farmers, and scientists. Feed is the largest single cost for producing milk so farmers and feed companies have a substantial interest in data from nutrition experiments. Nutrition also impacts dairy cow health which makes veterinarians interested. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We found that the international unit system (i.e., IU) did not accurately value RRR-tocopheryl acetate. Cows fed RRR tocopheryl acetate had higher concentrations of tocopherol in blood, milk, and neutrophils than cows fed the same amount (IU/day basis) of vitamin E from all-rac tocopheryl acetate. Serum from calves fed colostrum from their dams which were fed RRR tocopheryl acetate had higher concentrations of tocopherol than calves from dams fed all-rac tocopheryl acetate. Conversely, neutrophil function was slightly depressed when cows were fed RRR tocopheryl acetate (this could be a results of excessive vitamin E supplementation). The overall impact of these results is that supplementation rates for RRR-tocopheryl acetate should be less than those for all-rac tocopheryl acetate. This should reduce diet costs and may lead to improved animal health. Both of which can lead to increased profitability by dairy farms. The method we developed and published using milk selenium concentrations to evaluate methionine sources has substantial potential. Methionine is often the most limiting amino acid for milk production and supplements and ingredients that increase methionine supply often, but not always increase milk protein yield. These supplements and feed ingredients are often very expensive. This method (which can be used for on-farm experiments) can determine whether a methionine source is actually increasing the supply of methionine (this has very difficult to determine because of rumen metabolism). This will allow farmers and nutritionists to make wiser decisions regarding methionine supplementation. Ammonia that is lost from manure can be an important atmospheric pollutant and is currently or might be regulated. A method is needed so farmers and regulators can estimate the amount of ammonia being lost from manure. This will allow appropriate regulations to be applied and it will also allow farmers to evaluate the effects of different manure handling methods and different diets on manure ammonia production. Measuring ammonia losses from a farm is essentially impossible so accurate estimation methods are needed. The method we developed is based on simply assays (nitrogen and ash) from easily obtained samples (feed, milk, and manure). Compared to actual ammonia losses from manure, estimated losses were within 10% of actual. Although additional validation is required, this degree of accuracy is probably adequate. The last experiment found that the inclusion of supplemental fat interacts with amount of forage in a diet to determine energy balance in dairy cows. Cows fed supplemental fat with low forage diets partitioned energy towards milk production but when early lactation cows were fed supplemental fat with high forage diets, that energy was partitioned to body stores. The amount of forage in a diet must be considered when using supplemental fat. The application of these results should allow farmers and nutritionists to use supplemental fat (a very expensive ingredient) to its best advantage resulting in increased profitability of dairy farms.
Publications
- Weiss, W.P., J. S. Hogan, and D.J. Wyatt. 2009. Relative bioavailability of all-rac and RRR vitamin E based on neutrophil function and total a-tocopherol and isomer concentrations in periparturient dairy cows and their calves. J. Dairy Sci. 92: 720-731.
- Weiss, W.P., and N.R. St-Pierre. 2009. A Method to Quantify Changes in Supply of Metabolizable Methionine to Dairy Cows Using Concentrations of Selenium in Milk. J. Dairy Sci. 92:2835-2842.
- Weiss, W.P., L. B. Willett, N. R. St-Pierre, D. C. Borger, T. R. McKelvey, and D. J. Wyatt. 2009. Varying Type of Forage, Concentration of Metabolizable Protein, and Source of Carbohydrate Affects Manure Excretion, Manure Ammonia, and N Metabolism of Dairy Cows. J. Dairy Sci. 92:5607-5919.
- Weiss, W.P., N.R. St-Pierre, and L.B. Willett. 2009. Varying Type of Forage, Concentration of Metabolizable Protein, and Source of Carbohydrate Affects Nutrient Digestibility and Production by Dairy Cows. J. Dairy Sc. 92:5595-5606.
- St-Pierre, N.R., and W.P. Weiss. 2009. Technical Note: Designing and analyzing quantitative factorial experiments. J. Dairy Sci. 92:4581-4588.
- Weiss, W.P., and J. M. Pinos-Rodriguez. 2009. Production responses by dairy cows when fed supplemental fat in low and high forage diets. J. Dairy Sci. 92:6144-6155.
- Weiss, W.P. 2009. Does in vitro digestibility values have a use in formulating diets for dairy cows. J. Dairy Sci. 92 (suppl 1): 194.
- Paz, H.A., and W.P. Weiss. 2009. Use of ash and nitrogen concentrations in manure to estimate loss of ammonia over time. J. Dairy Sci. 92 (Suppl. 1):41.
- Weiss, W.P. 2009. An update on vitamins for dairy cows. Proc. Liquid Feed Symp. AFIA, Nashville, TN, Pp 130-143.
- Weiss, W.P. 2009. Nutritional influences on the prevalence and severity of mastitis in dairy cows. Proc. Natl. Mastitis Council Regional Meet. Wilkes-Barre, PA, pp 44-54.
- Weiss, W.P. 2009. Feeding in todays economy. Proc. Penn State Dairy Cattle Nutr. Workshop, Grantville, PA, Pp 11-16.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Activities completed for this project include five separate experiments. The first experiment was conducted to determine the relative bioavailability of two forms of supplemental vitamin E (all-rac vs. RRR). Periparturient cows were fed one of the two supplements or a negative control (no supplemental vitamin E). Neutrophil function, concentrations of tocopherol and tocopherol isomers in blood and milk, and tocopherol status of newborn and very young calves were measured. Another experiment was conducted to determine digestible energy concentrations of diets that contained various fat supplements. Cows were fed a control diet (no supplemental fat) or two types of fat supplements at two concentrations and digestibility of nutrients, including energy were measured. A third experiment was conducted to determine how concentration of forage in a diet affected the production response of cows when diets contained supplemental fat. Diets contained 40 or 60 percent forage (a blend of corn silage and alfalfa silage) with 0 or 2.5 percent supplemental fat. Cows were fed one of the four diets for 15 weeks and production was measured. A fourth experiment was conducted to determined whether concentration of selenium in milk could be used to estimate bioavailability of methionine. Cows were fed a basal diet containing 0.3 mg/kg of supplemental selenium from selenium yeast and then abomasally infused with water or methionine and concentration of selenium in milk was measured. The last experiment was conducted to determine whether a probiotic (predominantly propioniibacteria) improved energetic efficiency of dairy cows. Cows were fed a control diet or the same diet supplemented with live propioniibacteria each day for the first 120 days of lactation. Production, feed intake, and efficiency were measured. Dissemination of information occurred primarily via two avenues. Publication in scientific journals (below) and presentations at nutrition conferences whose primary audience is nutritionists and veterinarians. Data generated from this project were the basis of talks presented this year at the California Animal Nutrition Conference (approximate attendance = 75 people), 4-State Dairy Management Conference (450 people), the Tristate Dairy Nutrition Conference (450 people) and the Northeast Dairy Nutrition Conferences (250 people). Data from this project also contributed material for lectures presented in Lithuania (European Association for Animal Production, primary audience was scientists), Spain (International Center for Advanced Mediterranean Agronomic Studies, audience = graduate students), Argentina (Argentine Animal Science Association, audience = nutritionists), and Costa Rica (Regional Course in Animal Nutrition-Dairy, audience = nutritionists and graduate students). PARTICIPANTS: W.P. Weiss (PI) D.J. Wyatt (technician) T. McKelvey (technician) Normand St-Pierre (collaborator, OSU) Joe Hogan (collaborator, OSU) Jeff Firkins (Collaborator, OSU) Henry Paz (M.S. student, learned how to conduct applied nutrition studies and digestion trials) TARGET AUDIENCES: Target audiences are scientists, industry advisers such as nutritionists and veterinarians, students, and dairy farmers. Publications in scientific journals, talks at scientific meetings, and private and group discussions are the primary effort to cause a change in knowledge for that audience. Advisors are reached via talks and nutrition conferences, publications in proceedings and other extension-type publications, phone, email, and personal consultations, and farm visits. Students are reached primarily via formal classroom lectures and field trips that include on-farm visitations. Farmers are reached via telephone, email, and personal consultations and limited farm visits PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Results from the experiment evaluating propioniibacteria were published in a scientific journal. We found that cows fed the probiotic were about 5 percent more efficient than cows not fed the supplement. The primary mode of action was probably via altered rumen fermentation (more propionic acid) which resulted in more efficient production of ATP. If results of this experiment are accepted by the industry and this product is used, it should reduce the cost of producing milk (lower feed cost per unit of milk produced) and should reduce manure output per unit of milk produced. The other significant outcome of this project were the changes in action resulting from dissemination of information to the dairy nutrition industry. Talks presented at major nutrition conferences on formulating diets for energy has resulted in at least two feed companies changing the way they formulate diets. Based on data developed during the life of this project, making this change should result in more efficient diets and diet formulations that more accurately predict energy balance in cows. This may result in improved reproduction (fewer skinny cows). Talks were presented on mineral nutrition of cows. If the information presented is applied, overformulation of diets for minerals (i.e., providing substantially more of a specific mineral than the cow needs for production and health) should be reduced. Reducing oversupplementation of minerals results in less excretion of minerals in manure (reducing negative environmental effects) and should reduce feed costs resulting in increased profibability.
Publications
- Weiss, W.P., and N.R. St-Pierre. 2008. Understanding, measuring, and managing variation in nutrient composition of feeds and diets. Proc Northeast Ag and Feed Alliance Dairy Programs, Syracuse, NY and W. Lebanon, NH, Pp 25-34.
- Weiss, W.P. 2008. Do not let feed sorting lead to acidosis. Progressive Dairyman July 8 edition, page 7.
- Weiss, W.P., and D. Mahan. 2008. Oxidative stress during the lifecycle of animals. J. Dairy Sci. 91 (E-suppl. 1): 383.
- Weiss., W.P. 2008. Practical aspects of energy nutrition of high producing dairy cows. Book of Abstracts, 59th Ann. Meeting. European Assoc. Anim. Prod. No. 14, pg 86.
- Spears, J.W., and W.P. Weiss. 2008. Role of antioxidants and trace elements in health and immunity of transition dairy cows. Vet. J. 176:70-76.
- Weiss, W.P., D.J. Wyatt, and T.R. McKelvey. 2008. Effect of feeding propionibacteria on milk production by early lactation dairy cows. J. Dairy Sci. 91:646-652.
- Weiss, W.P. 2008. Managing high feed costs. Dairy Herd Mgmt Electronic Newsletter (http://nutritionist.dairyherd.com)
- Weiss, W.P. 2008. Diet factors that affect manure output by cows. Proc. California Animal Nutr. Conf. Fresno, CA, Pp 95-102.
- Weiss, W.P. 2008. Feed energy applications. Proc. 4-State Dairy Nutr. Conf. Dubuque, IA, Pp 22-27.
- Weiss, W.P. 2008. Nutritional factors that affect manure output by dairy cows. Proc. 4-State Dairy Nutr. Conf. Dubuque, IA, Pp 5-8.
- Weiss, W.P. 2008. Mineral tolerances of animals. Proc. Tri-State Dairy Nutrition Conf. Ft. Wayne, IN, Pp 59-64.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Two experiments were conducted to determine whether measures of biotin status used in humans and rodents can be useful in estimating bioavailability of biotin to dairy cows. An experiment was conducted to evaluate a novel method of estimating bioavailabilty of methionine by dairy cows. An experiment was started to evaluate the amount of energy provided by various fat supplements when fed to dairy cows in different basal diets. A series of extension meetings were held throughout Ohio discussing the nutritional and economic value of distillers grain for cattle. Talks were presented at four nutrition conferences throughout the US (TX, NV, GA, and MN)
PARTICIPANTS: Donna Wyatt, Research Associate; Tonya McKelvey, Research Assistant; and Gonzalo Ferriera, Graduate Research Associate
TARGET AUDIENCES: Dairy farmers, nutritionists and veterinarians
Impacts
In a series of two experiments using dairy cows, we showed that 1) milk yield response to supplemental biotin was immediate (within 24 hours) and was dependent on initial milk yield. Cows producing approximately 22 kg of milk/d did not respond to supplemental biotin but those producing approximately 40 kg/d produced approximately 2 kg/d more milk when given supplemental biotin. In addition we showed that feeding supplemental biotin increased concentrations of biotin in blood plasma and milk (showing the biotin was absorbed) but excretion of various urinary metabolites was not affected by biotin status. This is in contrast to previous data from human subjects and rodents. Most likely this reflects differences in enzyme regulation between ruminants and non-ruminants. Results from these experiments should allow dairy farmers to optimize return on investment by supplementing biotin only to higher producing cows. In addition measuring concentrations of biotin in milk or
blood will not be predictive of the response to supplemental biotin. In another experiment the use of selenium concentrations in milk to estimate bioavailability of dietary methionine was evaluated. This experiment is not finished but results appear promising.
Publications
- Ferreira, G. and W. P. Weiss. 2007. Effect of biotin on activity and gene expression of biotin-dependent carboxylases in the liver of dairy cows. J. Dairy Sci. 90:1460-1466.
- Ferreira, G., W. P. Weiss, and L. B. Willett. 2007. Changes in measures of biotin status do not reflect milk yield responses when dairy cows are fed supplemental biotin. J. Dairy Sci. 90:1452-1459.
- Weiss, W. P. and J. S. Hogan. 2007. Effects of vitamin C on neutrophil function and responses to intramammary infusion of lipopolysaccharide in periparturient dairy cows. J. Dairy Sci. 90:731-739.
- Weiss, Bill, Maurice Eastridge, Diane Shoemaker, Normand St-Pierre. 2007. Distillers Grains. OSU Extension Fact Sheet. 4 pages.
- Weiss, W.P., and N.R. St-Pierre. 2007. Understanding and managing variation in nutrient composition. Pp29-38. Proc. 8th Western Dairy Management Conf., Reno, NV.
- Weiss, W.P., and J.L. Firkins. 2007. Silages and starch sources for cows. Pp 7-13. Proc. Mid-South Ruminant Nutrition Conf. Arlington, TX.
- Weiss, W.P. 2007. Energetics for the practicing nutritionist. Pp 9-18. Proc. 68th Minnesota Nutrition Conf. Minneapolis MN.
- Weiss, W.P., 2007. An update on vitamins for dairy cows. Pp18-29. Proc. Southeast Dairy Herd Management Conf., Macon GA.
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Progress 01/01/06 to 12/31/06
Outputs
The objectives of Experiment 1 were: 1) determine whether corn silage hybrid affected protein requirements of lactating dairy cows; 2) determine how corn silage hybrid affected excretion of manure and N by lactating dairy cows. Six Holstein cows were used in a partially replicated 4 X 4 Latin square experiment. Cows were fed one of four treatments (2 X 2 factorial arrangement). Diets consisted of corn silage (55% of diet dry matter) from a conventional hybrid or corn silage made from a brown midrib hybrid. The corn silages were fed with a concentrate with high or low concentration of protein so that total dietary protein was either 14 or 17.5%. The low protein diets were formulated to meet 85% of the metabolizable protein requirement of the cows and the high protein diets were formulated to provide 115% of the metabolizable protein requirement. The major findings were: 1) increasing dietary protein increased urine excretion by about 25% but because of a tendency of
decreased wet fecal output, manure output was only increased by about 5%. Feeding brown midrib silage reduced output of total manure by about 5%. Increasing dietary protein increased excretion of N via manure by 25% (both fecal and urine N excretion was increased). Cows fed brown midrib silage excreted less N at a specific N intake than cows fed conventional corn silage (approximately 15 g/d less). The objective of Experiment 2 was to determine factors affecting the response by dairy cows to supplemental biotin. Early lactation, high producing cows (approximately 45 kg/d) and late lactation, low producing cows (approximately 20 kg/d) were fed identical diets with and without 20 mg/d of supplemental biotin. Milk production increased significantly within 2 days of supplementation in high producing cows but yield did not change with low producing cows. The differential response of milk yield to supplemental biotin did not mirror changes in biotin status (i.e., both production groups had
similar changes to biotin status when biotin was fed). Liver biopsies were performed on a separate group of animals and supplemental biotin increased activity of propionyl Co-A carboxylase (a biotin containing enzyme) but did not affect activity of pyruvate carboxylase (a biotin-containing enzyme). The increased activity of propionyl Co-A carboxylase may increase glucose supply which could account for increased milk yield. Biotin supplementation did not affect expression of the genes for those enzymes
Impacts
Social, environmental, and economic costs are associated with manure. We found that manure output by dairy cows could be reduced by about 5% (equal to approximately 7 lbs./cow/day) by feeding brown midrib silage as compared to conventional silage. Feeding lower protein diets (less than current recommended standards) greatly reduced excretion of nitrogen by dairy cows but did not affect milk production. Simple diet manipulations can be used to reduce the many costs associated with manure. In the second experiment we found that only early lactation cows responded to biotin supplementation. If cows are grouped by stage of lactation, this finding will allow targeted supplementation which will reduce feed costs and increase economic return to biotin supplementation.
Publications
- Weiss, W. P. and D. J. Wyatt. 2006. Effect of corn silage hybrid and metabolizable protein supply on nitrogen metabolism of lactating dairy cows. J. Dairy Sci. 89:1644-1653.
- Ferreira, G. 2006. Effect of biotin supplementation on the metabolism of lactating dairy cows. Ph.D. Diss., The Ohio State Univ., Columbus, OH.
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Progress 01/01/05 to 12/31/05
Outputs
Experiment 1. The objective of this experiment was to compare bioavailability of different manganese sources for dairy cows and attempt to quantify the Mn requirement of dry and lactating cows. Based on apparent digestibility and tissue retention, Mn sulfate and Mn-methionine had equal bioavailability. Using a large data base of Mn tissue retention we estimated that the Mn requirement was approximately twice as high as the NRC estimated requirement. Experiment 2. The objective of this experiment was to compare bioactivity of two different selenium sources when fed to dairy cows. Cows were fed Se from selenate or Se from a Se-yeast compound. Blood and milk concentrations of Se and transfer of Se to the fetus was significantly higher for Se-yeast but function of neutrophils and inflammatory response was not affected by Se source. Experiment 3. The objective of this experiment was to determine if in vitro or in situ methods of estimating fiber digestibility were accurate
methods of estimating in vivo fiber digestibility by lactating cows. Three diets that differed in source and concentration of NDF were formulated. All diets had equal in vitro NDF digestibility. In vivo NDF digestibility did not differ among diets but was higher than in vitro estimates. Replacing NDF with starch did not negatively affect NDF digestibility but did reduce energy digestibility. Based on rumen measurements and digestibility, NDF from a mixture of soybean hulls and cottonseed hulls was equal to NDF from corn silage.
Impacts
Organic forms of trace minerals such as manganese and selenium are much more expensive than inorganic sources. In a series of experiments we showed that there was little difference between organic and inorganic sources when fed to dairy cows. This means that dairy farmers can often feed the less expensive sources thereby reducing feed costs. However, feeding organic selenium greatly increased the concentration of selenium in milk. Because of potential anti-carcinogenic properties of Se this may have human health benefits.
Publications
- Beckman, J.L., and W.P. Weiss. 2005. Nutrient digestibility of diets with different fiber to starch ratios when fed to lactating dairy cows. J. Dairy Sci. 88:1015-1023.
- Weiss, W.P., and M.T. Socha. 2005. Manganese retention in dry and lactating Holstein cows. J. Dairy Sci. 88:2517-2523.
- Weiss, W.P., and J.S. Hogan. 2005. Effect of selenium source on selenium status, neutrophil function, and response to intramammary endotoxin challenge of dairy cows. J. Dairy Sci. 88:4366-4374.
- T. D. Nennich, J. H. Harrison, L. M. VanWieringen, D. Meyer, A. J. Heinrichs, W. P. Weiss, N. R. St-Pierre, R. L. Kincaid, D. L. Davidson, and E. Block. 2005. Prediction of Manure and Nutrient Excretion from Dairy Cattle. J. Dairy Sci. 88: 3721-3733.
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Progress 01/01/04 to 12/31/04
Outputs
Experiment 1 was designed to determine the effect of increasing dietary starch concentration (and decreasing fiber concentration) on nutrient digestibility and manure excretion in dairy cows. Three diets were formulated that contained 42% corn silage, 34.8, 29.1, or 23.3% ground corn, and 0, 5.6, or 11.2% of a mixture containing cottonseed hulls and soybean hulls were fed to lactating dairy cows. The 30 hour in situ digestibility of NDF was equal in all diets. The excretion of feces, urine, and total manure (wet basis) linearly decreased as the concentration of corn grain in the diet increased. Digestibility of dry matter and energy decreased linearly as corn grain decreased by digestibility of other nutrients was not affected greatly by diet. Experiment 2 was conducted to determine bioavailability of manganese sources to dry dairy cows. Dry cows were fed a control diet (no supplemental manganese) or diets with supplemental manganese from manganese sulfate or from
manganese methionine. Source of supplemental manganese had little effect on manganese absorption, excretion, or blood concentrations. However, absorption of manganese (as a percent of manganese intake) was higher for cows fed supplemental manganese. In an ancillary experiment, a meta-analysis of data from previous experiments was conducted. Based on manganese retention data, a dietary concentration of approximately 28 mg of manganese per kilogram of dry matter intake was needed to obtained a manganese retention of 0 mg/day. This value is approximately two times higher than the NRC requirement for manganese.
Impacts
Estimating the concentration of energy that is digested when fed to cows is extremely important. Diets that do not provide adequate digestible energy will not support high levels of milk production. Experimental data showed that the model of the National Research Council accurately estimated digestible energy in diets. In a second experiment we determined that the vitamin C concentration in milk is markedly reduced when cows have mastitis. Milk from cows with mastitis is low quality and because vitamin C is a potent antioxidant in milk, milk from cows with mastitis will also be much more prone to developing off flavor caused by oxidation. In two other experiments, factors affecting digestibility of magnesium and phosphorous were determined. We developed equations that accurately estimated phosphorous excretion by dairy cows that can be used in nutrient management programs. We also developed equations that will allow accurate supplementation of magnesium when diets
contain high concentrations of potassium. This should help prevent magnesium deficiencies from developing in dairy cows.
Publications
- Weiss, W.P. , J.S. Hogan, and K.L. Smith. 2004. Changes in vitamin C concentrations in plasma and milk from dairy cows after an intramammary infusion of Escherichia coli. J. Dairy Sci. 87:32-37.
- Weiss, W. P., and D. J. Wyatt. 2004. Digestible energy values of diets with different fat supplements fed to lactating dairy cows. J. Dairy Sci. 87:1446-1454.
- Weiss, W.P. 2004. Macromineral digestion by lactating dairy cows: Factors affecting digestibility of magnesium. J. Dairy Sci. 87:2167-2171
- Weiss, W. P. And D. J. Wyatt. 2004. Macromineral digestion by lactating dairy cows: Estimataing phosphorous excretion via manure. J. Dairy Sci. 87:2158-2166.
- Weiss, W.P., and M. T. Socha. 2004. Manganese for lactating and dry dairy cows. J. Dairy Sci. 87 (suppl. 1): 118 (abstract).
- Nennich, T.D., J.H. Harrison, D. Meyer, W. Weiss, N. R. St-Pierre, R. Kincaid, M. Wattiaux, and D. Davidson. 2004. Evaluation of prediction equations for estimating urinary output of nitrogen in lactating dairy cows. J. Dairy Sci. 87 (suppl. 1):162 (abstract).
- Weiss, W.P. 2004. Randomness rules: Living with variation in the nutrient composition of concentrate feeds. Pp. 39-46. Proc. Midsouth Ruminant Nutr. Conf., Arlington, TX.
- Weiss, W.P. 2004. Fine-tuning energy calculations. Pp. 131-142. Proc. Tri-state Dairy Nutr. Conf., Ft. Wayne, IN.
- Weiss, W.P. 2004. Factors affecting manure excretion by dairy cows. Proc. Cornell Animal Nutr. Conf. Pp 11-20.
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Progress 01/01/03 to 12/31/03
Outputs
Experiment 1 was conducted to compare measured digestible energy concentrations of diets with different fat supplements to digestible energy values estimated using the dairy NRC model. High producing (milk yield = 42 kg/d) Holstein cows were fed one of five diets that differed in concentration and type of supplemental fat. Nutrient digestibility, including digestible energy, was measured by total collection of feces and urine. The measured digestible energy concentration of the control diet (no supplemental fat) was 2.97 Mcal/kg, identical to the value estimated using the NRC model. The diets with 1.7 or 3.4% added fatty acids from calcium salts of palm fatty acids had measured digestible energy concentrations of 3.04 and 3.16 Mcal/kg compared with estimated values of 3.01 and 3.13 Mcal/kg. The two diets with an experimental type of supplemental fat had measured digestible energy concentrations of 2.97 and 2.97 Mcal/kg compared to an estimated values of 2.96 and 2.97
Mcal/kg. For these diets, the NRC model accurately estimated digestible energy concentrations. Experiment 2 was conducted to determine whether feeding dairy cows supplemental fat influenced the concentration of tocopherol (vitamin E) in milk. Diets with no supplemental fat, tallow, or roasted soybeans with 25, 125, or 250 IU of supplemental vitamin E/kg were fed to dairy cows. Cows fed diets with supplemental fat (tallow and roasted soybeans) had significantly higher concentrations of tocopherol in plasma compared to cows fed the control diets but concentrations of tocopherol in milk were not affected by fat supplementation. Fat supplementation had no effect on concentrations of tocopherol in plasma when they were expressed relative to plasma cholesterol. The concentration of tocopherol in milk increased linearly as the concentration of tocopherol in plasma expressed per unit of plasma cholesterol increased. Data from this experiment suggests that in order to increase the tocopherol
concentration in milk, the lipid pool of plasma (not total plasma) must be enriched with tocoperhol. Experiment 3 was conducted to determine factors affecting magnesium absorption by dairy cows. Digestibility of magnesium by lactating dairy cows was measured using total collection of feces and urine. Cows were fed 39 different diets that varied in forage source, fiber concentration, type of byproduct, and fat supplementation. Magnesium digestibility averaged 18% (range was -3.8 to 33.3%). The average value was 30% lower than the average digestibility estimated by NRC. The primary factor causing reduced magnesium digestibility was the concentration of potassium in the diet. Equations were developed that can be used to adjust magnesium supplementation to ensure adequate intake of digestible magnesium when diets contain excessive concentrations of potassium.
Impacts
Estimating the concentration of energy that is digested when fed to cows is extremely important. Diets that do not provide adequate digestible energy will not support high levels of milk production. Experimental data showed that the model of the National Research Council accurately estimated digestible energy in diets. Milk that contains higher than normal concentrations of vitamin E should have a longer shelf life and be more nutritious when consumed. Another experiment determined that the vitamin E concentration of milk can be increased only if the concentration of vitamin E in the lipid fraction of cows is increased. This means that when dairy cows are fed diets supplemented with fat, additional vitamin E must also be fed to maintain concentrations of vitamin E in milk. In the last experiment, the effect of dietary potassium on magnesium digestibility was determined. Under field conditions, dairy cows can develop magnesium deficiencies. Equations were developed
that will allow accurate supplementation of magnesium when diets contain high concentrations of potassium.
Publications
- Weiss, W.P., and Wyatt, D.J. 2003. Effect of dietary fat and vitamin E on a-tocopherol in milk from dairy cows. J. Dairy Sci. 86:3582-3591
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Progress 01/01/02 to 12/31/02
Outputs
Experiment 1. Eight midlactation Holstein cows were fed one of four different diets in a replicated Latin square experiment. Diets consisted of silage made from a standard dual purpose corn hybrid or a hybrid that was selected to have higher than average neutral detergent fiber concentrations (NDF) and higher than average in vitro NDF digestibility (IVNDFD). Two diets contained the same concentration of corn silage from the two different hybrids and two diets contained the same concentration of NDF from corn silage. As expected, the high fiber, high digestible silage had higher NDF (49.0 vs. 42.4%) and higher IVNDFD (46.3 vs. 41.5%). However, higher IVNDFD did not correspond to higher in vivo NDF digestibility. No differences were observed in concentrations of measured total digestible nutrients between hybrids, dry matter intake, or milk production. Experiment 2. The vitamin E concentration in meat from lambs grazing alfalfa or ryegrass were compared to that of lambs
fed all concentrate diets with 15, 150, or 300 IU of supplemental vitamin E/kg. The vitamin E concentration in muscle of grazing lambs were similar to that of lambs fed all concentrate diets with 150 IU of supplemental vitamin E. Some color measurements of the meat after storage were improved by vitamin E supplementation. Experiment 3. Lactating dairy cows were fed diets that contained 25, 125, or 250 IU of supplemental vitamin E/kg with no supplemental fat, or 2.25% added fat from tallow or roasted soybeans. Vitamin E concentrations in plasma linearly increased with increasing vitamin E and were higher when cows were supplemented with fat. Milk vitamin E increased linearly with increasing dietary vitamin E but was not affected by fat supplementation. Equations were developed to estimate transfer of vitamin E from diet to plasma to milk.
Impacts
Corn silage with higher than average concentrations of fiber are equal to typical corn silage but increase the yield of fiber per acre which might result in lower feed costs to dairy farmers Meat from grazing lambs had high concentrations of vitamin E which might results in greater shelf life and improved nutrition of consumers of lamb Feeding high vitamin E diets to dairy cows increases milk vitamin E only slightly. Therefore it is unlikely that diet supplementation will have a great impact on vitamin E content of milk.
Publications
- Turner, K.E., K.E. McClure, W.P. Weiss, R.J. Borton, and J.G. Foster. 2002. Alpha-tocopherol concentrations and case life of lamb muscle as influenced by concentrate or pasture finishing. J. Anim. Sci. 80:2513-2521.
- Weiss, W. P. and D. J. Wyatt. 2002. Effects of feeding diets based on silage from corn hybrids that differed in concentration and in vitro digestibility of neutral detergent fiber to dairy cows. J. Dairy Sci. 85:3462-3469.
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Progress 01/01/01 to 12/31/01
Outputs
Experiment 1. Lactating dairy cows were fed a control diet with ingredients naturally high in selenium (Se concentration of 0.2 mg per kg dry matter) or the same diet plus selenized yeast to make total diet Se concentration 0.5 mg per kg of dry matter. Concentrations of Se in milk and plasma were measured. Cows fed the control diet had milk Se concentrations much higher than usually obtained when selenite is supplemented (0.035 mg per liter). Cows fed the supplemented diet had much higher milk concentrations (0.078 mg per liter). Blood plasma concentrations were elevated with supplementation but the difference between treatments was much less than that found for milk. Experiment 2. Lactating cows were fed supplemental biotin (0, 10, or 20 mg per day) starting 14 days prepartum and continuing the first 100 days of lactation. Biotin supplementation increased milk production and also significantly increased concentrations of biotin in milk. Cows fed the control diet
averaged 22 ng of biotin per ml of milk. Cows fed 20 mg averaged about 70 ng per ml. Biotin supplementation at 20 mg per day increased concentrations of biotin in colostrum by more than 20 times (15 ng per ml for control and 306 ng per ml for treatment). Experiment 3. Lactating cows were fed a control diet that provided 0, 3, 16, or 30 g of ascorbic acid (vitamin C) per day. Concentrations of ascorbic acid in milk were not affected by dietary supplementation, however concentrations in plasma were increased. Based on a kinetic analysis transfer of ascorbic acid into milk was already at its Vmax when no supplemental ascorbic acid was fed.
Impacts
The diet a dairy cow eats can influence the nutritional value of the milk. We are conducting experiments to determine whether we can increase the concentrations of trace minerals and vitamins in milk. This should result in improved nutrition of humans. We found that the selenium concentration of milk can be increased by more than three times above normal concentrations. Biotin concentration in milk could be more than doubled. Dietary modification, however, did not affect vitamin C concentrations in milk.
Publications
- Weiss, W.P. 2001. Effect of dietary vitamin C on concentrations of ascorbic acid in plasma and milk. J. Dairy Sci. 84:2302-2307
- Zimmerly, C.A., and W.P. Weiss. 2001. Effects of supplemental dietary biotin on performance of Holstein cows in early lactation. J. Dairy Sci. 84:498-506.
- Ivancic, Jr., J., and W. P. Weiss. 2001. Interactions between dietary sulfur and selenium on selenium balance of lactating Holstein cows. J. Dairy Sci. 84:225-232.
- Timmons, J. S., W. P. Weiss, D. L. Palmquist, and W. J. Harper. 2001. Contribution of dietary roasted soybeans and milk composition to the development of spontaneous oxidized flavor in milk. J. Dairy Sci. 84:2440-2449.
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