Location: Dairy Forage Research
2023 Annual Report
Objectives
Objective 1: Develop and evaluate dietary feed formulation strategies that increase the utilization of conventional feeds/forages and alternative feeds/forages that reduce competition with human food consumption, increase milk production, enhance nutrient use efficiency, and reduce greenhouse gas emissions in dairy production systems.
Sub-objective 1.A: Evaluate effects of forage type, amount, and quality on animal performance, nutrient digestibility, and feed conversion efficiency.
Sub-objective 1.B: Evaluate effects of alternative/byproducts feeds that replace or reduce traditional concentrate feeds in the diet on animal performance, nutrient digestibility, feed conversion efficiency, and gas emissions.
Sub-objective 1.C: Evaluate the inclusion of feed additives to forage-based diets on animal performance, nutrient digestibility, feed conversion efficiency, and gas emissions.
Objective 2: Develop and evaluate dietary feed formulation strategies using partial mixed rations (PMR), based on forage base, nutrient composition and feed physical form, to enhance individual animal feed efficiency and reduce environmental impact of dairy farms.
Sub-objective 2.A: Evaluate individual animal energetic usage and efficiency based on plane of nutrition and management that can impact feeding in a Partial Mixed Ration (PMR) system.
Sub-objective 2.B: Evaluate effects of one versus two feeds, nutrient composition, and feed forms on feed efficiency, precision data collected, environmental impacts and measurements within and between individual or small groups of cows using a PMR.
Objective 3: Evaluate the effects of forage/feed type and soil health management interventions on farm carbon balance, nutrient losses, and milk productivity and quality in dairy production systems.
Sub-objective 3.A: Evaluate soil health factors for their effects on forage productivity and nutritive value, to inform management practices and forage selection that will improve milk yield and quality.
Approach
Objective 1. A series of dairy cattle studies will be conducted to evaluate the effect of forage type, forage amount, and forage quality on animal performance, nutrient digestibility, and feed conversion efficiency. In addition, alternative forages and byproduct feedstuffs will be evaluated as replacements for traditional feedstuffs used in dairy cattle diets. Inclusion of feed additives to forage-based diets will be evaluated for animal performance, nutrient digestibility, feed conversion efficiency, and gas emissions. We will collect production measurements, rumen samples, feces, urine and gaseous emissions to determine the effects of altering fiber digestibility on ruminal fermentation, lactation performance, and environmental output.
Objective 2. A series of dairy cattle studies will be conducted to evaluate dietary feed formulation strategies using partial mixed rations (PMR), based on forage base, nutrient composition and feed physical form, to enhance individual animal feed efficiency and reduce environmental impact of dairy farms. In the first study, calves born to either nutrient-restricted dams and nutrient-sufficient dams will be followed through to adulthood to determine whether nutrient-restricted heifers with emit be less productive and have greater environmental impact due to reduced productive efficiency relative to their herdmates. In a second study, cows will be evaluated on how milking permissions in automatic milking systems impact animal metabolism. In a third study, the effects on a one or two feed system, nutrient composition and feed forms of cows fed a partial mixed rations will be evaluated for production measures, feed efficiency, and environmental impacts.
Objective 3. Two exploratory field investigations and a greenhouse trial are planned to evaluate the effects of forage/feed type and soil health management interventions on farm carbon balance, nutrient losses, and milk productivity and quality in dairy production systems. Field investigations will investigate fields with different management and land cover differences to determine whether specific soil health indicators are positively correlated with forage nutritive quality or digestibility. A greenhouse trial will be conducted implementing a factorial arrangement of treatments with the following factors: soil source, crop type (corn silage, alfalfa) and water availability (optimal vs 50% optimal water availability). 4 x 2 x 2 factorial design with the following factors: soil source, crop type (corn silage, alfalfa) and water availability (optimal vs 50% optimal water availability). Optimal water availability will be determined based on the field capacity of soils, with 50% of field capacity for the drought treatment. This trial will 1) determine the effects of soil health indicators on forage quality and productivity; 2) Compare input costs for soil source x crop type for an assessment of production efficiency; and 3) Compare carbon assimilation and water use efficiency of crops under varied soil conditions.
Progress Report
For Objective 1, a study was conducted to evaluate the effects of forage level and branched-chain fatty acids supplementation on milk composition and yield and on changes in the rumen microbiome of dairy cows (Objective 1.A). Branched-chain fatty acids are produced by rumen microorganisms and previous studies conducted have demonstrated that branched-chain fatty acids may protect people against inflammation and metabolic diseases when consumed in food. Branched-chain fatty acids are increased in milk when cows consumed high levels of forages in the diet. In addition, branched-chain fatty acids can be supplemented in the diet. Laboratory analysis is currently underway. Additional analysis will be completed before a manuscript can be written.
A study was conducted to evaluate diets formulated with first-cutting reduced-lignin alfalfa silage compared to first-cutting conventional alfalfa silage at two different harvest intervals on lactation performance, nutrient digestibility, and rumen fermentation of lactating dairy cows (Objective 1.A). Improvements in fiber digestibility will allow producers to formulate greater amounts of forages in diets without compromising milk yield resulting in similar or more milk production at lower input costs. Laboratory analysis has not yet started. Once sample analysis and statistical analysis has been completed, a journal manuscript will be written.
A study was conducted to evaluate the effects of alternative/byproduct feeds (canola meal) to replace or reduce traditional concentrate feeds (soybean meal) in the diet on animal performance, nutrient digestibility, and feed conversion efficiency (Objective 1.B). In addition, an additional objective was to determine whether cows identified as high efficiency cows respond with production increases when fed canola meal compared to soybean meal more efficiently than low efficiency cows, thereby increasing the environment sustainability of milk production. Cows designated as either high or low efficiency did not utilize either canola meal based or soybean meal based diets more effectively for milk production, however cows fed canola meal had greater milk persistency over time compared to cows fed soybean meal regardless of whether they were identified as high efficiency or low efficiency. Laboratory analysis has been conducted and a manuscript is currently in preparation.
For Objective 2, an on-going study is being conducted to accomplish Sub-objective 2.A, Hypothesis 2.A.1. Evaluate individual animal energetic usage efficiency, microbiome, blood metabolites and growth parameters in calves based on the maternal plane of nutrition. As animals age the addition of enteric greenhouse gas production will be measured. All experimental animals have been born, n= 38 females (20 control, 18 nutrient restricted), and n = 26 males (11 control, 15 nutrient restricted). Data has been collected through 60 days of age for individual starter and milk intake, growth and body measurements, and blood metabolite measurements. Control heifers have greater average daily gain and body size compared to nutrient restricted heifers. Opposingly, bulls born to nutrient restricted dams have greater average daily gain and size compared to control bulls. Heifers have been sampled since six months of age and will continue through their first lactation. Laboratory analysis is on-going. Once sample analysis and statistical analysis has been completed, multiple manuscripts will be written.
Two experiments were conducted to meet Hypothesis 2.A.2. One study evaluated changes in milking permissions or milking frequency in automatic milking systems on animal stress, as indicated by increased cortisol, activity and heart rate in Holstein and Jersey dairy cows. Milk yield was not impacted by increasing milking permissions from six to four times per day. However, stress responses from cows including lower lying time, greater idling time, tail switching and stepping. Stronger behavioral changes, stress response, and activity were measured for multiparous cows. Additional laboratory analysis is on-going to support manuscripts for fiscal year 2024.
The second pilot lactation study evaluated milking permissions in automatic milking systems and their impact on animal metabolism, and rumen and animal transcriptome in early lactation. Milk yield, milk fat content, and pellet intake were greater when cows were milked six times versus three times per day. Increases in blood fatty acids, lower beta-hydroxyburytate, and lower rumen butyrate concentrations in cows milked six times suggest nutrient partitioning to support greater milk production, particularly in three and greater parities. Laboratory analysis has been conducted and a manuscript is currently in preparation. Additional laboratory analysis is on-going to support manuscripts for fiscal year 2024.
In support of Objective 3.A, Evaluate soil health factors for their effects on forage productivity and nutritive value to inform field management practices and forage selection that will improve milk productivity and quality, research continued investigating the relationships among soil health and forage productivity and its nutritive value. A greenhouse research trial completed in March 2023. Laboratory analysis is currently underway.
Accomplishments
1. Canola meal supplementation in dairy cow diets improved milk production for both high and low efficiency dairy cows. Canola meal is a high protein, high fiber byproduct produced from the canola oil industry, and ARS previously demonstrated that supplementing dairy cattle diets with it increases milk production. However, effects of canola supplementation on dairy cows determined to be either high efficiency or low efficiency has not been evaluated. ARS researchers at Madison, Wisconsin, demonstrated that cows designated as either high or low efficiency did not utilize either canola containing or soybean containing diets more effectively for milk production, however cows fed canola meal had greater milk persistency over time compared to cows fed soybean meal regardless of whether they were identified as high efficiency or low efficiency. These findings demonstrate to dairy producers that canola meal is an effective protein supplement for all cows to improve intake and milk production, no matter the animal’s calculated efficiency level.
Review Publications
Coates, L.C., Durham, S., Storms, D.H., Magnuson, A.D., Van Hekken, D.L., Plumier, B.M., Finley, J.W., Fukagawa, N.K., Tomasula, M.M., Lemay, D.G., Picklo, M., Barile, D., Kalscheur, K., Kable, M.E. 2023. Associations among milk microbiota, milk fatty acids, milk glycans, and inflammation from lactating Holstein cows. Microbiology Spectrum. 11(3). Article e04020-22. https://doi.org/10.1128/spectrum.04020-22.
Fischer, A., Dai, X., Kalscheur, K. 2022. Feed efficiency of lactating Holstein cows is repeatable within diet but less reproducible when changing dietary starch and forage concentrations. Animal-The International Journal of Animal Biosciences. 16(8). Article 100599. https://doi.org/10.1016/j.animal.2022.100599.
Dai, X., Kalscheur, K., Huhtanen, P., Faciola, A.P. 2022. Effects of ruminal protozoa on methane emissions in ruminants – A meta-analysis. Journal of Dairy Science. 105(9):7482-7491. https://doi.org/10.3168/jds.2021-21139.
Pintens, D.A., Shinners, K.J., Friede, J.C., Digman, M.F., Kalscheur, K. 2023. Altering physical properties of wilted alfalfa by impact – shredding processing. Applied Engineering in Agriculture. 39(2):187-195. https://doi.org/10.13031/aea.15168.
Pintens, D.A., Shinners, K.J., Friede, J.C., Digman, M.F., Kalscheur, K. 2023. Impact-shredding processing of whole-plant corn: Machine performance, physical properties, and in situ ruminant digestion. Agriculture Journal. 13(1). Article 160. https://doi.org/10.3390/agriculture13010160.
