Location: Dairy Forage Research
2022 Annual Report
Objectives
Objective 1: Develop and evaluate strategies that optimize growth and development; maximize feed nutrient use efficiency; increase milk production potential; and increase the lifetime productivity, health, and well-being of dairy heifers.
Objective 2: 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, enhance nutrient use efficiency, and increase milk production.
• Sub-objective 2.A. Evaluate effects of forage type, amount, and quality on animal performance, nutrient digestibility, and feed conversion efficiency.
• Sub-objective 2.B. Evaluate effects of alternative/byproduct feeds that replace or reduce grain in the diet on animal performance, nutrient digestibility, and feed conversion efficiency.
Objective 3: Develop and evaluate dairy diets that enhance milk production and quality, reduce manure nutrient excretions, and reduce environmental impacts of dairy farms.
Approach
Objective 1. Dry matter intake, body weight, and growth measurements at prepubertal (6 months of age) and postpubertal (12 months of age) stages of dairy heifers growth will be determined as part of a study that will help us determine whether efficiency of growth changes during the lifetime of the dairy animal. Growth measurements for prepubertal and postpubertal dairy heifers will be combined with calfhood and mature cow measurements to evaluate if growth efficiency is correlated through the lifespan of a dairy animal.
Objective 2. A series of lactating dairy cow 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 cow diets. We will collect production measurements, gaseous emissions, digesta, and feces to determine the effects of altering fiber digestibility on ruminal fermentation, lactation performance, and environmental output.
Objective 3. Several studies will be conducted to evaluate dairy diets that enhance milk production, reduce nutrient excretion, and reduce the environmental impacts of dairy production systems. Cows will be fed diets with differing ratios of alfalfa silage and corn silage at high and low forage inclusions and at different dietary crude protein concentrations to evaluate the effect of diet formulation on production measures, gas emissions, and nutrient excretion. Manure collected from these experiments will further studied in laboratory emission chambers to determine effect of manure chemistry on gaseous emission during storage. Stored manure will then be applied to a field to determine plant nutrient uptake during a growing season. Gas measurements will be taken to evaluate the impact of manure application on carbon dioxide, ammonia, and nitrous oxide emissions.
Progress Report
This is the final report for this project which will terminate in August 2022. The new project is titled “Forage and Feed Characteristics on Performance, Feed Efficiency, Environmental Impact, and Farm Nutrient Cycling of Dairy Production Systems” (Project # 5090-31000-027-000D).
For Objective 1, one study was conducted to evaluate strategies that optimize growth and development, maximize feed nutrient use efficiency, and increase the milk production potential, lifetime productivity, health, and well-being of dairy heifers. In this study, the impact of dosing newborn and pre-weaned calves with rumen fluid from cows with different milk production efficiency status on intake, structural growth, and feed efficiency at different stages of growth was evaluated in a long term, collaborative study. Calves were inoculated with one of three types of rumen fluid: 1) from a cow with high milk production efficiency, 2) from a cow with low milk production efficiency, and 3) a control treatment containing a sterilized mixture of the two rumen fluids. This portion of the larger collaborative study evaluated how the dosing of different rumen inoculums impact feed intake, body weight, and structural growth of the calves from weaning until calving at approximately two years of age. Inoculation with different types of rumen fluid did not affect intake, structural growth or feed efficiency of the growing dairy heifer. Inoculation of different rumen fluid did not alter growth performance of dairy heifers.
For Objective 2, studies were conducted to evaluate dietary feed formulation strategies that increase the utilization of conventional feeds/forages and alternative feeds/forages that reduce competition with human food consumption, enhance nutrient use efficiency, and increase milk production. For Sub-objective 2.A., several studies were completed to evaluate the effect of forage type, forage amount, and forage quality on animal performance, nutrient digestibility, and feed conversion efficiency. Inclusion of reduced-lignin varieties of alfalfa are proposed as a way to increase forage concentrations in lactating dairy cow diets without decreasing lactation performance. Higher forage diets often decrease intake resulting in lower milk production; however, reduced-lignin varieties of alfalfa may potentially result in higher overall nutrient digestibility and greater rates of passage in the rumen, resulting in similar milk production to a control diet at lower forage concentrations. In one study, the substitution of non-forage fiber feedstuffs of up to 18% of the diet with a high-quality alfalfa silage decreased dry matter intake without affecting milk production. In addition, milk fat percentage and milk fat yield increased with increasing concentration of forage in the diet. Because milk production was unaffected by diet, feed conversion efficiency increased linearly from 1.63 to 1.83 when high quality alfalfa increased in the diet. These findings demonstrate to dairy producers that high quality, highly digestible alfalfa silage can be used as replacement for purchased protein and non-fiber feedstuffs without negatively affecting milk production, while improving the dairy cow’s ability to convert feed to milk. In a second study, diets were formulated with two types of corn silages [conventional corn silage (CS) and brown midrib corn silage (BMR)] and two types of alfalfa haylages [conventional (AH) alfalfa haylage and reduced- lignin (RL) alfalfa haylage] to determine if fiber digestibility affected lactation performance and methane (CH4) emissions of lactating dairy cows. In this experiment, the type of forage formulated into the diet did not affect dry matter intake or milk yield, however methane production was affected by the type of forage included in the total mixed ration.
Forages that use less water but are high in digestibility are sought as alternatives to corn silage. Brown midrib varieties of sudangrass are one possible alternative that can provide a high-quality summer forage as a replacement for corn silage. Also, as part of Sub-objective 2.A, two studies were conducted to evaluate sudangrass silage in lactating dairy cow diets. In the first experiment, lactation performance for cows fed brown midrib sudangrass silage compared to cows fed brown midrib corn silage and alfalfa silage was not different when included at 10% of the diet, but dry matter intake and milk yield decreased as brown midrib sorghum silage was included at 20% and 30% of the diet. In the second experiment, inclusion of 10% brown midrib sudangrass silage as a replacement for either conventional or brown midrib corn silage also did not affect intake or milk yield. These findings demonstrate to dairy producers that brown midrib sudangrass can be used as replacement for corn silage and alfalfa silage at 10% inclusion levels without negatively affecting milk production.
Corn stover historically has been used as an inexpensive bedding source for dairy cows or as a cost-effective alternative feed for cattle. Poor fiber digestibility of corn stover has limited its use in diets of lactating dairy cows. Treating corn stover with calcium hydroxide increases its fiber digestibility resulting in a feedstuff that could be used as a forage when traditional forages or limited or expensive. As part of Sub-objective 2.B, one study was conducted to evaluate the inclusion of an alkaline-treated corn stover pelleted with soybean meal or distillers grains into lactating dairy cow diets. The inclusion of the corn stover pellet decreased dry matter intake resulting in lower milk production. However, the conversion of feed to milk production (production efficiency) was similar or slightly improved for cows fed the treated corn stover pellet compared to the control diet. These findings demonstrate to dairy producers that alkaline–treated corn stover could be an alternative forage source when traditional feedstuffs are unavailable or limited.
Improving feed efficiency is a key component for dairy farmers to maintain or improve production while using fewer resources, especially by decreasing feedstuffs that are directly edible for human or non-ruminant consumption.
The determination of whether dairy cows are efficient on a high forage diet compared to a high starch diet or vice versa, would help producers select cows for specific types of dairy feeding systems. One study was completed demonstrating that lactating dairy cows were more able to maintain their feed efficiency when they were fed the same diet than when their diet was changed. These findings demonstrate to dairy producers and the scientific community that feed efficiencies should be considered within the same diet to avoid any misidentification of cows as most or least efficient.
For Objective 3, there was a critical vacancy, and the proposed experiments were not completed.
Accomplishments
Review Publications
Sikora, M.C., Hatfield, R.D., Kalscheur, K. 2021. Impact of long-term storage on alfalfa leaf and stem silage characteristics. Agronomy Journal. 11(12). Article 2505. https://doi.org/10.3390/agronomy11122505.
Coates, L.C., Storms, D.H., Finley, J.W., Fukagawa, N.K., Lemay, D.G., Kalscheur, K., Kable, M.E. 2022. A low starch and high fiber diet intervention impacts the microbial community of raw bovine milk. Current Developments in Nutrition. 6(6). Article nzac086. https://doi.org/10.1093/cdn/nzac086.
Durham, S.D., Lemay, D.G., Wei, Z., Kalscheur, K., Finley, J.W., Fukagawa, N.K., Barile, D. 2022. Dietary fiber to starch ratio affects bovine milk Oligosaccharide profiles. Current Developments in Nutrition. 6/6. https://doi.org/10.1093/cdn/nzac033.
Harnly, J.M., Picklo, M., Bukowski, M.R., Kalscheur, K., Magnuson, A.D., Fukagawa, N.K., Finley, J.W. 2021. Deriving information from complex data sets: Impact of forage on fatty acids in cow milk. Journal of Food Composition and Analysis. 107:104179. https://doi.org/10.1016/j.jfca.2021.104179.
Pintens, D.A., Shinners, K.J., Friede, J.C., Kalscheur, K., Digman, M.F., Combs, D.K. 2022. Intensive mechanical processing of forage crops to improve fibre digestion. Grass and Forage Science. 77(1):55-65. https://doi.org/10.1111/gfs.12559.
