Location: Dairy Forage Research2019 Annual Report
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.
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.
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 is being evaluated in a long-term, collaborative study (Objective 1). 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 study will evaluate how the dosing of different rumen inoculums may impact feed intake, body weight, and structural growth of the calves from weaning until calving at approximately two years of age. Body weight and structural growth of the animal will also be recorded at calving and near the end of the first lactation. This has been added to the existing experiment to provide growth information of each animal from birth to the end of the first lactation. Two studies were conducted to evaluate the inclusion of brown-midrib (BMR) sudangrass silage as an alternative to traditional forages such as corn silage and alfalfa silage in lactating dairy cow diets (Objective 2.A). Laboratory analysis has been completed except for the in vivo digestibility of diets. A manuscript related to production responses of cows fed sudangrass silage is currently in preparation and will be submitted once digestibility data is completed. A study was conducted to evaluate the ability of lactating dairy cows to maintain their feed efficiency when the nutrient composition of diet was altered (Objective 2.A). Improving feed efficiency of dairy cows is a key component for dairy farmers to maintain milk production when using fewer resources, particularly feeds that are in direct competition with human and non-ruminant animal consumption. In this study, cows were fed either a traditional control diet formulated with corn grain (high starch diet) or a higher forage diet formulated without corn grain (low starch diet). Lactation performance, nutrient digestibility, and feed efficiency were evaluated for cows fed either the high starch or low starch diet. In addition, rumen microbiome samples, blood samples, and liver and mammary biopsies were taken on a subset of these cows to evaluate the relationship of diet on feed efficiency of individual dairy cows. A study was conducted to evaluate the replacement of concentrate feeds with alternative/byproducts feeds in lactating dairy cow diets (Objective 2.B). Alkaline-treated corn stover pelleted with soybean meal or distillers grains was evaluated in lactating dairy cow diets. Laboratory analysis has been completed except for the in vivo digestibility of diets. A manuscript related to production responses of cows fed alkaline-treated corn stover pellet as a replacement for concentrate feeds has been written and will be submitted once digestibility data is completed.
1. Use of brown midrib (BMR) sudangrass as a replacement for traditional forages in dairy cow diets. 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. Recent research by ARS researchers at Madison, Wisconsin, demonstrated that 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 sudangrass silage was included at 20 and 30% of the diet. In a 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 grown to reduce water use on farms can be used as replacement for corn silage and alfalfa silage at 10% inclusion levels without negatively affecting milk production by dairy cows.
2. Use of treated-stover pelleted feedstuffs in dairy cattle diets. Use of treated-stover pelleted feedstuffs in dairy cattle diets. Corn stover has historically been used as an inexpensive bedding source for dairy cows or a cost-effective replacement 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 are limited or expensive. Recent research by ARS researchers at Madison, Wisconsin, demonstrated that the inclusion of an alkaline-treated corn stover pelleted with soybean meal or distillers grains into lactating dairy cow diets 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 used as an alternative forage source for feeding cows when traditional feedstuffs are in limited supply or not available.
Ranathunga, S.D., Kalscheur, K., Anderson, J.L., Herrick, K.J. 2018. Production of dairy cows fed distillers dried grains with solubles in low- and high-forage diets. Journal of Dairy Science. 101(12):10886-10898. https://doi.org/10.3168/jds.2017-14258.
Coblentz, W.K., Akins, M.S., Kalscheur, K., Brink, G.E., Cavadini, J.S. 2018. Effects of growth stage and growing degree day accumulations on triticale forages: 1) Dry matter yield, nutritive value, and in-vitro dry matter disappearance. Journal of Dairy Science. 101(10):8965-8985. https://doi.org/10.3168/jds.2018-14868.
Coblentz, W.K., Akins, M.S., Kalscheur, K., Brink, G.E., Cavadini, J.S. 2018. Effects of growth stage and growing degree day accumulations on triticale forages: 2) In-vitro disappearance of neutral detergent fiber. Journal of Dairy Science. 101(10):8986-9003. https://doi.org/10.3168/jds.2018-14867.
Ranathunga, S.D., Kalscheur, K., Garcia, A.D., Schingoethe, D.J. 2018. Fermentation characteristics and feeding value of ensiled wet corn distillers grains in combination with wet beet pulp. Professional Animal Scientist. 34(4):346-355. https://doi.org/10.15232/pas.2018-01727.
Sanchez-Duarte, J.I., Kalscheur, K., Garcia, A.D., Contreras-Govea, F.E. 2019. Short communication: Meta-analysis of dairy cows fed conventional sorghum or corn silages compared to brown midrib sorghum silage. Journal of Dairy Science. 102(1):419-425. https://doi.org/10.3168/jds.2018-14552.
Sikora, M.C., Hatfield, R.D., Kalscheur, K. 2019. Fermentation and chemical composition of high-moisture lucerne leaf and stem silages harvested at different stages of development using a leaf stripper. Grass and Forage Science. 74(2):254–263. https://doi.org/10.1111/gfs.12423.