Publications by authors named "K F Kalscheur"

70 Publications

Key Considerations for the Use of Seaweed to Reduce Enteric Methane Emissions From Cattle.

Front Vet Sci 2020 23;7:597430. Epub 2020 Dec 23.

Foundation for Food and Agriculture Research, Washington, DC, United States.

Enteric methane emissions are the single largest source of direct greenhouse gas emissions (GHG) in beef and dairy value chains and a substantial contributor to anthropogenic methane emissions globally. In late 2019, the World Wildlife Fund (WWF), the Advanced Research Projects Agency-Energy (ARPA-E) and the Foundation for Food and Agriculture Research (FFAR) convened approximately 50 stakeholders representing research and production of seaweeds, animal feeds, dairy cattle, and beef and dairy foods to discuss challenges and opportunities associated with the use of seaweed-based ingredients to reduce enteric methane emissions. This article describes the considerations identified by the workshop participants and suggests next steps for the further development and evaluation of seaweed-based feed ingredients as enteric methane mitigants. Although numerous compounds derived from sources other than seaweed have been identified as having enteric methane mitigation potential, these mitigants are outside the scope of this article.
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http://dx.doi.org/10.3389/fvets.2020.597430DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7785520PMC
December 2020

Evaluation of warm season annual forages for forage yield and quality in the north-central United States.

Transl Anim Sci 2020 Jul 30;4(3):txaa145. Epub 2020 Jul 30.

USDA-ARS, US Dairy Forage Research Center, Madison, WI.

Grazing-based dairy operations require productive, high-quality forages capable of supporting the nutritional needs of mid-lactation dairy cows. Our objectives were to evaluate primary and regrowth harvests of two cultivars of sudangrass (SU), sorghum-sudangrass (S×SU), and pearl millet (PM) forages for growth and nutritive characteristics within the specific context of suitability for grazing by dairy cows. Three harvest cycles, including primary and regrowth cycles in 2016, and a single harvest cycle of primary growth in 2017, were evaluated at two locations (Prairie du Sac and Marshfield, WI). Within each cycle, sampling was initiated when canopy height was about 41 cm and continued thereafter on weekly intervals for 5 weeks, resulting in six equally spaced sampling dates per harvest cycle. Data were analyzed as a split-plot design with cultivars (6) as whole-plots arranged in randomized complete blocks and weekly harvest dates (6) as subplots. Yields of dry matter (DM) were less consistent at the more northern location (Marshfield), which is known for its heavier, poorly drained soils. Despite locational differences, the taller-growing cultivar within each forage type frequently exhibited yield advantages over dwarf or shorter-growing cultivars; this occurred for 7 of 9 intra-forage-type comparisons ( ≤ 0.021) across three harvest cycles at Prairie du Sac, and for 6 of 9 similar comparisons ( ≤ 0.032) at Marshfield. In 2016, shorter-growing cultivars had greater percentages of leaf in 4 of 6 intra-forage-type comparisons at both locations ( ≤ 0.004), which is especially relevant for grazing. Similarly, PM cultivars exhibited shorter canopy heights ( ≤ 0.002), but greater percentages of leaf ( < 0.001), than all other cultivars during all harvest cycles at both locations. However, the greater leaf percentages exhibited by PM cultivars did not translate into reduced percentages of structural plant fiber () on a whole-plant basis during any harvest cycle at either location; furthermore, asNDFom concentrations for PM cultivars were greater ( ≤ 0.047) than observed for other cultivars within 3 of 6 harvest cycles across both locations. Ruminal in-situ degradation of asNDFom for whole-plant forages based on a 48-h incubation was significantly greater ( ≤ 0.006) for PM compared with other cultivars in 4 of 6 harvest cycles. Pearl millet cultivars generally exhibited more suitable characteristics for grazing livestock than SU or S×SU cultivars.
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http://dx.doi.org/10.1093/tas/txaa145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7568508PMC
July 2020

Validating the Use of Bovine Buccal Sampling as a Proxy for the Rumen Microbiota by Using a Time Course and Random Forest Classification Approach.

Appl Environ Microbiol 2020 08 18;86(17). Epub 2020 Aug 18.

US Dairy Forage Research Center, USDA-Agricultural Research Service, Madison, Wisconsin, USA

Analysis of the cow microbiome, as well as host genetic influences on the establishment and colonization of the rumen microbiota, is critical for development of strategies to manipulate ruminal function toward more efficient and environmentally friendly milk production. To this end, the development and validation of noninvasive methods to sample the rumen microbiota at a large scale are required. In this study, we further optimized the analysis of buccal swab samples as a proxy for direct bacterial samples of the rumen of dairy cows. To identify an optimal time for sampling, we collected buccal swab and rumen samples at six different time points relative to animal feeding. We then evaluated several biases in these samples using a machine learning classifier (random forest) to select taxa that discriminate between buccal swab and rumen samples. Differences in the inverse Simpson's diversity, Shannon's evenness, and Bray-Curtis dissimilarities between methods were significantly less apparent when sampling was performed prior to morning feeding ( < 0.05), suggesting that this time point was optimal for representative sampling. In addition, the random forest classifier was able to accurately identify nonrumen taxa, including 10 oral and putative feed-associated taxa. Two highly prevalent (>60%) taxa in buccal and rumen samples had significant variance in relative abundances between sampling methods but could be qualitatively assessed via regular buccal swab sampling. This work not only provides new insights into the oral community of ruminants but also further validates and refines buccal swabbing as a method to assess the rumen bacterial in large herds. The gastrointestinal tracts of ruminants harbor a diverse microbial community that coevolved symbiotically with the host, influencing its nutrition, health, and performance. While the influence of environmental factors on rumen microbes is well documented, the process by which host genetics influences the establishment and colonization of the rumen microbiota still needs to be elucidated. This knowledge gap is due largely to our inability to easily sample the rumen microbiota. There are three common methods for rumen sampling but all of them present at least one disadvantage, including animal welfare, sample quality, labor, and scalability. The development and validation of noninvasive methods, such as buccal swabbing, for large-scale rumen sampling is needed to support studies that require large sample sizes to generate reliable results. The validation of buccal swabbing will also support the development of molecular tools for the early diagnosis of metabolic disorders associated with microbial changes in large herds.
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http://dx.doi.org/10.1128/AEM.00861-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7440797PMC
August 2020

Symposium review: Strategies to improve the efficiency and profitability of heifer raising.

J Dairy Sci 2020 Jun 5;103(6):5700-5708. Epub 2020 Mar 5.

Department of Animal Science, The Pennsylvania State University, University Park 16802.

Regional Research Project NC-2042 has a main objective to study calf and heifer nutrition. Within this objective, feeding the postweaned heifer is considered a major priority to improve the profitability and sustainability of US dairy farms. Through optimizing nutrient utilization by precision feeding, using alternative feeds, high-fiber diets, and feed additives, this research group has worked to enhance dairy heifer nutrition. Research has focused on precision feeding heifers and incorporating high- and low-fiber diets into this system of feeding. This is accomplished by meeting the nutrient needs of the heifer for a desired rate of growth while enhancing total-tract nutrient digestibility, reducing waste and improving profitability. High-fiber forages have been studied as a means of controlling ad libitum dry matter intakes and thus weight gain in heifers. These results provide producers with a means of feeding heifers while reducing costs. Similarly, utilizing alternative feedstuffs in heifer diets has also been a major research area for this group including comprehensive research on distillers co-products, and new protein sources such as camelina and carinata meals. Results indicated that these products can be satisfactorily incorporated into heifer diets. Studying feed additives has also been a function of the research group. Research with Ascophyllum nodosum and cinnamaldehyde indicated that calves find these additives unpalatable and that supplementing cinnamaldehyde to postweaned heifers showed no benefit. However, sodium butyrate and yeast supplementation proved to be beneficial in the growth and feed efficiency of heifers. Research from this group has an effect on heifer feeding, resulting in new information that can aid in the sustainability of dairy farms. This review will focus on the area of postweaned heifer nutrition.
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http://dx.doi.org/10.3168/jds.2019-17419DOI Listing
June 2020

The bovine epimural microbiota displays compositional and structural heterogeneity across different ruminal locations.

J Dairy Sci 2020 Apr 11;103(4):3636-3647. Epub 2020 Feb 11.

Department of Bacteriology, University of Wisconsin-Madison, Madison 53706. Electronic address:

Dairy cattle are globally important agricultural animals. Central to their biology is the rumen, which houses an essential microbial community, or microbiome, important for providing nutrition from otherwise host-inaccessible dietary components. The rumen environment is noted for its substantial spatial heterogeneity, as illustrated by the stratification into ruminal solid and liquid phases. A third microbiota found directly attached to the ruminal epithelium (the epimural microbiota) also exists but is less well understood because of challenges in sampling the ruminal epithelium. As a result, our understanding of the epimural microbiota is based on analyses of cannulated animals sampled at a single location-the ventral sac-and does not account for other ruminal locations, which may have importance for overall rumen function. To address this knowledge gap, we hypothesize that the epimural microbiota at different ruminal locations differs due to known morphological, physiological, and functional differences across the geographic spread of the rumen epithelium. Here, we characterized bacterial epimural communities at different sites within 8 lactating Holstein dairy cows using 16S rRNA gene sequencing. Four different sites were sampled via rumen tissue biopsy: cranial sac (CS), ventral sac (VS), caudodorsal blind sac (CDBS), and caudoventral blind sac (CVBS). We found that locations differed in both epimural bacterial community structure and composition, with the CDBS community displaying the greatest diversity. Across all sampling sites, epimural bacterial communities were dominated by members of the phyla Bacteroidetes, Firmicutes, and Proteobacteria. Bacteria within Prevotellaceae, Butyrivibrio, Campylobacter, Mogibacterium, and Desulfobulbus all showed high relative sequence abundance and differential distributions according to sample location. There appears to be a core epimural microbiota present across all locations in all cows, although relative abundance was highly variable. The difference in relative abundance in epimural microbial communities, perhaps influenced by host physiology and the diversity within rumen contents, likely has important consequences for nutrition acquisition and general health. To the best of our knowledge, this work represents the first characterization of the ruminal epimural microbiota across different epithelial locations for any bovine ruminant.
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http://dx.doi.org/10.3168/jds.2019-17649DOI Listing
April 2020