Dairy Research 2020

Kansas State University is pleased to present the 2020 Dairy Research Report of Progress. Topics include milk processing, physiology, management, nutrition, and feeding of dairy cattle

Control Strategies for Hybrid Vehicles in Mountainous Areas

AbstractThis paper presents control strategies for a Hybrid Electric Vehicle (HEV) aiming at fuel and battery consumption reduction in real life conditions. For years, car manufacturers have modeled and simulated control strategies using standardized driving cycles based on theoretical speed values such as the NEDC in Europe, leaving important external parameters out of the equation. Establishing driving cycles made out of GPS acquisitions and segmenting them into road sections, classified in different categories depending on the input parameters, including slope, allows the creation of logic rules defining the driving mode to adopt in each situation. Using Fuzzy Logic, those rules can be interpreted and used to adapt the control strategy to road conditions, resulting in many strategies covering every kind of road segment and offering different opportunities of energy savings

Combined Risk Factors and Digestive Disorders in Mid-Lactation Holstein Cows: A Case Study

Digestive disorders can be a significant cause of disease on dairies and are frustrating because of their unpredictability. Diets that may support excellent health in most cases may nonetheless result in significant gastrointestinal disease, even leading to deadly conditions such as hemorrhagic bowel syndrome. To our knowledge, there is limited research on these conditions, as many risk factors fail to reproduce disease when experimentally administered to cows, leading many to conclude that these disorders are generally multifactorial in nature and difficult to replicate. In this case study, we document the outbreak and resolution of digestive disorders among 15 control cows enrolled in a larger production study. Over 14 weeks, cows were individually fed, with milk yield and composition, blood variables, and health observations recorded. The diet included drought-stressed corn silage that introduced difficulties including low energy density, high dry matter content (making it unstable at feedout), and mycotoxin contamination. By weeks 4–5 on the study, sporadic diarrhea began to appear and milk fat content had dropped from 3.7% to 3.4%, on average. Coincident with the onset of environmental heat stress, three cows developed severe digestive disorders, resulting in a displaced abomasum in one cow. At that point, the diet was changed to replace some corn silage with wheat straw, a direct-fed microbial was added to the diet, and organic acid treatment of the silage face was initiated. Within a month after these changes were implemented, essentially all signs of digestive problems resolved, including milk fat content, fecal consistency, and blood plasma concentrations of haptoglobin and D-lactate. This case study points to multiple factors that likely combined to lead to microbial and gastrointestinal disruptions resulting in clinical disease in a subset of cows

Association of Horizontal Silo Pad Type, Elevation and Core Depth With Indicators of Silo Ramp Hygiene, Forage Quality, and Digestibility

Horizontal silo piles without walls are constructed using packing equipment to adequately pack the forage for air exclusion. During packing, the equipment uses a ramp of forage to access the top of the pile, potentially introducing soil into the forage when the base of the silo is made of soil. Soil contains microorganisms which may cause malfermentation and pose health risks to livestock. The objective of this study was to assess the association of horizontal silo pad type, elevation, and core depth with indicators related to silage hygiene and nutrient quality. We hypothesized that ash and mineral content, microbiological profile, and fermentation profile in silos with soil pads would be indicative of soil contamination, and that measures of potential contamination would be lesser at higher elevations within the silo. Eleven horizontal silos on 7 farms were sampled in a split-split-plot design, with silo pad type as the whole plot factor, elevation on the ramp as the split-plot factor, and core depth as the split-split-plot factor; data were analyzed using mixed models to appropriately recognize experimental units for each factor. Regardless of core depth and elevation, silage pH was increased in concrete pads relative to soil pads. Also, for soil pads, phosphorus (P) was increased in samples of the outer core depth compared to inner core depths. Further, on both pad types, iron (Fe) content was greater at lower vs. medium elevations, but there was no evidence of difference for peak Fe content compared with the other elevations. On soil pads, outer layers had decreased 120- and 240-hour neutral detergent fiber (NDF) and 7-hour starch digestibility compared with inner cores regardless of eleva­tion. The outer segments also had increased pH and decreased density compared with inner core depths, regardless of pad type or elevation. Further, independent of pad type or elevation, outer layers increased NDF, acid detergent fiber (ADF), lignin, ash, and minerals, but decreased crude protein (CP) compared with inner core depths. Addi­tionally, compared with inner layers, outer layers had decreased NDF and starch digest­ibility, and increased undigestible NDF regardless of pad type or elevation. Overall, changes in Fe and P may be indicative of soil contamination on soil pads. Furthermore, the decreased quality of forage in the outer layers of the silo reinforces the importance of an anaerobic environment for the adequate preservation of silage

The Effects of an Evaporative Cooling System on Reducing Heat Load in Lactating Dairy Cows

This study was conducted to evaluate the effect of 2 cooling systems on barn temperature, core body temperature (CBT), respiration rate, rear udder temperature, and lying time in lactating Holstein dairy cows. Twenty lactating Holstein dairy cows were randomly assigned to 1 of 2 treatment groups: CONV, where cows were housed in a conventional, open-sidewall freestall barn equipped with feedline soakers and fans located over the feedline and stalls; and TUNNEL, where cows were housed in a tunnel-ventilated freestall barn utilizing an evaporative cooling system. TUNNEL was effective at reducing barn temperature humidity index (THI) compared to CONV, but failed to alter CBT (101.5 ± 0.04°F). TUNNEL cows had reduced respiration rates (52.0 vs. 57.9 ± 2.2 breaths per minute) and skin temperatures (91.8 vs. 94.1 ± 0.6°F) compared to CONV, while TUNNEL cows had increased lying time by 1 hour per day (11.8 vs. 10.8 ± 0.3 hours per day). Overall, the evaporative cooling system (TUNNEL) was effective in reducing barn THI leading to reduced respiration rates and rear udder temperatures and increased daily lying time. No treatment differences were detected for CBT, however, likely a result of the cooler ambient conditions under which the study took place

Effects of Pre-Cutting Round Alfalfa Hay Bales on Forage Quality and Processing Time

Round hay balers with knives that cut the hay as it enters the baling chamber reduce the particle size upon baling, and eliminate the need for a tub grinder. The objective of this study was to evaluate the effects of a round hay baler with knives on forage quality of alfalfa hay at baling and after storage, and the effects of the processing method on nutrient composition and particle size distribution. Alfalfa hay was baled (560 M Megawide HC2, John Deere, Moline, IL) with knives every 4 inches (CUT; theo­retical length of cut) or without knives (NORM). At baling and after 6 months of uncovered storage, bales were weighed, measured, and 10 core samples were obtained for nutrient analysis. Cores were separated into outer 6 inches and inner 6- to 18-inch segments to determine the depth of spoilage. After storage, particle size was reduced to approximately 4 inches using a mixer wagon for CUT (CUT-MIX) or a tub grinder for NORM (NORM-GRIND). Compared with NORM, CUT increased bale weight and density. Core depth interacted with storage timepoint whereby acid detergent fiber (ADF) concentration increased more for outer than inner cores from baling to the end of storage, with similar effects for lignin and 240-hour undigest­ible NDF. Compared with NORM, CUT increased concentrations of aNDF organic matter, ADF, and lignin, and decreased relative forage quality (RFQ). The CUT-MIX treatment increased time to reduce particle size, but decreased processing shrink by 6.1% compared with NORM-GRIND. Additionally, when compared with NORM-GRIND, CUT-MIX increased fiber content and decreased fiber digestibility, which may have been due to sampling error from longer particle size. In summary, CUT produced larger, more dense bales and increased fiber content slightly, and CUT-MIX decreased processing shrink but increased fiber content with additional longer particles after processing, which could be advantageous for physically effective fiber in ruminant diets. Further work should continue to evaluate leaf loss during baling, and options for processing and incorporating pre-cut hay into diets

Atomic picture of ligand migration in toluene 4-monooxygenase

Computational modeling combined with mutational and activity assays was used to underline the substrate migration pathways in toluene 4-monooxygenase, a member of the important family of bacterial multicomponent monooxygenases (BMMs). In all structurally defined BMM hydroxylases, several hydrophobic cavities in the α-subunit map a preserved path from the protein surface to the diiron active site. Our results confirm the presence of two pathways by which different aromatic molecules can enter/escape the active site. While the substrate is observed to enter from both channels, the more hydrophilic product is withdrawn mainly from the shorter channel ending at residues D285 and E214. The long channel ends in the vicinity of S395, whose variants have been seen to affect activity and specificity. These mutational effects are clearly reproduced and rationalized by the in silico studies. Furthermore, the combined computational and experimental results highlight the importance of residue F269, which is located at the intersection of the two channels.This work has been funded by the EU projects INDOX (KBBE20137613549) and ERC 2009Adg25027PELE (to V.G) and the Spanish Ministry of Education and Science project CTQ201348287 (to V.G).Peer ReviewedPostprint (author's final draft

Impact of COVID-19 on vascular patients worldwide: analysis of the COVIDSurg data

BACKGROUND: The COVIDSurg collaborative was an international multicenter prospective analysis of perioperative data from 235 hospitals in 24 countries. It found that perioperative COVID-19 infection was associated with a mortality rate of 24%. At the same time, the COVER study demonstrated similarly high perioperative mortality rates in vascular surgical patients undergoing vascular interventions even without COVID-19, likely associated with the high burden of comorbidity associated with vascular patients. This is a vascular subgroup analysis of the COVIDSurg cohort. // METHODS: All patients with a suspected or confirmed diagnosis of COVID-19 in the 7 days prior to, or in the 30 days following a vascular procedure were included. The primary outcome was 30-day mortality. Secondary outcomes were pulmonary complications (adult respiratory distress syndrome, pulmonary embolism, pneumonia and respiratory failure). Logistic regression was undertaken for dichotomous outcomes. // RESULTS: Overall, 602 patients were included in this subgroup analysis, of which 88.4% were emergencies. The most common operations performed were for vascular-related dialysis access procedures (20.1%, N.=121). The combined 30-day mortality rate was 27.2%. Composite secondary pulmonary outcomes occurred in half of the vascular patients (N.=275, 45.7%). // CONCLUSIONS: Mortality following vascular surgery in COVID positive patients was significantly higher than levels reported pre-pandemic, and similar to that seen in other specialties in the COVIDSurg cohort. Initiatives and surgical pathways that ensure vascular patients are protected from exposure to COVID-19 in the peri-operative period are vital to protect against excess mortality

First Detection of Leishmania major DNA in Sergentomyia (Spelaeomyia) darlingi from Cutaneous Leishmaniasis Foci in Mali

Leishmania major complex is the main causative agent of zoonotic cutaneous leishmaniasis (ZCL) in the Old World. Phlebotomus papatasi and Phlebotomus duboscqi are recognized vectors of L. major complex in Northern and Southern Sahara, respectively. In Mali, ZCL due to L. major is an emerging public health problem, with several cases reported from different parts of the country. The main objective of the present study was to identify the vectors of Leishmania major in the Bandiagara area, in Mali. Methodology/Principal Findings: An entomological survey was carried out in the ZCL foci of Bandiagara area. Sandflies were collected using CDC miniature light traps and sticky papers. In the field, live female Phlebotomine sandflies were identified and examined for the presence of promastigotes. The remaining sandflies were identified morphologically and tested for Leishmania by PCR in the ITS2 gene. The source of blood meal of the engorged females was determined using the cyt-b sequence. Out of the 3,259 collected sandflies, 1,324 were identified morphologically, and consisted of 20 species, of which four belonged to the genus Phlebotomus and 16 to the genus Sergentomyia. Leishmania major DNA was detected by PCR in 7 of the 446 females (1.6%), specifically 2 out of 115 Phlebotomus duboscqi specimens, and 5 from 198 Sergentomyia darlingi specimens. Human DNA was detected in one blood-fed female S. darlingi positive for L. major DNA. Conclusion: Our data suggest the possible involvement of P. duboscqi and potentially S. darlingi in the transmission of ZCL in Mali