U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

PubAg

Main content area

You searched for: Author "K. Nichols" Remove constraint Author: "K. Nichols"
Start Over

Search

32  Search Results

« Previous | 1 - 20 of 32 |
Number of results to display per page

Search Results

1. Review: Unlocking the limitations of urea supply in ruminant diets by considering the natural mechanism of endogenous urea secretion

Author:
K. Nichols,   et al.   ; I.P.C. de Carvalho; R. Rauch; J. Martín-Tereso;     Show all 4 Authors
Source:
Animal 2022 v.16 pp. 100537
ISSN:
1751-7311
Subject:
absorption; ammonia; carbohydrates; digestible protein; digestive tract; energy; excretion; fermentation; meat; milk; portal vein; ruminants; secretion; toxicity; urea; urea nitrogen
Abstract:
... Ruminants have evolved with the capability to recycle endogenous urea to the gastrointestinal tract (GIT). Ruminal ammonia derived from urea recycling makes a net contribution to digestible N flow if it is used to synthesise microbial protein. The dynamics of urea recycling and its quantitative importance to the N economy of ruminants are affected by dietary and physiological factors. In general, ...
DOI:
10.1016/j.animal.2022.100537

2. Essential amino acid profile of supplemental metabolizable protein affects mammary gland metabolism and whole-body glucose kinetics in dairy cattle

Author:
K. Nichols,   et al.   ; J. Dijkstra; M.J.H. Breuer; S. Lemosquet; W.J.J. Gerrits; A. Bannink;     Show all 6 Authors
Source:
Journal of dairy science 2022 v.105 no.9 pp. 7354-7372
ISSN:
0022-0302
Subject:
Holstein; ad libitum feeding; alfalfa hay; amino acid composition; casein; catabolism; corn silage; digestible protein; energy; essential amino acids; fistulated animals; galactose; glucose; jugular vein; lactose; mammary glands; milk; milk protein yield; standard deviation; total mixed rations
Abstract:
... This study investigated mammary gland metabolism and whole-body (WB) rate of appearance (Ra) of glucose in dairy cattle in response to a constant supplemental level of metabolizable protein (MP) composed of different essential AA (EAA) profiles. Five multiparous rumen-fistulated Holstein-Friesian dairy cows (2.8 ± 0.4 lactations; 81 ± 11 d in milk; mean ± standard deviation) were abomasally infuse ...
DOI:
10.3168/jds.2021-21576

3. Efficient hyper-parameter determination for regularised linear BRDF parameter retrieval

Author:
N. K. Nichols,   et al.   ; J. M. Zobitz; T. Quaife;     Show all 3 Authors
Source:
International journal of remote sensing 2020 v.41 no.4 pp. 1437-1457
ISSN:
1366-5901
Subject:
data collection; models; moderate resolution imaging spectroradiometer; reflectance; remote sensing
Abstract:
... Linear kernel driven models of the surface Bidirectional Reflectance Distribution Function (BRDF) are valuable tools for exploiting Earth observation data acquired at different sun–sensor geometries. Here we present a method that efficiently determines linear BRDF model weights using Tikhonov smoothing where the smoothing parameter λ is determined via a Generalized Singular Value Decomposition wit ...
DOI:
10.1080/01431161.2019.1667552

4. Energy and nitrogen balance of dairy cattle as affected by provision of different essential amino acid profiles at the same metabolizable protein supply

Author:
K. Nichols,   et al.   ; A. Bannink; J. Dijkstra;     Show all 3 Authors
Source:
Journal of dairy science 2019 v.102 no.10 pp. 8963-8976
ISSN:
0022-0302
Subject:
Holstein; ad libitum feeding; alfalfa hay; amino acid composition; body protein; casein; cattle feeds; climate; corn silage; dairy cows; digestibility; dry matter intake; energy; essential amino acids; lactose; milk; milk fat; milk protein yield; nitrogen balance; protein content; standard deviation; total mixed rations; total nitrogen; urea; urine
Abstract:
... Amino acid composition of metabolizable protein (MP) is important in dairy cattle diets, but effects of AA imbalances on energy and N utilization are unclear. This study determined the effect of different AA profiles within a constant supplemental MP level on whole-body energy and N partitioning in dairy cattle. Five rumen-fistulated Holstein-Friesian dairy cows (2.8 ± 0.4 lactations; 81 ± 11 d in ...
DOI:
10.3168/jds.2019-16400

5. Mammary gland utilization of amino acids and energy metabolites differs when dairy cow rations are isoenergetically supplemented with protein and fat

Author:
K. Nichols,   et al.   ; H. van Laar; A. Bannink; J. Dijkstra;     Show all 4 Authors
Source:
Journal of dairy science 2019 v.102 no.2 pp. 1160-1175
ISSN:
0022-0302
Subject:
3-hydroxybutyric acid; Holstein; acetates; amino acids; blood sampling; corn silage; dairy cows; diet; energy; free fatty acids; glucose; grass hay; grass silage; insulin; lactose; long chain fatty acids; mammary glands; milk synthesis; milk yield; rapeseed; soybeans; triacylglycerols
Abstract:
... Mammary gland utilization of AA and other metabolites in response to supplemental energy from protein (PT) and supplemental energy from fat (FT) was tested in a 2 × 2 factorial arrangement using a randomized complete block design. Fifty-six Holstein-Friesian dairy cows were adapted during a 28-d control period to a basal total mixed ration consisting of 34% grass silage, 33% corn silage, 5% grass ...
DOI:
10.3168/jds.2018-15125

6. Review: Rumen sensors: data and interpretation for key rumen metabolic processes

Author:
K. Nichols,   et al.   ; J. Dijkstra; S. van Gastelen; K. Dieho; A. Bannink;     Show all 5 Authors
Source:
Animal 2020 v.14 no.S1 pp. s176
ISSN:
1751-732X
Subject:
acidosis; animals; decision making; diet; diurnal variation; farm management; fermentation; pH; redox potential
Abstract:
... Rumen sensors provide specific information to help understand rumen functioning in relation to health disorders and to assist in decision-making for farm management. This review focuses on the use of rumen sensors to measure ruminal pH and discusses variation in pH in both time and location, pH-associated disorders and data analysis methods to summarize and interpret rumen pH data. Discussion on t ...
DOI:
10.1017/S1751731119003112

7. Mammary gland metabolite utilization in response to exogenous glucose or long-chain fatty acids at low and high metabolizable protein levels

Author:
K. Nichols,   et al.   ; A. Bannink; J. Doelman; J. Dijkstra;     Show all 4 Authors
Source:
Journal of dairy science 2019 v.102 no.8 pp. 7150-7167
ISSN:
0022-0302
Subject:
3-hydroxybutyric acid; Holstein; ad libitum feeding; blood sampling; corn silage; dairy cows; digestible energy; energy; free fatty acids; glucose; grass silage; insulin; lactating females; lactose; lipogenesis; long chain fatty acids; mammary glands; milk; milk proteins; milk yield; palm oils; protein content; protein requirement; total mixed rations; triacylglycerols; urea
Abstract:
... We investigated mammary gland metabolism in lactating dairy cattle in response to energy from glucogenic (glucose; GG) or lipogenic (palm olein; LG) substrates at low (LMP) and high (HMP) metabolizable protein levels. According to a 6 × 6 Latin square design, 6 rumen-fistulated second-lactation Holstein-Friesian dairy cows (97 ± 13 d in milk) were abomasally infused with saline (LMP-C); isoenerget ...
DOI:
10.3168/jds.2019-16285

8. Energy and nitrogen partitioning in dairy cows at low or high metabolizable protein levels is affected differently by postrumen glucogenic and lipogenic substrates

Author:
K. Nichols,   et al.   ; J. Dijkstra; H. van Laar; S. Pacheco; H.J. van Valenberg; A. Bannink;     Show all 6 Authors
Source:
Journal of dairy science 2019 v.102 no.1 pp. 395-412
ISSN:
0022-0302
Subject:
Holstein; ad libitum feeding; blood glucose; climate; corn silage; dairy cows; diet; digestibility; digestible energy; dry matter intake; energy intake; fatty acid composition; glucose; grass silage; heat production; insulin; lactose; linoleic acid; metabolites; metabolizable energy; milk; milk fat yield; milk protein yield; nitrogen; oleic acid; palm oils; palmitic acid; protein content; total mixed rations; triacylglycerols; urea
Abstract:
... This study tested the effects of energy from glucogenic (glucose; GG) or lipogenic (palm olein; LG) substrates at low (LMP) and high (HMP) metabolizable protein levels on whole-body energy and N partitioning of dairy cattle. Six rumen-fistulated, second-lactation Holstein-Friesian dairy cows (97 ± 13 d in milk) were randomly assigned to a 6 × 6 Latin square design in which each experimental period ...
DOI:
10.3168/jds.2018-15249

9. Expression of genes related to energy metabolism and the unfolded protein response in dairy cow mammary cells is affected differently during dietary supplementation with energy from protein and fat

Author:
K. Nichols,   et al.   ; J. Dijkstra; H. van Laar; J.J.M. Kim; J.P. Cant; A. Bannink;     Show all 6 Authors
Source:
Journal of dairy science 2019 v.102 no.7 pp. 6603-6613
ISSN:
0022-0302
Subject:
3-methyl-2-oxobutanoate dehydrogenase (lipoamide); DNA; Holstein; amino acids; binding proteins; corn silage; dairy cows; dietary supplements; endoplasmic reticulum; energy; energy metabolism; epithelial cells; fatty acids; gene expression; genes; grass hay; grass silage; homeostasis; lactating females; malic enzyme; mammary glands; messenger RNA; metabolites; milk fat; milk production; quantitative polymerase chain reaction; rapeseed; soybeans; total mixed rations; tricarboxylic acid cycle; unfolded protein response
Abstract:
... Secretory capacity of bovine mammary glands is enabled by a high number of secretory cells and their ability to use a range of metabolites to produce milk components. We isolated RNA from milk fat to measure expression of genes involved in energy-yielding pathways and the unfolded protein response in mammary glands of lactating cows given supplemental energy from protein (PT) and fat (FT) tested i ...
DOI:
10.3168/jds.2018-15875

10. Feed and nitrogen efficiency are affected differently but milk lactose production is stimulated equally when isoenergetic protein and fat is supplemented in lactating dairy cow diets

Author:
K. Nichols,   et al.   ; A. Bannink; S. Pacheco; H.J. van Valenberg; J. Dijkstra; H. van Laar;     Show all 6 Authors
Source:
Journal of dairy science 2018 v.101 no.9 pp. 7857-7870
ISSN:
0022-0302
Subject:
Holstein; cattle feeds; corn silage; crude fat; crude protein; dairy cows; digestibility; digestible protein; energy; feeding methods; grass hay; grass silage; lactating females; lactation; lactose; milk; milk fat; milk production; milk proteins; nitrogen; nutrient intake; polyunsaturated fatty acids; rapeseed; soybeans; urea
Abstract:
... Fifty-six Holstein-Friesian cows were used in a randomized complete block design to test the effects of supplemental energy from protein (PT) and fat (FT) on lactation performance and nutrient digestibility in a 2 × 2 factorial arrangement. During the control period, cows were adapted for 28 d to a basal total mixed ration consisting of 34% grass silage, 33% corn silage, 5% grass hay, and 28% conc ...
DOI:
10.3168/jds.2017-14276

11. Compositional Analysis of Wax Esters in Human Meibomian Gland Secretions by Direct Infusion Electrospray Ionization Mass Spectrometry

Author:
Kelly K. Nichols,   et al.   ; Jianzhong Chen; Kari B. Green;     Show all 3 Authors
Source:
Lipids 2016 v.51 no.11 pp. 1269-1287
ISSN:
0024-4201
Subject:
electrospray ionization mass spectrometry; humans; ions; isomers; lipids; molecular weight; tandem mass spectrometry; wax esters
Abstract:
... Wax esters (WE) are one of the predominant lipid types in human meibomian gland secretions (meibum) and account for 40–50 % of total meibum lipids. Recently, we managed to quantify 51 isomeric groups of intact WE in normal human meibum samples by direct infusion electrospray ionization mass spectrometry (ESI–MS), with each WE peak in the MS spectrum corresponding to one isomeric group (Chen et al, ...
DOI:
10.1007/s11745-016-4183-4
PubMed:
27571784
PubMed Central:
PMC5075507

12. Near‐Surface Soil Property Responses to Forage Production in a Semiarid Region [Erratum: January 2022, v.86(1), p. 157]

Author:
K. Nichols,   et al.   ; M. A. Liebig; J. R. Hendrickson; J. G. Franco; D. W. Archer; D. L. Tanaka;     Show all 6 Authors
Source:
Soil Science Society of America journal 2018 v.82 no.1 pp. 223-230
ISSN:
0361-5995
Subject:
Medicago; Pisum sativum; Thinopyrum intermedium subsp. intermedium; Triticum aestivum; agricultural land; alfalfa; cropping systems; ecosystem services; forage; forage production; pH; particulate organic matter; peas; perennial grasses; sandy loam soils; semiarid zones; soil acidification; soil density; soil quality; spring wheat; water stable soil aggregates; North Dakota
Abstract:
... Core Ideas Information about forage‐induced changes to soil properties is lacking. Soil responses to perennial forages were quantified in a semiarid region over 5 yr. Perennial forages maintained or improved near‐surface soil conditions. However, effects were subtle and changes to soil properties occurred slowly. Integration of perennial forages in annual cropping systems can expand ecosystem serv ...
DOI:
10.2136/sssaj2017.07.0237

13. Exogenous essential amino acids stimulate an adaptive unfolded protein response in the mammary glands of lactating cows

Author:
K. Nichols,   et al.   ; J. Doelman; J.J.M. Kim; M. Carson; J.A. Metcalf; J.P. Cant;     Show all 6 Authors
Source:
Journal of dairy science 2017 v.100 no.7 pp. 5909-5921
ISSN:
0022-0302
Subject:
DNA; binding proteins; biogenesis; cell proliferation; dairy cows; endoplasmic reticulum; essential amino acids; gene expression; gene expression regulation; genetic markers; glucose; lactating females; lactation; longissimus muscle; mammary glands; messenger RNA; milk protein yield; milk proteins; phosphorylation; pro-apoptotic proteins; rapamycin; ribosomal proteins; ribosomes; skeletal muscle; stress response; transcription (genetics); transcription factors; translation (genetics); unfolded protein response
Abstract:
... The phosphorylation of mammalian target of rapamycin complex 1 (mTORC1) components and integrated stress response networks in the mammary glands of lactating cows have not accounted for the stimulation of milk protein yield by chronic supplementation with AA or glucose. Faster milk protein synthesis could be a consequence of increased milk protein mRNA per cell, the number of ribosomes per cell, t ...
DOI:
10.3168/jds.2016-12387

14. Long-term erosion rates of Panamanian drainage basins determined using in situ 10Be

Author:
Kyle K. Nichols,   et al.   ; Veronica Sosa Gonzalez; Paul R. Bierman; Dylan H. Rood;     Show all 4 Authors
Source:
Geomorphology 2016 v.275 pp. 1-15
ISSN:
0169-555X
Subject:
arithmetics; basins; climatic factors; data collection; geophysics; grains; gravel; humans; land use; landscapes; landslides; quartz; regression analysis; rivers; sand; sediment yield; silicates; soil creep; streams; tectonics; temperature; topography; tropics; watersheds; weathering; Australia; Madagascar; Panama; Puerto Rico; Sri Lanka
Abstract:
... Erosion rates of tropical landscapes are poorly known. Using measurements of in situ-produced 10Be in quartz extracted from river and landslide sediment samples, we calculate long-term erosion rates for many physiographic regions of Panama. We collected river sediment samples from a wide variety of watersheds (n=35), and then quantified 24 landscape-scale variables (physiographic, climatic, seismi ...
DOI:
10.1016/j.geomorph.2016.04.025

15. Glucose supplementation stimulates peripheral branched-chain amino acid catabolism in lactating dairy cows during essential amino acid infusions

Author:
K. Nichols,   et al.   ; J.J.M. Kim; M. Carson; J.A. Metcalf; J.P. Cant; J. Doelman;     Show all 6 Authors
Source:
Journal of dairy science 2016 v.99 no.2 pp. 1145-1160
ISSN:
0022-0302
Subject:
Holstein; amino acid metabolism; chemical structure; crude protein; dairy cows; dairy protein; early lactation; energy; essential amino acids; excretion; gene expression; glucose; messenger RNA; milk; milk fat; milk fat yield; milk protein yield; muscle protein; muscles; protein degradation; protein synthesis; tissues; urea nitrogen
Abstract:
... To determine how glucose modulates protein synthesis when essential AA are in abundant supply, 5 early-lactation, rumen-fistulated Holstein dairy cows were fed a diet containing 6.95 MJ/kg of net energy for lactation and 12.4% crude protein and abomasally infused for 5d with saline, 844 or 1,126g/d of a complete essential AA mix, with and without the inclusion of 1,000g/d of glucose, in a 5×5 Lati ...
DOI:
10.3168/jds.2015-9912

16. Decadal climate prediction with a refined anomaly initialisation approach

Author:
Nancy K. Nichols,   et al.   ; Danila Volpi; Virginie Guemas; Francisco J. Doblas-Reyes; Ed Hawkins;     Show all 5 Authors
Source:
Climate dynamics 2017 v.48 no.5-6 pp. 1841-1853
ISSN:
0930-7575
Subject:
climate; climate models; ice; prediction; risk; salinity; surface temperature; Arctic region; Mediterranean Sea
Abstract:
... In decadal prediction, the objective is to exploit both the sources of predictability from the external radiative forcings and from the internal variability to provide the best possible climate information for the next decade. Predicting the climate system internal variability relies on initialising the climate model from observational estimates. We present a refined method of anomaly initialisati ...
DOI:
10.1007/s00382-016-3176-6

17. Characterization of Wax Esters by Electrospray Ionization Tandem Mass Spectrometry: Double Bond Effect and Unusual Product Ions

Author:
Kelly K. Nichols,   et al.   ; Jianzhong Chen; Kari B. Green;     Show all 3 Authors
Source:
Lipids 2015 v.50 no.8 pp. 821-836
ISSN:
0024-4201
Subject:
ammonia; dissociation; electrospray ionization mass spectrometry; energy; fatty acids; humans; ionization; ions; methanol; spectrometers; tandem mass spectrometry; wax esters
Abstract:
... A series of different types of wax esters (represented by RCOOR′) were systematically studied by using electrospray ionization (ESI) collision-induced dissociation tandem mass spectrometry (MS/MS) along with pseudo MS³ (in-source dissociation combined with MS/MS) on a quadrupole time-of-flight (Q-TOF) mass spectrometer. The tandem mass spectra patterns resulting from dissociation of ammonium/proto ...
DOI:
10.1007/s11745-015-4044-6
PubMed:
26178197
PubMed Central:
PMC4526438

18. Soil response to perennial herbaceous biofeedstocks under rainfed conditions in the northern Great Plains, USA

Author:
K. Nichols,   et al.   ; M.A. Liebig; G.-J. Wang; E. Aberle; E. Eriksmoen; P.E. Nyren; J.A. Staricka;     Show all 7 Authors
Source:
Geoderma 2017 v.290 pp. 10-18
ISSN:
0016-7061
Subject:
acidification; agricultural land; ecosystem services; electrical conductivity; perennials; salinity; soil degradation; soil density; soil organic carbon; soil pH; soil quality; North Dakota
Abstract:
... Perennial herbaceous biofeedstocks (PHB) have been proposed to confer multiple ecosystem services to agricultural lands. However, the role of PHBs to affect change in soil condition is not well documented, particularly for treatments with multiple species. The objective of this study was to quantify potential changes to soil properties resulting from PHB treatments in central and western North Dak ...
Handle:
10113/5631661
DOI:
10.1016/j.geoderma.2016.12.013

19. 10Be constrains the sediment sources and sediment yields to the Great Barrier Reef from the tropical Barron River catchment, Queensland, Australia

Author:
Kyle K. Nichols,   et al.   ; Paul R. Bierman; Dylan H. Rood;     Show all 3 Authors
Source:
Geomorphology 2014 v.224 pp. 102-110
ISSN:
0169-555X
Subject:
climate change; coasts; highlands; hurricanes; landscape management; rivers; sand; sediment yield; topographic slope; watersheds; Coral Sea; Great Barrier Reef; Pacific Ocean; Queensland
Abstract:
... Estimates of long-term, background sediment generation rates place current and future sediment fluxes to the Great Barrier Reef in context. Without reliable estimates of sediment generation rates and without identification of the sources of sediment delivered to the reef prior to European settlement (c. 1850), determining the necessity and effectiveness of contemporary landscape management efforts ...
DOI:
10.1016/j.geomorph.2014.07.019

20. Broad salinity tolerance in the invasive lionfish Pterois spp. may facilitate estuarine colonization

Author:
Patrick K. Nichols,   et al.   ; Zachary R. Jud; Craig A. Layman;     Show all 3 Authors
Source:
Environmental biology of fishes 2015 v.98 no.1 pp. 135-143
ISSN:
0378-1909
Subject:
Pterois; chronic exposure; coral reefs; economics; ecosystems; estuaries; fish; mortality; rivers; salinity; salt tolerance; seagrasses; Caribbean
Abstract:
... The ongoing invasion of non-native Indo-Pacific lionfish (Pterois spp.) represents a significant ecological threat throughout the Western Atlantic and Caribbean. As a generalist species, lionfish have been able to rapidly colonize a wide variety of ecosystems, including coral reefs, seagrass beds, mangroves, the sea floor at depths as great as 300 m, and even brackish estuaries. While lionfish hav ...
DOI:
10.1007/s10641-014-0242-y