Dry matter intake and energy balance in the transition period.     

Ric R Grummer  Doug G Mashek  A Hayirli 《Veterinary Clinics of North America: Food Animal Practice》2004,20(3):447-470

It is easy, based on theoretic considerations, to make the argument that maximizing DMI is important to minimize postpartum complications and losses in milk production that may be associated with them. However, research over the past several years provides ample evidence that successful "passage" through the periparturient period is more complicated than simply maximizing feed intake. Anecdotal evidence from veterinarians and nutrition consultants also confirm that feeding low-NDF diets to achieve high prepartum feed intakes during the prefresh transition period does not necessarily solve fresh-cow problems. Perhaps more important than maximizing feed intake is to minimize the likelihood of cows experiencing large drops in feed intake immediately before parturition. Retrospective analysis of existing data sets indicates that this hypothesis has merit; research must be conducted to vigorously test it. Until then, it seems reasonable to try to achieve high DMI, if it can be sustained through parturition. If it cannot, perhaps a more conservative approach is to limit voluntary intake by increasing dietary fiber, because data suggests that cows fed in such a manner experience less dramatic decreases in feed intake as parturition approaches. We examined the importance of parity, body condition score, and various diet components that may influence DMI during the final 3 weeks before parturition, but they only explained 18% of the variation in intake among cows. Clearly, there are many other factors that affect intake that need to be identified. Aspects of farm management that may influence animal stress need to be investigated, particularly during the prefresh transition period when cows are inherently prone to reductions in feed intake.  相似文献   

An updated geographic distribution of Myxobolus cerebralis (Hofer, 1903) (Bivalvulida: Myxobolidae) and the first diagnosed case of whirling disease in wild-caught trout in the south-eastern United States     

Steven P. Ksepka  Jacob M. Rash  Brandon L. Simcox  Doug A. Besler  Haley R. Dutton  Micah B. Warren  Stephen A. Bullard 《Journal of fish diseases》2020,43(7):813-820

Myxobolus cerebralis (Bivalvulida: Myxobolidae), the aetiological agent of salmonid whirling disease, was detected in 2 river basins of North Carolina during 2015, which initiated the largest spatial–temporal monitoring project for the disease ever conducted within the south-eastern United States (focused mainly in eastern Tennessee and western North Carolina). A total of 2072 rainbow trout Oncorhynchus mykiss, 1,004 brown trout Salmo trutta and 468 brook trout Salvelinus fontinalis were screened from 113 localities within 7 river basins during June 2017 through October 2019. Infections were detected by pepsin–trypsin digest, microscopy and the species-specific nested polymerase chain reaction (PCR) in 19 localities across 6 river basins. Myxospore morphology was indistinguishable from the published literature. In 2019, five rainbow trout that symptomatic for whirling disease (sloping neurocranium and lordosis) were captured and processed for histopathology. Myxospores were detected in the calvarial cartilage of two deformed trout with associated erosion of the cartilage consistent with reported whirling disease lesions. This is the first report of M. cerebralis in Tennessee and the first histologically confirmed cases of whirling disease in southern Appalachian (south-eastern United States) rivers and streams and expands the distribution of M. cerebralis throughout western North Carolina and eastern Tennessee.  相似文献   

Bacillimidazoles A−F,Imidazolium-Containing Compounds Isolated from a Marine Bacillus     

Jia-Xuan Yan  Qihao Wu  Eric J. N. Helfrich  Marc G. Chevrette  Doug R. Braun  Heino Heyman  Gene E. Ananiev  Scott R. Rajski  Cameron R. Currie  Jon Clardy  Tim S. Bugni 《Marine drugs》2022,20(1)

Chemical investigations of a marine sponge-associated Bacillus revealed six new imidazolium-containing compounds, bacillimidazoles A–F (1–6). Previous reports of related imidazolium-containing natural products are rare. Initially unveiled by timsTOF (trapped ion mobility spectrometry) MS data, extensive HRMS and 1D and 2D NMR analyses enabled the structural elucidation of 1–6. In addition, a plausible biosynthetic pathway to bacillimidazoles is proposed based on isotopic labeling experiments and invokes the highly reactive glycolytic adduct 2,3-butanedione. Combined, the results of structure elucidation efforts, isotopic labeling studies and bioinformatics suggest that 1–6 result from a fascinating intersection of primary and secondary metabolic pathways in Bacillus sp. WMMC1349. Antimicrobial assays revealed that, of 1–6, only compound six displayed discernible antibacterial activity, despite the close structural similarities shared by all six natural products.  相似文献   

Confluence configuration of river networks controls spatial patterns in fish communities     

Boddy  Nixie C.  Booker  Doug J.  McIntosh  Angus R. 《Landscape Ecology》2019,34(1):187-201

Landscape Ecology - Given the importance of spatial heterogeneity in altering dispersal, interspecific interactions, and population persistence, high rates of habitat homogenisation across the...  相似文献   

Nitrogen fertilizer and urease inhibitor effects on canola seed quality in a one-pass seeding and fertilizing system   总被引：1，自引：0，他引：1  

Cynthia A. Grant  Doug A. Derksen Debra L. McLaren  R. Byron Irvine 《Field Crops Research》2011,121(2):201-208

Field studies were conducted over three years on a clay loam (CL) and fine sandy loam (FSL) soil on the eastern Canadian prairies to evaluate the impact of urea and urea ammonium nitrate (UAN), with or without the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT), placed near the seed-row in a one-pass seeding and fertilizing operation on seed protein, oil, chlorophyll and glucosinolate content of canola (Brassica napus L.). Application of N fertilizer as a side-band application at the time of seeding increased protein concentration and decreased oil concentration. Protein and oil yield increased with low to moderate N rates, but stabilized or fell with high N rates due to reductions in yield from seedling toxicity. Both chlorophyll and glucosinolate concentrations increased with increasing N rates. Use of UAN led to higher protein, chlorophyll and glucosinolate and lower oil concentration than urea on the CL soil. Use of the urease inhibitor NBPT generally increased oil concentration on both soils and reduced the chlorophyll and glucosinolate concentration on the CL soil. Observed difference may have been due to delayed maturity and reduced stand density caused by seedling damage and high N rates. High N rates applied as a side-band of urea or UAN near the canola seed row can negatively influence both seed yield and quality in canola and the negative effects may be reduced by the use of the urease inhibitor NBPT.  相似文献