Agronomic assessment of grazing method of corn residues on cow performance, residue utilization, crop yield, and soil properties

The objectives were to evaluate the effects of beef cows grazing corn residues on cow performance, residue utilization, subsequent crop yield, and soil physical and chemical properties. Two grazing methods (strip grazing, (SG) and continuous grazing, (CG)) and a control (ungrazed, (CT)) were arranged in a randomized complete block design with 3 replications each yr for 3 yr. Within SG, subplots were assigned with a grazing order (1, 2, 3). Thirty-six spring-calving, multiparous, Angus cows were utilized in yr 1 (BW = 648 ± 41 kg) and 2 (BW = 710 ± 71 kg) at a stocking density of 3.0 cows·ha-1, and 42 winter-calving Angus heifers (BW = 566 ± 39 kg) were utilized in yr 3 at a stocking density of 3.6 heifers·ha-1. Cattle grazed for 42 d beginning on 29 Sept. 2012 (yr 1), 2 Nov. 2013 (yr 2), and 4 Oct. 2014 (yr 3). Residue samples were collected on d 14 and d 28 of grazing and after grazing in yr 1, and before and after grazing in yr 2. Soil samples were collected before and after cattle grazing in yr 1 and 2. Paddock dimensions were marked during yr 1 with GPS coordinates so that the same treatment was applied to the same paddock area and location each yr. Cows within the SG treatment were heavier (P = 0.04) after grazing and had an increase (P = 0.04) in body weight change compared to CG. At d 28 in yr 1, SG residue had decreased (P ˂ 0.01) acid detergent fiber and tended (P = 0.08) to have increased organic matter compared to CG. At the conclusion of grazing, SG had decreased (P = 0.02) neutral detergent fiber compared to CG. Within SG in yr 2, strip 3 tended to have increased (P = 0.10) total residue available compared to strips 1 and 2 after grazing. Strip 1 had increased (P = 0.02) acid detergent fiber and tended (P = 0.09) to have decreased crude protein compared to strips 2 and 3. No differences (P = 0.19) were detected between treatments for subsequent corn yield following two grazing seasons. However, within SG, the first strip tended (P = 0.10) to have reduced yields compared to the second strip, with the third strip being intermediate. Soil bulk density was increased (P ˂ 0.01) in both grazing treatments compared to CT, but penetration resistance was not affected (P = 0.56) by treatment. Water aggregate stability was decreased (P = 0.01) in CG and SG compared to CT. Soil nitrate was increased (P = 0.03) in CG compared to SG, with CT being intermediate. Soil ammonium was not affected (P = 0.14) by grazing treatment. Soil pH was increased (P ˂ 0.01) in SG compared to CG and CT. Grazing order in SG did not affect (P ≥ 0.25) soil physical or chemical properties. Strip grazing corn residues increased cow performance. Grazing residue did not affect subsequent crop performance, yet the effects that strip grazing has on crop performance need to be further investigated. Although livestock grazing increased soil compaction, root restricting levels of compaction were not reached. Results indicate that cattle and crops can be integrated with the grazing of corn residue, resulting in minimal effects on soil properties and subsequent crop yield

An Essential Role for Dermal Primary Cilia in Hair Follicle Morphogenesis

The primary cilium is a microtubule-based organelle implicated as an essential component of a number of signaling pathways. It is present on cells throughout the mammalian body; however, its functions in most tissues remain largely unknown. Herein we demonstrate that primary cilia are present on cells in murine skin and hair follicles throughout morphogenesis and during hair follicle cycling in postnatal life. Using the Cre-lox system, we disrupted cilia assembly in the ventral dermis and evaluated the effects on hair follicle development. Mice with disrupted dermal cilia have severe hypotrichosis (lack of hair) in affected areas. Histological analyses reveal that most follicles in the mutants arrest at stage 2 of hair development and have small or absent dermal condensates. This phenotype is reminiscent of that seen in the skin of mice lacking Shh or Gli2. In situ hybridization and quantitative RT-PCR analysis indicates that the hedgehog pathway is downregulated in the dermis of the cilia mutant hair follicles. Thus, these data establish cilia as a critical signaling component required for normal hair morphogenesis and suggest that this organelle is needed on cells in the dermis for reception of signals such as sonic hedgehog

The Oak Ridge Polycystic Kidney mouse: Modeling ciliopathies of mice and men

The Oak Ridge Polycystic Kidney (ORPK) mouse was described nearly 14 years ago as a model for human recessive polycystic kidney disease. The ORPK mouse arose through integration of a transgene into an intron of the Ift88 gene resulting in a hypomorphic allele (Ift88(Tg737Rpw)). The Ift88(Tg737Rp omega) mutation impairs intraflagellar transport (IFT), a process required for assembly of motile and immotile cilia. Historically, the primary immotile cilium was thought to have minimal importance for human health; however, a rapidly expanding number of human disorders have now been attributed to ciliary defects. Importantly, many of these phenotypes are present and can be analyzed using the ORPK mouse. In this review, we highlight the research conducted using the OPRK mouse and the phenotypes shared with human cilia disorders. Furthermore, we describe an additional follicular dysplasia phenotype in the ORPK mouse, which alongside the ectodermal dysplasias seen in human Ellis-van Creveld and Sensenbrenner's syndromes, suggests an unappreciated role for primary cilia in the skin and hair follicle

Performance Benchmarks for Screening Mammography

PURPOSE: To retrospectively evaluate the range of performance outcomes of the radiologist in an audit of screening mammography by using a representative sample of U.S. radiologists to allow development of performance benchmarks for screening mammography. MATERIALS AND METHODS: Institutional review board approval was obtained, and study was HIPAA compliant. Informed consent was or was not obtained according to institutional review board guidelines. Data from 188 mammographic facilities and 807 radiologists obtained between 1996 and 2002 were analyzed from six registries from the Breast Cancer Surveillance Consortium (BCSC). Contributed data included demographic information, clinical findings, mammographic interpretation, and biopsy results. Measurements calculated were positive predictive values (PPVs) from screening mammography (PPV(1)), biopsy recommendation (PPV(2)), biopsy performed (PPV(3)), recall rate, cancer detection rate, mean cancer size, and cancer stage. Radiologist performance data are presented as 50th (median), 10th, 25th, 75th, and 90th percentiles and as graphic presentations by using smoothed curves. RESULTS: There were 2 580 151 screening mammographic studies from 1 117 390 women (age range, /=80 years). The respective means and ranges of performance outcomes for the middle 50% of radiologists were as follows: recall rate, 9.8% and 6.4%-13.3%; PPV(1), 4.8% and 3.4%-6.2%; and PPV(2), 24.6% and 18.8%-32.0%. Mean cancer detection rate was 4.7 per 1000, and the median [corrected] mean size of invasive cancers was 13 mm. The range of performance outcomes for the middle 80% of radiologists also was presented. CONCLUSION: Community screening mammographic performance measurements of cancer outcomes for the majority of radiologists in the BCSC surpass performance recommendations. Recall rate for almost half of radiologists, however, is higher than the recommended rate