147 research outputs found
Deliberate Exercise of Pregnant Holstein Heifers Improves Milk Composition During Lactation
Exercise has substantial impacts on systemic physiology, but little research has been conducted to assess how it may influence dairy cattle in modern confined production systems. Dairy heifers were walked for up to 45 minutes, 4 days per week for 8 weeks during pregnancy to assess impacts on subsequent health and productivity. Heifers that were exercised had increased milk protein and solids-not-fat concentrations for up to 15 weeks into lactation, and increased milk fat and energy-corrected milk production at some time points during this period, as compared to sedentary contemporaries. No adverse or beneficial effects of exercise were found on locomotion, calving ease, date of parturition, or somatic cell scores. These findings point to potential impacts on lactation productivity following exercise in pregnant heifers
Site of semen deposition and fertility in lactating beef cows synchronized with GnRH and PGF2α
Our objective was to determine the effect of site of semen deposition on pregnancy rate in beef cows inseminated at a fixed time or after observed estrus. Cows were synchronized with a combination of gonadotropin-releasing hormone (GnRH) prostaglandin-F α (PGF). GnRH was injected 7 days before PGF (day 0; first of breeding season). The trial was conducted at two locations, one in Kansas (147 cows) and one in Colorado (313 cows). At each location, cows were assigned to be inseminated after observed estrus (ESTRUS-AI) or at a fixed time (TIMED-AI). Within these two groups, cows either were inseminated in the uterine body (BODY-bred) or in both uterine horns (HORN-bred). Cows in the ESTRUS-AI group were observed for estrus each morning and evening until day 5 afterPGF and then inseminated 12 hr after first detected estrus. Cows in the TIMED-AI group received a second dose of GnRH on day 2 and were inseminated at that time (48 to 56 hr after PGF). Heat response, AI conception rate, and pregnancy rate were analyzed for BODY-bred and HORN-bred cows within each treatment at each location. No differences in these variables occurred between locations, so the results were combined. Within the ESTRUS-AI group, neither conception rate (70% vs. 73%) nor pregnancy rate (39% vs. 40%) was different between BODY-bred and HORN-bred cows respectively. Pregnancy rate within the TIMED-AI group tended (P=.09) to be greater for BODY-bred (53%) compared to HORN-bred (42%) cows. When BODY-bred and HORN-bred treatments were combined, the pregnancy rate of TIMED-AI cows (48%) tended (P=.07) to be greater than that of ESTRUS-AI cows (39%). Timed-insemination resulted in a greater pregnancy rate than inseminating cows according to estrus. No advantage was seen in conception rates when semen was deposited in the uterine horns compared to the uterine body
Sampling techniques for and interpretation of milk urea nitrogen concentration
Representative MUN values can be obtained
by testing a milk sample before milking,
at AM or PM milking, or with an in-line siphon
sampling device. MUN values obtained from
homogenous milking strings are as accurate as
an average MUN value obtained by sampling
each cow in the string. Bulk tank sampling is
not advisable because of the variation in MUN
caused by stage of lactation. Small herds that
feed a single TMR should use the average
MUN from cows between 60 and 200 days in
milk. Monthly sampling is recommended to
build a database. The effect of diet changes on
MUN can be assessed within 7 days
Speakers and the Spotlight: Explaining Media Coverage of Leadership in the House of Representatives
Previous scholarship has described how members of Congress struggle to attract media attention. The Speaker of the House, however, is uniquely positioned to drive media agendas. That position may be conditioned though by the framework in which the Speaker operates, shocks to the system of leadership in the House, and the process of legislating. We inquire into the conditions under which the Speaker of the House receives increased or decreased attention from newspapers, network newscasts, and cable newscasts. We also examine the contraction and expansion of the gap between levels of presidential and Speaker coverage. We find that Speaker coverage is often shaped by increases in House polarization, changes in which party holds the position, Speaker scandal, and turning bills into laws.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
The cellular and synaptic architecture of the mechanosensory dorsal horn
The deep dorsal horn is a poorly characterized spinal cord region implicated in processing low-threshold mechanoreceptor (LTMR) information. We report an array of mouse genetic tools for defining neuronal components and functions of the dorsal horn LTMR-recipient zone (LTMR-RZ), a role for LTMR-RZ processing in tactile perception, and the basic logic of LTMR-RZ organization. We found an unexpectedly high degree of neuronal diversity in the LTMR-RZ: seven excitatory and four inhibitory subtypes of interneurons exhibiting unique morphological, physiological, and synaptic properties. Remarkably, LTMRs form synapses on between four and 11 LTMR-RZ interneuron subtypes, while each LTMR-RZ interneuron subtype samples inputs from at least one to three LTMR classes, as well as spinal cord interneurons and corticospinal neurons. Thus, the LTMR-RZ is a somatosensory processing region endowed with a neuronal complexity that rivals the retina and functions to pattern the activity of ascending touch pathways that underlie tactile perception
A review of the benefits and drawbacks to virtual field guides in today’s Geoscience higher education environment
Virtual Field Guides are a way for educators to tackle the growing issue of funding pressures in areas of higher education, such as geography. Virtual Field Guides are however underutilised and can offer students a different way of learning. Virtual Field Guides have many benefits to students, such as being more inclusive, building student skills and confidence in a controlled environment pre fieldtrip and can increase engagement in the topic studied. There are also benefits to the educator, such as reduced cost, more efficient students on fieldwork tasks and the ability to tailor and update their field guides to suit their needs. However there are drawbacks in the challenge of creation and their outcome as educational standalone tools. This paper reviews the literature around the benefits and draw backs to the creation and incorporation of virtual field guides in geoscience education. © 2017, The Author(s)
Multiple Phenotypes in Adult Mice following Inactivation of the Coxsackievirus and Adenovirus Receptor (Car) Gene
To determine the normal function of the Coxsackievirus and Adenovirus Receptor (CAR), a protein found in tight junctions and other intercellular complexes, we constructed a mouse line in which the CAR gene could be disrupted at any chosen time point in a broad spectrum of cell types and tissues. All knockouts examined displayed a dilated intestinal tract and atrophy of the exocrine pancreas with appearance of tubular complexes characteristic of acinar-to-ductal metaplasia. The mice also exhibited a complete atrio-ventricular block and abnormal thymopoiesis. These results demonstrate that CAR exerts important functions in the physiology of several organs in vivo
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