Does Shrub Removal Increase Groundwater Recharge in Southwestern Texas Semiarid Rangelands?

Evapotranspiration (ET) is a key component limiting groundwater recharge past the root zone in semiarid regions. Vegetation management may alter groundwater recharge if ET is altered due to changes in vegetation type or cover. This study quantifies changes in groundwater recharge following vegetation cover change from native woodland to pasture in a semiarid region of southwest Texas. The Carrizo–Wilcox aquifer is a valuable groundwater resource in this area, where overuse by dependent farming practices has lowered aquifer levels significantly in the last 85 yr. Combining data from short-term (30 mo) monitoring of the changes in soil moisture and long-term (5–30 yr) changes in total soil chloride indicated deep drainage increased slightly where land had been cleared of vegetation. Annual recharge rates below rooting depths (standardized to 155 cm) averaged only 0.72 ±  mm · yr^-1 (mean ± SE) in areas not cleared of woody vegetation, as estimated by chloride mass balance. Upon clearing, 72% of the total chloride naturally occurring in the soil profile was flushed away within 30 yr, leading to an estimated 2.59 ±  mm · yr^-1 additional recharge. Deep soil moisture in recently cleared land increased by up to 17% during the growing season of wet years (double the average rainfall) but did not increase in dry or normal precipitation years, providing supporting evidence that more water penetrated below the roots under certain environmental conditions. These results demonstrate that brush management can increase recharge by modest, but measurable, amounts depending on site-specific soil characteristics and degree of reduction in vegetation.     

Reproductive Causes of Hypocalcemia

Reproductive causes of hypocalcemia include puerperal tetany (eclampsia) and mild hypocalcemia during whelping. This article reviews the pathophysiology, signalment, clinical signs, and treatment of eclampsia in the bitch and queen. The second part of the article focuses on the consequences and treatment of hypocalcemia prior to and during whelping in dogs and cats.     

A Fresh Look at the Process of Arriving at a Clinical Prognosis Part 4: Fractures

Equine bone and biomechanics research continues to provide us with sound and practical concepts for preventing fractures in equine athletes, accelerating a safe return to training and competition, and avoiding recurrence. Bone is a living, dynamic tissue that is constantly in a state of turnover as part of its ongoing maintenance, and is constantly responding to the various forces it experiences, from within and without. Even the seemingly inert, acellular components of bone are in a perpetual state of flux under both biomechanical and metabolic/nutritional influences. Homeostasis in bone involves both modeling and remodeling; modeling is bone's adaptive response to increases or decreases in load that are of insufficient magnitude to damage the bone. It involves the addition or removal of existing bone, changing the shape and loading capacity of the bone as needed. Remodeling is bone's reparative response to injury; it involves the removal and replacement of bone in the area of damage. Fractured bone needs the following conditions for best repair: protection—remove the primary cause of bone injury and prevention of further such injury; stability—depends on the type and site of fracture; blood flow—bone is dependent on good blood supply for repair; competent immune response—a robust white cell response is necessary both for tissue repair and for prevention/resolution of bacterial infection at the site; nutrients—all living tissues need adequate calories, and protein, minerals (including trace minerals), and vitamin D are of primary importance for optimal bone repair; and load—after fracture healing, increasing the loading capacity of the bone directs further bone repair and modeling. The prognosis may be adversely affected when any of these conditions are not met adequately. Generally, fractures in horses are not fatal injuries by themselves but most often prompted by a poor prognosis for return to soundness because of the fracture type, the development of serious complications, and the economic investment required for adequate repair. Factors that determine the prognosis for survival are degree of structural failure, ease of fixation and potential for complications, adequacy of stabilization, concurrent and complicating conditions, owner's wishes, and prognosis for return to athletic performance. Fractures of the metacarpus and metatarsus are used to illustrate the aforementioned principles.     

Venograms for Use in Laminitis Treatment

Venography is a very valuable tool that can be used in the diagnosis and treatment of laminitis. It can be used to assess vascular damage in the hoof before changes in radiographic detail occur. When used at onset, the venogram proves to be most valuable. They can not only give baseline measurements but can also show the level of damage that has already occurred. Initial venograms allow farriers and veterinarians to evaluate what degree of corrective treatment is necessary for the best outcome. In addition, a series of venograms can show the process of pathology as well as recovery. From here, treatment can be altered to accommodate the case.     

基因组学和生理学在家禽福利育种中的应用

<正>1最近十年的欧洲家禽福利经验在欧洲,农场动物福利是一个主要的问题。近年来人们对动物福利法规及其相关方面的科学研究日益增多。由于家禽福利状况堪忧,导致标准化家禽生产的话题被关注。选育的影响经常遭到质疑。事实上,在进行商业选育的最初,很少考虑家禽的适应能力,因此出现了某些性状的退化。但是现在,对福利相关性状和遗传选育的越来越关注,     

Recovery threshold of Toxocara canis eggs from soil

The purpose of this study was to evaluate the threshold of Toxocara canis eggs form soil samples through utilisation of a centrifuge-flotation technique (CFT). Aliquots of soil (1 g each) were artificially contaminated with known numbers of T. canis eggs (1, 10, 25, 50, 100, and 200 eggs). The threshold was evaluated based on a CFT using zinc sulphate (Zn₂SO₄) and sodium nitrate (Na₂NO₃) solutions at a specific gravity of 1.20. The number of eggs recovered was directly proportional to the number of eggs employed to seed the soil. Both solutions enabled full recovery of samples containing merely three eggs; only Zn₂SO₄ demonstrated efficiency in soil contaminated with a single egg. A recovery rate of 100% was obtained for all tests with samples containing 10 and 25 eggs for Zn₂SO₄ and Na₂NO₃, respectively_. There was no difference in the mean number of recovered eggs regarding either the efficacy of the solutions or the repetition of evaluations in the same trial (p > 0.05). Therefore, the CFT is efficient for the detection of Toxocara eggs, even in samples containing low egg numbers.     

Getting a grip on strangles: recent progress towards improved diagnostics and vaccines

'Strangles', caused by infection with the bacterium Streptococcus equi, remains one of the most commonly diagnosed and important infectious diseases of horses world-wide. This review discusses the diagnosis and pathogenesis of strangles with particular attention to the significance of persistent infections in disease transmission and the rapid progress now being made towards the development of effective preventative vaccines. It is now possible combine recent sequence data from the N-terminal region of the SeM protein and reassign the SeM alleles using the on-line database http://pubmlst.org/szooepidemicus/seM/. Hypotheses concerning the origin of this variation and the potential for its exploitation for the epidemiological analysis of outbreaks are proposed. Advances in understanding of the molecular evolution of S. equi highlight the role played by phage-mediated acquisition of virulence factors and suggest new avenues for prophylactic intervention.