Pasteurella haemolytica A1 and Bovine Respiratory Disease: Pathogenesis

The severe fibrinonecrotic pneumonia associated with pneumonic pasteurellosis usually results from colonization of the lower respiratory tract by Pasteurella haemolytica biotype A, serotype 1(A1). Despite recent research efforts, the authors lack a detailed understanding of the interactions and host response to P. haemolytica in the respiratory tract. The authors hypothesize that management and environmental stress factors or viral infection alters the upper respiratory tract (URT) epithelium allowing P. haemolytica to colonize the epithelium. Once the URT is colonized, large numbers of organisms enter the lung where they interact with alveolar macrophages. Endotoxin, released from the bacteria, crosses the alveolar wall where it activates pulmonary intravascular macrophages, endothelium, neutrophils, lymphocytes, platelets, complement, and Hageman factor leading to complex interactions of cells and mediators. It is the progression of this inflammatory response with neutrophil influx that is ultimately responsible for the pulmonary injury. Leukotoxin is a major virulence factor of P. haemolytica that allows it to survive by destroying phagocytic cells. At subcytolytic concentrations it may also enhance the inflammatory response by activating cells to produce mediators and release reactive oxygen metabolites and proteases.     

Genetics of Body Color in Tilapia mossambica

Gold, bronze, and black (normal pigmentation) body colors in Tilapia mossambica are controlled by a single autosomal gene with incomplete dominant gene action: GG fish are black gg fish are gold; Gg fish are bronze. Because gold body color is produced by the recessive genotype, it is easy to produce and to maintain a truebreeding population of gold T. mossambica for commercial purposes. If all other colors are culled, the population will breed true, because gold × gold will always produce 100% gold offspring. The G gene will be a valuable genetic marker for many genetic studies, such as the production of gynogenetic T. mossambica .     

Effect of hay type on cecal and fecal microbiome and fermentation parameters in horses

The effect of hay type on the microbiome of the equine gastrointestinal tract is relatively unexplored. Our objective was to characterize the cecal and fecal microbiome of mature horses consuming alfalfa or Smooth Bromegrass (brome) hay. Six cecally cannulated horses were used in a split-plot design run as a crossover in two periods. The whole plot treatment was ad libitum access to brome or alfalfa hay fed over two 21-d acclimation periods with subplots of sampling location (cecum and rectum) and sampling hour. Each acclimation period was followed by a 24-h collection period where cecal and fecal samples were collected every 3 h for analysis of pH and volatile fatty acids (VFA). Fecal and cecal samples were pooled and sent to a commercial lab (MR DNA, Shallowater, TX) for the amplification of the V4 region of the 16S rRNA gene and sequenced using Illumina HiSeq. The main effects of hay on VFA, pH, and taxonomic abundances were analyzed using the MIXED procedure of SAS 9.4 with fixed effects of hay, hour, location, period, and all possible interactions and random effect of horse. Alpha and beta diversities were analyzed using the R Dame package. Horses fed alfalfa had greater fecal than cecal pH (P ≤ 0.05), whereas horses fed brome had greater cecal than fecal pH (P ≤ 0.05). Regardless of hay type, total VFA concentrations were greater (P ≤ 0.05) in the cecum than in feces, and alfalfa resulted in greater (P ≤ 0.05) VFA concentrations than brome in both sampling locations. Alpha diversity was greater (P ≤ 0.05) in fecal compared with cecal samples. Microbial community structure within each sampling location and hay type differed from one another (P ≤ 0.05). Bacteroidetes were greater (P ≤ 0.05) in the cecum compared with the rectum, regardless of hay type. Firmicutes and Firmicutes:Bacteroidetes were greater (P ≤ 0.05) in the feces compared with cecal samples of alfalfa-fed horses. In all, fermentation parameters and bacterial abundances were impacted by hay type and sampling location in the hindgut.     

Resynchronization of estrus in beef cattle: ovarian function, estrus and fertility following progestin treatment and treatments to synchronize ovarian follicular development and estrus

The objective was to optimize rebreeding of nonpregnant, previously inseminated beef cattle. In Experiment 1, 43 cows received a used intravaginal progesterone-releasing insert (IVPRI; Days 0-7) 12.3 d after ovulation and received concurrently no treatment, 100 microg gonadotropin releasing hormone (GnRH), 1 mg estradiol cypionate (ECP), or 150 mg progesterone. Emergence of a new ovarian follicular wave was most synchronous (P < 0.0001) in the GnRH group. In Experiment 2, 675 heifers were given GnRH or no treatment on Day 0, fed melengestrol acetate (MGA; 0.5 mg/head/d) from Days 0-5 (Day 0 = 13-14 d after timed insemination; TAI), given 0.5 mg ECP or nothing on Day 7, and reinseminated 6-12 h after onset of estrus. Estrus was more synchronous (P < 0.05) in heifers given GnRH versus no treatment on Day 0. In Experiment 3, 317 TAI heifers were resynchronized with either MGA or a used IVPRI with or without ECP on Day 7; estrus was more synchronous (P < 0.05) and pregnancy rates were higher (54.1% versus 39.2%, P < 0.05) in heifers given a used IVPRI than those fed MGA. For resynchronization of heifers, pregnancy rates were not significantly improved with GnRH treatment, but were higher with a used IVPRI than with MGA.     

Bacteraemia in neonatal foals: clinicopathological differences between Gram-positive and Gram-negative infections, and single organism and mixed infections

REASONS FOR PERFORMING STUDY: Treatment for bacteraemia in foals must be started before the identity of the causative organism is known. Information aiding selection of effective antimicrobials should improve outcome. OBJECTIVES: To describe differences in clinical and clinicopathological data and outcome in foals with bacteraemia due to different classes of bacteria. METHODS: Records of foals with a positive blood culture, age < 10 days and presenting to a university hospital 1995-2004, were reviewed. Bacterial culture results, subject details, historical information, physical examination findings at admission and clinicopathological data generated during the first 48 h of hospitalisation were analysed. Results from foals with Gram-positive or Gram-negative organisms, single or mixed organism bacteraemias, and with bacteraemia due to 3 commonly isolated organisms were compared. RESULTS: Eighty-five foals met the inclusion criteria. Gram-negative organisms (n = 59) Gram-positive organisms (n = 13) or multiple organisms (n = 19) were cultured from individual foals. Foals with Gram-negative bacteraemia had lower total white blood cell and lymphocyte counts at admission than did those from which only Gram-positive bacteria were cultured. Mixed organism bacteraemia was associated with tachycardia, increased serum concentrations of sodium, chloride and urea nitrogen, acidosis, respiratory distress, recumbency on admission and nonsurvival. Actinobacillus spp. infections were associated with leucopenia, neutropenia, lymphopenia and depression on hospital admission. CONCLUSIONS AND POTENTIAL RELEVANCE: Recognising particular patterns of clinical and clinicopathological findings associated with infection with specific groups of bacteria may, in the future, aid antimicrobial selection and influence prognosis in bacteraemic foals.     

Potential farmer contributions to the design process: Indications from Indonesia

The paper argues that conventional irrigation design processes rely heavily on predetermined design criteria, often without allowing for interactions with farmers and revising of criteria during implementation. Six cases from a tertiary development project in North Sulawesi, Indonesia are described, where farmers altered what had been designed and constructed by contracting and agency engineers. Through field inspections and farmer interviews, the farmers' alternative set of design criteria was elicited to explain why the farmers changed what had been constructed. A total of 27 cases are analyzed to show the relative importance of:

Bilateral anterior segment dysgenesis in a 7-week-old domestic shorthaired cat

A 7-week-old, intact, female domestic shorthaired cat was presented to the Atlantic Veterinary College (AVC) Ophthalmology service for a 1-week history of buphthalmia in the left eye and bilateral elevated intraocular pressures. Ocular examination revealed bilateral non-visual glaucomatous eyes. Bilateral enucleations were performed without complications and histopathology revealed anterior segment dysgenesis of varying degrees in both eyes.Key clinical message:Anterior segment dysgenesis is a developmental condition that can result in primary congenital glaucoma for which the best course of treatment is enucleation.     

Plant carbon inputs and environmental factors strongly affect soil respiration in a subtropical forest of southwestern China

Soil respiration is a large component of global carbon fluxes, so it is important to explore how this carbon flux varies with environmental factors and carbon inputs from plants. As part of a long-term study on the chemical and biological effects of aboveground litterfall denial, root trenching and tree-stem girdling, we measured soil respiration for three years in plots where those treatments were applied singly and in combination. Tree-stem girdling terminates the flow of carbohydrates from canopy, but allows the roots to continue water and nutrient uptake. After carbon storage below the stem girdles is depleted, the girdled trees die. Root trenching immediately terminates root exudates as well as water and nutrient uptake. Excluding aboveground litterfall removes soil carbon inputs, but allows normal root functions to continue. We found that removing aboveground litterfall and the humus layer reduced soil respiration by more than the C input from litter, a respiration priming effect. When this treatment was combined with stem girdling, root trenching or those treatments in combination, the change in soil respiration was indistinguishable from the loss of litterfall C inputs. This suggests that litterfall priming occurs only when normal root processes persist. Soil respiration was significantly related to temperature in all treatment combinations, and to soil water content in all treatments except stem girdling alone, and girdling plus trenching. Aboveground litterfall was a significant predictor of soil respiration in control, stem-girdled, trenched and stem-girdled plus trenching treatments. Stem girdling significantly reduced soil respiration as a single factor, but root trenching did not. These results suggest that in addition to temperature, aboveground carbon inputs exert strong controls on forest soil respiration.