Factors affecting the reproductive performance of the weaned sow.

The majority of sows return to estrus within 2 weeks after weaning. Swine practitioners attempt to optimize production by reducing the WEI. Some sows fail to resume estrous cyclicity after weaning; however, the endocrinologic pathogenesis of these anestrous sows is speculative. The average WEI is influenced by numerous factors, including season, environmental temperature, photoperiod, nutrition, stress, facility design, lactation length, and management practices. It is evident that the majority of these factors have a more profound influence on primiparous sows than on multiparous sows. Optimum protein and energy consumption by sows during lactation and after weaning and effective utilization of breeding facilities reduce the WEI. The precise roles of photoperiodic changes, elevated environmental temperatures, and stress in seasonal infertility remain poorly understood. Fortunately, current management techniques have reduced the WEI on most farms without instituting therapeutic measures.     

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.     

Hematological parameters and visceral lesions relationships in rabbit viral hemorrhagic disease.

Twenty rabbits were inoculated with a suspension of Viral Hemorrhagic Disease virus. Hemostatic functions were assessed every sixth hour from 6 to 60 hours post-inoculation. Tissue samples obtained at the same intervals allowed the study of the development of lesions throughout the experiment. Biological signs of Disseminated Intravascular Coagulation (DIC) were detected on and after 30 h post-inoculation and consisted of prolonged One Stage Prothrombin Time and Activated Partial Thrombin Time, the decrease of factors V, VII, and X and high levels of soluble fibrin monomer complexes and D-dimers. A reduction of thrombocyte numbers, heterophils and lymphocytes was associated. The close association of DIC and necrotizing hepatitis lesions suggested the hepatic lesions to be the most important DIC triggering factor. Other mechanisms are discussed.     

Transrectal ultrasonography for the evaluation of stallion accessory sex glands.

This article reviews the capabilities of transrectal ultrasonography for determining the distribution of fluid and tissue within stallion accessory sex glands. Emphasis is placed on describing the normal ultrasonographic appearance of the accessory sex glands, excurrent ducts, and pelvic urethra of stallions during rest, after teasing, and after ejaculation and using this information to detect glandular abnormalities.     

Prevention of estrus in the queen with chlormadinone acetate administered orally.

The possibility of estrus prevention in the queen by the oral administration of chlormadinone acetate was examined. The animals used were 29 mature and 15 immature queens. For 16 mature females, 4-12.5 mg was given daily by mouth for 7 days every 3 months. Ten of the 16 queens given this treatment came into estrus within 4 months of the first treatment. For 28 females including the immature, 2-12.5 mg was given once a week throughout the experiment. This treatment prevented estrous activity for at least 1 year. In the queens in this study, the side effects were not observed excepting an increase in body weight during treatment. Our results showed that oral administration of this drug weekly is safe and reliable for long-range prevention of estrus in queens.     

Cumulus Oophorus Expansion of Bovine Oocytes Cultured in vitro: A SEM and TEM Study

Bovine cumulus-oocyte complexes (COCs) were aspirated from antral follicles (3–6 mm in diameter). COCs with a compact multilayered cumulus investment were cultured for 9, 13 and 24 hours, respectively, and processed for scanning or transmission electron microscopy after different periods of culture including a 0 hour control group. In all 0 hour control COCs initial formation of cumulus cell projections, blebs and microvilli were observed. The start of cumulus-oocyte disconnection in cattle was observed after 9 hours of in vitro culture. These connections were almost completely discrupted after 13 hours, when a continuous production of extracellular matrix was observed. The full expansion of corona radiata cells was not observed even after 24 hours. Some cumulus oophorus cells were bound together with junctions of the zonula adherens type after 24 hours when extracellular matrix was found only in deeper layers. The full expansion of corona radiata cells was not the prerequisite for disconnection of cumulus-oocyte complex. Inhalt: Kumulus oophorus Expansion von in vitro kultivierten Rinderoozyten: Eine SEM und TEM Untersuchung Kumulus-Oozyten-Komplexe (COC) von Rindern wurden aus antralen Follikeln aspiriert (Durchmesser 3–6 mm). COC's mit kompakten mehrschichtigen Kumulus wurden für 9, 13 und 24 Stunden kultiviert und für die Scanner- oder Transmissionselektronenmikroskopie vorbereitet. Verschiedene Kulturzeiten incl. einer 0-Stundengruppe als Kontrolle wurden untersucht. In allen Kontroll COC's wurden beginnende Formationen yon Kumuluszellprojektionen, Bläschen und Mikrovilli beobachtet. Nach 9-stündiger in vitro Kultur begann die Lösung zwischen Kumulus und Oozyte. Die Verbindungen waren nach 13 Stunden vollständig unterbrochen, wobei eine kontinuierliche Produktion extrazellulärer Matrix beobachtet wurde. Eine vollständige Expansion der Corona radiata Zellen wurde auch nicht nach 24 Stunden beobachtet. Nach 24 Stunden waren einige Cumulus Oophorus Zellen über Verbindungen des Zonula adherens Typs verknüpft, wobei extrazelluläre Matrix nur in den tieferen Zellschichten gefunden wurde. Eine vollständige Kumulusexpansion ist keine Voraussetzung für die Auflösung des Kumulus-Oozyten-Komplexes.     

Dynamics of the Cumulation of Macroelements – Phosphorus, Potassium, Calcium and Magnesium During Development to Maturity of Soybean Seed

Dynamics of the cumulation of phosphorus, potassium, calcium and magnesium in developing seed of four soybean genotypes under the defined climatic conditions in the course of three years was observed. Samples were being taken at weekly intervals from the point at which the grain reached a size suitable to be analyzed up to the full maturity of the seed. By analyzing the results it was found out that the intense cumulation of the minerals tested took place during the stages III and IV of the seed development, that is, in the course of intense cumulation of dry matter and the most expressive metabolic activity in the seed. Investigation of the impact of climatic conditions provides evidence that cumulation of the tested macroelements has been favourably influenced by increased precipitation along with moderate air temperatures within the seed developing period. The highest content of the minerals found with the cultivar Maksimirka independently of the year investigated reveals that mineral cumulation in soybean seed is affected by the cultivar and genetic particularity.     

Changes in several blood and urine parameters during combined hyperfluid therapy for the treatment of chronic obstructive bronchitis (COB) in the horse

During the combination of oral and intravenous application of saline solution for treatment of the COPD of horses the level of hydraemia basing on the total protein concentration in the serum, the urine production and the specific weight of urine was determined. Additionally the development of serum concentration and of renal excretion rates of potassium, calcium and magnesium were ascertained. The level of hydraemia resulting from the combined method is almost identical with the solely intravenous performed hyperinfusion therapy. Due to the excessive application of fluid an extremely high level of urine production is reached which causes a reduced specific weight as well as an increased renal excretion of potassium, calcium and magnesium. The result is a real loss of electrolytes which is - apart from hydraemia - the reason for the lower level of the corresponding serum concentrations. This seems to be important, especially for potassium and magnesium, because the organism is unable to compensate the loss of these electrolytes in the same way as the loss of calcium. In connection with the renal loss of electrolytes during the high level of urine production glucosuria is observed.     

The Content of β-endorphin-like Immunoreactivity in Porcine Corpus Luteum and the Potential Roles of Progesterone, Oxytocin and Prolactin in the Regulation of β-endorphin Release from Luteal Cells in vitro

The amount of β‐endorphin‐like immunoreactivity (β‐END‐LI) in porcine corpora lutea from several stages of the oestrous cycle and the effects of progesterone, oxytocin, and prolactin on β‐END‐LI secretion in vitro by luteal cells were studied. Porcine corpora lutea obtained on days 1–5, 6–10, 11–13, 14–18, and 19–21 of the cycle were used to prepare extracts for β‐END‐LI determination. Additionally, corpora lutea from days 11–13 and 14–18 were enzymatically dissociated and isolated luteal cells were used for further study of β‐endorphin secretion in vitro. Cells were cultured in serum‐free defined M 199 medium (10⁶ cells/ml) at 37°C under 5% CO₂ in air, for 12 h. The influences of the following factors on β‐END‐LI secretion by luteal cells were tested: progesterone (10^–9, 10^–7 and 10^–5M ), oxytocin (0.01, 0.1, 1 and 10 ng/ml), and prolactin (0.1, 1, 10 and 100 ng/ml). The β‐END‐LI contents in extracts and media were measured by radioimmunoassay. The tissue concentration of β‐END‐LI was lowest on days 1–5 of the cycle (0.35 ± 0.03 ng/g wet tissue). Subsequently, it constantly increased to the highest value on days 14–18 (16.58 ± 0.52 ng/g wet tissue) and on days 19–21 it declined (11.10 ± 0.52 ng/g wet tissue). Progesterone at a low dose (10^–9 M ) resulted in significant (p < 0.05) increases and decreases in β‐END‐LI secretion by luteal cells from days 11–13 and 14–18, respectively. Higher doses of progesterone (10^–7 and 10^–5 M ) had no effect on β‐END‐LI release, compared with the control group. All dose‐levels of oxytocin used decreased β‐END‐LI secretion by luteal cells on days 11–13 and 14–18 of the cycle. Prolactin at doses of 0.1 and 1 ng/ml on days 11–13, and all doses tested on days 14–18 resulted in decreases in β‐END‐LI release from luteal cells. These results document evident changes in β‐END‐LI content in the pig corpus luteum during its development and indicate the potential roles of progesterone, oxytocin, and prolactin in luteal cell secretion of β‐END‐LI.