Lehr- und Prüfungsmethoden im Fach veterinärmedizinische Botanik mit besonderer Berücksichtigung des Konzepts o-test

Um Studierende der Veterinärmedizin für das vorklinische Fach Botanik zu motivieren, wurden "student-generated questions" (MC LEAOD & SNELL 1996) als Basis für die Klausur in die Vorlesung integriert. Bestimmungsübungen mit Kurzexkursionen dienten dazu, das für den Arztberuf entscheidende diagnostische Beobachtungsvermögen (an pflanzlichen Objekten) zu schulen. Zur Prüfung entsprechender praktischer Kompetenzen direkt am Wuchsort der Pflanzen entwickelten wir den outdoor-test (o-test). Ziel war festzustellen, ob (1) durch die neue Schwerpunktsetzung in der Vorlesung eine höhere Motivation für das Fach Botanik erreicht wird, (2) praktische Übungen aus Sicht der Studierenden das diagnostische Beobachten verbessern und (3) der o-test praxistauglich ist. Ergebnis: (1) Die Abnahme der pro Vorlesung generierten Fragen von 61 auf 11 von Semesterbeginn bis zum Ende erwies diese Methode als ungeeignet, um ein höheres fachliches Interesse zu erreichen. (2) Die diagnostische Kompetenz wurde durch Bestimmungsübungen gefördert, doch schien es den Studierenden unsicher, ob ihre Methodenkenntnis für die Anwendung in der Prüfung ausreichen würde. (3) 219 Studierende in 43 (meist) Fünfer-Gruppen absolvierten mit einem Tablet-PC pro Person den einstündigen o‑test im universitätseigenen Botanischen Garten an einem Tag. Der hohe Mittelwert von 89,9 % erreichter Leistung zeigte, dass es misslang, den weiter­gegebenen Informationswert der für alle Teilnehmer identi­schen zehn single choice-Fragen gering zu halten. Andererseits zeigten un­informierte Studierende, welche in den ersten Gruppen den Test durchliefen, normalverteilte Leistungen. Somit waren Anforderungsniveau und didaktische Konzeption der Fragen angemessen. Wenn es gelingt, die eher planerischen Mängel zu beseitigen, bildet der o-test ein praxistaugliches Konzept zur Kontrolle praktischer Lernziele am Standort. 15.04.2011 | Sabine Aboling, Karl-Heinz Windt, Denise Pohl & Jan P. Ehlers (Hannover

Beyond Digestion: Can Animals Shape the Landscape According to Their Species–Specific Salivary Secretions?

Several functions are acknowledged for saliva secretion in different animal species following prehension and mastication of feed. Most of such are linked to the specific role of lubrication and softening of the bolus to allow taste perception and easy swallowing. Moreover, enzymatic components are produced in the saliva, some of which are destined to contribute to the digestion of different nutrients (to various extents according to animal species) and to exert antimicrobial activity (lysozyme). In addition, the buffering power and the virtuous recycle of water, electrolytes, and other metabolites are of particular importance for proper digestion and for nutrition–related aspects. Moreover, salivation appears to be involved in a number of other functions. Recent studies on salivary production and roles point to salivary glands as target organs of neuroendocrine regulation in response to many external stimuli coming from the outer world, for which feed still represents the chief external stimulus. Various animal species establish an adaptive strategy when coming into contact with different feeding stuffs and/or dietary substances by modifying both the composition and amount of saliva produced. In the light of recent updates, this review provides a focus on the functional roles of saliva secretions, showing the broad involvement of salivary response in several mechanisms beyond the digestive function and influencing feed selection

Grazing Ecology of Sheep and Its Impact on Vegetation and Animal Health in Pastures Dominated by Common Ragwort (Senecio jacobaea L.)—Part 1: Vegetation

Species-rich pastures naturally contain potentially toxic plants such as common ragwort (Senecio jacobaea L.), whose pyrrolizidine alkaloids (PA) impose a risk, mainly for cattle and horses. Although in vitro studies showed detoxification capacity of PA in sheep, few field data are available to ascertain whether grazing sheep can both tolerate and reduce ragwort. In a two-year study in a ragwort-rich pasture with a stocking density of 12 sheep/hectare, we documented (1) the extent of voluntarily ingested ragwort, (2) the correlation of nutritional parameters and feeding behavior, and (3) the impact of grazing on the yield proportion and number of flowers of dominant plants. Every six weeks the vegetation underwent a botanical survey and a chemical analysis. Sheep continuously ingested ragwort between 1.2 and 4.9 kg (2020) and 1.0 and 2.2 kg (2021) per individual per day without any impact on animal health. The more biomass ragwort produced, the more it contained sugar (r = 0.59–0.74), and the more sheep ingested it (r = 0.94–0.95). Other herbs increased their yield proportion from 23.3 to 36.5%, while that of ragwort decreased from 26.3 to 18.8% (2020/2021), doubling its flowers. Sheep preferred and tolerated ragwort, making their grazing an option to control ragwort from both an animal health and a nature conservation perspective

Grazing Ecology of Sheep and Its Impact on Vegetation and Animal Health in Pastures Dominated by Common Ragwort (<i>Senecio jacobaea</i> L.)—Part 1: Vegetation

Species-rich pastures naturally contain potentially toxic plants such as common ragwort (Senecio jacobaea L.), whose pyrrolizidine alkaloids (PA) impose a risk, mainly for cattle and horses. Although in vitro studies showed detoxification capacity of PA in sheep, few field data are available to ascertain whether grazing sheep can both tolerate and reduce ragwort. In a two-year study in a ragwort-rich pasture with a stocking density of 12 sheep/hectare, we documented (1) the extent of voluntarily ingested ragwort, (2) the correlation of nutritional parameters and feeding behavior, and (3) the impact of grazing on the yield proportion and number of flowers of dominant plants. Every six weeks the vegetation underwent a botanical survey and a chemical analysis. Sheep continuously ingested ragwort between 1.2 and 4.9 kg (2020) and 1.0 and 2.2 kg (2021) per individual per day without any impact on animal health. The more biomass ragwort produced, the more it contained sugar (r = 0.59–0.74), and the more sheep ingested it (r = 0.94–0.95). Other herbs increased their yield proportion from 23.3 to 36.5%, while that of ragwort decreased from 26.3 to 18.8% (2020/2021), doubling its flowers. Sheep preferred and tolerated ragwort, making their grazing an option to control ragwort from both an animal health and a nature conservation perspective

Rejection behaviour of horses for hay contaminated with meadow saffron (Colchicum autumnale L.)

Background Extensively used grasslands are frequently utilised for hay production for equines. Especially, extensive meadows have a great variety of plant species, which may include plants that are poisonous for equines such as meadow saffron (Colchicum autumnale L.). To authors’ knowledge investigations about horses` avoidance behaviour towards dried meadow saffron in hay are missing. Reports of farmers are contrary to clinical symptoms described in case reports and associated with meadow saffron in hay. Objectives The aim of this study was to determine the rejection behaviour of horses for hay contaminated with meadow saffron (MS) when fed ad libitum. Study design An 18-day feeding trial with six adult geldings to observe the rejection behaviour for hay contaminated with MS. Methods The horses were fed a basal diet containing hay ad libitum and a mineral supplement during the feeding trial. At six different daytimes, hay contaminated with 1% or 2% dried MS was provided to the horses over a duration of 1 h. The rejection behaviour was observed personally and by video recordings. If a horse ingested more than two plants of MS during one observation period, the observation was stopped and repeated at another day. When the observation period had to be stopped twice, the horse was excluded from the experiment. Results Five of six horses ingested MS during the first feeding periods. One horse rejected leaves and capsules at the beginning of the study, but it showed repeated ingestion of MS after the seventh observation period. Main limitations Lack of knowledge about secondary plant metabolites affecting taste and their variability between fresh and dried plants. Conclusions The intake of MS in hay by horses could not be ruled out with certainty. Therefore, feeding hay contaminated with MS should be avoided for equids

Grazing Ecology of Sheep and Its Impact on Vegetation and Animal Health on Pastures Dominated by Common Ragwort (Senecio jacobaea L.)&mdash;Part 2: Animal Health

Common ragwort (Senecio jacobaea L.) naturally occurs on species-rich grasslands. Containing pyrrolizidine alkaloids (PA), it endangers livestock health through contaminated feed. Although in vitro studies showed a detoxification capacity of PA in sheep, few field data are available on the ability of grazing sheep to cope with ragwort. During two grazing seasons on a ragwort-rich pasture, we studied: (1) To what extent do sheep voluntarily ingest ragwort and (2) What impact their grazing behavior has on animal health. Ragwort intake was monitored by counting missing plant parts and calculating their weight. From 70 sheep, seven were slaughtered at the beginning and in six-week intervals at the end of each grazing period to monitor blood parameters and liver tissue. Sheep continuously preferred ragwort. The daily intake was above the currently assumed lethal dose, varying between 0.2&ndash;4.9 kg per sheep. Clinical, hematologic, and blood biochemistry parameters mostly remained within the reference limits. Initially elevated liver copper content declined over time. The liver of all 70 animals displayed slight to moderate hepatitis, fibrosis, and proliferation of the bile ducts, but no morphological signs of liver cirrhosis. Sheep preferred and tolerated ragwort, making their grazing an option to control ragwort from both an animal health and nature conservation perspective