Incidence of ryegrass staggers in white rhinoceros (Ceratotherium simum) at Auckland Zoo

Abstract

Extract

Most perennial ryegrass (Lolium perenne) plants in pastures in New Zealand contain a naturally occurring fungal endophyte, Neotyphodium lolii. Endophyte-infected perennial ryegrass produces alkaloids that vary in concentration during the year. Some alkaloids enhance the persistence and productivity of ryegrass pastures by protecting them against insect attack. However, when other alkaloids are consumed they can reduce animal performance and lead to health problems. The alkaloid lolitrem B, for example, causes the neuromuscular disorder ryegrass staggers (Fletcher et al 1999 Fletcher, LR, Sutherland, BL and Fletcher, CG. 1999. “The impact of endophyte on the health and productivity of sheep grazing ryegrass-based pastures”. In Ryegrass endophyte: an essential New Zealand symbiosis Grassland Research and Practice Series Edited by: Woodfield, DR and Matthew, C. Vol. 7, 11–17.  [Google Scholar]). Clinical symptoms of ryegrass staggers in animals range from slight muscular tremors through to staggering and complete collapse. Severely affected animals create management problems and are prone to accidental death. Outbreaks occur sporadically, particularly in summer and autumn and affect sheep, cattle, deer, horses, llamas (Lama glama) and alpaca (Lama pacos). Lolitrem B appears to be a stable compound, which tends to be concentrated in the leaf sheath at the base of the ryegrass plant and in the seed-heads (di Menna et al 1992 di Menna, ME, Mortimer, PH, Prestidge, RA, Hawkes, AD and Sprosen, JM. 1992. Lolitrem B concentrations, counts of Acremo ni um lolii hyphae, and the incidence of ryegrass staggers in lambs on plots of A. lolii-infected perennial ryegrass. New Zealand Journal of Agricultural Research, 35: 211–217. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]; Keogh et al 1996 Keogh, RG, Tapper, BA and Fletcher, RH. 1996. Distributions of the fungal endophyte Acremonium lolii, and of the alkaloids lolitrem B and peramine, within perennial ryegrass. New Zealand Journal of Agricultural Research, 39: 121–127. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). Hay made from endophyte-infected perennial ryegrass contains large numbers of seed-heads and lolitrem B concentrations can be high, especially if it is made in late summer or autumn and, consequently, animals fed such hay are at risk of developing ryegrass staggers.     

Direct and indirect effects of Johne's disease on farm and animal productivity in an Irish dairy herd

Johne's disease (JD) is caused by infection with the organism Mycobacterium avium spp. paratuberculosis, leading to chronic diarrhoea and ill thrift in adult cattle. JD is considered to adversely affect farm performance and profitability. This retrospective case study was undertaken on a single commercial dairy herd in the south west of Ireland. Animal production records were interrogated to assess the effect of JD on milk yield (total kg per lactation), somatic cell count (the geometric mean over the lactation), reasons for culling, cull price and changes in herd parity structure over time. JD groups were defined using clinical signs and test results. One control animal was matched to each case animal on parity number and year. Specific lactations (clinical, pre-clinical and test-positive only) from 1994 to 2004 were compared between JD case and control cows. A significantly lower milk yield (1259.3 kg/lactation) was noted from cows with clinical JD in comparison to their matched control group. Clinical animals had an average cull price of €516 less than animals culled without signs of clinical disease. In contrast, little effect was noted for sub-clinical infections. These direct effects of JD infections, in combination with increased culling for infertility and increasing replacement rates, had a negative impact on farm production. Results from this study provide preliminary information regarding the effects of JD status on both herd and animal-level performance in Ireland.     

Imaging electron wave functions of quantized energy levels in carbon nanotubes

Carbon nanotubes provide a unique system for studying one-dimensional quantization phenomena. Scanning tunneling microscopy was used to observe the electronic wave functions that correspond to quantized energy levels in short metallic carbon nanotubes. Discrete electron waves were apparent from periodic oscillations in the differential conductance as a function of the position along the tube axis, with a period that differed from that of the atomic lattice. Wave functions could be observed for several electron states at adjacent discrete energies. The measured wavelengths are in good agreement with the calculated Fermi wavelength for armchair nanotubes.     

Photonic channels for quantum communication

A general photonic channel for quantum communication is defined. By means of local quantum computing with a few auxiliary atoms, this channel can be reduced to one with effectively less noise. A scheme based on quantum interference is proposed that iteratively improves the fidelity of distant entangled particles.     

Incidence of lymphoma in a captive-bred colony of hamadryas baboons (Papio hamadryas)

Objective   To assess the incidence of lymphoma and wasting-related deaths in the National Baboon Colony of Australia and relate it to the presence of simian T-cell lymphotrophic virus 1 (STLV-1) infection.
Design and procedure   The records of all animals that had died since establishment of the National Baboon Colony in Australia were reviewed retrospectively. The clinical signs and histopathological findings were recorded and assessed to determine the involvement of lymphoma in the deaths. The presence of STLV-1 was recorded if known and correlated with the STLV-1 status of the colony.
Results   Of the deaths from disease or illness, 53% were diagnosed as or suspected to be lymphoma, occurring in mature animals with no sex predisposition. The most common presentation was rapidly occurring generalised lymphadenomegaly.
Conclusions   This study has described a relatively high prevalence of lymphoma in a colony of captive-bred baboons, and it is evident that STLV-1 may play a role in the disease. Management practices in baboon colonies need to take into account the possible presence of STLV-1 and aim to reduce the transmission of the virus by preventing sexual contact between positive and negative animals. Lymphoma needs to be considered as one of the more common causes of wasting and death.     

Clinical pathology of Australian bluetongue virus serotype 16 infection in Merino sheep

SUMMARY Viraemic blood from an ox naturally infected with Australian bluetongue (BLU) virus serotype 16 was passaged twice in sheep. Twelve 2- to 4-years-old Merino ewes, negative in a bluetongue agar gel Immunodiffusion test, were Inoculated with viraemic blood from the second sheep passage. They were examined for 18 days and compared with a control group. Significant changes in haematological measurements, namely packed cell volume, total white cell count and lymphocyte count, and in plasma enzyme concentrations, namely aspartate transaminase and creatine kinase, occurred in the infected sheep. All Infected sheep became sick. The antibody response, and clinical and necropsy findings were consistent with other reports of mild to moderate disease with Australian BLU serotypes.     

Thermographic selection of effective catalysts from an encoded polymer-bound library

A general method is introduced for the rapid and simultaneous evaluation of each member of large encoded catalyst libraries for the ability to catalyze a reaction in solution. The procedure was used to select active catalysts from a library of potential polymer-bound multifunctional catalysts. From approximately 7000 beads screened (3150 distinct catalysts), 23 beads were selected for catalysis of an acylation reaction. Kinetic experiments indicate that the most strongly selected beads are also the most efficient catalysts.     

Solarization for the control of Pueraria montana (kudzu)

The effects of translucent polyethylene sheeting as a thermal covering to eradicate Pueraria montana (kudzu) were investigated at Clemson, South Carolina on a clay loam. In 2005, the highest reduction of live root crowns was observed where P. montana was covered for the entire growing season (May–October) with a reduction of 42% of live root crowns compared with the control plots. Where P. montana was covered for alternate weeks throughout the growing season live root crowns were reduced by 35%. Covering P. montana for one week and then uncovering for four weeks repeatedly through the season killed 24% of root crowns. In 2006, the second year of treatment to the same plots, the three solarization treatments had similar efficacy of about 97%. The use of polyethylene sheeting appears not to be cost‐effective for general control of large P. montana infestations, but may be useful for small patches.     

Studies on preweaning piglet diarrhoea

SUMMARY The aim of this study was to determine the cause and risk factors Involved in preweaning piglet diarrhoea. Faecal samples from 2380 diarrhoeic piglets, 5 to 30 days of age, were examined for enteropathogens. Isospora suls oocysts were detected in 53.8% of samples, Escherichia coll in 18.2% and rotavirus in 16.9%. I suis had the widest distribution, being present on 70.9% of 151 piggeries. The onset of diarrhoea occurred mainly between 7 and 14 days (77.5%), peaking at 10 days. Records of 4086 litters from two intensive piggeries were analysed and showed no seasonal variation or effect of sow parity on the incidence of piglet diarrhoea. I suis was the most common enteropathogen associated with diarrhoea in piglets from 5 days of age until weaning.