Physiological and behavioral responses of sheep to gaseous ammonia

Ammonia can accumulate in highly stocked sheep accommodation, for example during live export shipments, and could affect sheep health and welfare. Thus, the objective of this experiment was to test the effects of 4 NH(3) concentrations, 4 (control), 12, 21, and 34 mg/m(3), on the physiology and behavior of wether sheep. Sheep were held for 12 d under a micro-climate and stocking density similar to shipboard conditions recorded on voyages from Australia to the Middle East during the northern hemispheric summer. Ammonia increased macrophage activity in transtracheal aspirations, indicating active pulmonary inflammation; however, it had no effect (P > 0.05) on hematological variables. Feed intake decreased (P = 0.002) in proportion to ammonia concentration, and BW gain decreased (P < 0.001) at the 2 greatest concentrations. Exposure to ammonia increased (P = 0.03) the frequency of sneezing, and at the greatest ammonia concentration, sheep were less active, with less locomotion, pawing, and panting. Twenty-eight days after exposure to NH(3), the pulmonary macrophage activity and BW of the sheep returned to that of sheep exposed to only 4 mg/m(3). It was concluded that NH(3) induced a temporary inflammatory response of the respiratory system and reduced BW gain, which together indicated a transitory adverse effect on the welfare of sheep.     

Serologic evidence of chicken infectious anemia in commercial chicken flocks in southwest Nigeria

Sera samples from seven poultry farms in southwest Nigeria consisting of 7 broiler, 10 pullet, 1 layer, 1 cockerel, and 1 broiler breeder flocks were tested for the presence of chicken infectious anemia virus (CIAV) antibodies using a commercial enzyme-linked immunosorbent assay kit. Eleven of the 20 flocks (55%) and six out of seven (86%) farms were positive for CIAV antibodies. The seroprevalence largely depended on the age of the flocks. Seroprevalence was higher within the older pullet and layer flocks (83%-100%) than in the younger broiler flocks (0%-83%). In essence, all flocks older than 6 to 8 wk became infected. This is the first report of serologic evidence of CIAV in Subsaharan Africa. Since Southwest Nigeria is the main port of entry of imported chicken and the hub of major poultry breeders, the disease can probably be found throughout the country and beyond. Further studies are necessary to assess economic losses due to CIAV and the cost benefit of countermeasures.     

From the germinal cells to the newborn animal: the transmission of genes and life through the generations

The technology of reproduction progressed considerably during the last decade, leading to a certain availability of in vitro methods for fertilisation, oocyte maturation and embryo culture. The most spectacular manipulations are cloning and transgenesis. This review focuses on the early appearance of germinal cell precursors and the long-standing fate of gametes in mammals. The evident complexity and long-term programming of events in gametes and early embryos explain part of the difficulties encountered during the development of in vitro and in vivo methods such as multiple ovulation and embryo transfer (MOET), oestrus synchronisation, ovulation induction, superovulation, in vitro maturation and fertilisation, cryopreservation, transgenesis, nuclear transfer and cloning) and the occurrence of unexpected alterations of development, e.g. embryonic or fetal mortality, large-weight newborn syndrome and other dysregulations in imprinting or DNA transmission.     

Effect of monensin and tylosin on average daily gain, feed efficiency and liver abscess incidence in feedlot cattle

Fourteen trials were conducted to evaluate the effects of feeding monensin at 33 ppm alone, tylosin at 11 ppm alone and the two feed additives in combination on the average daily gain, average daily feed intake, feed:gain ratio and the incidence of liver abscesses in feedlot cattle. Monensin reduced feed intake and improved feed efficiency (P less than .05), and had no effect on average daily gain. Tylosin improved average daily gain (P less than .05) and had no effect on daily feed intake. The effect of tylosin on feed efficiency approached significance. The interaction of monensin and tylosin was nonsignificant for daily gain, daily feed intake and feed:gain ratio. Monensin had no effect on liver abscess incidence, while tylosin reduced abscess incidence from 27 to 9%.     

Flooding causes loss in viability and pathogenicity of sclerotia of Rhizoctonia tuliparum

Samenvatting Rhizoctonia tuliparum veroorzaakt kwadegrond in tulp en iris. Sclerotiën van deze schimmel kunnen in grond zeer lang levensvatbaar en pathogeen blijven. Van sclerotiën van enkele schimmels is bekend, dat ze gevoelig zijn, voor inundatie die een aantal weken duurt. Inundatie wordt in Nederland vanaf 1982 door verscheidene, bollentelers 's zomers toegepast ter bestrijding van ziekten en onkruid.Sclerotiën vanR. tuliparum werden verpakt in nylon zakjes, ingegraven in emmers met grond en 1–6 weken geïnundeerd bij 17 °C. Op verschillende tijdstippen werden geïnundeerde en niet-geïnundeerde sclerotiën hetzij ontsmet, in 2,5% formaldehyde en vervolgens uitgeplaat op moutagar met oxytetracycline, hetzij aangebracht tussen de bruine huid en de buitenste bolrok van in kleine potjes geplante tulpebollen (cv. Apeldoorn); iedere bol werd geïnoculeerd met, een sclerotium. Na twee maanden werden de planten beoordeeld op symptomen van kwadegrond.In de eerste proef, waarbij sclerotiën werden uitgeplaat op agar, bleek er uit sommige sclerotiën die 2 weken waren geïnundeerd nog mycelium te groeien, terwijl dit na, 4 weken inundatie niet meer plaatsvond. In de tweede proef kiemden de sclerotiën op agar niet meer na 2 weken inundatie, maar meer dan de helft van de geïnoculeerde tulpebollen vertoonde wel symptomen. Pas als de sclerotiën 4 weken geïnundeerd waren bleken ze zodanig geïnactiveerd te zijn, dat er geen symptomen van kwadegrond werden waargenomen. Resultaten van veldproeven moeten nog worden afgewacht.     

Canine parvovirus 2c infection in central Portugal

Canine parvovirus (CPV) has been evolving, generating new genetic and antigenic variants throughout the world. This study was conducted to determine the types of CPV circulating in dogs in Figueira da Foz, Portugal. Thirty fecal samples, collected between 2006 and 2007 from dogs with clinical signs of CPV infection, were tested for CPV by a rapid, in-clinic, enzyme-linked immunosorbent assay (ELISA)/immunomigration test, by conventional real-time polymerase chain reaction (PCR), and by minor-groove binding TaqMan PCR. Of the 29 PCR-positive samples, 15 were identified as CPV-2b and 14 as CPV-2c. No CPV-2a was detected. The sensitivity of the ELISA test was 82.76% compared with the PCR assays. No significant associations were found between CPV type, clinical outcome, breed, vaccination status, or age.     

Isolation and detection of Fasciola hepatica DNA in Lymnaea viatrix from formalin-fixed and paraffin-embedded tissues through multiplex-PCR

Detection of Fasciola hepatica infection in Lymnaea viatrix through analysis of histological cuts is based upon morphological characters of the parasite during the intra-mollusk phase of parasitism. At this stage, trematode forms are very similar and, thus, very difficult to differentiate. Specific detection may also be impaired by the presence of other helminthes in the mollusk. Histological samples are usually fixed in formalin, embedded in paraffin, sectioned and HE stained. In the current study, a method for the extraction of DNA from formalin-fixed, paraffin-embedded tissues was standardized by means of deparaffinizing with xylol and digesting with proteinase K. Extracted DNA was amplified in a multiplex-PCR, by using simultaneous primers in a single reaction under high stringency conditions. Results showed specific amplification of DNA from the trematode and the snails. The technique was sensitive enough to detect F. hepatica infections in L. viatrix, in histological sections in which the presence of larval stages could not be observed through brightfield microscopy. The profiles generated were: stair bands referring to F. hepatica DNAmt amplification; a band of 1200 bp referring to L. viatrix ITS and another of 1300 bp referring to F. hepatica ITS and other trematodes. Multiplex-PCR has shown to be a fast, safe, highly sensitive and specific method, which is able to amplify DNA from fixed tissues, despite a low DNA quantity and its degradation caused by fixation processes. Such methodology may be useful in studies on fascioliasis epidemiology, enabling the use of material from histological collections.