The occurrence of Cryptosporidium parvum,Campylobacter and Salmonella in newborn dairy calves in the Manawatu region of New Zealand

AIM: To determine the occurrence of Cryptosporidium parvum oocysts, Campylobacter spp and Salmonella spp in faecal samples taken from newborn dairy calves on 24 dairy farms in the Manawatu region of New Zealand.

METHODS: A cross-sectional study was conducted during the 2002 calving season. Faecal samples were collected from 185 newborn calves from a convenience sample of 24 dairy farms. The samples were tested microscopically for the presence of C. parvum oocysts, and bacteriologically for the presence of Campylobacter spp and Salmonella spp.

RESULTS: Infections with C. parvum were identified in 33/156 (21.2%) calves from 10 farms. More than 10⁶ oocysts/g (OPG) faeces were detected in calves from four farms. Campylobacter spp were isolated from 58/161 (36%) calves from 18 farms; in particular, C. jejuni subsp jejuni was isolated from 11/161 (6.8%) calves from seven farms. Salmonellae were not detected.

CONCLUSIONS: Despite the short and concentrated calving pattern and the long interval between calving seasons characterising most dairy farms in New Zealand, C. parvum is widespread among calves. Campylobacter spp, especially C. jejuni, rapidly colonise the intestinal tract of newborn calves.

RELEVANCE: This study provided an estimate of the ecological impact of newborn dairy calves with regard to the potentially zoonotic enteric pathogens most frequently isolated from human gastrointestinal infections in New Zealand.     

Pregnancy Rates in Angus Cross Beef Cows Bred at Observed Oestrus With or Without Second GnRH Administration in Fixed‐Time Progesterone‐Supplemented Ovsynch and CO‐Synch Protocols

Crossbred cows (n = 1073) from five locations had oestrous cycles synchronized with 100 μg of GnRH IM and insertion of controlled internal drug release device (CIDR) on Day 0 followed by 25 mg of PGF_2α IM and CIDR removal on Day 7. Kamar^® patches were placed on all cows at CIDR removal. Cows were observed three times daily for oestrus after PGF_2α administration. In the Ovsynch‐CIDR group, cows detected in oestrus (n = 193) within 48 h after PGF_2α were inseminated using the AM–PM rule. Among these cows, 80 received and 113 did not receive a second GnRH at 48 h after PGF_2α. Cows (n = 345) not detected in oestrus received a second GnRH at 48 h after PGF_2α on Day 9, and fixed‐time AI 16 h after the GnRH on Day 10. In the CO‐Synch‐CIDR group, cows detected in oestrus (n = 224) within 48 h after PGF_2α were inseminated using the AM–PM rule. Among these cows, 79 received and 145 did not receive a second GnRH at 64 h after PGF_2α. Cows (n = 311) not detected in oestrus received a second GnRH on Day 10 at the time of AI, 64 h after PGF_2α. The AI pregnancy rates were not different between the Ovsynch‐CIDR and CO‐Synch‐CIDR groups (p = 0.48). There were no differences in the AI pregnancy rates for cows inseminated at a fixed time (p = 0.26) or at detected oestrus (p = 0.79) between the treatment groups. Among cows inseminated in oestrus, there were no differences in the AI pregnancy rates between cows that received or did not receive the second GnRH (p = 0.47). In conclusion, acceptable AI pregnancy rates can be achieved with or without inclusion of oestrus detection in the Ovsynch‐CIDR and CO‐Synch‐CIDR protocols. Among cows detected in oestrus, cows that received a second GnRH yielded similar pregnancy rates when compared with cows that did not receive the second GnRH.     

Efficacy of Vapam fumigant against clubroot (Plasmodiophora brassicae) of canola

Clubroot, caused by Plasmodiophora brassicae, has become a serious threat to canola (Brassica napus) production in western Canada. Experiments were conducted under greenhouse and field conditions to assess the effect of Vapam fumigant (dithiocarbamate; sodium N‐methyldithiocarbamate) on primary and secondary infection by P. brassicae, clubroot severity, and growth parameters in canola. Preliminary trials showed a 12–16‐fold reduction in primary and secondary infection and clubroot severity at all of the Vapam application rates (0·4–1·6 mL L^?1 soil) assessed. Vapam was also found to be effective in reducing clubroot severity and improving seed yield of canola under field conditions. Application of Vapam at soil moisture levels in the range of 10–30% (v:v) had a large effect on both disease severity and infection rates and plant growth parameters. The results suggest that Vapam can effectively reduce clubroot severity and may be useful for the treatment of transplant propagation beds in brassica vegetable production, and for the containment of small, localized clubroot infestations in commercial canola crops.     

Molecular diversity of methanogens in fecal samples from Bactrian camels (Camelus bactrianus) at two zoos

Animals are dependent on mutualistic microbial communities that reside in their gastrointestinal track for essential physiological functions such as nutrition and pathogen resistance. The composition of microbial communities in an animal is influenced by various factors, including species, diet and geographical location. In this preliminary study, the population structure of fecal methanogens in Bactrian camels (Camelus bactrianus) from two zoos was studied using separate 16S rRNA gene libraries for each zoo. While methanogen sequences belonging to the genus Methanobrevibacter were dominant in both libraries, they showed significant differences in diversity (p=0.05) and structure (p<0.0001). Population structure analysis revealed that only two operational taxonomic units (OTUs) were shared between libraries, while two OTUs were unique to the Southwick Zoo library and seven OTUs were unique to the Potter Park Zoo library. These preliminary results highlight how methanogen population structures can vary greatly between animals of the same species maintained in captivity at different locations.     

Evaluation of rare-earth markers using an in vitro ruminal fermentation system and effect of processing method on ruminal turnover of sized corn particles

A two-stage in vitro ruminal fermentation experiment was conducted to determine the extent of marker migration and the effects of marker addition on digestibility. Fermentation studies were terminated either at the end of stage I, the fermentation phase, or stage II, the pepsin digestion phase. Treatment diets contained ytterbium-marked corn plus chopped Coastal bermudagrass hay and nonmarked corn plus chopped hay. After stage I of the in vitro ruminal fermentation, 90% of ytterbium was recovered. Of this, 8.8% of the ytterbium had migrated to the hay, 2% was recovered in the supernatant and 89.2% remained bound to the corn. After completion of both stages, 72% was recovered, of which 7.9% was bound to corn, 33.6% was bound to the hay, 1.1% was recovered in the stage I supernatant and 57.4% was associated with the acid pepsin supernatant. Dry matter digestion was not affected after stage I but after stage II, digestibility was decreased 7% due to marker addition. A ruminal-cannulated Holstein steer weighing approximately 680 kg was used to determine turnover rates from the rumen of liquid and five different particle sizes of corn. Corn from each of two processing methods was fractionated into five particle sizes by dry-sieving. The corn particles included steam-rolled corn (SRC) retained on a 4-mm sieve and marked with dysprosium, SRC retained on a 2-mm sieve and marked with erbium, cracked corn (CC) retained on a 4-mm sieve and marked with yttrium, CC retained on a 2-mm sieve and marked with ytterbium, and CC retained on a 1-mm sieve and marked with samarium.(ABSTRACT TRUNCATED AT 250 WORDS)     

Symposium on limb fractures in the dog and cat. I. The mechanics of fracture repair; first aid

Abstract— A review is presented of the classification of fractures, radiography and the instrumentation necessary for fracture repair. The mechanics of fracture repair in small animals in comparison to man is discussed as are the principles of first aid in fracture cases. Résumé— Un compte-rendu est présenté sur la classification des fractures, la radiographic et l'instrumentation nécessaire pour la réparation des fractures. La mécanique des réparations des fractures chez les petite animaux, en comparaison avec celle de l'homme est discutée ainsie que les principes de secourisme dans les cas de fracture. Zusammenfassung— Es wird ein Überblick über die Klassifikation von Brüchen, Radiographic und die erforderlichen Instrumente zur Einrichtung von Brüchen gegeben. Die mechanische Behan-dlung bei Brucheinrichtungen wird für kleine Tiere im Vergleich zum Menschen besprochen und ebenso die Grundlagen der ersten Hilfe bei Bruchfällen.     

Problems and solutions with the design and execution of an epidemiological study of white spot disease in black tiger shrimp (Penaeus monodon) in Vietnam

White spot disease (WSD) is caused by white spot syndrome virus (WSSV) and is an acutely fatal pandemic disease of crustaceans. It has resulted in massive losses to the shrimp-farming industry in Asia and has now spread to the Americas. This paper reports the problems and solutions associated with the design and execution of a longitudinal epidemiological study of shrimp (Penaeus monodon) health on farms practising a crop rotation of rice and shrimp in the Mekong Delta of Vietnam. The pre-sampling phase of the project involved selecting an appropriate site and sampling variables, obtaining permission and establishing the necessary laboratory and logistic facilities. At the start of the sampling phase, 40 farmers were selected and 32 of these were visited and interviewed. This resulted in the enrolment of only 17 farmers. A further seven had to be enrolled to obtain the maximum number of farmers that could be sampled by the study team. Compliance was enhanced through meetings, regular visits by senior members of the project team and ensuring that visits were punctual and that all information was treated confidentially. The production cycle began in January 1998 and lasted for approximately 5 months. An attempt was made to collect 500 post larvae (PL) before each pond was stocked to assess the health of the batch and to test for the presence of WSSV by one-step PCR. After stocking, the wild crustaceans also were sampled from the pond for PCR analyses. Information was collected on the management practices and samples of water, pond bottom, feed and shrimp collected throughout the production cycle. Water quality variables with predictable diurnal variation were sampled in the morning and afternoon, twice a week. Two months after stocking, the first outbreak of WSD occurred; subsequently, 18 farms conducted a complete emergency harvest due to the actual or perceived presence of a WSD outbreak. Detectable mortalities were reported from 19 farms, and moribund shrimps were collected from four of these for PCR and histological analyses.     

Measurement of Ovine Pregnancy-Associated Glycoprotein (PAG) During Early Pregnancy in Lacaune Sheep

This study describes ovine pregnancy‐associated glycoprotein (ovPAG) concentrations in 20 Lacaune sheep during early pregnancy. Measurements were performed by using semi‐purified ovPAG as standard, tracer and immunogens for antibody production in rabbits. Antisera R780 (against ovPAG_57+59kDa) and R805 (against ovPAG5_58+61kDa) were used respectively in RIA‐780 and RIA‐805. Blood samples were collected at days 0, 18, 20, 22 and 25 after artificial insemination. From day 18 after breeding onward, the mean ovPAG concentration was significantly higher (p < 0.001) in plasma samples from pregnant ewes (n = 17) than in non‐pregnant ones (n = 3). The specific activity of the tracer was 11 760 Ci/mmol in RIA‐780 and 14 900 Ci/mmol in RIA‐805. The minimal detection limits for RIA‐780 and RIA‐805 were 0.2 ng/ml and 0.3 ng/ml, respectively. The intra‐assay CV of samples with low (1.0 ng/ml), medium (2.5 ng/ml) and high (4.0 ng/ml) PAG concentrations were 3%, 6% and 9% for RIA‐780 and 8%, 9% and 5% for RIA‐805. The inter‐assay CV in the same samples were 13%, 12% and 7% for RIA‐780 and 13%, 11% and 5% for RIA‐805. The recovery was higher than 95% in both assays. No cross‐reaction was observed with members of aspartic proteinase family as well as with other tested proteins. In both RIA‐780 and RIA‐805, inhibition of the binding of the tracer by antisera was parallel between standard curve and serial dilutions of pregnant ewe samples. In conclusion, the two homologous RIA systems are suitable for early quantification of ovPAG concentrations in ewe plasma samples from day 18 after breeding.