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21.
Energy balance and pulsatile LH secretion in early postpartum dairy cattle   总被引:6,自引:0,他引:6  
The relationships between energy balance (EB), pulsatile LH secretion and circulating levels of insulin and various energy metabolites were assessed in ten lactating Holstein cows. Cows were blood sampled every 12 min via indwelling jugular catheters for 8 hr twice weekly beginning in the first week postpartum (PP) through first ovulation (1stOV). Days to negative EB nadir and days to 1stOV were highly correlated (P less than .02). LH pulse frequency (P less than .01), LH baseline (P less than .05) and mean LH (P less than .1) increased, while LH pulse amplitude tended to decrease when comparing the frequent sampling series immediately before and after the negative EB nadir. Plasma levels of non-esterified fatty acids (NEFA, r = -.40, P less than .01), insulin (r = .38, P less than .01), glucose (r = .31, P less than .01) and beta-hydroxybutyrate (r = .19, P less than .06) were correlated with EB. For within animal comparisons, NEFA was significantly correlated (r = -.44 to -.89, P less than .05) with EB in 8 of 10 cows, but no other correlations were significant. Additionally, none of the metabolites nor insulin were significant in multiple regression models for 1stOV. Therefore, it appears that pulsatile LH secretion is suppressed until the negative EB nadir is reached, at which time LH pulse frequency increases stimulating 1stOV. Since NEFA and EB are directly related, NEFA may serve as a peripheral signal of EB to the central nervous system.  相似文献   
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Objective To survey finches in pet shops for Cochlosoma infection and evaluate the efficacy of antiprotozoal therapy with metronidazole or ronidazole.
Design A survey of pet shop finches and drug efficacy trials.
Procedure Finches in pet shops were randomly selected and their faeces examined microscopically for motile Cochlosoma sp trophozoites. Drug trials were carried out on 60 adult finches with naturally occurring infections. Body weight was measured and the faeces of each bird was examined for trophozoites at the beginning and 7 days after the end of treatment. In some birds, additional daily faecal examinations were done until three consecutive negative results were obtained. Metronidazole was administered at various dose rates by crop gavage or in drinking water to eight groups of five to ten finches each. Ronidazole was given in water for 7 days to ten finches. In addition, six finches whose faeces tested positive were necropsied and their tissues collected for histological examination.
Results Motile flagellates in the faeces were identified as C anatis -like protozoa. Red-headed parrot-finches, Bengalese and Lady Gould finches were found to be most commonly infected. Cochlosoma sp was also found in the blue-faced parrot-finch, zebra finch, painted finch, nutmeg mannikin and double-barred finch. Metronidazole and ronidazole were found to be effective against Cochlosoma sp. Histological findings on infected adult finches were normal, except for the presence of numerous flagellates between the colorectal villi and cloacal mucosal folds.
Conclusions Cochlosoma anatis -like organisms can infect several species of finches and in adult finches are confined to the colorectum and cloaca. Infection in adult finches was mostly subclinical and could be treated effectively with metronidazole or ronidazole.  相似文献   
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The application of polymer matrix ear tags impregnated with 8.5% w/w cypermethrin to 6 wethers following shearing reduced lice to non-detectable levels on 4 of them at 29 weeks after tagging. At the conclusion of the study at 45 weeks the mean count of lice on tagged wethers was 3 per sheep compared to 158 on untreated wethers. In a second experiment, 6 non-infected sheep were treated at shearing with cypermethrin tags, 6 with 25 g/l cypermethrin backline formulation, 6 with tags plus backline and 6 were left untreated. Each group was exposed to 6 sheep with moderate to heavy infestations of lice. Compared to controls, all treatments delayed infestation, but cypermethrin tags gave no longer protection than backline treatment. All sheep were infested by 17 weeks after commencement of the study. At 45 weeks mean counts of lice were 38, 27, 20 and 74 respectively for sheep treated with tags, backline formulation, backline plus tags and untreated. Possible reasons for the better effect observed from applying tags to infested sheep than to sheep which were not infected at application but which were subsequently exposed to infested sheep are discussed.  相似文献   
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Meat chickens housed on a commercial broiler farm in Australia were vaccinated once at 10 to 11 days-of-age by aerosol with live V4 Newcastle disease virus (NDV) vaccine. Groups of vaccinated and unvaccinated birds were flown to Malaysia, where they were challenged with a virulent strain of NDV. Survival rates in vaccinated chickens challenged 7, 14, 21 or 31 d after vaccination were 0.47, 0.77, 0.97 and 0.92, respectively. All unvaccinated chickens died due to Newcastle disease (ND) following challenge. Chickens in Australia and Malaysia were bled and the serums tested for haemagglutination-inhibiting (HI) antibody to NDV. Many vaccinated birds with no detectable antibody, and all birds with a log2 titre of 2 or greater, survived challenge. The results showed that this V4 vaccine induced protective immunity in a significant proportion of chickens within 7 d of mass aerosol vaccination. This early immunity occurred in the absence of detectable circulating HI antibody. Non-HI antibody mediated immunity continued to provide protection up to 31 d after vaccination. Almost all vaccinated birds were protected within 3 w of vaccination. It is concluded that the V4 vaccine is efficacious and could be useful during an outbreak of virulent ND in Australia.  相似文献   
27.
Clinical and pathological findings of Babesia infection in dogs   总被引:1,自引:0,他引:1  
The clinical and pathological findings of Babesia infection in 32 dogs in northern Australia are presented. Eleven different breed types were represented from 6 localities in north Queensland and one locality in northern Western Australia. Twenty three (72%) were males. Babesia-infected dogs were grouped by the degree of haematological disturbance and clinical severity: Acute babesiosis (25/32), all pups with severe haemolytic anaemia; subclinical carriers (5/32) with non-specific malaise, characterised haematologically by a normal erythrogram but marked leucopenia; chronic anaemia, observed in 2 adult dogs. Pups were azotaemic (serum urea greater than 6.6 mmol/l) and had elevated serum bilirubin levels (20.8 to 48.5 mmol/l). Total serum protein was usually within the normal range. Pups that died were also hypoglycaemic and severely hyperkalaemic (K+ greater than 10 mmol/l). Low parasitaemias in routine blood smears complicated diagnosis but smears made from ear or toe capillaries, or after haematocrit concentration, greatly enhanced finding parasitised cells. At necropsy, pallor and jaundice were the most consistent observations. Haemoglobinuric nephrosis, an active reticulo-endothelial system and capillaries packed with large numbers of infected erythrocytes were the main histopathological findings. A combination of imidocarb dipropionate at 5 mg/kg body weight, given intramuscularly, with fluid therapy and blood transfusion was the most successful treatment.  相似文献   
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Monensin, a polyether ionophore antibiotic, is potentially an important agent for bloat relief in dairy cows grazing temperate legume-based pasture. A series of studies was undertaken to determine the effect of monensin, when delivered continuously in the rumen of lactating dairy cows by means of controlled-release capsules (monensin CRC). Such devices release approximately 300 mg/head/day for 100 d. A short-term pilot study made at Ruakura, New Zealand, tested monensin CRC in cows selected for high susceptibility to bloat and grazing lucerne (Medicago sativa) or red clover (Trifolium pratense). Treatment significantly reduced the incidence of bloat, while milk yield and protein yield were increased. There was no effect on fat yield. Following the pilot study, 6 large-scale field experiments involving a total of 368 lactating dairy cows, were made in Australia and New Zealand to confirm the effectiveness of monensin CRC for bloat control and to measure the effect of such treatment on milk production and composition. A severe bloat problem occurred in 2 experiments, mild bloat occurred in 2 others, while no visual signs of bloat were observed in the remaining 2 experiments. Bloat was significantly (P less than 0.05) reduced by monensin CRC treatment when data was pooled over the 4 experiments in which bloat occurred. Daily milk yield was increased in all experiments from a mean of 17.7 in untreated groups to 18.8 kg/head/day (P less than 0.05) in monensin CRC-treated cows. Protein percentage was not affected by treatment, while there was a decrease from 4.29 to 4.10% fat, although total fat yield was not affected.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
30.
The cross-protection afforded by three inactivated infectious coryza vaccines was evaluated. Each vaccine contained one of the following strains of Haemophilus paragallinarum, HP31, HP60 and HP14. Strain HP31 belongs to Kume serovar C-2, strain HP60 belongs to Kume serovar C-4 while strain HP14 belongs to Kume serovar A-4. Four groups of twenty six-week-old specific-pathogen-free chickens were either given a single dose of an aluminium-hydroxide based vaccine (three groups) or left as unvaccinated controls. Three weeks after vaccination, all four groups were challenged with virulent H paragallinarum. One half of each group was challenged with the strain HP31 and the other half with strain HP60. The efficacy of the vaccines was assessed in terms of the prevention of the typical clinical signs and macroscopic lesions of infectious coryza as well as the prevention of any colonisation by the challenge organism. The serovar C-2 and serovar C-4 vaccines protected more than 50% of birds against either a serovar C-2 or C-4 challenge while the serovar A-4 vaccine protected less than 50% of birds.  相似文献   
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