THE EFFECT OF LICE INFESTATION ON THE GROWTH OF HEREFORD CALVES   总被引：1，自引：0，他引：1  

L. J. Cummins  J. F. Graham 《Australian veterinary journal》1982,58(5):194-196

SUMMARY Two experiments were carried out to examine the effects of cattle lice on the productivity of young calves. In both experiments the main species present was Linognathus vituli. In the first experiment, treatment of grazing heifers and their suckled calves did not improve the overall bodyweight gain of either the heifers or the calves. The calves experienced a rapid build-up in lice populations during autumn and early winter which was associated with mild transient pathogenic effects, but this was followed by an apparent ‘self-cure’ reaction and compensatory gain during late winter. In the second experiment young calves were placed in feedlots and fed high and low planes of nutrition. Treatment to remove lice did not result in any improvements in growth rate on either plane of nutrition; however it was clear that untreated, undernourished calves had heavier lice infestation.  相似文献   

Dinitrogen Cleavage by a Three-Coordinate Molybdenum(III) Complex     

Laplaza CE  Cummins CC 《Science (New York, N.Y.)》1995,268(5212):861-863

Cleavage of the relatively inert dinitrogen (N(2)) molecule, with its extremely strong N identical withN triple bond, has represented a major challenge to the development of N(2) chemistry. This report describes the reductive cleavage of N(2) to two nitrido (N(3-)) ligands in its reaction with Mo(NRAr)(3), where R is C(CD(3))(2)CH(3) and Ar is 3,5-C(6)H(3)(CH(3))(2'), a synthetic three-coordinate molybdenum(III) complex of known structure. The formation of an intermediate complex was observed spectroscopically, and its conversion (with N identical withN bond cleavage) to the nitrido molybdenum(VI) product N identical withMo(NRAr)(3) followed first-order kinetics at 30 degrees C. It is proposed that the cleavage reaction proceeds by way of an intermediate complex in which N(2) bridges two molybdenum centers.  相似文献   

Potassium flux in juvenile striped bass (Morone saxatilis): influence of external concentrations of sodium chloride and calcium     

John M. Grizzle  Keith A. Cummins 《Fish physiology and biochemistry》1996,15(2):181-186

Whole-body influx and efflux of K⁺ were determined for 25-day-old striped bass,Morone saxatilis, in conditions that simulated harvesting fish from ponds. During the first 5h in fresh water with combined high NaCl (80 mM) and low Ca²⁺ (0.12 mM) concentrations, a combination that is acutely lethal to this age of striped bass, K⁺ influx for fish in 0.07 mM K⁺ was 21±1.7 (SEM) compared to 3.4±0.33 nmol g^–1 h^–1 for fish in water with low Na⁺ (0.25 mM) or high Ca²⁺ (2.5 mM) concentrations. Influx of K⁺ was inhibited during the first few hours after fish were placed in flux chambers. Potassium efflux as percentage of⁴²K lost per hour was two-fold higher from fish in the high Na-low Ca treatment compared to fish in low concentrations of Na⁺ or high concentrations of Ca²⁺. Potassium efflux was probably much greater than influx, but exact values for efflux could not be calculated from the data available. Survival of fish in water with high Na-low Ca was not increased by addition of KCl to the water, indicating that the net loss of K⁺ was probably not the cause of death.  相似文献   

Developmental alterations in the regulation of glucagon and insulin secretion in Holstein calves     

S W Owens  J L Sartin  R J Kemppainen  K A Cummins  F F Bartol  M A Bowman 《American journal of veterinary research》1986,47(2):263-269

Twenty-one Holstein bull calves were randomly assigned at birth to 3 groups. Two groups (each of 7 calves) were raised as follows: fed a milk diet alone or fed milk with grain supplementation after 2 weeks of age; studies were done when calves reached 4 weeks of age. The 3rd group was fed on milk with grain supplementation until weaning after which the calves were maintained on grain and pasture. These calves (older calves) were studied at 12 weeks of age. Either propionate (0.28 mmol/kg) or glucose (0.56 mmol/kg) was injected IV in a random order. Samples of blood were obtained from the calves before and immediately after injections were done and at 2, 5, 10, 15, 30, 45, and 60 minutes after secretagogue injection. Plasma was examined for glucose by a glucose oxidase procedure and for immunoreactive insulin (IRI) and glucagon (IRG) by radioimmunoassay. The IRI response to the injection of glucose was greater in older calves (P less than 0.02). Patterns of IRI secretion, as determined by heterogeneity of regression, showed age differences for both secretagogues (P less than 0.05). Base-line IRG was greater in milk/grain-fed calves than in milk-fed calves (P less than 0.05). Mean IRG response to propionate injection was higher (P less than 0.05) in milk/grain-fed calves than in milk-fed calves. Plasma glucose concentration increased in older calves, but decreased in milk-fed calves after propionate injection. The data indicate that maturation in the ruminant is accompanied by altered regulation of insulin and glucagon secretion.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Effects of levamisole and human chorionic gonadotrophin on ostertagiasis in western Victoria, Australia.     

L J Cummins  A P Callinan 《The Veterinary record》1979,104(4):77-78

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Larvicidal activity of substituted chalcones against Aedes aegypti (Diptera: Culicidae) and non‐target organisms     

Sabrina K Targanski  Janaína R Sousa  Geilly MS de Pdua  Jssica M de Sousa  Lucas CC Vieira  Marcos A Soares 《Pest management science》2021,77(1):325-334

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Transmissible venereal tumour (TVT) in a dog     

AJM Richards  CC Williamson 《New Zealand veterinary journal》2013,61(1)

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Comparison of Different Treatments for Oestrous Induction in Seasonally Anovulatory Mares     

G Vizuete  E Diez  J Galisteo  E Agüera  E Aguilera‐Tejero  CC Perez‐Marín 《Reproduction in domestic animals》2013,48(3):463-469

The aim of this study was to evaluate the effects of different treatments for induction and synchronization of oestrus and ovulation in seasonally anovulatory mares. Fifteen mares formed the control group (C), while 26 mares were randomly assigned to three treatment groups. Group T1 (n = 11) were treated with oral altrenogest (0.044 mg/kg; Regumate^®) during 11 days. Group T2 (n = 7) was intravaginally treated with 1.38 g of progesterone (CIDR^®) for 11 days. In group T3 (n = 8), mares were also treated with CIDR^®, but only for 8 days. All mares received PGF2α 1 day after finishing the treatment. Sonographic evaluation of follicles, pre‐ovulatory follicle size and ovulation time was recorded. Progesterone and leptin levels were analysed. Results show that pre‐ovulatory follicles were developed after the treatment in 88.5% of mares. However, the pre‐ovulatory follicle growth was dispersal, and sometimes it was detected when treatment was not finished. While in mares treated with intravaginal device, the follicle was soon detected (1.5 ± 1.2 days and 2.3 ± 2.0 days in T2 and T3 groups, respectively), in T1 group, the pre‐ovulatory follicle was detected slightly later (3.9 ± 1.6 days). The interval from the end of treatment to ovulation did not show significant differences between groups (T1 = 13.1 ± 2.5 days; T2 = 11.0 ± 3.6 days; T3 = 13.8 ± 4.3 days). The pregnancy rate was 47.4%, similar to the rate observed in group C (46.7%; p > 0.05). Initial leptin concentrations were significantly higher in mares, which restart their ovarian activity after treatments, suggesting a role in the reproduction mechanisms in mares. It could be concluded that the used treatments may be effective for oestrous induction in mares during the late phase of the seasonally anovulatory period. Furthermore, they cannot synchronize oestrus, and then, it is necessary to know the reproductive status of mares when these treatments are used for oestrous synchronization.  相似文献   

Simulation of the factors affecting β-glucan levels during the cultivation of oats     

Uma Tiwari  Enda Cummins 《Journal of Cereal Science》2009,50(2):175-183

A Monte Carlo simulation technique was employed to simulate the factors influencing the level of β-glucan content in both hulled (HO) and naked (NO) oat cultivars during cultivation of the crop. Probability density functions were used to model the uncertainty and variability in the input factors. A scenario analysis was subsequently developed to look at the impact of different model assumptions and input parameters. The simulated mean β-glucan level in harvested oats grain was 3.50 and 4.25 g/100 g for hulled (HO) and naked (NO), respectively. A sensitivity analysis highlighted that cultivar selection was the most important input parameter compared to other inputs in determining the final β-glucan level (correlation coefficients of 0.64 and 0.79 for HO and NO, respectively). The analysis also indicated the positive effect of delayed sowing on β-glucan content (correlation coefficients of 0.32 and 0.25 for HO and NO, respectively). Germination and storage factors showed a negative impact on the final β-glucan levels. The scenario analysis shows the applicability of the proposed model for various agronomic practices. This approach establishes a quantitative scientific ranking of factors influencing β-glucan levels during the cultivation of oats.  相似文献   

Collar insertion depth effects on soil respiration in afforested peatlands     

A.?Jonay?Jovani-Sancho  Thomas?Cummins  Kenneth?A.?ByrneEmail authorView author&#;s OrcID profile 《Biology and Fertility of Soils》2017,53(6):677-689

Using collars for measuring soil respiration and its component fluxes in closed chamber systems relies on two main assumptions. Firstly, it is assumed that shallow collars prevent lateral soil gas leakage beneath the chamber’s walls and the underestimation of soil CO₂ fluxes, and secondly, the insertion of deeper collars excises all living roots and the autotrophic flux is eliminated. It was hypothesised that previous findings on collar insertion impacts on autotrophic and total soil respiration also apply to afforested peatlands. In these ecosystems, a large fraction of fine roots grow close to the soil surface. Therefore, the use of shallow collars may sever some fine roots and hyphae of mycorrhizal fungi, and therefore, it may lead to underestimation of total soil respiration. It was also hypothesised that this underestimation may be greater than a possible CO₂ leakage from lateral diffusion of soil gas as a result of not using collars. In this study, we measured soil CO₂ efflux in a Sitka spruce and a lodgepole pine plantation on blanket peat in southern Ireland. A surface collar (not inserted into the ground) and six insertion depths (5, 10, 15, 25, 35 and 45 cm) were established to assess the effect of the collar insertion depth on autotrophic and total soil respiration. The insertion depth of 5 cm reduced total soil respiration by 47 and 32% in the spruce and pine stands, respectively. Using nonlinear equations, it was estimated that a frequently used shallow insertion of 1.5 cm would have reduced this efflux by 35 and 20% in each stand, respectively. Moreover, it was demonstrated that this reduction was greater than a possible lateral soil gas leakage. These results suggest that the insertion of shallow collars should be avoided and surface collars permanently anchored in the soil should be used instead.  相似文献