Prevalence of papillomatous digital dermatitis among culled adult cattle in the southeastern United States

OBJECTIVE: To determine prevalence of papillomatous digital dermatitis (PDD) among culled adult dairy and beef cattle in the southeastern United States. ANIMALS: 815 cattle examined during 4 visits to a slaughterhouse. PROCEDURE: The left hind foot of each animal was examined for gross lesions of PDD. Breed and sex of the animals were recorded. Lesions were examined histologically for pathologic changes and bacteria, especially spirochetes. RESULTS: 22 of 76 (29%) dairy cattle and 29 of 739 (4%) beef cattle had gross lesions of PDD. Detection of lesions was not associated with sex of dairy cattle, but male beef cattle were more likely to have lesions of PDD than were female beef cattle. Histologically, acute and chronic lesions were seen; the most severe changes were localized to the stratum corneum. Spirochetes were seen in lesions from 31 of 51 (61%) cattle. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that PDD is common among culled adult cattle. Prevalence was higher in culled adult dairy cattle than in culled adult beef cattle.     

Variation in the colour of broiler breast fillets in the UK

1. The normal range in colour of broiler breast muscle was assessed using an objective (instrumental) measure of colour in portioned breast fillets at a commercial processing plant. In addition, the relationship between colour and ultimate muscle pH (pH(ult)) was also examined. 2. Considerable variation in colour was evident although minimal inter-flock variation was found. The exceptions were 2 free range flocks which produced breast fillets significantly lighter and less red. 3. Extremes of colour are likely to be discriminated against at the point of purchase. 4. A clear relationship between pH(ult) and L* values was found which provides more evidence for the existence of a PSE like condition in broiler breast meat.     

In vitro elution of gentamicin, amikacin, and ceftiofur from polymethylmethacrylate and hydroxyapatite cement

OBJECTIVE: To compare the elution characteristics of ceftiofur and liquid and powdered gentamicin and amikacin from polymethylmethacrylate (PMMA) and from hydroxyapatite cement (HAC). METHODS: PMMA and HAC beads in triplicate were impregnated with various amounts and formulations of antibiotics. Beads were immersed in 5 mL of phosphate buffered saline that was replaced at 1, 3, 6, and 12 hours, and 1, 2, 3, 5, 7, 10, 14, 18, 22, 26, and 30 days. The eluent was stored at -70 degrees C until assayed within 2 weeks by microbiological assay (gentamicin and amikacin) or capillary electrophoresis (ceftiofur). RESULTS: Rate of elution for all beads was greatest within the first 24 hours. Cumulative release of total antibiotic dose from beads over 30 days was significantly greater from HAC than PMMA. Antibiotic elution was directly related to the amount of antibiotic incorporated into the cement. Powdered and liquid forms of gentamicin had similar elution rates from PMMA. Elution of amikacin from PMMA beads was greater when the powdered form was used compared with liquid amikacin. Eluent concentrations of ceftiofur were similar to those of the aminoglycosides during the first 3 to 7 days but then decreased precipitously by comparison. CONCLUSIONS: Elution of antibiotics from HAC was greater than from PMMA. Gentamicin- and amikacin-impregnated PMMA and HAC released bactericidal concentrations of antibiotic for at least 30 days. Ceftiofur-impregnated PMMA or HAC is unlikely to provide long-term bactericidal concentrations. CLINICAL RELEVANCE: Gentamicin and amikacin elute effectively from PMMA and HAC.     

Estimation of rates of recombination and migration in populations of plant pathogens

ABSTRACT A method of estimating the frequency of recombination in field populations of ascomycete fungi is presented. This is a development of a technique described by J. Zhan, C. C. Mundt, and B. A. McDonald, in which field plots were inoculated with isolates of Mycosphaerella graminicola of known genotypes and then, later, the proportions of the fungal populations in the plots that originated as recombinant progeny of matings between the inoculated isolates or as immigrants from the local population were estimated. It is argued that J. Zhan, C. C. Mundt, and B. A. McDonald's method is inappropriate in terms of its approach to statistical inference and that the lack of confidence intervals for rates of recombination (r) or immigration (m) is a further weakness. An improvement to their method would involve the use of inoculated isolates that can be clearly distinguished from the local population, for instance, by the use of DNA markers. There should also be sufficient markers for there to be a negligible probability that progeny of matings between inoculated isolates will have the same genotype as either of their parents. With this experimental design, estimates of r and m can be found by a standard maximum likelihood method, while confidence intervals for the parameters can be estimated by a simple bootstrap procedure. The method appears to be about an order of magnitude more efficient than are the existing ways of estimating the frequency of recombination in ascomycete fungi.     

Blood lead levels of wild Steller's eiders (Polysticta stelleri) and black scoters (Melanitta nigra) in Alaska using a portable blood lead analyzer.

Sea duck populations are declining in Alaska. The reasons for the decline are not known; environmental lead exposure is one suspected cause. Thirty wild Steller's eider ducks (Polysticta stelleri) and 40 wild black scoter ducks (Melanitta nigra) were tested for blood lead levels using a portable blood lead analyzer (LeadCare; ESA, Inc., Chelmsford, Massachusetts 01824, USA). Sixty-seven and one-tenth percent of the sea ducks had undetectable blood lead levels, 30.0% had values indicating normal or background lead exposure, and 2.9% had values indicating lead exposure. None of the birds had values indicating lead toxicity, and no birds demonstrated clinical signs of toxicity. Birds in areas with higher human population density had higher blood lead levels than those in less densely populated areas. This is the first time a portable blood lead analyzer has been utilized with sea ducks in a field setting. Because it provides immediate results, it is valuable as a screening tool for investigators carrying out surgical procedures on birds in the field as well as establishing baseline blood lead data on sea ducks. Lead exposure does occur in wild sea ducks, and the study indicates that additional research is needed in order to determine the role environmental lead plays in declining sea duck populations.     

Resting heart rate and tympanic temperature in operant conditioned western lowland gorillas (Gorilla gorilla gorilla).

The conscious, resting heart rate and body temperature of healthy western lowland gorillas (Gorilla gorilla gorilla) is not reported in the literature. To obtain this information, two clinically healthy adult male western lowland gorillas in a training program were conditioned to allow auscultation and obtain tympanic temperatures. The mean heart rate was 73.8 +/- 8.96 beats per minute (n = 176), and it was lower than mean heart rate reported in studies on anesthetized gorillas. The mean tympanic temperature was 35.5 +/- 0.7 degrees C (95.9 +/- 1.23 degrees F) (n = 209). The right tympanic temperature (rtt) and left tympanic temperature (ltt) were recorded separately for one gorilla. A small but statistically significant difference was present between the mean rtt of 35.8 +/- 0.7 degrees C (96.5 +/- 1.2 degrees F) (n = 137) and the mean ltt of 35.7 +/- 0.8 degrees C (96.2 +/- 1.3 degrees F) (n = 121).     

Effects of Body Condition and Protein Supplementation on LH Secretion and Luteal Function in Sheep

In ruminants, nutrition is one of the exogenous inputs affecting reproductive function at different levels of the hypothalamic-hypophyseal-gonadal axis. However, the exact mechanisms or even the identification of the signalling metabolic compounds by which nutrition affects reproductive function still need further clarification. The role of static body condition (BC) and its interaction with a short-term protein supplementation (PL), on secretion of metabolic hormones [growth hormone (GH), insulin and insulin-like growth factor-1 (IGF-1)], as well as on secretion of LH and progesterone (P4) was evaluated in sheep. Twenty-four Rambouillet ewes divided into two groups, with lower (LBC) and higher body condition (HBC), were randomly assigned within BC to one of two PL levels: low (LPL, 24% of crude protein; 14 g/animal/day), and high (HPL, 44% of crude protein; 30 g/animal/day). The secretion of GH, insulin, IGF-1 and LH was evaluated on day 10 of the oestrous cycle; appearance and timing of oestrous behaviour were previously detected using rams. Progesterone secretion was evaluated on day 13 of the same cycle. No differences were found (p > 0.05) between PL groups on serum GH concentrations during the sampling period (overall mean of 4.0 +/- 0.3 ng/ml), but a trend for lower values in HBC sheep was found (3.6 +/- 0.4 vs 4.4 +/- 0.4 ng/ml, p = 0.06). A BC effect was observed (p < 0.05) on serum IGF-1 level, with higher values in HBC sheep (p < 0.05). Neither BC nor PL affected (p > 0.05) secretion of LH and the number of corpora lutea, nor serum P4 and insulin concentrations. Results indicate a predominance of the static component of nutrition on sheep metabolic hormone responses, GH and IGF-1, with no effect of short-term PL on secretion of pituitary and ovarian hormones as well as luteal number and activity.