Effect of dietary cation-anion balance in mineral balance in anaerobically exercised and sedentary horses

Eight geldings and four mares were randomly assigned treatments within three 4x4 Latin square design experiments to study the effects of dietary cation-anion balance (DCAB) on mineral balance and dry matter digestibility in sedentary and anaerobically exercised horses. Four diets with an average DCAB (calculated as meq ((Na+K+) - Cl-)/kg of diet dry matter) of +24 (Low, L), +127 (Medium Low, ML), +227 (Medium High, MH) and +352 (High, H) were fed for a 21 day adjustment period followed by a 72 hour collection period. Diets consisted of a pelleted base concentrate of com, soybean meal and cottonseed hulls fed with either native prairie grass or bermuda grass hay in a 60:40 ratio. Diet L was formed by adding calcium chloride and ammonium chloride to the base concentrate, diet ML was formed by adding calcium chloride, and diet H was formed by adding potassium citrate and sodium bicarbonate. Diet MI-I received no supplementation and served as the control. Representative samples of feed, feces and urine were analyzed for mineral content and mineral balances were calculated by difference. Fecal output was greater (p <.05), and thus, dry matter digestibility was lower in exercised homes consuming diet L versus diet H. Sodium balance was greater (p <.05) in sedentary horses consuming diet MH as compared to those consuming diets ML and L Sodium balance was greater (p <.05) in exercised homes consuming diet H as compared to those consuming diets ML and L Potassium balance was greater (p <.05) in sedentary horses consuming diet H as compared to those horses consuming diet ML, however, potassium balance was not affected by DCAB in exercised horses. No significant differences were detected in chloride or magnesium balances in the sedentary horses, although chloride balance was greater (p <.05) and magnesium balance was lower (p <.05) in exercised homes consuming diet L as compared to all other diets. In sedentary homes, phosphorus balance was reflective of intake with differences (p <.05) observed between all treatments. However, in exercised homes, phosphorus balance was lower (p <.05) oniy for those consuming diet L. Calcium balance decreased significantly as DCAB decreased between all treatments in sedentary horses, while calcium balance in exercised homes was greater (p <.05) for homes consuming diet H as compared to those consum- ing diet L.Previous research from our laboratory has shown that both exercised and sedentary horses consuming diets with a low DCAB experience a nutritionally induced metabolic acidosis. The current data indicate that anaerobically exercised and sedentary horses consuming these diets excrete significantly more calcium in the urine resulting in decreased calcium balances. Prolonged consumption of diets with a low DCAB may lead to a significant demineralization of bone and a subsequent weakening of the skeleton.     

Feline nasal and paranasal sinus tumours: clinicopathological study, histomorphological description and diagnostic immunohistochemistry of 123 cases

Histological examination was performed in 123 cats with primary nasal and paranasal sinus tumours; 117 had undergone surgical biopsy and six necropsy. Special stains and immunohistochemistry were performed on poorly differentiated cases. Ninety-two percent (113/123) of the tumours were malignant. There was an increased risk for old cats (mean age of 10.9 years), and a male predilection (59% males). Clinical signs and breeds varied with the histological type of tumour. Thirty-nine percent (48/123) of the cases presented with nasal discharge, 21% (26/123) with dyspnea, 20% (24/123) with facial swelling, and 15% (19/123) with epistaxis. Forty-three percent (53/123) of the tumours were of epithelial origin. Adenocarcinomas (18/53) and squamous cell carcinomas (17/53) were the most common epithelial tumours. Fifty percent (26/53) of the epithelial tumours originated from the pseudo-stratified respiratory epithelium of the nasal cavity, 28% (15/53) from the stratified squamous epithelium of the vestibule, 9% (5/53) from olfactory epithelium, 9% (5/53) from submucosal glands and 4% (2/53) from minor salivary glands. Malignant lymphoma (35/123) was the most common tumour. Seventy-one percent (25/35) of the malignant lymphomas were B-cell tumours and 29% (10/35) were T-cell tumours. Six cases of malignant lymphomas were proved to be epitheliotropic T-cell lymphomas. This is the first report of a primary nasal epitheliotropic T-cell lymphoma in cats.     

Toxicity of the entomopathogenic fungus, Metarhizium anisopliae (Deuteromycotina: Hyphomycetes) to adult females of the blowfly Lucilia sericata (Diptera: Calliphoridae)

The fungus Metarhizium anisopliae (Metchnikoff) (Deuteromycotina: Hyphomycetes) is a natural component of soil flora world-wide and is a causal agent of the green muscardine diseases of insects. The use of this pathogen as a potential biocontrol agent against adult females of the blowfly, Lucilia sericata (Meigen) (Diptera: Calliphoridae) was considered. The blowfly L sericata is an economically important agent of cutaneous myiasis of sheep, particularly in northern Europe. Exposure of flies to suspensions of fungal spores by immersion, topical application or tarsal contact with treated surfaces all resulted in high levels of fatal infection. Spores suspended in silicone oil resulted in higher levels of infection (50-70%) than those formulated in a 0.3 glitre(-1) solution of the detergent Tween 80 (10-20%). Spore concentration had a significant effect on levels of infection of flies, with the highest levels of mortality (64%) resulting from a suspension of 1 x 10(7) conidia ml(-1). The duration of tarsal contact had a significant effect on levels of infection. Mean infection levels of 30% were observed following exposure of free-flying adults to a single spore-treated, 5 x 15 cm2 cloth surface suspended from the roof of a cage (30 cm cube). The implications of the results for the potential use of M anisopliae in the biocontrol of blowflies are discussed.     

Use of ultrasound to predict body composition changes in steers at 100 and 65 days before slaughter

Steers from research crossbreeding projects (n = 406) were serially scanned using real-time ultrasound at 35-d intervals from reimplant time until slaughter. Cattle were evaluated for rump fat depth, longissimus muscle area (ULMA), 12th-rib fat thickness (UFAT), and percentage of intramuscular fat (IMF) to determine the ability of ultrasound to predict carcass composition at extended periods before slaughter. Additional background information on the cattle, such as live weight, ADG, breed of sire, breed of dam, implant, and frame score was also used. Carcass data were collected by trained personnel at "chain speed," and samples of the 12th-rib LM were taken for ether extract analysis. Simple correlation coefficients showed positive relationships (P < 0.01) between ultrasound measures taken less than 7 d before slaughter and carcass measures: ULMA and carcass LM area (CLMA, r = 0.66); UFAT and carcass 12th-rib fat thickness (CFAT, r = 0.74); and IMF and carcass numeric marbling score (r = 0.61). The same correlation coefficients for ultrasound measures taken 96 to 105 d before slaughter and carcass values (P < 0.01) were 0.52, 0.58, and 0.63, respectively. Steers were divided into source-verified and nonsource-verified groups based on the level of background information for each individual. Regression equations were developed for the carcass measurements; 46% of the variation could be explained for CLMA and 44% of CFAT at reimplant time, 46% of the variation in quality grade and 42% of the variation in yield grade could be explained. Significant predictors of quality grade were IMF (P < 0.001), natural log of 12th-rib fat thickness (LUFAT, P < 0.001), and ADG (P < 0.01), whereas LUFAT (P < 0.001), ULMA (P < 0.01), live weight (P < 0.001), hip height (P < 0.001), and frame score (P < 0.001) were significant predictors of yield grade. Regressions using ultrasound data taken 61 to 69 d before slaughter showed increasing R2. Live ultrasound measures at reimplant time are a viable tool for making decisions regarding future carcass composition.     

Control of the cattle louse Bovicola bovis with the fungal pathogen Metarhizium anisopliae

The effects of the entomopathogenic fungus Metarhizium anisopliae (Metschnikoff) were evaluated against the common louse parasite of cattle, Bovicola bovis (Piaget) (Trichodectidae: Ischnocera). Two different concentrations and formulations of conidial suspensions were applied to contained populations of adult female lice. In vitro, lice immersed in suspensions of M. anisopliae formulated in 0.03% Tween 80 developed infections; at the highest concentration (1x10(8)conidia ml-1) a mean of 71% (+/-11.52%, 95% C.I.) of lice became infected. Lice exposed to the Tween 80 only in vitro, showed high levels of survival and zero infection. In vivo, fungal conidia were applied to louse populations contained in 7 cm diameter circular arenas glued to the backs of Holstein cattle, maintained in controlled climate conditions. Conidia were formulated in either Tween 80 or silicone oil. The treatment with M. anisopliae resulted in high levels of infection and there was no overall difference between the two formulations in the number of infections observed. At the highest concentration (1x10(8)conidia ml-1) a mean of 73% (+/-15.57%, 95% C.I.) lice became infected. It is concluded that the strategic seasonal use of a fungal pathogen on cattle, applied in early winter, may be of value in suppressing the winter increase in abundance, preventing the population increasing to clinically significant levels.     

Estimating Lyme disease risk using pet dogs as sentinels

The reported number of cases of Lyme disease, Borrelia burgdorferi sensu lato, is thought to have increased in the UK over the past decade, but consistent surveillance data are lacking. Here the prevalence of B. burgdorferi in ticks attached to pet dogs was examined - using them as sentinels for human disease risk. Dogs give a good indication of the exposure of their human owners to infected ticks, since they largely share the same environment and visit the same outdoor areas. PCR was used to test 739 tick samples collected from 3534 dogs selected at random as they visited veterinary practices over a period of six months. Overall, the prevalence of infected ticks on all dogs was 0.5% giving an estimated 481 infected ticks per 100,000 dogs. The data suggest that the prevalence of Borrelia in the UK tick population is considerably higher than most recent estimates indicate.     

Pyrethroid tolerance in the chewing louse Bovicola (Werneckiella) ocellatus

Equine pediculosis is a significant health and welfare issue, particularly in elderly and chronically debilitated animals. Currently infestation is controlled predominantly using topically applied pyrethroid insecticides, allowing limited scope for the rotation of drugs and increasing the risk of selection for resistance. Here the insecticidal efficacies of two pyrethroid-based products against the louse Bovicola (Werneckiella) ocellatus collected from donkeys were examined in vitro. The products were cypermethrin (Deosect?, Pfizer Ltd., 5% (w/v) cypermethrin, cutaneous spray) and permethrin (Switch?, VetPlus Ltd., 4% (w/v) permethrin, pour-on). The pyrethroid efficacy was contrasted with that of the organophosphate diazinon, since the louse populations examined were unlikely to have had prior exposure to this compound. The efficacy of diluted pure permethrin, the excipient, butyl dioxitol and the synergist piperonyl butoxide in the presence of the pyrethroids, were also considered. At the concentrations recommended for animal application, neither 4% (w/v) permethrin, nor 0.1% (w/v) cypermethrin had any significant effect on the mortality of B. ocellatus and neither induced significantly more mortality than an acetone-only control. In contrast, 0.04% diazinon caused 70% mortality within 4h and 100% mortality after 24h exposure. The addition of a potential pyrethroid synergist, piperonyl butoxide, in combination with cypermethrin and permethrin, resulted in no significant increase in mortality. It is concluded that the population of lice tested display a high level of pyrethroid tolerance which is likely to reflect the development of resistance. Twenty-four hours after routine treatment of 10 donkeys with a pour-on permethrin product (Switch?, VetPlus Ltd., 4% (w/v) permethrin, pour-on) hair tufts taken from their flanks were not significantly insecticidal compared with hair from the midline application site, implying a low level of insecticide distribution. Such a distribution pattern is likely to create an insecticide concentration gradient over the body and further facilitate selection for resistance.     

Evaluation of dicyclanil (CLiKZiN®) treatment for the early-season protection of ewes against blowfly strike

Protecting sheep against early season myiasis (strike) is a significant problem in northern temperate farming systems, where fully-fleeced ewes and early-season lambs approaching market weight, are at high initial risk. Here, the prevention of early-season blowfly strike in ewes was examined on matched commercial sheep farms in south west England, using a new formulation of dicyclanil (CLiKZiN(?) pour on) with a short withdrawal period of 7 days. The ewes on seven farms received a prophylactic treatment with dicyclanil (CLiKZiN 1.25% pour-on suspension) in April 2011; ewes on three control farms received no treatment. The lambs at all farms remained untreated. No adverse reactions to treatment were recorded. On the treatment farms no ewe strikes were recorded between April and June (10 weeks). On control farms, there were 16 strike cases in ewes over the same period, giving a cumulative incidence of 31 cases per 1000 ewes. On the treatment farms only one lamb was struck whereas at the control farms 10 lamb strikes were recorded. The data demonstrate that CLiKZiN was highly effective at protecting ewes against early season strike-challenge.     

Preliminary evaluation of serial (18) FDG-PET/CT to assess response to toceranib phosphate therapy in canine cancer

Palladia(TM) (toceranib phosphate-Pfizer Animal Health) is a novel orally administered receptor tyrosine kinase inhibitor (TKI) approved for treatment of canine mast cell tumors. Receptor tyrosine kinase dysregulation leads to tumor growth, progression, and metastasis. Toceranib's targets include vascular endothelial growth factor receptor (VEGFR-2/Flk-1/KDR), platelet-derived growth factor receptor, and kit. Positron Emission Tomography/Computed Tomography (PET/CT) is used commonly to diagnose, prognosticate, and monitor response to antineoplastic therapy in human patients. In this study, serial PET/CT imaging with (18) F-fluorodeoxyglucose ((18) FDG) was used to assess response to toceranib therapy in dogs with measurable solid malignancies. Six tumor-bearing dogs underwent tumor assessment using both standard RECIST criteria and PET/CT prior to and at a median of 5 weeks postinitiation of toceranib treatment. Toceranib was prescribed initially at a target dose 3.25 mg/kg PO q48 h, with subsequent modifications based on observed toxicity. Treatment was continued in patients achieving stable disease with acceptable drug tolerance. One dog was maintained on drug despite dose modification due to toxicity; measurable clinical and image-based responses were seen after 10 weeks of therapy. All others had stable or progressive disease based on clinical restaging and PET/CT at first recheck. . Due to discordance with anatomic and metabolic imaging, further studies are needed to investigate the role of molecular imaging in assessment of drug response and identify other potential molecular targets of toceranib.