Assessment of the ultrasonographic characteristics of the podotrochlear apparatus in clinically normal horses and horses with navicular syndrome

OBJECTIVE: To characterize the normal ultrasonographic appearance of the podotrochlear apparatus in horses by use of standardized measurements and identify soft tissue changes associated with navicular syndrome. DESIGN: Prospective study. ANIMALS: 7 clinically normal horses and 28 horses with navicular syndrome. PROCEDURE: The feasibility of identifying and measuring the soft tissue structures of the podotrochlear apparatus ultrasonographically via the transcuneal approach was assessed in 2 additional horses without navicular syndrome; both horses were euthanatized, and the structures identified ultrasonographically were confirmed at necropsy. Ultrasonographs were obtained in the study horses. Objective and subjective data were obtained to characterize ultrasonographic changes associated with navicular syndrome. RESULTS: Abnormalities of the flexor surface of the distal sesamoid (navicular) bone, the impar ligament, the distal digital annular ligament, deep digital flexor tendon (DDFT), and the podotrochlear (navicular) bursa were assessed via the transcuneal ultrasonographic approach. No significant differences were found between the measurements of the podotrochlear apparatus in normal horses and those with navicular syndrome; however, important subjective differences were detected ultrasonographically in horses with navicular syndrome. In horses with navicular syndrome, ultrasonographic findings were indicative of navicular bursitis, dystrophic mineralization of the DDFT and impar ligament, tendonitis and insertional tenopathy of the DDFT, desmitis of the impar ligament, and cortical changes in the flexor surface of the navicular bone. CONCLUSIONS AND CLINICAL RELEVANCE: Findings of ultrasonographic evaluation of the hoof appear to be useful in determining the cause of caudal heel pain and characterizing the components of navicular syndrome in horses.     

A linear functional relationship model for circular data with an application to the assessment of ocean wave measurements

This article suggests a linear functional relationship model for comparing two sets of circular data subject to unobservable errors. Unlike the corresponding and relatively well-studied model for linear data, maximum likelihood estimation for this model is very complicated and no explicit solutions are possible. Using a numerical approximation, we are able to solve the likelihood equations approximately, and to obtain good approximations to the likelihood estimates of the parameters. The quality of our estimates and the feasibility of the estimation method are illustrated via simulation. By establishing a parallel with the model for linear data, we are able to explain the various problems occurring in the process of estimation and to substantiate our numerical results. The interest in the model arose in connection with the study of ocean wave data; an application to such data is also given.     

Technical note: Constrained optimization of breed composition in composite populations to balance net merit and risk

We developed a method to derive optimum composite genotypes when the proportion of a specific breed (or combination of breeds) in the composite is constrained to a desired level. The method allows development of composites that balance net merit according to available parameters and reflects the production system and(or) risk preference, particularly when traits in the breeding objective do not represent all traits important for production. The method can also be used to evaluate the cost of constraining breed use. For example, when the true optimal composite is difficult to obtain in the time frame available to the producer, the predicted merit of the composite with breed proportion restricted to those that are obtainable in practice can be compared with the predicted merit of the true optimum composite. In a case study the method is used to optimize a tropical composite using Brahman, Charolais, and Belmont Red breeds. The proportion of Charolais is to be constrained to 50%. Using growth parameters from a tropical crossbreeding experiment, the unconstrained optimum composite was 32.5% Brahman, 11.1% Belmont Red, and 56.3% Charolais. When the proportion of Charolais in the composite was constrained to 50%, optimum proportions of Brahman and Belmont Red were 33.9% and 16.1% respectively. In the case study net merit (annualized profit per cow exposed, $), as defined by the growth parameters, was .2% less than that of the unconstrained optimum composite.     

Potentiation of malathion by other insecticides against Musca domestica

Twenty-seven insecticides, including organochlorine, organophosphorus compounds and carbamates were tried for potentiation of the toxic effect of malathion. Carbaryl, diazinon, fenthion, gamma-BHC, parathion and tetrachlorvinphos potentiated the action of malathion. Fourteen insecticides gave additive effects while seven proved antagonistic. Insecticides which showed potentiation, were further tested by mixing with malathion in the ratios of 1:9, 3:7, 5:5, 7:3 and 9:1. All the five combinations in the six mixtures gave potentiating effects. Maximum potentiation of 17.6 times was observed in 1:9 combination of malathion and gamma-BHC. The proportions in which the insecticides were mixed had a pronounced effect on the toxic effect of malathion.     

Behavioural and physiological responses of sheep to 16 h transport and a novel environment post-transport

The effect of a novel lairage environment on the ability of sheep to recover from 16 h of transport was investigated. Sheep were transported from grass paddocks to either novel outside paddocks or inside pens, and housed groups were transported to either familiar or novel inside pens. During transport, sheep from outside paddocks lay down less than those from inside pens. In sheep transported to inside pens, those from outside paddocks spent more time lying and spent less time eating; hay and water intakes during the first 12 h post-transport were lower than those previously kept inside. There was no obvious effect of a novel environment post-transport on blood biochemistry, suggesting that the lower post-transport feed and water intakes in a novel environment did not have a significant effect on the ability of the sheep to recover from the feed and water deprivation associated with transport.     

Epidemiology of porcine non-specific colitis on Scottish farms

The objective of this study was to investigate epidemiological risk factors for porcine non-specific colitis (NSC). Forty-seven Scottish pig farms, with and without a clinical history of diarrhoea during the growing period (15-40 kg), were selected. The study included farm visits, clinical inspection of pigs, completion of farm management questionnaires, pathological tests into the cause of the diarrhoea and analysis of the non-starch polysaccharide (NSP) content of feeds. The results from 17 farms designated as NSC and 10 control farms suggest dietary associations with NSC. Farms with NSC fed diets with significantly higher levels of NSPs, especially containing the sugars glucose, arabinose and xylose. Few management factors were identified, although the high prevalence of infectious colitis reduced the power of the study.     

The performance of a thermometer screen on an automatic weather station

The performance of a Didcot-type thermometer screen on an Automatic Weather Station and a conventional Stevenson screen were compared, both with each other and against an aspirated Assmann psychrometer. Maximum temperature in the Didcot screen exceeded the conventional screen maximum by up to 1 K on calm, sunny days, and Didcot minimum temperatures were as much as 1.5 K less than the screen minima on still, clear nights; mean temperature discrepancies between screens were + 0.3 and − 0.4 K for maxima and minima, respectively. The apparent psychrometric constant for the Didcot screen was 1.0 mbar K⁻¹ which increased to 1.2 mbar K⁻¹ when u < 2 m s⁻¹ in contrast to the value of 0.799 mbar K⁻¹ frequently used for the Stevenson screen.