Diagnosis of equine stifle joint disorders: three cases

The clinical, radiographic, arthrographic, arthroscopic, and pathological findings of three horses with femorotibial joint injuries are presented. Overall diagnostic accuracy is improved when clinical signs, arthrography, and arthroscopy are combined. Treatment of these injuries remains limited. One horse was euthanized, and two were treated by stall rest after diagnosis. Of the two surviving horses, one became a successful breeding animal, and the other was unable to perform as a pleasure horse.     

Efficacy of parenteral antibiotics for disease prophylaxis in feedlot calves

Trimethoprim-sulfadoxine (TMPSDX) and two formulations of oxytetracycline (OTC) were examined for their prophylactic efficacy in feedlot calves when given by intramuscular injection on arrival at a large commercial feedlot. The study included 2,112 high-risk feeder calves that developed disease early in the feeding period. Both formulations of OTC reduced bovine respiratory disease morbidity during the first two weeks on feed and for the entire feeding period by 15-19% (p<0.05), and they also reduced all fatal fibrinous pneumonia by 67% and 84% (p<0.05). All three drugs significantly reduced all fatal disease in animals first treated during the second week on feed, but not for the overall feeding period. Oxytetracycline with 2-pyrrolidone reduced the incidence of all fatal disease by 44% (p<0.05) during the entire feeding period. The case fatality risk for calves first treated during the second week on feed was lower (p<0.05) in the TMPSDX group and in the OTC with polyvinyl-pyrrolidone group.     

"Benchmark" - a large observational study of Ontario beef breeding herds: Study design and collection of data

The methods used in a large field study which investigated the health and productivity of Ontario beef breeding herds are described. Beginning in the calving season of 1986, 180 breeding herds on 170 randomly sampled farms were followed for a two year period, using producer records and annual farm visits.

The response (cooperation) rate among the eligible producers initially contacted was 70%. Approximately two-thirds of producers maintained individual animal records, primarily calving season records. Approximately 40% recorded disease occurrences.

The advantages, disadvantages, and interpretation of “on-farm” observational studies are discussed.

     

Relationship between equivalent salt solution series of different soils

Equivalent salt solution series have been previously defined as solutions with combinations of sodium absorption ratio (SAR) and electrolyte concentration (E_c) producing the same extent of clay swelling in a given soil. The present study shows that there is a high (r²>0.96) positive correlation between log E_c and log SAR of equivalent salt solutions series, in the equation: where a₁ and b₁ are constants for each equivalent salt solution series for a given soil. Log a₁ could also be represented as a linear function of b₁ resulting in the equation: where a₂ and b₂ are constants for a given soil. Solving this equation using any given value of b₁ yields the combinations of SAR and E_c which make up each equivalent salt solution series for a given soil. The relationship between log a₁ and b₂ for three soils from western United States, namely Waukena, Pachappa and Grangeville, was similar, with their combined data having a r² value of 0.96. This indicated that a single set of equivalent salt solution series values could be used for these three soils which have different clay contents and clay mineralogy. Prediction of hydraulic conductivity decreases with E_c reduction at given values of SAR in red-brown and alluvial soils from southern Tasmania, using the equivalent salt solution series values for Waukena soil, showed similar patterns to measured values and also to those predicted using the equivalent salt solution values applicable to the respective Tasmanian soils. Thus, available data indicate that the same set of equivalent salt series could be applied to the five soils studied. If further testing shows that a single set of equivalent salt solutions values could be applied to all or large groups of soils, this would facilitate the application of the equivalent salt solution concept to predict salt solution flow in the field.