Quantified evaluation of agricultural soil capability at the local scale: a GIS-assisted case study from Ontario, Canada

Abstract. Rural agricultural areas in southern Ontario, Canada, with potential for aggregate extraction have become a focus of conflict over proposed land use change. Geophysical and soil physical field measurements were used to map soil variation for quantitative land evaluation at the farm level. Apparent electrical conductivity of terrain was shown to be strongly correlated with depth to the groundwater table on two separate test sites. A digital terrain model was used to create thematic maps of the predicted pre-growing season soil water regime by contouring irregularly spaced electromagnetic survey and soil inspection points. Overlay analysis with a geographical information system (GIS) was used to produce an agricultural soil capability map for crop production. Adoption of a larger map scale provided significant refinement in detail over the published Canada Land Inventory soil capability ratings for agriculture, but both showed that Class 2 soils are dominant. The approach can improve the reproducibility of land capability assessments.     

Liver haemorrhages induced by rapeseed meal: incidence in adult male and female fowls

Adult cockerels of a commercial egg-producing strain did not develop liver haemorrhages when maintained for 12 weeks on a diet containing 400 g rapeseed meal/kg food. Haemorrhages occurred in 43% of laying hens of the same strain as the cockerels and 33% of laying hens of another strain maintained on the same diet for the same period. Oestrogenisation of the male birds did not influence the incidence of haemorrhage.     

Studies on the process of digestion in the fowl: dry matter and total nitrogen

Four pelleted diets, based on soybean meal (N = 4.40%), fish meal (N = 2.41%), field bean (Vicia faba L.) meal (N = 2.05%) and maize dextrin (N = 0.10%), were each offered to sixteen 13‐week‐old pullets for a 2 h period. Four birds from each group were killed 2, 4, 6 and 8 h after the feeding period and samples of the ingesta were removed from the gastro‐intestinal tract. The same experimental procedure, using the soybean meal diet, was also applied to sixteen 17‐week‐old and sixteen 24‐week‐old pullets.

Nitrogen and chromium sesquioxide were determined on the freeze‐dried ingesta removed from the crops, proventriculi and gizzards, duodena, jejuna, ilea, caeca and large intestines of all the groups.

The results indicated that the crop, proventriculus and gizzard acted as food reservoirs, that passage of food through the duodenum was very rapid and that the amount of the ingesta in the caeca depended on the diet, and was possibly affected by the nature of the carbohydrate. The rate and mode of digestion of the dietary protein was not dependent on time after the meal nor on bird age.

Differences appeared to exist in the digestion of the different diets, particularly with respect to the amount of endogenous nitrogen present in the duodenal ingesta. These differences could not be explained in terms of the nitrogen contents of the diets, but may have been the result of the extrusion procedure when the texture of the diets and, hence, ingesta were important factors. The nitrogen values of the duodenal contents from the birds given the fish meal diet indicated a two‐fold increase over that of the food, whereas the corresponding values for those from the birds given the soybean meal and field bean meal were five‐ and fifteen‐fold respectively.     

Studies on the effect of lysine and methionine supplementation of a high‐protein maize‐soyabean diet and of a low‐protein barley‐white fish meal diet on the performance of caged layers

Selected literature relating to the amino acid supplementation of layers’ diets is reviewed and the results of two experiments are presented.

In the first experiment a basal soyabean meal diet (14.3 per cent crude protein) was supplemented with L‐lysine and DL‐methionine, singly and together. Supplementation of the basal soyabean diet with the amino acids caused no significant effects on egg production, mean and total egg weight or food conversion efficiency. None of the soyabean diets proved as satisfactory for egg production or food conversion efficiency as a fish meal control diet (16.9 per cent crude protein).

In the second experiment the effect of adding 0.1 per cent each of L‐lysine and DL‐methionine or 0.2 per cent each of l‐lysine and DL‐methionine to a low fish meal diet (2.5 per cent fish meal) was examined. The addition of 0.2 per cent of each amino acid caused an increase in egg production.

Mean egg weight was improved by the addition of amino acids at both levels although this effect was not statistically significant. Comparison of the low fish meal diets with a fishmeal control diet (10 per cent fishmeal) showed that at the 0.2 per cent addition of amino acids, egg production, total egg weight and food conversion efficiency were better than on the 10 per cent fish meal control diet.

Two breeds, light and medium hybrids were used in both experiments.

The results are discussed with reference to their practical significance.     

Assessment of a caudal external thoracic artery axial pattern flap for treatment of sternal cutaneous wounds in birds

OBJECTIVE: To assess the use of a caudal external thoracic artery axial pattern flap to treat sternal cutaneous wounds in birds. ANIMALS: 16 adult Japanese quail. PROCEDURE: A cutaneous defect in the region of the mid-sternum was surgically created in all quail. In 6 quail (group I), an axial pattern flap was created from the skin of the lateral aspect of the thorax and advanced over the sternal defect. In 8 quail (group II), a flap was similarly created and advanced but the flap vasculature was ligated. All quail were euthanatized at 14 days after surgery and had necropsies performed. Sections of the flap and the surrounding tissue were examined histologically to assess flap viability. RESULTS: All axial pattern flaps in group-I quail had 100% survival. In group II, mean percentage area of flap survival was 62.5%; mean area of necrosis and dermal fibrosis of flaps were significantly greater than that detected in group I. In flaps of group-II quail, neovascularization in the deep dermis and profound necrosis of the vascular plexus in the superficial dermis were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the caudal external thoracic artery axial pattern flap could be used successfully in the treatment of surgically created sternal cutaneous defects in quail with no signs of tissue necrosis or adverse effects overall. Use of this technique to treat self-mutilation syndromes or application after surgical debulking of tumors or other masses might be beneficial in many avian species.     

Recurrence of thoracolumbar intervertebral disk extrusion in chondrodystrophic dogs after surgical decompression with or without prophylactic fenestration: 265 cases (1995-1999)

OBJECTIVES: To evaluate a population of chondrodystrophic dogs treated for Hansen type 1 intervertebral disk (IVD) disease by surgical decompression with or without prophylactic fenestration and determine the rate and location of surgically confirmed recurrence of intervertebral disk extrusion. ANIMALS: 265 dogs. STUDY DESIGN: Retrospective study. PROCEDURES: Medical records of dogs that underwent spinal decompression between 1995 and 1999 were reviewed. RESULTS: 3 (4.9%) dogs were euthanatized or died prior to discharge. Fenestration was performed in 252 dogs, including 37 (14.7%) at the site of decompression only, 48 (19%) at 3 to 4 disk spaces, and 167 (66%) at 5 to 7 disk spaces. There were 12 instances of recurrent disk extrusion confirmed by removal of disk at a second surgery 3.5 to 33 months after the first surgery. Recurrence was always at a new disk space, and rates did not significantly differ between dogs that underwent single or multiple fenestrations. Two recurrences were at a previously fenestrated disk space. Seven recurrences were at a site immediately adjacent to a fenestrated disk space, and 5 recurrences were at L4-5. CONCLUSIONS AND CLINICAL RELEVANCE: Prophylactic fenestration is generally successful in preventing future disk extrusions at fenestrated disk spaces. Prospective evaluation is still required to determine whether fenestration decreases the overall rate of recurrence. Prophylactic fenestration could promote disk extrusion at adjacent, nonfenestrated disk spaces. This could have a substantial clinical impact if recurrence develops at L4-5.     

Idiopathic gastroesophageal reflux disease in an adult horse

Chronic gastroesophageal reflux disease was diagnosed in a 22-year-old female Tennessee Walking Horse that had signs of bruxism and ptyalism. Esophageal ulceration was detected via endoscopy. Compared with the damage to the proximal portions of the esophagus, the severity of the ulceration increased toward the gastroesophageal junction. Esophageal ulceration attributable to chronic gastric acid reflux is usually secondary to pyloric outflow obstruction in horses. In the horse of this report, there was no evidence of either a chronic pyloric or duodenal obstruction that could have resulted in esophageal ulceration. Esophageal ulceration in this horse was attributed to gastroesophageal reflux disease, a common condition in humans in which the underlying abnormality is functional incompetence of the gastroesophageal junction. Treatment is directed at decreasing gastric acidity and protecting the ulcerated mucosa. In the horse of this report, treatment was unsuccessful and the horse was euthanatized; a physical cause of gastroesophageal reflux disease was not identified during an extensive postmortem examination.