Spring barley growth, grain quality and soil physical conditions in a cultivations experiment on a sandy loam in Scotland

Widely differing cultivations for spring barley, ranging from conventional ploughing to direct drilling and including broadcasting on to undisturbed soil, were examined over two seasons (1979 and 1980), conventional ploughing yielding highest and either chisel ploughing or direct drilling lowest. Yield differences were associated with plant population differences; they were significant only in the abnormally wet season of 1980. Broadcasting before tine cultivation to 50 mm resulted in lower seedbed strength and higher yield than drilling after a similar cultivation. Compaction by the same level of seedbed traffic was greater in a treatment cultivated to 50 mm depth than in the conventional ploughing treatment. Grain milling energy, which is inversely related to endosperm suitability for malting, and grain nitrogen content both decreased with increasing yield. Total nitrogen removed per ha in the grain in 1979 was similar in all treatments (about 72% of applied). In 1980, it was generally lower (about 62% of applied). After allowing for differences in plant populations it was lowest after direct drilling, broadcasting and very shallow tine cultivation (60% of applied), highest after conventional ploughing (70% of applied) and intermediate after rotary cultivating and shallow tine cultivation (65% of applied). Soil water release characteristics were described by logistic equations. Treatment differences were greatest at matric potentials greater than -3 kPa at 10 and 60 mm depth. The porosities of the cultivated soils were similar to each other, and were greater than those of the direct drilled treatments.     

HUMPY BACK OF SHEEP. CLINICAL AND PATHOLOGICAL OBSERVATIONS

Humpy back, a disease of Merino sheep in western Queesland, occurs during mustering for shearing. It is usually seen in summer 6-10 weeks after substantial rainfall and is thought to be caused by the ingestion of a toxic plant. The disease is characterised clinically by a short-stepping, stilted gait of the hind limbs, followed by lowering of the head, arching of the back and inability to continue walking. Histopathological examination of 8 cases from 5 properties revealed a Wallerian degeneration of the white matter throughout the length of the spinal cord with the ventral and lateral columns most severely affected. A similar degenerative change was seen in the posterior cerebellar peduncles of 3 of the sheep. A more severe hind limb incoordination with more extensive degeneration of the white matter of the spinal cord, medulla and cerebellum was seen in a case of humpy back of two years duration. Similar, but much milder, spinal cord lesions were found in apparently unaffected sheep from the same group as the sheep affected with humpy back on 2 properties. Severe myodegeneration of hind limb muscle groups was seen in 3 affected sheep. It was thought to be associated with the long rail journey (1500 km) to the laboratory after the sheep were affected in the field.     

Investigation to determine digestibility coefficients of various raw materials in diets for gilthead sea bream, Sparus auratus L.

A number of raw materials were tested to obtain the in vivo apparent digestibility coefficients of protein, lipid and gross energy for gilthead bream. Sparus auratus L., under controlled conditions. In the case of protein digestibility assessment, a standard in vitro method was also included for comparison. Protein digestibility coefficients were generally high, with values between 60% and 96% being observed for most of the materials studied. However, some exceptions were apparent in materials of both animal and plant origin. Lipid digestibilities also ranged between 50% and 90%. Values for energy digestibilities indicated a much greater variation, from 6% to 80%. These observations are discussed in relation to the nature and source of ingredients and to the type of processing technology employed.