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A study was conducted to record the deaths that occurred during export, and to examine the temporal pattern of pellet feeding in the feedlot and ascertain the variation in mortality between groups of sheep from different farms. Between November 1985 and April 1987, 5 cohorts of sheep were selected on arrival at a feedlot before live export by sea from Western Australia to the Middle East. Each cohort consisted of 4,118 to 9,612 Merino wethers from 15 to 35 farms (lines). There were few deaths during trucking to the feedlot (rate 0.9, range 0.0 to 3.0 per 10,000 sheep) and during lot-feeding (rate 6.2, range 1.2 to 12.2 per 10,000 sheep). Most of the deaths occurred aboard ship (rate 210.7, range 152.7 to 271.5 per 10,000 sheep). The proportion of sheep that ate pelleted feed increased with increasing length of time in the feedlot. By the end of lot-feeding the percentage of sheep that had not eaten pellets was 23.3, 4.4, 1.2, 2.1 and 0.2 in a representative sample of each of the 5 cohorts. It was considered that offering hay throughout lot-feeding was undesirable for the purpose of maximising the number of sheep that ate pellets before loading on the ship. Half of the deaths aboard ship occurred in 25% of 133 lines of sheep in the 5 cohorts. In each cohort the median per cent death rate (and range) per line was 1.3 (0.3 to 11.9), 1.1 (0.0 to 5.7), 1.8 (0.0 to 6.8), 2.3 (0.0 to 14.3) and 0.9 (0.1 to 5.4).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Striga seeds were extracted from soils collecled in Mali and the viahility of these seeds was estimated. Striga seeds were found in 45 of 46 samples taken from 23 fields. Siriga hermonthica (Del.) Benth. growmg on the host crop millet, was present at all 46 sites sampled. The a size uf the Striga seedbaiik measured lo a depth of 15 cm was estimated to be 38 800 m -2 of surface area (geometnc mean 11 500). The average number of S. hermonthica plants observed per millei hill was 8.83 (geometric mean 3.89) or 13.98 m-2 (gcometrie mean 5.69 m-2). Higher crop hill densities tended to result in higher densities of emerged S. hermonthica per hill. The relationship between seeds m-2 and S. her-monhica plants m-2 was fitied to a reetungular hyperbola and used to reassess an existing model of S. herniouhica control. 相似文献
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