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排序方式: 共有93条查询结果,搜索用时 15 毫秒
1.
Adult wethers (n = 750) were lot-fed for 13 days, 8 days or 3 days before a simulated voyage lasting 18 days to examine whether the period of lot-feeding affected the proportion of sheep that ate pelleted feed and their body weight change during simulated shipping. There was no significant difference in the proportion of non-feeders between treatment groups on days 7 and 14 of the voyage. Body weights were not significantly different between the treatment groups on days 14 and 18 of the voyage. Overall body weight loss, from the farm to the end of simulated shipping, was 4.08 kg (+/- 0.28, s.e.m.), 4.58 kg (+/- 0.28) and 4.51 kg (+/- 0.28) in sheep lot-fed for 13 days, 8 days and 3 days, respectively, and was not significantly different between treatments. It was concluded that lot-feeding for 13 days conferred no advantage in body weight or numbers of non-feeders compared with shorter periods in this study. 相似文献
2.
SR Cho SA Ock JG Yoo B Mohana kumar SY Choe GJ Rho 《Reproduction in domestic animals》2005,40(2):171-176
The present study was designed to examine the effects of cell-cycle synchronization protocols, such as confluent, roscovitine treatment and serum starvation, in bovine foetal fibroblasts on synchronization accuracy at G0/G1, viability, apoptosis, necrosis and ploidy for use as a nuclei donor. The cells in 5-10 passages were randomly allocated into three treated groups. Cells were cultured either in Dulbecco's modified Eagle's medium (DMEM) + 10% foetal bovine serum (FBS) until 90% confluent (group 1, confluent), in DMEM + 10% FBS + 30 microM roscovitine for 12 h (group 2, roscovitine), or in DMEM + 0.5% FBS for 5 days (group 3, serum starvation). Most of the cells (>80%) in all groups were arrested at the G0/G1 stage. Although the rates did not differ, cells in group 1 showed an increased cell population arrested at the G0/G1 phase. Significantly (p < 0.05) higher rates of apoptosis occurred in group 3 than in group 1 and 2 (10% vs 6% and 6%, respectively). No differences in chromosomal abnormality were observed among groups. However, by increasing the number of cell culture passages up to 15, significantly (p < 0.05) higher chromosomal abnormality was observed than in 5 and 10 passages (39% vs 28% and 23%, respectively) in group 1. The results clearly indicated that bovine foetal fibroblasts could be effectively synchronized at G0/G1 stages by all the three different treatments, confluent, roscovitine and serum starvation. However, cells in confluent showed reduced apoptosis and necrosis when they underwent 5-10 passages, exhibiting increased percentage of cells with stable chromosome diversity. Hence, cells in confluent merit further studies before they could be used as nuclear donors. 相似文献
3.
RT NORRIS CL McDONALD RB RICHARDS MW HYDER SP GITTINS GJ NORMAN 《Australian veterinary journal》1990,67(7):244-247
In the first of 2 experiments, a simulated voyage was conducted to examine the effects of various treatments on bodyweight change and feeding frequency of inappetant sheep at the end of lot-feeding (non-feeders). The treatments, applied during simulated shipping, were: normal quantities of feed and length of troughs; extra trough length; extra feed. Adult Merino wethers (n = 108) were used in each treatment. A voyage to the Middle East was then conducted to establish whether shipboard mortality could be reduced by separating non-feeders (n = 305) from feeders (n = 5,620) late in the feedlot hase and housing the groups separately aboard ship. A control group of non-feeders (n = 215) mixed with feeders (n = 5,732) was used for comparison. Bars (marker bars), containing a coloured dye, were attached to feed troughs to mark sheep that fed. Most non-feeders (82%) began eating when placed in shipping pens in both studies. However, there was no significant difference in percentage of sheep that fed between non-feeders given extra trough length or extra feed compared with non-feeders given standard management at any stage of simulated shipping. There was no significant difference in mean bodyweights between treatment groups on days 1, 8 and 15 of simulated shipping. Differences in bodyweight on d 22 were probably associated with different levels of gut fill. Death rates were not significantly different in separated and control groups (1.1%, 0.9%, P = 0.6) in the voyage of 14 d to the Middle East.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Monensin controlled-release intraruminal capsule for control of bloat in pastured dairy cows 总被引:1,自引:0,他引:1
LB LOWE GJ BALL VR CARRUTHERS† RC DOBOS‡ GA LYNCH PJ MOATE PR POOLE† SC VALENTINE 《Australian veterinary journal》1991,68(1):17-20
Monensin, a polyether ionophore antibiotic, is potentially an important agent for bloat relief in dairy cows grazing temperate legume-based pasture. A series of studies was undertaken to determine the effect of monensin, when delivered continuously in the rumen of lactating dairy cows by means of controlled-release capsules (monensin CRC). Such devices release approximately 300 mg/head/day for 100 d. A short-term pilot study made at Ruakura, New Zealand, tested monensin CRC in cows selected for high susceptibility to bloat and grazing lucerne (Medicago sativa) or red clover (Trifolium pratense). Treatment significantly reduced the incidence of bloat, while milk yield and protein yield were increased. There was no effect on fat yield. Following the pilot study, 6 large-scale field experiments involving a total of 368 lactating dairy cows, were made in Australia and New Zealand to confirm the effectiveness of monensin CRC for bloat control and to measure the effect of such treatment on milk production and composition. A severe bloat problem occurred in 2 experiments, mild bloat occurred in 2 others, while no visual signs of bloat were observed in the remaining 2 experiments. Bloat was significantly (P less than 0.05) reduced by monensin CRC treatment when data was pooled over the 4 experiments in which bloat occurred. Daily milk yield was increased in all experiments from a mean of 17.7 in untreated groups to 18.8 kg/head/day (P less than 0.05) in monensin CRC-treated cows. Protein percentage was not affected by treatment, while there was a decrease from 4.29 to 4.10% fat, although total fat yield was not affected.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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This paper looks at the role of firm size, location, and in‐house research and development (R&D) in the innovation performance of U.S. firms in the commercial geographic information systems (GIS) industry. Data from a survey of 300 GIS firms are presented. The results suggest that innovation‐intensity varies directly with in‐house R&D spending (scaled as a proportion of company sales), but inversely with company size (total employment). Significant regional variations in the innovation performance of GIS firms are identified. It is argued that the geography of innovation is influenced by the spatial distribution of young and/or small firms, in that R&D‐productivity is found to vary inversely with company size. An important finding is that creative inputs to support innovation are almost evenly divided between internal and external sources. A surprising result is that the academic community is not viewed as a particularly important source of new ideas for innovative firms. The paper concludes with a discussion of the implications of the survey data for future empirical work on the GIS sector. 相似文献
9.
The influence of a low cobalt intake on the neutrophil function and severity of Ostertagia infection in cattle 总被引:3,自引:0,他引:3
Two trials involving housed cattle examined the effect of Co depletion and supplementation on immune status as assessed by the neutrophil function test which measures the ability of isolated neutrophils to kill the yeast Candida albicans. A third trial investigated the extent to which Co status influenced the severity of Ostertagia ostertagi infection. In the first two trials liveweight gains were unaffected until some 40-60 weeks on the low dietary Co intake despite very low serum vitamin B12 values being recorded after 10 weeks. However, the immune status as measured by the neutrophil function test was reduced within 10 weeks of commencing the low Co diet. On administration of Ostertagia ostertagi larvae, Co-depleted cattle showed a greater weight loss than Co-supplemented cattle but showed no difference in the length of the prepatent period, worm egg production or serum gastrin and pepsinogen concentrations. After anthelmintic treatment both groups showed a similar response. It is postulated that the lowered immune response of Co-depleted cattle resulted in the greater severity of the Ostertagia ostertagi infection. 相似文献
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