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981.
982.
983.
Avian influenza virus (A/Chicken/Pennsylvania/83; H5N2) was recovered from the yolk, albumen, and shell surface of eggs obtained from naturally infected chicken flocks in Pennsylvania and Virginia. These findings represent the first reported isolation of avian influenza virus from the internal contents of eggs from naturally infected flocks. The need for adequate safeguards to prevent spread of the virus during commercial movement of table and hatching eggs, cracked and "checked" eggs, and egg flats and other materials is emphasized.  相似文献   
984.
Steers and bulls under feedlot conditions and on an apparently adequate ration developed transitory signs of diarrhea and unthriftiness. One animal became recumbent. Sick and clinically normal animals in the group had elevated serum creatine kinase and aspartate aminotransferase enzyme values and degenerative changes in muscle fibers on biopsy. Feed analysis was carried out and the animals were monitored over several weeks by means of muscle biopsy and serum enzyme analysis as well as by postmortem examination at slaughter. Subclinical myopathy was found in several animals and was thought to be related to low vitamin E content in the high moisture corn ration.  相似文献   
985.
986.
1. On average, over the laying year, a higher proportion of eggs were cracked from cages (4.6%) than from range (2.0%); the difference tended to increase as the flocks aged.

2. There was evidence that eggs from range had stronger shells: they required more energy to crack, shell thickness was greater and shell deformation at 70 weeks was less (though the difference was not significant).

3. The differences between systems in shell strength, although real, were small. It is probable that environmental insults make a much larger contribution than shell strength to differences in crack incidence.

4. Eggs laid by hens on range were larger (+ 6.8% at 36 weeks and + 2.9% at 70 weeks) than those laid by the same stock housed in cages.  相似文献   

987.
1. Automatic weighing equipment was tested on a flock of 752 roaster chickens reared on litter to 10 weeks of age.

2. Mean body weights obtained automatically were lower than those obtained manually, mainly because of birds perching on the automatic weighing perch with part of their body in contact with the floor.

3. Birds observed on the weighing perch on one day of the week were 3–5 times more likely to use the perch again on the following 2 d than expected on the basis of random perch use by flock members. These birds were also more likely to be seen in the area immediately surrounding the perch than in similar areas elsewhere in the pen.  相似文献   

988.
989.
Polyurethane foam plugs commonly are used as collars or supports to grow plants in solution culture. Despite their utility, these foam plugs can be quite toxic to plants, particularly to small seedlings. We have observed tissue injury in tests using plugs to support lettuce, red beet, and potato plants in solution culture. Typically, the injury is initiated on the hypocotyl or stem tissue in direct contact with the foam, and appears within 30 hr as a brownish discoloration on the tissue surface. This discoloration can be followed by complete collapse of affected tissue and eventual death of the seedling. When injury does not progress beyond surface browning, the seedling survives but growth is slowed. In this paper, we report on different treatments that can be used to remove the toxicity of these plugs so they can be used in plant research.  相似文献   
990.
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