金沙滩林场立地类型划分和树种选择

通过对金沙滩林场土壤、植被的详细调查和定点试验，认为土壤水分是影响树木成活及生长的主要因子，并以土壤水分为标准，把该林场划分为７个立地类型，针对各种立地类型的特点，提出了不同区域适宜栽植的树种和林种     

Determination of potato glycoalkaloids using a liposome immunomigration, liquid-phase competition immunoassay

Polyclonal anti-solanine antibodies were raised and used in the assembly of a liposome immunomigration, liquid-phase competition strip immunoassay. In this format, a similar cross-reactivity was observed between the glycoalkaloids alpha-solanine and alpha-chaconine. The strip assay was implemented to quantitate total glycoalkaloids (TGA) from potatoes. Recoveries in spiked potato samples using the strip assay and water:acetic acid:sodium bisulfite extracting solvent were in the range of 84-111%. The values of the TGA quantitations by the strip assay as compared with those obtained by HPLC, in nonspiked tubers coming from cloned potato samples donated by potato breeders, were equivalent and highly correlated (r(2) = 0.91). The strip assay proved advantageous over HPLC for extra-laboratory measurements such as the rapid identification of samples that should be rejected due to an elevated TGA content.     

Serum isocitrate dehydrogenase during polybrominated biphenyl toxicosis in dairy cattle

Bovine serum isocitrate dehydrogenase (sICDH) was investigated in dairy cattle as a clinical measurement indicative of hepatic injury. Conditions for optimization of isocitrate dehydrogenase assays for bovine serum are described. Assays of sICDH in normal cattle show average activities of .814 (SD = .202) units/ml serum with a range of .316 to 1.268 for 83 samples taken from 32 animals. Investigation of sICDH in pregnant dairy cattle experimentally dosed with polybrominated biphenyl (PBB) showed no discernible elevations until doses were sufficient to cause toxicosis (25,000 mg PBB/d). Cows lethally dosed with 25,000 mg PBB/d had moderate elevations of sICDH (approximately a twofold increase) concomitant with severe toxicosis in some but not all animals. This PBB dose also caused abortion or fetal death in pregnant animals; elevation of sICDH in these animals was coincident with fetal trauma. This suggests that sICDH may be influenced by fetoplacental contributions in pregnant animals. Non-pregnant cows, intoxicated with PBB, had minimal sICDH elevation as compared with 10-fold in a calf with experimentally induced hepatotoxicity (thioacetamide). This observation was consistent with histopathological findings of minimal, if any, hepatic involvement in dairy cattle lethally intoxicated with PBB. Serum isocitrate dehydrogenase appears to be a useful adjunct to the ordinary complement of serum chemistries used for clinical diagnosis; however, it does not appear to reflect exclusively hepatic injury.     

An automated in-line clinical mastitis detection system using measurement of conductivity from foremilk of individual udder quarters

AIM: To assess a novel method for automatic in-line detection of clinical mastitis.

METHODS: For a brief period at the start of milking for each cow, electrical conductivity of foremilk was measured for each quarter in turn, using a single sensor installed in the long milk tube (LMT) about 1.5 m downstream from the milking-machine claw. Sequential separation of flow between udder quarters was achieved by control of pulsation to individual teatcups within a conventional cluster. The ratio of conductivity values between quarters was used as an indicator of mastitis status. The concept was evaluated initially in a pilot trial in a 200-cow herd milked in a 23-stall swing-over herringbone milking parlour. It was then tested rigorously in a field trial in a 640-cow herd milked in a 50-stall rotary milking parlour. Both trials were conducted in the Waikato region of New Zealand. In the latter trial, sensor results were compared with visual inspection of a commercial in-line mastitis filter fitted to each milking unit. These filters were inspected for clots immediately after every cow's milking, for 3 weeks. The dataset of approximately 27,000 individual milkings was tested against several published or potential alter- native ‘gold standards’ for diagnosing clinical mastitis.

RESULTS: In the pilot trial, 12–14 clinical events were detected out of 19 true clinical quarters, with a false-alert rate of between three and five false electrical-conductivity alerts per 1,000 individual milkings. In the more rigorous field trial, sensitivity ranged from 68 to 88%, and the false-alert rate (false-alert episodes per 1,000 individual milkings) ranged from 2.3 to 7.0.

CONCLUSION: The novel clinical mastitis detection system, based on separation of the flow and measurement of electrical conductivity from foremilk of individual udder quarters, has the potential to provide a new tool for helping farmers to monitor clinical mastitis in herds milked with conventional clusters.     

Human psittacosis associated with commercial processing of turkeys.

Between May 1 and Aug 1, 1974, 114 of approximately 1,000 employees in 7 turkey processing plants in Texas (5), Missouri (1), and Nebraska (1) had an illness compatible with psittacosis. The illness was characterized by fever, severe headache, and pneumonia. Treatment with tetracycline was effective in most cases. Psittacosis was confirmed in 41 (36%) of the cases by a fourfold change in complement-fixation titer to the Chlamydia group antigen. Investigations implicated several turkey flocks from Texas as the source of the disease. Control measured, including screening turkey flocks before slaughter and assuring treatment of infected birds, were instituted by a special task force of state and federal veterinarians.