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31.
Ability of induced corpora lutea to maintain pregnancy in beef cows   总被引:1,自引:0,他引:1  
Experiments were conducted in beef cows without a primary CL, in which pregnancy had been maintained with exogenous progestogen. In preliminary trials, replacement CL induced ipsilateral to the embryo and after, rather than before, d 36 of pregnancy, maintained more pregnancies after withdrawal of exogenous progestogen (13/13 vs 2/6; P < 0.05). In Exp. 1, in cows with replacement CL induced by treatment with hCG on d 28 of pregnancy, treatment with flunixin meglumine on d 31 through 37 did not increase maintenance of pregnancy. Experiment 2 was conducted to evaluate directly the effects of concentrations of PGF2alpha and estradiol-17beta during d 31 through 35 of pregnancy on maintenance of pregnancy by replacement CL induced between d 28 and 31. In cows that maintained pregnancy while progestogen was provided, maintenance of pregnancy after withdrawal of exogenous progestogen tended to be greater with high (5/5) than with low (2/6; P < 0.10) concentrations of PGF2alpha and greater with low (6/7) than with high (2/6; P = 0.10) concentrations of estradiol-17beta. Secretion of progesterone by replacement CL was greater (P < 0.05) in cows with high than in those with low concentrations of PGF2, during d 31 through 35. Prostaglandin F2alpha may facilitate attachment of the bovine embryo (d 30 to 40) in a manner similar to that reported for implantation in other species. Cows that did not form CL in response to hCG on d 28 to 31 responded well when retreated after d 36. Again, maintenance of pregnancy was greater when replacement CL were induced after (9/9) rather than before d 36 (8/16; P < 0.05).  相似文献   
32.
T.Ahmad  M.Sarwar  吴云良 《中国家禽》2007,29(16):28-31
在家禽业中,缓解热应激的方法涉及饲养管理和改变日粮配方等.管理制度方面如提高鸡舍隔热效果,有流畅的通风设施,屋顶安装喷水装置和蒸发制冷系统,使用鼓风机,降低饲养密度.……  相似文献   
33.
The roots of 20 days old seedlings of tomato (Lycopersicon esculentum Mill.) at the time of their transplantation, were dipped in 10−8, 10−7, 10−6 or 10−5 M of 28-homobrassinolide (HBR) for 15, 30 or 45 min and were allowed to grow in earthen pots, in a net house. The leaves of the plants, at days 30 and 60, possessed elevated quantities of nitrate reductase (NR), carbonic anhydrase (CA) and the contents of chlorophyll. The values for all the above characteristics were significantly higher than that of the water-fed control. The fruits borned at the treated plants were more in number and possessed a lower quantity of ascorbic acid than the control. Moreover, the fruits at ripening, had higher levels of lycopene and β-carotene. Among the treatments, 15 min feeding of 10−8 M HBR proved best.  相似文献   
34.
The isolation and NMR spectra of otosenine (1) and seneciphylline (2) from Senecio lorenthii are reported.  相似文献   
35.
Seed presoaking improves wheat germination under marginal moisture conditions. The duration of seed presoaking was studied at The University of Arid Agriculture, Rawalpindi, using 10 wheat varieties. Seed presoaking beyond 12 h does not improve germination further, and beyond 21 h, germination rate is drastically reduced.  相似文献   
36.
Alkaline sulfite–anthraquinone (AS/AQ) pulping of wheat straw and totally chlorine free (TCF) bleaching of resulting pulps was investigated. Wheat straw was supplied by the Ferdosii University Experimental Station in Northeastern Iran, cleaned and chopped into about 3–5 cm long pieces. In the AS/AQ pulping experiments, the active alkali charge on oven dry wheat straw, heating time to maximum cooking temperature, AQ dose and liquor to straw ratio were kept constant at 16%, 60 min, 0.1% and 4/1, respectively. The alkali ratio, Na2SO3/NaOH, calculated as NaOH, was varied from 20/80 to 80/20. Cooking time at maximum temperature was varied from 30 to 90 min and maximum cooking temperature was adjusted between 152 and 160 °C. Reference soda and soda/AQ pulps were produced.AS/AQ and soda/AQ pulps with kappa numbers below 15 were produced easily. Cooking of corresponding soda pulps under comparable conditions stopped at a kappa number of 25. The characteristics of unbleached AS/AQ, soda/AQ and soda pulps were compared. AS/AQ and soda/AQ pulps had similar tensile strength but tear was in favor to AS/AQ. The latter had much higher yield and brightness.TCF bleaching of AS/AQ pulp was performed in O Q (OP) or O Q (OP) P sequences. Oxygen delignification (O) resulted in a delignification degree of approximately one third. Followed by a chelating treatment (Q) and a subsequent (OP) stage under drastic conditions a brightness of 82.7% ISO was achieved in an O Q (OP) sequence. The sequence O Q (OP) P, with 2% H2O2 in the final P stage, improved brightness from 77.2% ISO after the OP stage to 83.6% ISO. Bleaching led to only small losses in tensile and burst strength but enhanced tear strength. Short beating in a Jokro mill was sufficient to attain good pulp strength. The results of this study indicate that AS/AQ pulping and TCF bleaching is a convincing alternative to produce high-quality pulp from wheat straw for writing and printing paper.  相似文献   
37.
Identification of Manna excreting Aphids Up to now the origin of Manna in northern Iraq has not been known distinctly. As producers of the sweet excretions called Manna on oak trees were identified the following species of Aphididae:Aphis fabae Scop.,A. gossypii Glov.,Chromaphis juglandicola Kalt.,Myzocallis castanicola Bak.,Tuberculatus annulata Htg.,T. moerickei Hrl. andThelaxes sp.  相似文献   
38.
Ahmad MU  Rahman MA  Huq E  Chowdhury R 《Fitoterapia》2003,74(1-2):191-193
Pseudophrynamine, lunacridine and the new compound 2-(2',4',6'-trimethyl-heptenyl)-4-quinozolone were isolated from the leaves of Zanthoxylum budrunga.  相似文献   
39.
One myrsinol-type diterpene ester (1) isolated from Euphorbia decipiens was evaluated for analgesic activity in the acetic acid induced writhing test in mice. Different dose (5-20 mg/kg i.p.) of the compound showed significant antinociceptive activity, which was comparable to standard analgesic drugs, aspirin and ibuprofen (100 mg/kg i.p.).  相似文献   
40.
Four known coumarins, coumarin (1), 7-hydroxy-3-methylcoumarin (2), oreoselone (3) and heraclenin (4), were isolated from aerial part of Halocnemum strobilaceum. Their structures were determined by 1 and 2-D NMR techniques.  相似文献   
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