Dynamics of urea concentration in cockerels during the 1st month of life]

The concentration of urea in the blood serum of 190 cockerels (The Primant commercial hybrid) was determined by means of diacetylmonoxim (Homolka, 1971). Uremia reached values from 0 to 23.20 +/- 5.29 mg per 100 ml. A high individual variability of uremia was found.     

Restriction of Application Losses during Aerial Sprayings1

Results are reported on the prevention of losses of pesticide liquids due to droplet drift during aerial spraying. The effect of two basic factors was tested: a) change in drop size achieved either by use of different nozzles or by their modification or by regulation of the physical properties of the pesticide liquids; b) change of external conditions of drop fall achieved by the regulation of flight altitude, arrangement of nozzles on the aircraft, accuracy of operation of the spraying equipment The experiments proved that droplet size was most affected by use of TeeJet nozzles with Sabatka terminals, and to a lesser extent by the Lo-Drift agent Both factors limited the formation of the smallest drops, up to 100 μm especially. Accurate operation and maintenance of the spraying equipment (especially timely turning off at the end of lanes) has a great effect on limiting drift Optimum flight altitude (according to wind speed) is a compromise between the effort to limit drift and droplet evaporation and the achievement of required uniformity of deposition (CV). With the Z-37 aircraft, the optimum flight altitude in good weather conditions is about 4-5 m. Earlier experiments (to 1978) indicated good results with the addition of Ulvapron agent (21/ha) and Trition CS 7 (0.3%) mainly in warm (above 20°C) and dry (below 60 % R.H.) weather.     

Analgesia in Dogs After Intercostal Thoracotomy: A Clinical Trial Comparing Intravenous Buprenorphine and Interpleural Bupivacaine

We prospectively studied 26 dogs that presented for intercostal thoracotomy. Dogs were pre-medicated with oxymorphone, induced with diazepam and etomidate, and anesthesia was maintained with isoflurane in oxygen. Preoperatively, animal patients were randomly assigned to one of two groups. Group 1 (n = 13) received buprenorphine (10 μg/kg intravenously [IV]) every 6 hours for 24 hours starting 10 minutes before tracheal extubation. Group 2 (n = 13) received 0.5% bupivacaine (1.5 mg/kg) administered interpleural (IP) by slow injection through a pediatric feeding tube fixed to the most dorsal aspect of the thoracotomy incision. Interpleural injections were administered with each dog placed in lateral recumbency with the incision positioned ventrally; IP injections were administered every 4 hours for 24 hours starting 10 minutes before tracheal extubation. All cases were monitored in the intensive care unit for 24 hours postoper-atively. The analgesic efficacy of each regimen was evaluated using a pain scoring system that included a subjective pain score, heart rate, and respiratory rate. Arterial blood pressure, arterial blood gases, oxygen saturation, body temperature, and changes in the electrocardiogram or neurological status were also noted. Significant increases in mean heart rate, respiratory rate, and total pain score occurred after surgery in dogs in the buprenorphine group. In contrast, dogs in the bupivacaine group had no significant changes when compared with their preoperative values. Dogs in the bupivacaine group had significantly decreased total pain scores and better PaO₂ and oxygen saturation values when compared with the dogs receiving buprenorphine. Hypoventilation did not occur in either group.     

偏重亚硫酸钠钝化生豆粕胰蛋白酶抑制因子的研究

试验用不同浓度的Ｎａ２Ｓ２Ｏ５处理生豆粕，进行适宜水平研究。结果表明，当生豆粕ＴＩＡ和ＵＡ分别为２９．７２酶活单位和１．９５△ｐＨ时，分别用０．３％、０．４％、０．５％和０．６％ＮａＳ２Ｏ５处理ＲＳＢＭ，ＴＩＡ依次降低了５１．８％、５５．９６％、５９．８３％和５２．０５％，均极显著地低于ＲＳＢＭ（Ｐ＜０．０１）。０．３％Ｎａ２Ｓ２Ｏ５对ＵＡ无影响，其它处理ＵＡ提高约０．０６△ｐＨ。     

神经网络智能PID参数最优控制及应用

本文提出了一种神经网络智能ＰＩＤ参数最优控制系统，给出了有效的基于共轭梯度的神经网络学习算法。仿真实验和应用结果表明，这类智能控制器可用于难以建立数学模型的控制系统。     

Epidemiologic and economic analyses of an unusually long epizootic of trichomoniasis in a large California dairy herd

An epizootic of trichomoniasis in a large California dairy herd caused an estimated economic loss of $66,538 ($665/infected cow). Greatest losses were caused by infertility (about 50% of losses caused by excess days open). The disease continued in the herd, despite culling older bulls and replacing them with young uninfected bulls and despite institution of an artificial insemination (AI) breeding program for 2 high-production strings. The AI breeder's practice of checking for estrus by vaginal examination was implicated in the spread of the disease. Of 5 cows that became infected before or at conception, 1 had the infection throughout the gestation period and into the next lactation. The prevalence of trichomoniasis in the herd (estimated on the basis of culture results) was 10.67%. The culture method had a calculated sensitivity of only 58.7%. Of 940 cows in the herd, 132 aborted during the epizootic (8 aborted twice); 45 abortions would have been expected in a dairy herd of this size in the absence of trichomoniasis. In high-density mass-bred herds, conditions and/or management practices may be conducive for trichomoniasis transmission, and generally recommended control programs should be adjusted on such dairies. In particular, dairy operators should not assume that culling older bulls and replacing them with young uninfected bulls and that institution of an AI program will be effective in limiting the spread of the disease. Moreover, a diagnostic test with improved sensitivity would greatly assist in the identification of infected cows.