Phosphoric acid ester preparations used in cattle, swine and sheep with special reference to cholinesterase activity. 4. Use of phosphoric acid esters and their effect on acetylcholinesterase activity in sheep]

The use of organophosphorus preparations for the control of ectoparasites and endoparasites of sheep, particularly systemic application, is discussed. Experiments on 13 groups of sheep with five preparations produced in the German Democratic Republic in various formulations and concentrations showed that external application had good contact activity, but little was absorbed. Acetylcholinesterase activity was not inhibited, except by pour-on application of doses several times the normal dose. The preparations were arranged in order of cholinesterase inhibition. In contrast to cattle, diminished cholinesterase activity was unreliable as in indicator of systemic toxicity of organophosphorus preparations in sheep.     

Phosphoric acid ester preparations used in cattle, swine and sheep with special reference to cholinesterase activity. 3. Use of phosphoric acid ester preparations and their effect on acetylcholinesterase activity in swine]

The use of organophosphorus preparations in the treatment of ectoparasites and endoparasites of pigs is discussed. Treatment of 43 store pigs with preparations produced in the German Democratic Republic by washing and by the pour-on method resulted in considerable inactivation of acetylcholinesterase, which implies good systemic action. Overdosage increased this effect, but without producing signs of toxicity. The oral dosages for pigs cited in the literature were confirmed. Repeated treatment was recommended for the best results, as pigs rapidly break down the preparations. It is necessary to take into account adverse effects of oral administration on palatability of the ration and on weight gain. Addition of a preparation to a batch of food for a group of pigs is likely to be less successful than individual dosing, which is the best method for sows.     

新型防霉剂富马酸酯类

1新型防霉剂的优点长期以来,广泛应用的化学防霉防腐剂主要是有机酸及其盐类,如苯甲酸及其钠盐,山梨酸及其钠、钾盐,丙酸及其钠、钙盐,脱氢醋酸及其钾盐等。它们都对细菌和霉菌有很强的抑制作用,但其毒性都较高,有些品种如苯甲酸钠、脱氢醋酸钠等被世界卫生组织禁止使用;即使使用,其使用条件和使用范围也受到很大限制。20世纪80年代以后,新开发的有机酸酯作为防霉防腐剂已被广泛采用,原因主要有以下几大特点:1)毒性较低,使用安全。有机酸酯类与有机酸盐作为防霉防腐剂的毒性比较,见表1。2)杀菌力极强,且具有广谱性,对霉菌有特殊抑制效果,特…     

Testing a new virtual fencing system on sheep

Abstract

The aim of the present experiment was to investigate the function of a virtual fencing system, consisting of collars eliciting sound signals and weak electric shocks when a sheep crosses a global positioning system (GPS) based (virtual) border. In experiment 1, 24 ewes were individually attracted to a virtual border to determine how many animals would learn to avoid electric shocks in three repetitions. Nine of the ewes succeeded and there were large individual differences in how they responded. In experiment 2, these nine ewes were kept in a virtual enclosure, with and without a physical fence outside the border, for four days. The ewes stayed inside the intended pasture when the border was kept stationary. Moving the border resulted in the ewes escaping over the virtual border. The results from the study indicate challenges with this virtual system. This has implications for the use of animal virtual fences for commercial sheep production.     

The development of a new breed of sheep in Colombia

A new breed of sheep has been developed in Colombia by crossing Scottish Blackface rams with the indigenous Criolla ewes and then interbreeding the progeny, with selection based on performance. It has been given the name Manchada Paramuna. The breed has been developed to provide the small producer (campesino) with a breeding ewe which has a high level of fertility, a good fleece, and which produces lambs with high survival rate and good growth rate.     

Laboratory investigations in sheep with a new anthelmintic.

The efficacy of fenbendazole against the following gastrointestinal nematodes was tested in experimentally infected lambs: O circumcincta, H contortus, T colubriformis and N filicollis. As low a dose as 0.5 mg per kg reduced the egg output of a patent infection with H contortus and T colubriformis by 85 per cent to 100 per cent. A dose of 3.5 mg per kg has a 100 per cent effect on three or 10-day-old stages of H contortus and one of more than 99 per cent or 100 per cent T colubriformis. The same dose reduces seven-day-old stages of O circumcincta and N filicollis by more than 94 per cent or 100 per cent, while 10 mg per kg produces a 100 per cent elimination of seven-day-old stages of O circumcincta. In field trials and efficacy of more than 99 per cent was determined after oral dosage with 5.0 mg per kg against Ostertagia, Haemonchus, Trichostrongylus, Cooperia, Nematodirus and Chabertia. Fenbendazole has a wide therapeutic-toxic dose ratio. Discoloration of the wool does not occur. Fenbendazole can be administered as a drench or with the feed.     

磷酸三丁酯致鸡脊髓神经元凋亡的试验研究

为研究鸡有机磷中毒后对动物迟发性神经病(OPIDN)所起的作用及其动态病理改变.采用给鸡一次性肌肉内注射磷酸三丁酯染毒的方法建立疾病模型,以染毒后4、6、8、10、14、18 d为时间点分别取材,以HE染色、尼氏法和原位末端标记法(TUNEL)观察其第二腰椎(L2)的病理改变,神经元数量及细胞凋亡的变化.鸡于肌肉注射磷酸三丁酯第8 d前后出现进行性肌无力和共济失调等OPIDN的典型症状.HE染色染毒4 d后母鸡脊髓前角大神经元出现细胞核红色深染,至18 d消失;尼氏法染色显示鸡脊髓前角神经元数量呈进行性减少(从73土4个/mm2到60土6个/mm2);TUNEL法显示鸡腰脊髓TUNEL阳性细胞于染毒后6 d左右开始出现(18±2个/mm2),以8 d(24士3个/mm2)数量最多,19 d消失.在鸡OPIDN发病过程中出现腰髓前角神经元渐进性细胞凋亡.