The ability of biochemical and haematological tests to predict recovery in periparturient recumbent cows

Blood samples from 433 periparturient recumbent cows submitted by veterinary practitioners to Ruakura Animal Health Laboratory during 1983 and 1984 were analysed and results related to whether cows recovered, died or were euthanased. Generally cows were sampled only once and the time varied from 15 minutes to 20 days after becoming recumbent. During 1983 serum calcium, magnesium, phosphorus, creatine phosphokinase (CK), aspartate amino transferase (AST), glutamate dehydrogenase (GDH), gamma glutamyl transferase (GGT) were analysed. In 1984 serum urea, creatinine, fibrinogen and haematological examination (haemoglobin, haematocrit, total and differential white cell counts) were added to the panel. Overall 39% of cows recovered, 30% died and 32% were destroyed. Precalving cows had 111% more deaths and 7% less survivors than postcalving recumbent cows (P<0.1). There was little difference (3%) in euthanasia prevalence. Tests that were most useful in predicting a lack of recovery were serum urea and muscle enzymes. Using these tests and duration of recumbency when sampled a model was produced to predict the probability of recovery from 254 cases.     

Relative efficacy of organophosphorus insecticides against susceptible and resistant strains of the strike blowfly Lucilia cuprina (Calliphoridae) in New Zealand sheep

Four groups of five Romney lambs were treated by plunge dipping with one of four registered organophosphorus flystrike preventatives. Untreated lambs acted as controls. The sheep were challenged at weekly intervals with larval implants of organophosphate-susceptible and -resistant strains of Lucilia cuprina. All four treatments provided 19-21 weeks protection against susceptible larvae but chlorfenvinphos provided the longest protection (16-17 weeks), followed by propetamphos (15-16 weeks), dichlofenthion (10-13 weeks) and diazinon (9-13 weeks), against the resistant strain.     

Polioencephalomalacia in cattle consuming water with elevated sodium sulfate levels: A herd investigation

Polioencephalomalacia (PEM), hereafter used to refer to the specific lesion of cerebrocortical necrosis, developed in 11 of 110 mature cattle on pasture in central Saskatchewan. The primary water source contained a markedly elevated level of sodium sulfate (7200 ppm). The significant clinical findings of the herd investigation included depression, ataxia, cortical blindness, dysphagia, and death. Diagnosis of PEM was confirmed by histopathological evidence of cerebrocortical and subcortical necrosis with microvascular fibrinoid necrosis predominantly in the thalamic region of three affected cattle. The histopathology of sulfate-associated PEM observed in this herd appears to be unique and its features are presented and discussed. Mean levels for serum transketolase, copper, red blood cell transketolase activity, and thiamine (vitamin B₁) in all exposed young (n = 100) and mature (n = 99) animals did not reveal evidence of deficiencies. Although the blood thiamine status of the seven surviving, affected animals was not evaluated before treatment with exogenous thiamine, 199 members of the herd had blood thiamine levels within the reference range at the time of the outbreak. The outbreak resolved after cattle were moved to a water source containing acceptable levels of sodium sulfate.     

Parasites of Chamois in New Zealand

Abstract Sir, - Andrews'((2)) checklist of helminth parasites of wild ruminants in New Zealand recorded the presence of 10 species of gastrointestinal nematodes in chamois (Rupicapra rupicapra rupicapra L.) from "Central South Island". In October 1978 we examined 28 freshly-shot chamois cadavers from the Harper-Avoca watershed in the headwaters of the Rakaia River. Six of the nematode species reported by Andrews were found again; viz. Ostertagia ostertagi, O. circumcincta, O. trifurcata, Nematodirus filicollis, Oesophagostomum venulosum and Trichuris ovis. The 4 species found by Andrews that were not recovered by us from the animals we examined were: Trichostrongylus axei, T. vitrinus, Spiculotragia spiculoptera and S. asymmetrica. On the other hand we found 4 helminths not encountered by Andrews: 3 nematodes: Nematodirus spathiger (Railliet, 1896), N. abnormalis (May, 1920), and Chabertia ovina (Fabricius, 1794), and 7 specimens of the cestode Moniezia expansa (Rud., 1805). Nematodirus spathiger was the most commonly encountered Nematodirus species, but generally the numbers of all 3 species encountered were low as might be expected in a sample of adult and almost year-old animals. It is probable that most of the adults had acquired some measure of immunity((3)), and the most susceptible group, the kids, would not be born until late November. Because peptic digestion was not used to recover juveniles from the intestinal submucosa, only small numbers of adults were obtained.     

不同声音对草鱼幼鱼负趋音性行为反应影响研究

声驱鱼技术作为辅助过鱼措施之一,承担着保证鱼类洄游顺利通过过鱼设施,继而保护鱼类资源和恢复河流连通性的重要作用。本研究采用交替播音的形式,以草鱼(Ctenopharyngodon idellus)幼鱼为研究对象进行负趋音性实验,旨在探究草鱼幼鱼面对不同声音的行为反应。实验水槽(3.6 m×1.1 m×1.0 m)布置于下牢溪周围水域,平均水深为0.5 m,平均流速为0.06 m/s。实验使用1种单频音(1 000 Hz)和5种复杂音(鱼游动声、引擎声、短吻鳄叫声、打桩声和游艇声),声压级(sound pressure level)为(117.69±2.77) dB re 1 μPa,对照组为未播放声音时草鱼的行为反应数据。结果显示,播放复杂音时,草鱼的反应次数、趋音速度、运动时间比均显著高于单频音和对照组(P<0.001),草鱼的初次反应时间、平均反应时间均显著低于单频音和对照组(P<0.001);复杂音中,受到游艇声刺激的草鱼反应次数和趋音速度最大,受到鱼游动声刺激的草鱼反应次数、趋音速度最小;复杂音中,受到游艇声刺激的草鱼初次反应时间最短,为(23.40±5.13) s;受到引擎声刺激的草鱼初次反应时间最长,为(146.00±7.82) s,显著低于其他复杂音(P<0.05);受到游艇声和打桩声刺激的草鱼平均反应时间最短,分别为(26.52±3.01) s和(28.76±4.07) s;受到鱼游动声刺激的草鱼平均反应时间最长,为(64.76±17.82) s;复杂音中,受到鱼游动声刺激的草鱼运动时间比最高,为(98.47±0.48)%;受到引擎声刺激的草鱼运动时间比最低,为(94.58±0.54)%;播放单频音时,草鱼的反应次数、初次反应时间、平均反应时间、运动时间比均与对照组无显著差异(P>0.05)。本研究表明,5种复杂音(鱼游动声、引擎声、短吻鳄叫声、打桩声和游艇声)对草鱼幼鱼具有驱赶效果。本研究在丰富鱼类负趋音性研究的同时,为实际工程中声驱鱼辅助过鱼设施的设计和优化提供了科学依据。