THE EFFECT OF MIXED GRAZING OF SHEEP AND CATTLE ON WORM BURDENS IN LAMBS

Lambs from ewes grazed without cattle at 4.9, 7.4 and 9.9 ewes and lambs per hectare and from ewes run with steers at an equivalent median stocking rate at four ratios in which sheep comprised 30%, 40%, 50% and 70% of the animal equivalents were killed and examined for worms. When sheep grazed alone, there was no significant increase in the number of worm species normally found in sheep, namely Ostertagia circumcincta and Nematodirus spathiger, with an increase in stocking rate. When sheep grazed with cattle, there was a decrease in the number of worm species normally found in sheep but an increase in the number of those normally found in cattle, namely Cooperia oncophora and Trichostrongylus axei, as the proportion of cattle in the ratio increased. The total worm burdens were low due to the management of the flock and parasites were not shown to have affected productivity. The results are discussed and the practical aspects of the findings are presented.     

奶牛胎儿的父亲对母亲产奶量的影响

用中国黑白花奶牛研究了胎儿的父亲及犊牛初生重对母亲当胎及下一个泌乳期产奶量的影响,结果指出胎儿的父亲对母亲当胎及下一个泌乳期90天和305天的产奶量,都有极显著的影响,各占产奶总变异量的9.4％,15.3％及3.77％(P<0.01)。犊牛初生重对母亲产奶量的影响也显著(P<0.05)。当根据公牛的产奶预期差(PDM)将胎儿的父亲分为两组后,发现差异显著(P<0.05),胎儿父亲的PDM高,胎儿母亲的产奶量也高,因此胎儿母亲产奶量不仅受胎儿重量的影响,也受父亲PDM的影响。     

牛肝胆超声断层扫描的研究

利用Ｐｉｅ Ｄａｔａ ＳＣ－４００型超声扫描仪,对１２头临床健康牛进行肝胆超声断层扫描的反复实验。结果：牛肝脏可在右侧第８～１２肋间显示,呈均匀的弱回声影像,肝下缘切面轮廓为锐角的楔状图像,肝壁面及脏面整齐、清晰：门静脉和肝静脉能在多数牛的第１０～１２肋间显示,并可根据其管壁回声强弱等加以分辨;胆囊多在右侧第１１或１０肋间探到,为边缘光滑整齐、轮廓清晰的类三角形或椭圆形无回声液性暗区。并测定了试验     

人工培植牛黄对牛血清AKP,r—GT及Ch的影响

本文采用化学方法分别测定了人工植黄牛血清中AKP和r-GT的活性及Ch的含量。实验结果表明,植黄牛血清中AKP的活性比未植黄牛血清中AKP的活性有所升高(P<0.05),而血清中r-GT的活性和Ch的含量在两组牛之间未存在明显差别(P>0.05)。植黄牛与未植黄牛血清中三项指标分别为:AKP 13.16±4.99与8.68±2.13金氏单位:r-CT 37.44±7.70与35.78±6.71活力单位/dl;Ch 171.70±27.10与158.79±19.04mg/dl。     

BRUISING IN CATTLE FASTED PRIOR TO TRANSPORT FOR SLAUGHTER

Three trials, each with 100 bullocks previously grazing improved pasture, compared bruising in cattle fasted for 0, 24 and 48 hours prior to transport for slaughter. Overall the weight of bruised trim from unfasted bullocks (0.48 kg) was significantly less (P less than 0.01) than from bullocks fasted for 24 h (0.99 kg) or 48 h (1.03 kg). length of fast overall had no significant effect. This pattern was not consistent within trials.     

THE EFFECT OF AGE ON RESISTANCE OF CATTLE TO BABESIA BOVIS

SUMMARY Susceptible Hereford cattle of different ages were inoculated with 2 times 10⁸Babesia bovis organisms. Experiment 1 consisted of cows aged 6 to 7 years, steers aged 17 to 18 months and calves aged 5 to 6 months, while experiment 2 consisted of cows aged 6.5 to 7.5 years, steers aged 23 to 24 months and yearlings aged 11 to 12 months. Daily measurements of temperature, parasitsemia and packed cell volume were made in order to determine susceptibility of the different ages. Twenty-four of the 36 animals in experiment 1, which included all 12 cows, required treatment. One cow died as a result of an enlarged ruptured spleen, and 2 steers and 1 calf died with classical babesiosis symptoms. No treatment was given to experiment 11 animals, and 5 of the 12 cows died, but the steers and yearlings underwent relatively mild reactions. Statistical analysis confirmed the high susceptibility to B. bovis of the aged cows in both experiments, and the innate resistance of 5 to 6 month old calves in experiment 1. The reaction of the 18-month-old steers in experiment 1 was significantly greater than that of the calves, but significantly less severe than that of the aged cows. Two-year-old steers and yearlings in experiment 2 underwent similar mild reactions, suggesting that innate immunity may persist for longer periods when compared to aged cows. Age groups showing reduced susceptibility were found to reach peak parasitaemia, temperature and anaemia before the more susceptible age groups. Heterologous challenge of the remaining experiment 1 and experiment 2 animals at 6 and 8 months respectively after primary inoculation, revealed all animals of all ages had a solid resistance to B. bovis.     

THE EFFECT OF CATTLE TICK (BOOPHILUS MICROPLUS) ON PREGNANT AND LACTATING BRAHMAN-CROSS AND BRITISH-BREED COWS IN NORTHERN AUSTRALIA

Natural infestations of cattle tick (Boaphilus microplus) on breeding Hereford, Shorthorn and Brahman-cross cows were observed in a dry tropical environment. Herefords were dipped three times and Shorthorns four times during a 12 month period, while the Brahman-cross cattle were dipped twice during a 3-year period. No differences in tick infestations could be shown between pregnant and non-pregnant or lactating and non-lactating cows even though they were under severe nutritional stress. No consistent negative correlations were shown between body- weight changes and tick counts. This was probably due to the effect of dipping in the Herefords and Shorthorns. There was a trend towards significant negative correlations in July and August over each of three years for undipped Brahman-cross cows. Some form of tick control on breeding Brahman-cross cows, aimed at reducing tick burdens during July to September may be beneficial in the environment under study.     

新型饲料添加剂对稻草对牛瘤胃降解特性影响的研究

以3头装有瘤胃瘘管的湖北本地黄牛为实验动物 ,研究了在以稻草为主的日粮条件下 ,补喂SL添加剂和B(SL)舔块对稻草干物质(DM)和中性洗涤纤维(NDF)瘤胃降解率的影响 ,同时测定了瘤胃液的 pH和氨氮浓度。结果表明 :添加SL后 ,加快了稻草的消化速度 ;饲喂B(SL)后 ,显著加快了稻草的消化速度(P<0.01) ,明显提高了稻草DM和NDF降解率(P<0.05) ;添加SL或B(SL)舔块后 ,瘤胃液pH有下降趋势 ,但差异不显著 ;2种舔加剂均显著降低采食4h内的瘤胃液氨氮浓度(P<0.01) ,并使氨氮浓度曲线趋于平缓 ,说明有效提高了瘤胃微生物对降解氮的转化能力。