The effect of thiaminase-induced subclinical thiamine deficiency on growth of weaner sheep

Three experiments were performed to examine for causes of poor growth of young Merino sheep. Weekly testing of animals 42 weeks of age for 10 weeks revealed that 90% of clinically poor animals were excreting high levels of thiaminase in their faeces; low levels of activity were present in 20% of clinically normal animals. There were significant differences in the mean erythrocyte transketolase activity of the thiaminase excreting poor animals and the thiaminase free normal animals. Other known causes of poor growth could not be demonstrated. Weekly monitoring of thiaminase activity in the faeces from 80 lambs 6 weeks of age showed 23% to be excreting significant levels of enzyme (>3mUg^–1 DM) throughtut a 10 week test period. Mean growth rates of these lambs were significantly below those of lambs not excreting thiaminase or excreting low levels intermittently. Supplementation of thiaminase excreting lambs with intra-muscular injections of thiamine HCl was associated with a statistically significant improved growth rate (P<0.01) compared to unsupplemented sheep excreting thiaminase. Mean growth rates of lambs not excreting thiaminase on a continuous basis (sampled weekly) were the same with or without thiamine HCl supplementation. High thiaminase levels were found in the ruminal fluids of trial animals excreting the enzyme in their faeces, confirming this previously established association.Bacillus thiaminolyticus was isolated from faeces and ruminal fluids from clinically poor animals and is the most likely source of the thiaminase. Subclinical thiamine deficiency was indicated by low erythrocyte transketolase activities and elevated TPP effects and is proposed as the cause of the poor growth by the young sheep.     

Oral treatment of polioencephalomalacia and subclinical thiamine deficiency with thiamine propyl disulphide and thiamine hydrochloride

Thiaminase type I production by Bacillus thiaminolyticus and activity in vitro were repressed by the primary substate thiamine and by thiamine monophosphate and thiamine propyl disulphide. At thiamine concentrations of 300-3000 mumol/l production of active enzyme by B. thiaminolyticus, and activity of purified enzyme, were totally repressed. Growth of B. thiaminolyticus was inhibited by thiamine propyl disulphide at 3000 mumol/l. Activity of purified thiaminase was lost when incubated with ruminal fluid from healthy thiaminase free sheep. Enzyme activity was also lost when exposed to mildly alkaline conditions but was stimulated and stabilized against heat denaturation if treated with dithiothreitol. Thiaminase activities in the ruminal fluids of cases of ovine polioencephalomalacia were repressed within 2 h of oral administration of thiamine propyl disulphide. Blood pyruvate levels and transketolase activities were restored to normal following treatment. Treated animals recovered clinically and were returned to pasture.     

Severe thiamine deficiency in sheep with acute ruminal lactic acidosis

BACKGROUND: Thiamine status of ruminants is adversely affected in acidic rumen conditions. However, there have been limited published case study data related to thiamine deficiency of ruminants with acute ruminal lactic acidosis (ARLA). HYPOTHESIS: Thiamine deficiency would occur in sheep with ARLA. ANIMALS: Thirteen Ak-Karaman (white Karaman) sheep with ARLA, aged 1 year (ARLA group) and 10 healthy Ak-Karaman sheep, aged 1 year (control group) were used. METHODS: After clinical examination, rumen fluid samples of all sheep were obtained with a stomach tube and examined immediately. Blood samples were taken from a jugular vein of the sheep. Erythrocytic transketolase enzyme activity and hence thiamine pyrophosphate (TPP) effect were determined according to Clausen's method. RESULTS: History revealed that all sheep in the ARLA group had accidentally consumed excessive amounts of cracked barley. During clinical examination of the ARLA group, disturbed general condition, engorged scleral vessels, moderate to severe dehydration, and ruminal atony were recorded in the sheep. The results of the ruminal fluid analyses of the ARLA group demonstrated characteristics of ARLA. The results of clinical and ruminal fluid examination of control group were normal. The mean TPP effect (%) in the ARLA group (109 +/- 28) was significantly higher than in the control group (22.2 +/- 3.7) (P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: The present study revealed that severe thiamine deficiency occurred in sheep with ARLA. This result indicates that thiamine administration to sheep suffering from acute ruminal acidosis caused by overconsumption of readily fermentable carbohydrates could be beneficial in alleviating thiamine deficiency caused by ruminal acidosis.     

A study of nutritional myopathy in weaner sheep

The effectiveness of various treatments upon, and pathological and biochemical changes in, ovine weaner nutritional myopathy were observed. Clinical myopathy was already apparent in the sheep at the start of the study, and they were fed decreasing amounts of a ration containing low levels of selenium and alpha-tocopherol, and periodically deprived of water. In spite of this management there was a spontaneous remission of the clinical myopathy in the sheep, but a subclinical myopathy was identified in some of the sheep at the end of the trail. The conclusions were that the myopathy was not caused by a low dietary intake of selenium and/or alpha-tocopherol alone, that alpha-tocopherol was involved in the aetiology, that alpha-tocopherol was completely effective and selenium possibly partially effective in treating it, and that the condition may be a Type II muscle fibre disease. Data on plasma creatine phosphokinase and erythrocyte glutathione peroxidase activities, and terminal liver selenium and alpha-tocopherol concentrations are presented, and their roles in the diagnosis of ovine weaner nutritional myopathy discussed.     

"宝肠安"对断奶仔猪生长性能的影响

在昆明天佑种猪场使用阿尔宝尔公司的“宝肠安”,用48头5周龄断奶的仔猪,于2003年1月15日至2004年1月15日作了效果对比试验,以验证“宝肠安”对断奶仔猪的促生长作用。试验结果表明:添加宝肠安的试验组可提高日增重13.13%,料肉比下降1.40%,下痢头次减少30.77%每公斤增重饲料成本下降了1.53%。说明宝肠安通过刺激仔猪肠道有益微生物的增生,抑制有害细菌的繁殖,提高了饲料转化率,改善了仔猪的健康状况。“宝肠安”对断奶仔猪生长性能的影响@鲍英慧$云南神农集团 @李晓珍$云南神农集团…     

The effect of footrot on body weight and wool growth of sheep

Body weight and traits associated with production of wool were measured over a 2-year period between 1985 and 1987 in south-western New South Wales in a flock of Merino wethers experimentally infected with footrot. The disease was allowed to spread freely amongst 150 of the flock but kept at very low prevalence in the remaining 50 by preventive footbathing during transmission periods. Severe, underrunning footrot had a significant adverse effect on body weight, for each year of the trial. Body weight was most severely reduced at times of the year when footrot was spreading among animals and lesions were severe. The mean body weight of the infected group at the end of the 2 years of observation was 7.3 kg (11.6%) below that of the control group. Footrot also depressed wool growth, with the mean clean fleece weight of the infected group being 0.4 kg (8%) lighter than that of the controls at each of the 2 annual shearings. There were no consistent differences between the groups for the other wool characteristics measured.     

The effect of Sarcocystis tenella on wool growth in sheep

A dose of 1 × 10⁴Sarcocystis tenella sporocysts produced significant depression of wool growth in lambs dosed at 1 month of age. No significant effect on wool growth was produced when lambs were dosed at 5 months of age.     

The prevalence of Eperythrozoon ovis infection in weaner and adult sheep in north eastern Victoria

A survey of weaner (6 to 12 months) and adult sheep for the presence of Eperythrozoon ovis antibodies using an immunofluorescent antibody assay was carried out. In 22 shires in north eastern Victoria over 2 years infection was demonstrated in 10% and 51% of weaner and adult sheep respectively.     

The effect feeding forage legumes as nitrogen supplement on growth performance of sheep

The effect of feeding forage legumes, Cowpea, Silverleaf desmodium and Oxley fine stem stylo, as protein supplements to natural pasture (veld) hay on intake, growth rate and nitrogen metabolism in growing lambs was evaluated. Thirty growing lambs were stratified according to body weight and randomly assigned, within a stratum, to five diets in a completely randomised design. The diets were veld hay alone (V), veld hay supplemented with either 10 g/kg of urea (VU), veld hay supplemented with 250 g/kg Cowpea (VC), 250 g/kg Silverleaf desmodium (VS) or 250 g/kg Oxley fine stem stylo (VF) forage legume hays. The V and the VU groups were used as control diets. Animals supplemented with either urea or the forage legume had higher (P < 0.01) total dry matter intake compared with the animals on V. The animals supplemented with the forage legumes had higher (P < 0.01) nitrogen intake and faecal nitrogen output than the non-supplemented group. All animals, across the treatments, lost body weight; lambs on V had higher (P < 0.01) body weight losses than those in the other treatments. The forage legume supplemented groups lost less (P < 0.01) body weight than those on the V and VU diets. Although supplementation with forage legumes enhanced feed intake and reduced weight losses it did not maintain body weights of lambs fed a basal diet of poor quality roughages.     

The effect of large doses of thiamine on the horse

Extract

In conjunction with a trial to determine the effect of nematode infestation upon the liveweight gain and wool production of young sheep (Brunsdon, unpublished), information was sought on the seasonal succession and availability on pasture of infective larvae of the principal trichostrongyle genera parasitic in sheep. Data were collected in the form of nematode populations found at postmortem examination of Romney lambs, previously maintained worm-free, which were exposed to risk of parasitism in the field. A series of these lambs ran with the flock in the above-mentioned trial and served as indicators of the abundance of infective larvae on the pasture.     

The effect of experimentally induced subclinical mastitis on milk yield of ewes and on the growth of lambs

In each of two experiments, subclinical mastitis was induced by inoculating both mammary glands of Welsh-Mountain and Dorset-Horn ewes with a coagulase-negative staphylococcus; groups of control ewes were also included. After inoculation, the somatic cell counts of milk of the inoculated ewes increased (P less than 0.01) and the milk yield decreased (P less than 0.01). The lambs of the inoculated ewes had a poorer growth than lambs of the control ewes (P less than 0.01).     

The effect of selenium deficiency on the feed consumption and growth of goats

The feed consumption of goats was only reduced after considerable Se depletion. The conversion of Se-depleted animals to an Se-rich ration increased feed consumption within one day. An intrauterine Se deficiency (less than 38 micrograms Se/kg DM of the ration) did not induce intrauterine growth depression in kids. Se depletion led to a highly significant postnatal growth depression which increased with advancing Se depletion both during the lactation period and after weaning.     

Experimental infection of weaner sheep with S strain Mycobacterium avium subsp. paratuberculosis

We sought to determine whether infection of recently weaned 12-16-week-old Merino lambs with an Australian S strain M. a. paratuberculosis, at doses consistent with natural exposure, could be detected in the first few months post-inoculation. Such detection would facilitate the use of weaner sheep as sentinel animals for the presence of infectious doses of M. a. paratuberculosis on pastures. In controlled pen trials, oral doses of approximately 10(7)-10(8) viable organisms were demonstrated to be infective, whereas doses below 10(4) organisms failed to produce detectable infection. Mycobacterium avium subsp. paratuberculosis (M. a. paratuberculosis) was isolated from intestinal and/or lymphoid tissues collected at necropsy 7 or 14 weeks after first infection, but there were no associated gross or microscopic lesions. Skin testing with intradermal Johnin detected all three infected lambs at 13 weeks post-infection, and one of the three infected lambs at 6 weeks post-infection, with 100% specificity. Results for whole blood IFN-gamma assay showed some correlation with infection status but lacked specificity. One infected lamb gave a positive result in an ELISA for antibodies to M. a. paratuberculosis, 14 weeks post-infection and 1 week after skin testing. This was the first demonstration of experimental infection with S strain M. a. paratuberculosis in Australian Merino sheep at doses likely to be representative of natural infection. Culture from tissues in the first few months post-exposure could facilitate the use of naive weaner sheep as tracer animals to detect heavy contamination of pastures with M. a. paratuberculosis, but low-level contamination may not be detected in such a system.     

自配复合酸对断奶仔猪生产性能和腹泻的影响

试验选用40窝214头7日龄,23日龄断奶、体重相近的仔猪(长×大)。分别添加不同剂量的复合酸化剂于日粮中,测定日粮的系酸力水平对断奶仔猪的影响。试验采用完全分组化设计,分成5个组,每组两个重复。饲养期28 d(含预饲期)。处理Ⅰ为空白对照,处理Ⅱ至Ⅴ为试验组,结果表明:随着饲料中复合酸化剂用量(0~6 g/kg饲料)的增加和饲料系酸力的降低(30~15),仔猪的腹泻率降低,采食量,日增重和料重比均有不同程度的改善。当用量过高(>4.5 g/kg饲料)时仔猪的采食量急剧上升而其生产性能则下降;还表明在饲料中添加3.0~4.5 g/kg(系酸力为23.0~19.5)时,仔猪的综合生产性能表现最佳。     

Comparison of three methods of thiamine supplementation by measurement of urinary thiamine excretion in sheep

The relative efficacy of thiamine supplementation to sheep by injection, subcutaneous implant and orally administered protected thiamine bolus was compared in two experiments using a grass and hay ration and a ration containing bracken rhizomes to induce thiamine deficiency. In both experiments, urinary excretion of thiamine was significantly higher in supplemented sheep than in the controls, and in sheep supplemented by injection than in sheep supplemented by implant or protected boluses. Thiamine excretion was lower in sheep fed the ration containing bracken rhizomes than in sheep fed the grass ration.     

硫胺素的生理作用及导致其缺乏的主要因素

本文主要就硫胺素的生理作用、吸收机制及导致其缺乏的主要因素作一综述。     

The effect of selenium supplementation on immunity, and the establishment of an experimental Haemonchus contortus infection, in weaner Merino sheep fed a low selenium diet

SUMMARY: Immunity in 12 weaner Merino sheep fed a low selenium (Se) diet (low Se sheep) was compared with that in 10 matching sheep fed the same diet but each given an intraruminal Se pellet (high Se sheep), while the sheep were housed in individual, sheltered pens. All sheep were challenged with killed Brucella abortus cells (days 0 and 28), rabbit red blood cells (days 0, 7 and 28) and corynebaclerium pseudotuberculosis toxoid (days 0 and 28), and serum antibody titres were measured weekly for 8 weeks from day 0. The sheep were then experimentally infected with Haemonchus conforfus, and slaughtered 8 weeks later. The mean antibody titre to B. abortus, measured by 4 different tests, was significantly higher in the high Se sheep on occasions during the primary immune response phase (Rose Bengal test - day 21 (p < 0.05), day 28 (p < 0.025); complement fixation - day 7 (p < 0.05); enzyme-llnked immunosorbent assay - day 14 (p < 0.01); serum agglutination - no differences), but not during the secondary phase. The mean antibody titre to rabbit red blood cells, measured by haemagglutination test, was marginally higher in the high Se sheep on day 49 (p = 0.049). The mean antibody titre to C. pseudotuberculois, measured by enzyme-linked immunosorbent assay, was not significantly different between the groups at any time during the trial. In addition, the mean invitro responsiveness of peripheral blood lymphocytes to stimulation with phytohaemagglutinin in the high Se sheep was significantly greater than that in 10 sheep from the low Se group on day 22 (p < 0.01), but not day 50. However, there were no significant differences in the mean number of sheep in which the infection with H. contortus established, time to first shedding of eggs in faeces, abomasal worm burdens at necropsy, or inflammatory response in the abomasal mucosa in the sheep in each group. The results showed that the low Se sheep produced strong overall immune responses that were largely comparable to those in the high Se sheep.