Inhibition of alpha-glucosidase in cattle by Castanospermum australe: an attempted phenocopy of Pompe''s disease

Pompe's disease is characterised by an absence of lysosomal alpha-glucosidase, but this enzyme is also inhibited by Castanospermum australe seeds. Four calves were fed C. australe seeds at the rate of 0.15 g/kg body weight for periods from 1 to 4 days. Lymphocyte alpha-glucosidase activity was reduced by at least 90%, with the majority of inhibition occurring within 8 h of dosing. Several weeks elapsed before activity returned to normal. Significant inhibition of muscle alpha-glucosidase occurred and the ratio of plasma alpha-glucosidase activity measured at pH 5.6 relative to that at pH 3.7 was depressed. In an attempt to induce Pompe's disease, 2 calves were dosed with 1.2 g C. australe seed/kg body weight/day for 13 months. Lymphocyte and muscle alpha-glucosidase activities were markedly reduced over the entire period of feeding, but the animals showed no clinical signs of disease. Tissue cells were not vacuolated nor did they show any apparent accumulation of glycogen. Despite significant inhibition of alpha-glucosidase in skeletal and cardiac muscle, liver, kidney and brain, it is suggested that there was sufficient residual enzyme to prevent induction of a phenocopy of Pompe's disease.     

Prickly paddy melon (Cucumis myriocarpus) poisoning of cattle

Twenty-six Hereford heifers died after eating mostly ripe fruit of Cucumis myriocarpus growing in a fallowed cultivation paddock. Four affected cattle were dehydrated and apparently had abdominal pain. Necropsy of three revealed intense congestion with haemorrhage of the alimentary tract, numerous C. myriocarpus seeds in ruminal contents, pulmonary congestion and oedema and, in two, swollen livers. Midzonal swelling and vacuolation of hepatocytes occurred in these two. C. myriocarpus fruit (83% by weight ripe) were dosed to two calves at 60 g wet weight/kg live weight. Both collapsed with tachycardia and dyspnoea and died within 6 h. Their packed cell volumes just before death had increased to 0.7. They had hydropic degeneration and necrosis of the ruminal mucosa, intense congestion and oedema of the rumen, abomasum and intestines, swollen and vacuolated hepatocytes and foci of myocardial degeneration and necrosis. Two other calves were dosed daily with 20 g fruit/kg for three days, then 40 g/kg for three days. One calf received a further 40 g/kg next day. Both calves developed persistent diarrhoea and neutrophilia, and their plasma gamma glutamyltransferase and bilirubin concentrations increased. Necropsy revealed necrosis and oedema of the rumen and swollen degenerate hepatocytes.     

Effects of intermittent and continuous administration of decoquinate on bovine coccidiosis in male calves

Male Holstein calves were each inoculated with 350,000 sporulated oocysts of Eimeria bovis. Two calves were given decoquinate (0.5 mg/kg of body weight) continuously in dry feed for 29 days, and 2 calves each were given 0.5, 1, or 1.5 mg of decoquinate/kg on an every 2nd-or 3rd-day schedule for 29 days. Calves given decoquinate continuously did not discharge oocysts but had slightly loose feces. In general, the number of oocysts discharged increased and fecal consistency decreased as the time between feeding of medicated feed increased. Calves given 0.5 or 1.5 mg of decoquinate/kg every 3rd day discharged more oocysts and had more diarrhea than did calves given 1 mg of decoquinate/kg every 3rd day. At postinoculation day 29, calves were euthanatized. At necropsy, intestinal tissues of calves given decoquinate were mostly normal. Apparently, reduced infections along with the elapsed time were sufficient to resolve most intestinal lesions caused by the coccidia. Decoquinate was most effective when fed continuously at 0.5 mg/kg. However, when fed at 1 or 1.5 mg of decoquinate/kg every 2nd day or 1.5 mg of decoquinate/kg every 3rd day, oocyst production was reduced and clinical coccidiosis was prevented.     

Prophylactic efficacy of an ivermectin sustained-release bolus against challenge exposure with gastrointestinal and pulmonary nematode infective larvae in calves

Twelve Holstein calves were used to determine the prophylactic efficacy of ivermectin against challenge exposure with gastrointestinal and pulmonary nematodes. Two groups of 6 calves (mean body weight, 205 kg) each were formed by restricted randomization according to body weight. Group-1 calves served as nonmedicated controls. Each calf of group 2 was orally given one prototype sustained-release bolus designed to deliver ivermectin at a continuous daily dose of 8 mg. Third-stage nematode infective larvae were given to the calves on posttreatment days 28 and 42. The calves were euthanatized 77 or 78 days after treatment. Ivermectin was 100% effective (P less than 0.05) in preventing the establishment of infection by Haemonchus placei, Ostertagia ostertagi, Cooperia spp (C punctata, C oncophora, C surnabada), Nematodirus helvetianus, Oesophagostomum radiatum, and Dictyocaulus viviparus and was greater than 99% effective against Trichostrongylus axei. Incidental infection by Trichuris spp was reduced by 94% (P = 0.08).     

Productivity of Crossbred Dairy Cows Suckling their Calves for 12 or 24 Weeks Post Calving

An experiment on restricted suckling of crossbred dairy cows was conducted at the Livestock Research Centre, Tanga in northeast Tanzania. Thirty-six Bos taurus (Holstein Friesian and Jersey) x Bos indicus (East African Zebu) cows were allocated alternately as they calved to suckling their calves for either 12 or 24 weeks after calving. Cows grazed improved pastures and were offered 4 kg concentrate daily. Milking occurred twice daily by hand; calves were allowed to suck residual milk for 30 min following each milking. Calves were also allowed access to grazing and were offered a maximum of 1 kg concentrate daily to 24 weeks of age. Weaning age had no significant effect on lactation milk yield for human consumption, the mean (SE) yield being 1806 (102.0) L and 1705 (129.1) L for 12- and 24-week weaning, respectively. Cows from the two treatments suffered similar losses of live weight and body condition score during lactation and neither group had returned to the original body condition score 40 weeks following calving. Post-partum anoestrous intervals were prolonged. Although not significant, cows suckling calves to 24 weeks had a mean interval to first oestrus extended by 38 days compared with cows suckling calves to 12 weeks. The mean (SE) daily live weight gains of the calves to 52 weeks were 263 (14.1) g/day and 230 (18.1) g/day for calves weaned at 12 and 24 weeks, respectively, such that 12-month weights were 119 (5.6) kg and 110 (7.3) kg, respectively. Twelve-week-weaned calves consumed more concentrate (p<0.05) from 13 to 24 weeks than did 24-week weaned calves. Calculation of residual milk consumption removed by calves from birth to 12 weeks indicated that it accounted for 28%) of total yield. No benefits in cow and calf performance and welfare were found to justify prolonging the suckling period to 24 weeks.     

The effect of parenteral iron supply on hematology, health, growth and meat classification in veal calves.

Twenty veal calves were fed milk substitute containing 19 mg Fe/kg; ten calves were supplemented with iron in accordance with their requirements and the other 10 were unsupplemented controls. Serum iron (SI), hemoglobin (Hb) and packed cell volume (PCV) were determined at the start of the experiment and then every third week. From 3 weeks after the start to the end of the experiment there were significant differences between SI mean values between treated and untreated calves. In the treated group the Hb mean values were unchanged during the experiment while the untreated group had a significant decrease. The mean PCV values were also decreased. The daily gain was 1.36 g higher per calf in the treated group. The feed consumption per kg gain was 18 g lower and the carcass weight was 4.2 kg higher per calf in the treated group. The points for color and structure of carcass were 2.5 units higher per calf in the untreated group. The incidence of enteritis was less in the treated calves than in the untreated ones.     

Bovine Viral Diarrhea Virus and Escherichia Coli in Neonatal Calf Enteritis

This study was initiated to determine the etiologic and pathogenic significance of an American strain of bovine viral diarrhea (BVD) virus (strain NADL-MD) in enteritis of neonatal calves (calf scours).

Three colostrum-fed calves from dams exposed intravenously to BVD virus at 6, 16 and 25 days prepartum, respectively, had moderate diarrhea persisting until the eighth day of life. The BVD virus was isolated from all 3 calves and persisted up to 93 days in 1 calf, indicating either that BVD was transmitted in utero or via the dam's milk.

Three specific pathogen free (SPF) calves permitted dams' colostrum for the first 4 feedings and then given milk replacer were exposed orally on the day of birth to BVD virus. One calf died of neonatal enteritis 28 hours post-exposure and at necropsy the BVD virus was isolated from several of its organs. The remaining 2 calves had a mild diarrhea persisting to the eighth day of age.

Two calves permitted dams' colostrum ad lib. for 72 hours, and then weaned, were exposed orally to BVD virus. Both calves had a mild persistent diarrhea and BVD virus was isolated from their blood for 56 days post-exposure.

Of 13 SPF, colostrum-deprived calves exposed orally or intranasally at birth to the BVD virus, 4 had severe diarrhea and died of neonatal enteritis from 38 hours to 13 days postexposure. Isolations of BVD virus were made from several of the organs of the calves at necropsy. All of the 9 surviving calves had a moderate to severe diarrhea frequently persisting for 7 to 10 days, and BVD virus was isolated from the survivors up to 103 days postexposure.

Several strains of Escherichia coli were isolated from calves after the second day of life, but were neither pathogenic for mice, nor serologically related to strains of E. coli usually associated with outbreaks of calf scours. Four colostrum-deprived SPF calves were exposed orally at birth to a strain of E. coli isolated from the intestine of the calf with the most acute symptoms and fatal neonatal enteritis. None of the four calves receiving the E. coli had diarrhea. One calf, however, had respiratory distress and died on day 5.

Two SPF colostrum-deprived control calves had neither diarrhea nor respiratory distress.

The above findings support the conclusion that BVD virus should not be overlooked as a primary cause of the neonatal calf enteritis complex.

     

犊牛代乳粉对早期断奶犊牛生长发育的影响

选用出生后吃完初乳的荷斯坦母犊24头分为试验组和对照组,对照组饲喂鲜牛奶6kg/d/头,试验组饲喂代乳粉800g/d/头。结果表明:经过60d的饲喂试验,试验组比对照组多增重5.31kg(P<0.01),试验组犊牛日增重比对照组提高了88.5g(P<0.01),试验组犊牛的体高和胸围的增长速度均高于对照组。从经济效益来看,进食代乳粉组犊牛比对照组节省成本263.42元/头(鲜奶价格按2元/kg计算)。     

Growth, weaning performance and blood indicators of humoral immunity in Holstein calves fed supplemental flavonoids

The primary objective was to test the hypothesis that flavonoids mediate immune response and affect calf performance. Twenty Holstein calves [7 ± 2 days age; 41.4 ± 0.7 kg body weight (BW)] were randomly assigned to four treatments of (i) no; (ii) low (7.3 × 10⁻⁵ g/kg BW); (iii) medium (7.3 × 10⁻⁴ g/kg BW); and (iv) high (3.6 × 10⁻³ g/kg BW) doses of flavonoids intake in a completely randomized design. Calves received the treatments as a tablet until weaning or a daily intake of 680 g starter. After weaning, calves received no supplemental flavonoids and monitored until 120 days of age. The flavonoids were extracted from propolis. Treatments did not affect body length, wither height and the severity of scours. At week 5 of age, BW was higher when calves fed the high compared to the low dose of flavonoids. At week 6, calves fed the high dose of flavonoids had higher BW than those fed no or low doses of flavonoids. The serum immunoglobulin G (IgG) concentrations remained lower at the first 3 weeks of the experiment when calves received the low but not the high doses of flavonoids. At week 4, both medium and low doses of flavonoids moderated serum IgG. At week 8, the medium and high but not the low doses of flavonoids lowered serum IgG. At week 6, calves fed high and medium flavonoids doses had lower blood immunoglobulin M (IgM) than control calves. Results suggest that flavonoids affect the humoral immune response and can improve growth in young calves. This response depended on calf age. Future studies are needed to further evaluate the premise that dietary forages or the main source of flavonoids are helpful for a less stressful weaning in the modern calf raising.     

Anthelmintic efficacy of albendazole against adult Dictyocaulus viviparus in experimentally infected calves.

Anthelmintic activity of albendazole against adult Dictyocaulus viviparus was evaluated in a controlled experiment. Calves were raised nematode-free to approximately 8 weeks of age and were each given 4,000 infective 3rd-stage larvae. Twenty calves with patent parasitisms were allotted to 2 groups of 10 calves each. Calves in group 1 were used as nonmedicated controls, and calves in group 2 were given albendazole in paste formulation at the dosage concentration of 7.5 mg/kg of body weight on the 30th day after administration of infective larvae. At necropsy, nonmedicated control calves had a total of 308 adult D viviparus, whereas the albendazole-treated calves had 11, for an average efficacy of 96.4%. These reductions were statistically highly significant (P less than 0.01). At necropsy, none of the treated calves was passing 1st-stage C viviparus larvae in their feces, whereas control calves were passing an average of 46 larvae/10 g of feces.     

Evaluation of the morantel sustained release bolus in cows and calves

The efficacy of the morantel sustained release bolus (MSRB) in controlling gastrointestinal parasitism in beef cattle was assessed during the 1982 spring-autumn grazing season. Forty-eight cows and their calves were allotted to three equal groups. One group (T-1) served as a nonmedicated control group. One MSRB was administered to each calf of the T-2 group, and to each cow and calf of the T-3 group at the beginning of the study. The efficacy of the bolus was assessed by comparison of weight gain performance and parasitological data (fecal worm egg counts, herbage larval counts, worm counts from tracer and principal trial calves, and plasma pepsinogen level determinations). Though not statistically significant, treated calves from Group T-2 had a numerical mean weight gain advantage of 2.6 kg, and those from Group T-3 of 4.7 kg, over control calves. Average daily gains (ADG) for the three groups of calves were 0.69, 0.72, and 0.73 kg, respectively. Untreated cows from Group T-2 and treated cows from Group T-3 outperformed the control cows by 12.3 and 7.5 kg, respectively. Fecal worm egg counts from both groups of treated calves were significantly (P less than 0.01) lower than counts from control calves during the entire 169-day trial; notably, egg counts were reduced by 99% 28 days after MSRB administration to both groups of calves. There were no significant differences in the number of eggs counted from the three groups of cows, probably because of the very low numbers of eggs encountered. Mean total worm burdens of principal calves (six per group) necropsied at trial termination indicated a 91% (P less than 0.01) reduction in Group T-2 and an 87% reduction (P less than 0.01) in Group T-3. Worm-free tracer calves were introduced onto pastures every 28 days to monitor availability of infective larvae. The mean number of worms recovered at necropsy from tracer calves that grazed with control cattle increased as the season progressed. However, the numbers of parasites recovered each month from mid-August through mid-October from tracers that grazed pastures with treated cattle were lower (P less than 0.05) than those levels displayed at trial initiation. In addition, the mean numbers of worms from treated group tracers were lower than from the controls for each necropsy period.(ABSTRACT TRUNCATED AT 400 WORDS)     

Inhibition of bovine α-glucosidase by Castanospermum australe and its effect on the biochemical identification of heterozygotes for generalised glycogenosis type II (Pompe''s disease) in cattle

All 18 2-year-old Brahman bulls grazing in a paddock containing Castanospermum australe trees were diagnosed as heterozygotes for Pompe's disease by measurement of mononuclear cell alpha-glucosidase activity. However, removal of the bulls to a paddock free of C. australe and retesting 2 months later indicated that 15 were homozygous normal. An in vitro assay demonstrated that a crude aqueous extract of seeds from these C. australe trees contained a potent inhibitor of mononuclear cell alpha-glucosidase. Two Hereford steers were dosed with 0.6 g C. australe seed/kg bodyweight for 6 days. The alpha-glucosidase activity in blood mononuclear cells declined to 5% of normal within 48 h of commencement of dosing. It was therefore assumed that the bulls had consumed C. australe seeds. A means of differentiating true heterozygotes from animals consuming the toxic seed, using the ratio of plasma alpha-glucosidase activity at pH 5.6 to that at pH 3.7, is proposed.     

Control of bovine coccidiosis with monensin: in nonresistant newborn calves

Newborn Holstein male calves were purchased within 3 days after birth and were removed from the local farms to the Dixon Springs Agricultural Research Center. They were hand-fed for 7 weeks and then weaned to a prepared feed. Eight groups, each of 4 calves, were housed in separate pens. In each of 4 pens (pens 2 to 5), 1 calf was inoculated with sporulated oocysts of Eimeria bovis (and was not medicated); 1 calf was inoculated and given feed with added monensin at the dosage level of 10 g/906 kg of feed; and 2 calves were inoculated and given medicated feed with added monensin at the dosage level of 20 g/906 kg or 30 g/906 kg. In the 4 other pens (6 to 9), the calves were inoculated with E zuernii and otherwise were given feed without or with added monensin as in pens 2 through 5. Another group of 5 calves (all kept in 1 pen), served as noninoculated, nonmedicated controls. At 14 days after inoculations with E bovis, the single calves in each of the 4 pens that were given the nonmedicated feed began to show clinical signs of coccidiosis and discharged increasing numbers of oocysts. The other inoculated calves (given monensin) had fewer clinical signs and discharged fewer oocysts in the feces as the level of medication in the feed increased. The calves inoculated with E zuernii developed only moderately severe infections when compared with those inoculated with E bovis. Inoculated (with E bovis) nonmedicated calves had severe reductions in feed consumption and weight, and 3 of 4 died.(ABSTRACT TRUNCATED AT 250 WORDS)     

Restricted suckling of tropical dairy cows by their own calf or other cows' calves

The objective of this study was to compare restricted suckling of tropical cows by their own or another cow's calf with artificial rearing of the calves and no suckling. In Exp. 1, cows were mechanically milked twice daily, after which for 15 min they were either suckled by their own calf (Treatment O) or multiple-suckled by other cows' calves (Treatment M) or unsuckled, with the calves reared artificially (Treatment A). Machine milk yield was similar for the three treatments, but in the two suckling treatments the additional milk consumed by the calf increased (P = 0.02) total production (2,682, 2,634, and 2,336 kg/lactation for Treatments O, M, and A, respectively). Machine milk fat concentration was reduced (P = 0.05) by suckling (2.90, 3.07, and 3.20% for Treatments 0, M, and A, respectively), but the milk sampled just before suckling (to represent that taken by the calves) had a high fat concentration (mean 7.9%). Machine milk somatic cell count was also reduced (P = 0.05) by suckling, from 106,000/mL (Treatment A) to 85,000/mL (Treatment M) and 95,000 (Treatment O). Cows suckling their own calf lost more weight and body condition than cows whose calves were reared artificially, with multiple-suckled calves intermediate. Cows suckling their own calf had postpartum interval to first estrus increased (P = 0.01) by 31 d and conception rates to first service of 44% compared to 77% for the other two treatments (P = 0.01). The growth of the suckled calves was compared with that of the artificially reared calves, which were given recommended milk allowances. The artificially reared calves consumed more milk and concentrates, which were available ad libitum to all calves, and gained (P = 0.03) 0.07 kg/d more weight than suckled calves. A second experiment determined that suckling once daily did not reduce reproductive performance compared to artificial rearing. We conclude that suckling cows twice daily increases total milk production but reduces body weight in early lactation. Cows suckling their own calves have reduced reproductive performance compared to those suckling other calves or reared artificially.     

Effects of natural zeolite clinoptilolite on passive immunity and diarrhea in newborn Holstein calves

In the present study, the effects of natural zeolite clinoptilolite on absorption of immunoglobulins from colostrum and incidence of enteric diseases were evaluated. In a completely randomised design, thirty Holstein calves were fed pooled colostrum and then milk containing zero (control), 0.5 (T1), 1.0 (T2), 1.5 (T3) and 2.0 (T4) g clinoptilolite per kg body weight per day through day 45. Blood was collected after birth and at 24 h of age and plasma IgG and IgM concentrations were determined. Fecal consistency score and severity of diarrhea were recorded for each calf twice daily. Calves receiving T3 and T4 had lower (P < 0.05) plasma IgG concentration than control and other treatments. Calves on T2 had higher (P < 0.05) plasma IgG concentration than T3 and T4, but not T1 and control. Inclusion of clinoptilolite to colostrum did not affect (P > 0.05) IgM absorption from the intestine of newborn calves. Fecal consistency scores were lower (P < 0.05) for calves on T1 and T2 and higher for calves on T3 and T4 than calves on control. Percent calf days with diarrhea followed the same trend. In overall, seven calves died, those being one each on control and T1, two on T3 and three on T4. Based upon these results, addition of 1.0 g clinoptilolite per kg body weight per day to colostrum and milk could reduce diarrhea, but its effect on passive immunity was negligible. Over 1.0 g/kg body weight per day, clinoptilolite had adverse effect on passive immunity and diarrhea.     

The therapeutic efficacy and prophylactic activity of doramectin against Dictyocaulus viviparus in cattle

SUMMARY Three groups of 8, 4-month-old male Jersey or Jersey-cross calves were infected with 2400 Dictyocaulus viviparus L₃ larvae and either left untreated or injected subcutaneously with 200 μg/kg doramectin 5 or 25 days after infection (DAI). Lungworms were found in all untreated cattle (geometric mean = 49) at necropsy 39 or 40 DAI. None was found in any of the treated cattle. In a second experiment, groups of 6, 8-month-old calves were untreated or injected with 200 μg/kg doramectin 28, 21 or 14 days before each calf was challenged with 2700 D viviparus larvae. Lungworms were recovered at necropsy 32 to 34 DAI. The geometric mean worm burden in the untreated cattle was 550. This was reduced by 100%, 99.5% and 94.1% in calves treated with doramectin 14, 21 or 28 days, respectively, before infection. It was concluded that doramectin is a highly effective anthelmintic against D viviparus adult or L₄ infections of cattle, and that reinfection of treated cattle will be significantly reduced for at least 28 days after treatment.     

Neutrophil depletion of calves with hydroxyurea: methods and clinical and pathologic effects

Twenty-six Holstein calves were treated with hydroxyurea in order to induce neutropenia. Calves were given a daily dosage of hydroxyurea (70 mg/kg of body weight) for 4 consecutive days, and clinical signs, blood leukograms, hemograms, and platelet counts were monitored daily until the calves became neutropenic. Once a neutropenic state was induced, the calves were anesthetized and pulmonary function tests were performed. Subsequently, calves were euthanatized and complete necropsies were performed. Hydroxyurea treatment induced profound neutropenia in all calves by 8 days after initiating treatment, with mild decreases in circulating numbers of lymphocytes. Treatment did not cause clinical or pulmonary functional abnormalities. Severe pathologic changes were restricted to the bone marrow and consisted of partial to complete destruction of myeloid elements, with less severe effects on erythrocytic precursors and megakaryocytes. Hydroxyurea was useful for the induction of neutropenic states in calves and did not induce major toxic effects on other cells when given at 70 mg/kg.     

Pharmacokinetic properties of theophylline given intravenously and orally to ruminating calves

The disposition of theophylline in healthy ruminating calves was best described by a first-order 2-compartment open pharmacokinetic model. The drug had a mean elimination half-life of 6.4 hours and a mean distribution half-life of 22 minutes. Total body clearance averaged 91 ml/kg/h. The mean values for the pharmacokinetic volume of the central compartment, pharmacokinetic volume of distribution during the terminal phase, and volume of distribution at steady state were 0.502, 0.870, and 0.815 L/kg, respectively. Theophylline was readily absorbed after oral administration to the ruminating calf, with a mean fraction of 0.93 absorbed. The plasma concentrations after oral dosing peaked in approximately 5 to 6 hours, with a mean absorption half-life of 3.7 hours. A flip-flop model (rate constant of input is much smaller than the rate constant of output) of drug absorption was not found because the elimination process roughly paralleled that of the study concerning IV administration. In a multiple-dose trial that used a dosage regimen based on single-dose pharmacokinetic values, clinically normal calves responded as predicted. However, diseased calves had higher than expected plasma concentrations after being given multiple oral doses of theophylline at 28 mg/kg once daily. Overt signs of toxicosis were not seen, but this aspect of the drug was not formally investigated. Theophylline can be used as an ancillary therapeutic agent to treat bovine respiratory disease, but not without risk. The suggested oral dose of theophylline at 28 mg/kg of body weight once daily should be tailored to each case.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cerebro-cortical necrosis (C.C.N.) in calf. An experimental reproduction of the disease

In four ruminant calves a state of thiamine deficiency was brought about with a thiamine antagonist, amprolium. Twice daily the calves were given Amprolmix® containing 25 % amprolium through a stomach tube. The dosage was 350–500 mg/kg body weight daily during the entire experimental period. After 31 days the first calf showed fully developed symptoms; two other calves fell ill after another four and eight days respectively. The fourth calf was killed before the disease became clinically manifest. In all calves cerebrocortical necroses were found on histological examination. The clinical picture is described. It was similar to that in spontaneous C.C.N.In the calves exhibiting fully developed symptoms a moderate rise was observed in the pyruvate kinase and a heavy rise in the creatine Phosphokinase activity. On several occasions the total quantity of thiamine (free + phosphorylated) in the blood exceeded the upper normal limit without any extra supply of thiamine being given. Only on one occasion was a lowering observed, to a value just below the lower limit of normal variation.     

Ivermectin: controlled test of anthelmintic activity in dairy calves with emphasis on Dictyocaulus viviparus

Twelve dairy calves, naturally infected with lungworms and gastrointestinal parasites, were selected for a controlled test with single doses of ivermectin, administered subcutaneously, at the dose rate of 200 micrograms/kg. Specific interest was on efficacy of ivermectin against lungworms (Dictyocaulus viviparus), with ancillary interest directed on abomasal parasites. Ivermectin was administered to 6 calves, and the vehicle only, to 6 calves. At necropsy, 7 days after treatment, lungworms were not recovered from any of the treated calves; nontreated calves, given the vehicle only, were infected with 1 to 46 lungworms each. Removal efficacy against adult Ostertagia ostertagi was 99%. Fourth-stage Ostertagia spp and Trichostrongylus spp and mature Trichostrongylus axei, present in low numbers, were all removed. The fecal egg count for gastrointestinal parasites indicated all eggs, except for a few Nematodirus eggs, were cleared from treated calves. One treated calf showed signs of irritation of the neck at injection site for a short time after treatment and 1 treated calf had a slight indurated area at injection site at necropsy.