The toxicity of Castanospermum australe seeds for cattle

Two calves given a mean of 16.1 g and 16.4 g ripe Castanospermum australe seeds/kg body weight daily for 13 and 16 days respectively developed haemorrhagic gastroenteritis. The first calf died. The second calf had mild myocardial degeneration and necrosis and mild nephrosis at necropsy. Two calves given a mean of 16.8 g unripe C. australe seeds/kg body weight daily for 18 days remained clinically normal and had mild gastritis at necropsy. The activity of alpha-glucosidase was reduced in the mononuclear cells of peripheral blood and in skeletal muscle. This was attributed to the presence of the indolizidine alkaloid, castanospermine, in the seeds. The toxin causing the gastroenteritis and other lesions is unknown.     

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.     

Experimentally induced Cassia roemeriana poisoning in cattle and goats

The dried, ground aerial portions of the plant Cassia roemeriana were administered to each of seven calves at a dosage of 10 g/kg of body weight/day for 2 to 10.5 days and to each of six goats at a dosage of 10 g/kg/day for 5 days or 5 or 7 g/kg/day for 23 to 25 days. Experimentally induced C roemeriana poisoning in both species resulted in hepatopathic poisoning characterized by a brief survival period (3.9 to 7.9 days), moderate-to-severe hepatocellular damage, and little or no evidence of injury to skeletal muscle or resulted in myopathic poisoning characterized by a longer period of survival, mild-to-severe skeletal myopathy, and mild hepatocellular injury. The minimal dosage that induced hepatopathic poisoning (also the minimal lethal dosage) was 10 g/kg/day for 3 days in calves and for 5 days in goats. The minimal dosage that induced the myopathic syndrome (as determined by the earliest increase in serum creatine kinase activity) was 10 g/kg/day for 6 days for calves and 5 g/kg/day for 10 to 16 days for goats.     

Performance and ruminal changes of early-weaned calves fed lasalocid

Twenty-two neonatal calves were assigned to a control or lasalocid-fed group and weaned at 3 wk of age. They were fed a prestarter diet from 3 d of age until they consumed 227 g/d and then a mixture of 227 g prestarter daily and starter diet in ad libitum amounts. The lasalocid-fed group received lasalocid in milk at 1 mg/kg body weight daily from 4 to 7 d and at .5 mg/kg body weight daily in milk and medicated prestarter diet (88 mg lasalocid/kg) during the 2nd wk. After 2 wk, lasalocid-fed calves were given medicated prestarter and starter (44 mg lasalocid/kg) diets. Four calves in each group were ruminally cannulated at 3 to 5 d of age, and ruminal contents were obtained at weekly intervals to monitor microbial activity. Rectal fecal samples were collected from all calves and examined for coccidial oocysts. Lasalocid-fed calves had a greater weekly feed intake and weight gain than control calves after 6 wk of age. Total ruminal volatile fatty acid concentrations were higher, but the acetate:propionate ratio was lower in lasalocid-fed calves than in control calves. Total viable anaerobic and amylolytic bacterial counts were higher in lasalocid-fed calves than in control calves. No significant treatment effect was found for ruminal NH3-N concentration or ruminal lasalocid-resistant, lactobacilli, lactate-utilizing, cellulolytic or methanogenic bacterial numbers. No evidence of coccidiosis was detected in either group. In general, lasalocid-fed calves had greater feed intake, weight gain and ruminal microbial activity than the calves fed no lasalocid in the diet.     

Thermopsis montana-induced myopathy in calves

Six heifer calves were administered the dried and ground whole plant of Thermopsis montana by gavage once daily for 2 to 4 days at an initial dosage rate of 1 g/kg of body weight. Two of the 6 heifers died after the second dose, and the remaining 4 calves were humanely killed and their tissues were examined. Serum creatine kinase and aspartate transaminase activities were significantly (P less than 0.05) increased after initiation of plant administration. All calves had skeletal muscular degeneration or evidence of regeneration and repair of damaged myofibers in all skeletal muscle groups examined. Myoglobinuria and cardiac muscle degeneration were not detected in any of the calves.     

Determination of lactose and xylose malabsorption in preruminant diarrheic calves.

In preliminary studies feeding the poorly absorbed carbohydrate sorbitol at 2.3 g/kg body weight as an indication of maximal fermentative capacity failed to produce the expected large increase in breath hydrogen excretion but did produce a transient diarrhea in five out of six control calves. Twelve healthy control and eighteen diarrheic calves were fed lactose or D-xylose on consecutive days at 1.15 g/kg body weight and a concentration of 46 g/L. Breath and blood samples were collected at 1 h intervals from 0 to 7 h. After administration of lactose, there was a significant increase in breath hydrogen excretion in diarrheic versus control calves. The increase in plasma glucose concentrations was delayed in diarrheic calves but the area under the absorption curve was similar in control and diarrheic calves. After administration of D-xylose, breath hydrogen excretion did not increase significantly but plasma D-xylose concentrations were significantly reduced in diarrheic calves. The pathogens commonly isolated from the feces were Cryptosporidium species, rotavirus and coronavirus. The number of pathogens and the severity of the calves' acid-base deficit were not related to the severity of carbohydrate malabsorption. Decreased absorption of lactose and D-xylose may be the result of intestinal villous atrophy caused by viral or parasite infection. It was concluded that carbohydrate malabsorption rather than a specific lactose maldigestion is a significant problem in diarrheic calves. Diarrheic calves appear to digest and absorb lactose when fed in small amounts.     

Differences in the digestive tract characteristics of broiler chickens fed on complete pelleted diet or on whole wheat added to pelleted protein concentrate

1. The effects of whole grains of wheat on the digestive tract of broiler chickens was studied. A complete pelleted feed was compared with free choice feeding of whole wheat and a pelleted protein concentrate, given from 7 to 29 d of age. 2. Pepsin activity in proventriculus tissue was lower in whole wheat-fed birds than in complete diet-fed birds. The weight (g/kg body weight) of the gizzard was higher in whole wheat-fed birds and its contents had a lower pH. 3. In the intestine, there were no differences in deoxyribonucleic acid (DNA) concentration, protein/DNA, ribonucleic acid (RNA)/DNA, RNA/protein ratios or alkaline phosphatase activity expressed per tissue weight. The weight (g/kg body weight) of the duodenum was lower in whole wheat-fed birds and its contents had a higher pH. Also the activities of alkaline phosphatase and leucine aminopeptidase in the duodenum, and maltase in the ileum, expressed per unit of bird weight, were lower in whole wheat-fed birds. 4. These results suggest that whole grain feeding increases the chemical (pepsin in proventriculus) and physical (gizzard muscle) functionality of the upper part of the digestive tract but decreases the digestive capacity of the intestine. Higher gizzard functionality may play a positive role in the control of bacterial populations. The lower digestive enzyme activities in the intestine may be detrimental in situations of mucosal deterioration caused by intestinal disease.     

Effect of cortisol in vitro and in vivo on production of bovine interleukin 2

The influence of cortisol in vitro and in vivo on lymphocyte proliferative responses and interleukin 2 (IL2) production was evaluated in Hereford feeder calves. Cortisol, added to bovine mononuclear cell cultures, reduced (P less than 0.05) mitogen-stimulated lymphocyte proliferative responses and IL2 production. Lower IL2 activity from cortisol-treated cell cultures was not caused by a cortisol-mediated cytotoxicity or a residual cortisol effect on the IL2-indicator cell line. Calves given ACTH (1.0 IU/kg of body weight, IM) twice daily for 2 days had increased (P less than 0.001) plasma cortisol concentrations when compared with those of saline-treated controls. Leukocytosis (P less than 0.002), characterized mainly by a neutrophilia (P less than 0.007), was evident in ACTH-treated calves. Lymphocyte proliferative responses to the phytomitogens, concanavalin A, phytohemagglutinin, and pokeweed mitogen were decreased (P less than 0.05) in calves with increased plasma cortisol concentrations. Interleukin 2 production was lower (P less than 0.05) in concanavalin A-stimulated lymphocyte cultures from ACTH-treated calves. Seemingly, lower lymphocyte proliferative responses in cortisol-treated mononuclear cell cultures and in ACTH-treated calves were caused partly by lower IL2 production.     

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)。     

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.     

Effects of age on the pharmacokinetics of single dose ceftiofur sodium administered intramuscularly or intravenously to cattle

The effects of maturation on the intravenous (IV) and intramuscular (IM) pharmacokinetics of ceftiofur sodium following a dose of 2.2 mg ceftiofur equivalents/kg body weight were evaluated in 16 one-day-old Holstein bull calves (33-53 kg body weight initially; Group 1) and 14 six-month-old Holstein steers (217-276 kg body weight initially; Group 2). Group 1 calves were fed unmedicated milk replacer until 30 days of age and were then converted to the same roughage/concentrate diet as Group 2. Groups 1-IV and 2-IV received ceftiofur sodium IV, and Groups 1-IM and 2-IM received ceftiofur sodium IM. Group 1 calves were dosed at 7 days of age and at 1 and 3 months of age; group 2 calves were dosed at 6 and 9 months of age. Blood samples were obtained serially from each calf, and plasma samples were analysed using an HPLC assay that converts ceftiofur and all desfuroylceftiofur metabolites to desfuroylceftiofur acetamide. C_max values were similar in all calves, and were no higher in younger calves than in older calves. Plasma concentrations remained above 0.150 μg ceftiofur free acid equivalents/mL for 72 h in 7-day-old calves, but were less than 0.150 μg/mL within 48 h following IV or IM injection for 6- and 9-month-old calves. Intramuscular bioavailability, assessed by comparing the model-derived area under the curve (AUC_mod) from IM and IV injection at each age, appeared to be complete. After IV administration, the AUC_mod in 7-day-old and 1-month-old calves (126.92±21.1 μg-h/mL and 135.0±21.6 μg.h/mL, respectively) was significantly larger than in 3-, 6- and 9-month-old calves (74.0±10.7 μg.h/mL, 61.0±17.7 μg.h/mL and 68.5±12.8 μg.h/mL, respectively; P< 0.0001). The V_d(ss) decreased linearly within the first 3 months of life in cattle (0.345±0.0616 L/kg, 0.335±0.919 L/kg and 0.284±0.0490 L/kg, respectively; P= 0.031), indicative of the decreasing extracellular fluid volume in maturing cattle. The Cl_b was significantly smaller in 7-day-old and 1-month-old calves (0.0178±0.00325 L/h.kg and 0.0167±0.00310 L/h.kg, respectively) than in 3-, 6- and 9-month-old calves (0.0303±0.0046 L/h.kg, 0.0398±0.0149 L/h.kg and 0.0330±0.00552 L/h.kg, respectively; P≦0.001). This observation may be indicative of maturation of the metabolism and/or excretion processes for ceftiofur and desfuroylceftiofur metabolites. The approved dosage regimens for ceftiofur sodium of 1.1-2.2 mg/kg administered once daily for up to 5 consecutive days will provide plasma concentrations above the MIC for bovine respiratory disease pathogens for a longer period of time in neonatal calves than in older calves. Peak plasma concentrations of ceftiofur and desfuroylceftiofur metabolites were no higher in neonatal calves than in more mature cattle, highly suggestive that peak tissue concentrations would be no higher in neonatal calves than in more mature cattle.     

代乳粉用于早期断奶犊牛的效果研究

犊牛使用代乳品可以节省鲜奶，降低饲养成本，控制疾病的发生，促进消化系统的发育。试验用24头犊牛做试验，60日龄断奶。结果表明，代乳品组犊牛增重47．55千克；对照组增重41．72千克；吃代乳品的犊牛在30-60日龄的日增重达到1026克，高于对照组103克。吃代乳品的犊牛每增重1千克的直接饲料成本为15．13元，比鲜奶组犊牛低2．14元／千克。     

Effect of orally administered omeprazole on abomasal luminal pH in dairy calves fed milk replacer

The objective of this study was to determine whether oral administration of omeprazole, a proton-pump inhibitor, increased abomasal luminal pH in calves fed milk replacer. Four male dairy calves with cannulae in the abomasal body suckled milk replacer (60 ml/kg body weight every 12 h) and were administered a non-enteric-coated omeprazole (4 mg/kg body weight every 24 h) in a paste formulation for five successive days. Abomasal luminal pH was continuously measured using miniature glass pH electrodes. On the first day of omeprazole administration, there was a significant (P<0.05) increase in mean 24-h pH from 2.89 to 4.17. The mean 24-h pH on days 2, 3, 4 and 5 of omeprazole administration were 3.85, 4.02, 3.97 and 3.39 respectively. We conclude that oral administration of non-enteric-coated omeprazole increased abomasal luminal pH in calves fed milk replacer, but that the effect may decrease over time.     

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.     

The effect of cellulase on calves fed an acidified milk diet]

The purpose of this research was to establish the influence of 3 j Cx cellulase applied per gram of COT concentrate mixture, fed in combination with a milk diet acidified by formic acid to the value of pH 4.6, on calf growth performance in one metabolism and two field experiments. In the metabolism experiment two groups of calves, with six animals in each, were fed acidified whole milk, which was diluted stage by stage till weaning at 60 days of age. The average live weight gain in the control at the end of the milk feeding period, i.e. from 14 to 60 days of age, was 29.90 kg. This corresponds to a daily live weight gain of 0.650 g. The total live weight gain of male calves in the experimental group was 29.30 kg, corresponding to a daily live weight gain of 0.638 g (Tab. I). Tab. II shows the average feed and nutrient intakes per kg live weight gain. The calves which received the enzyme supplement tend to have the higher feed conversion rate. During the forage feeding period, i.e. from 61 to 90 days of age, the average daily live weight gains were 1.10 kg and 0.980 kg in the control and experimental groups, respectively (Tab. III). The average live weight of 90 days old male calves was 107.70 kg and 103.90 kg in the control and experimental groups, respectively. The amount of consumed nutrients (digestible protein and starch units); in relation to the total feed intakes, is lower in the experimental groups, which proves the higher feed conversion rate (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of orally administered cimetidine and ranitidine on abomasal luminal pH in clinically normal milk-fed calves

OBJECTIVE: To characterize the change of pH in the abomasal lumen throughout a 24-hour period, to determine whether pH of the abomasal body differs from pH of the pyloric antrum, and to determine whether oral administration of cimetidine and ranitidine alters pH of the abomasal lumen in milk-fed calves. ANIMALS: 5 male dairy calves (4 Holsteins-Friesian, 1 Ayrshire), 5 to 15 days old. PROCEDURE: Cannulas were surgically positioned in the abomasal body and pyloric antrum of each calf. Calves received the following treatments in a randomized crossover design: milk replacer (60 ml/kg of body weight, q 12 h [untreated control calves]), milk replacer and cimetidine (50 or 100 mg/kg, q 8 h), or milk replacer and ranitidine (10 or 50 mg/kg, q 8 h). The pH of the abomasal body and pyloric antrum was measured for 24 hours, using miniature glass pH electrodes. RESULTS: Suckling of milk replacer immediately increased abomasal luminal pH from 1.4 to 6.0, followed by a gradual decrease to preprandial values by 6 hours. Preprandial and postprandial pH values were not significantly different between the abomasal body and pyloric antrum, indicating lack of pH compartmentalization in the abomasum of milk-fed calves. Administration of cimetidine and ranitidine caused a significant dose-dependent increase in mean 24-hour abomasal luminal pH. CONCLUSIONS AND CLINICAL RELEVANCE: Abomasal acid secretion in milk-fed calves is mediated in part by histamine type-2 receptors. Cimetidine and ranitidine may be efficacious in the treatment of abomasal ulcers in milk-fed calves.     

Tissue residues of diacetoxyscirpenol in pigs and calves after intravenous dosing

Pigs (n = 19) were given 0, 0.1, 0.5, or 1 mg of diacetoxyscirpenol (DAS)/kg of body weight, and heifers (n = 7) were given 0 or 0.5 mg of DAS/kg. Animals were anesthetized and exsanguinated 8 hours after administration of DAS, and liver, kidney, skeletal muscle, mesenteric lymph node, and spleen were analyzed for DAS. Diacetoxyscirpenol was not detected in tissues from animals not given DAS. All tissues from pigs and calves given DAS contained at least traces (less than or equal to 10 ng/g of tissue) of DAS.     

Modification of the Pharmacokinetics and Dosage of Cefuroxime by Endotoxin-induced Fever in Buffalo Calves

The effect of endotoxin-induced fever on the pharmacokinetics and dosage regimen of cefuroxime was investigated in buffalo calves following a single intravenous dose of 10 mg/kg body weight. The fever was induced by intravenous administration of E. coli endotoxin at a dose of 1 g/kg body weight. The distribution and elimination half-lives were 0.100 h and 1.82 h, respectively, in healthy and 0.109 h and 2.28 h, respectively, in febrile buffalo calves. About 91% of the administered dose was excreted in the urine within 24 h. There was no effect of fever on the plasma protein binding of cefuroxime. The dosage regimen for intravenous administration of cefuroxime may be reduced in febrile conditions but the probability of this was only 0.3.     

Growth in the Reindeer

The growth of the reindeer from birth to adulthood is cumulative consisting of a rapid weight accretion during summers followed by a weight loss or stasis during winters. The birth weight of the newborn calves is about 5.3 kg. The peri- and neonatal growth rate is rather high, with a greatest individual daily weight gain as high as 400 g. The polynomial growth curve and its first order time derivative of calves show a deceleration of weight gain towards the autumn. The weight of calves at an age of 10 months was 36 to 40 kg. Adult body weight is reached by females at an age of 3 to 4 years and by males on average a year later. Serum alkaline phosphatase activity showed a negative linear correlation with age and weight in calves and it was highest both in calves and adults in summer. The creatine Phosphokinase activity in both calves and adults was higher in summer than in other seasons. Serum inorganic phosphorus was highest in the growing calves. On the other hand serum thyroxine (T4), blood glucose and calcium did not show significant age-dependent or seasonal variations.     

Comparative efficacy of tulathromycin versus florfenicol and tilmicosin against undifferentiated bovine respiratory disease in feedlot cattle

Four studies conducted at feedlots in Greeley and Wellington, Colorado; Nebraska; and Texas compared the efficacy of tulathromycin to florfenicol or tilmicosin for the treatment of cattle with undifferentiated bovine respiratory disease (BRD) and subsequent feedlot performance and carcass characteristics. In each study, 100 calves with BRD were treated with tulathromycin given SC at 2.5 mg/kg body weight. At the Greeley, CO, and Nebraska study locations, 100 calves were treated with florfenicol given SC at 40 mg/kg body weight, and at the Wellington, CO, and Texas study locations, tilmicosin was given SC at 10 mg/kg body weight. Cure rate, a derived variable that included assessments of mortality, rectal temperature, and attitude and respiratory scores from day 3 to day 28 and day 3 through harvest, was the primary assessment of BRD efficacy. Cure rates of calves treated with tulathromycin were significantly (P < or = .009) higher than those calves treated with florfenicol. At Wellington, CO, the cure rate of calves treated with tulathromycin was significantly higher (P < or = .018) compared with tilmicosin-treated calves. The differences in cure rates between tulathromycin and tilmicosin treatment groups in the Texas study were not significantly different (P > .05). Tulathromycin was more efficacious in the treatment of undifferentiated BRD compared with florfenicol and, in one study, compared with tilmicosin.