Accidental poisoning of a group of yearling cattle by the organophosphate insecticide trichloronat

Eight yearling cattle were accidentally poisoned with the agricultural organophosphate insecticide trichloronat. One animal showed signs of acute organophosphate poisoning and died. The others showed signs of chronic organophosphate poisoning (organophosphate-induced delayed neuropathy) after 2-3 weeks and one animal died from renal failure at 12 weeks. High levels of trichloronat were measured in fat samples at 6 1/2 weeks. The remaining animals still showed signs of ataxia, possibly due to distal axonopathy, 1 year later but no trichloronat was detected in fat samples at this time.     

Accidental poisoning of a group of yearling cattle by the organophosphate insecticide trichloronat

Eight yearling cattle were accidentally poisoned with the agricultural organophosphate insecticide trichloronat. One animal showed signs of acute organophosphate poisoning and died. The others showed signs of chronic organophosphate poisoning (organophosphate-induced delayed neuropathy) after 2–3 weeks and one animal died from renal failure at 12 weeks. High levels of trichloronat were measured in fat samples at 6 1/2 weeks. The remaining animals still showed signs of ataxia, possibly due to distal axonopathy, 1 year later but no trichloronat was detected in fat samples at this time.     

Examination of potential methods to predict pulmonary arterial pressure score in yearling beef cattle

Susceptibility of beef cattle to high altitude disease (HAD) is of major importance to economic and genetic selection on high elevation ranches. However, currently the best indicator of HAD susceptibility is the pulmonary arterial pressure (PAP) test, a test with high cost and invasive nature. Therefore, 2 experiments were undertaken to determine whether emerging technologies that predict blood components could be used to predict the PAP score in yearling Angus cattle. In Exp. 1, 39 yearling Angus bulls were used to determine if a relationship existed between PAP score and 10 blood components provided by a hemogram using whole blood or oxygen saturation as predicted by pulse oximetry in nonanesthetized cattle measured rectally or orally. Three of the hemogram values (packed cell volume, hemoglobin concentration, and red cell distribution width) were correlated (P < 0.10) with the PAP score. Prediction equations for PAP score were generated using the hemogram values and resulted in R2 values of 0.375 and 0.305 for the regression model using all of values and the best 2-variable model, respectively. Pulse oximetry was able to provide oxygen saturation predictions rectally or orally; however, the predicted values were not correlated with the PAP score (P > 0.10) or with each other (P > 0.10). In Exp. 2, 84 yearling Angus cattle (62 bulls, 22 heifers) were used to evaluate the ability of a portable clinical analyzer to predict the PAP score using 11 blood components from a sample of whole blood evaluated at the processing chute. The portable clinical analyzer was able to provide values for all of the 11 blood components; however, none of the predicted values were correlated with the PAP score (P > 0.10). In these preliminary experiments, 3 blood component values provided via the hemogram were the only variables both correlated with the PAP score and able to contribute to the development of a useful PAP prediction equation that could reduce the cost of traditional measures of HAD susceptibility. Future research is needed to determine whether additional blood components or emerging blood analysis technologies are able to accurately predict the PAP score in beef cattle.     

提高肉牛秸秆饲料营养价值的工程技术

该文综述了改善肉牛农作物秸秆营养价值的"单一"技术与整体利用技术——营养工程技术。     

Grazing and feedlot performance of yearling stocker cattle integrated with spring- and fall-calving beef cows in a year-round grazing system

Effects of calving season and finishing system on forage and concentrate consumption and carcass characteristics of calves were compared. In each of 3 yr, two replicates of three growing and finishing systems were compared including 1) spring calves finished on a high-grain diet in a feedlot immediately post-weaning (WF); 2) spring calves backgrounded on a hay-corn gluten diet over winter for 179 +/- 18 d after weaning, grazed for 98 +/- 9 d in cool-season grass-legume pastures, and finished on a high-grain diet in a feedlot (SGF); and 3) fall calves backgrounded on a hay-corn gluten feed diet over winter for 69 +/- 31 d after weaning, grazed for 98 +/- 9 d in cool-season grass-legume pastures, and finished on a high-grain diet in a feedlot (FGF). During the grazing phase, calves on the SGF and FGF treatments were equally stocked with spring-calving cow-calf pairs before grazing by pregnant fall-calving cows in a first-last rotational stocking system at a rate of 1.9 standard livestock units/ha. As designed, retained calves in the FGF system spent 110 fewer days in the drylot during backgrounding than retained calves in the SGF system (P = 0.01), resulting in less feed provided during winter. A greater (P < 0.01) quantity of hay was fed to SGF calves after weaning over winter (1,305 kg of DM per calf) than the quantity fed to FGF calves (305 kg of DM per calf). Quantity of grain (including commercial starter) fed to SGF calves after weaning did not differ (P = 0.28) from that fed to FGF calves (126 vs. 55 kg of DM per calf); however, calves in the FGF system required 80 and 71 kg of DM per calf more concentrate to finish to an equivalent external fat thickness compared with SGF and WF calves, respectively (P = 0.02). Average daily gains in the feedlot were greater (P < 0.01) for SGF and FGF calves than for WF calves during all 3 yr. There were no differences (P = 0.69) in carcass quality grades among calves in all groups, but SGF calves had greater (P < 0.01) hot carcass weight and LM area measurements at slaughter than FGF or WF calves. Although calves in the FGF system were 25 kg lighter than calves in the WF system at slaughter (P = 0.03), and had a lower dressing percent (P = 0.03), other carcass characteristics did not differ between these two groups. Lower stored-feed requirements and similar carcass quality characteristics made retention of a fall calf crop advantageous over retention of a spring calf crop for use as stocker animals before finishing.     

Breeding soundness examination of yearling beef bulls

Yearling beef bulls were subjected to a breeding soundness examination (BSE) at completion of performance testing programs at 4 locations over 5 years. Of 862 bulls, 80.1% were classified as satisfactory potential breeders, 7.3% as questionable potential breeders, and 12.7% as unsatisfactory potential breeders. Year (P less than 0.01), location (P less than 0.01), and breed (P less than 0.01) affected the percentage of bulls classified as satisfactory; age of the bulls did not affect this percentage. Adjusted mean scrotal circumference (SC) measurements were 31, 33.2, and 34.8 cm for bulls classified as unsatisfactory, questionable, and satisfactory (P less than 0.01), respectively. Of 109 bulls classified as unsatisfactory, 2.8% were so classified because of poor semen quality alone; 41.3% had no ejaculate in 4 separate electroejaculation attempts. Other abnormalities in these 109 bulls included reproductive tract infections (22%), persistent penile frenulum (16.5%), testicular abnormalities (8.3%), fibropapilloma (1.8%), hernia (1.8%), aplastic epididymis (1.8%), penile abnormalities (1.8%), pendulous sheath (0.9%), and eye abnormalities (0.9%). Age had a significant effect on SC in bulls at 3 locations and on percentage of normal cells, primary abnormalities, and secondary abnormalities as well as BSE score at 1 location. Percentage of primary and secondary abnormalities as well as SC were different across years at 2 locations, and percentage of normal and motile cells as well as BSE score were different across years at 1 location. Breed effects were significant for SC, percentage of primary abnormalities, and BSE score at 3 locations and for percentage of normal and motile cells at 1 location.     

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.     

Clinical observations on ostertagiasis in yearling cattle

The growth of a New Zealand strain of M. ovipneumoniae in broth culture at 37°C was examined. In these conditions, the organism had a minimum division time of 1.7 hr and attained a maximum titre of about 2×10⁹ CFU/ml. Growth produced sufficient turbidity, particularly in shaking cultures, to allow this to be correlated with the viable count. The cultures died rapidly following the attainment of maximum titre.

Electron microscopic examination revealed a morphology typical of mycoplasmas, except that most organisms measured 400 to 700nm in diameter which is relatively large. The presence of dumb-bell-shaped forms, and the absence of filaments suggest that the organisms divide by binary fission.     

维生素A在肉牛生产中的应用

针对维生素A对肉牛瘤胃发酵、生产性能及免疫功能的影响作一综述。     

The effects of nutritional management on carcass merit of beef cattle and on sensory properties of beef.

The ultimate goal of feeding beef cattle is to develop a meat product that satisfies consumer needs. Nutritional management plays a significant role in determining carcass merit of beef cattle. Certain management procedures (eg, metabolic modifiers, early weaning), general animal health (eg, history of respiratory disease), and certain feed ingredients (eg, trace minerals, antioxidants) can have positive and negative effects on the overall quality of beef that is supplied to the consuming public.