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The development of management control techniques for the dairy derd is discussed in this paper in relation to the rationale behind the construction of a detailed model of milk production in the individual cow. The movement towards a more flexible and individualised basis for predicting yield, which does not depend on historical records or standard energy systems, is highlighted.The overall concept and approach of the model are set out and the control aspects and structural framework of the program explained. Subsequent papers in the series will deal in more detail with the major sections of the program in order to illustrate how the mechanisms of the model actually operate and to provide results and an account of the validation procedure. 相似文献
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Efficacy of clavulanate-potentiated amoxycillin in experimental and clinical skin infections 总被引：1，自引：0，他引：1
The efficacy of clavulanate-potentiated amoxycillin was compared with amoxycillin alone in experimental staphylococcal infection in dogs and in a controlled trial in clinical cases of skin infection in dogs and cats. The experimental infection was produced by subdermal inoculation with beta-lactamase producing (amoxycillin resistant) staphylococci absorbed in cotton dust. This produced discrete, localised lesions with no systemic involvement. In a cross over study, six animals were randomly allocated to treatment with either amoxycillin alone (10 mg/kg, dosed twice daily) or a formulation of clavulanate-potentiated amoxycillin (12.5 mg/kg, of a 1:4 ratio, dosed twice daily). The lesions of the animals treated with clavulanate-potentiated amoxycillin resolved more quickly than those treated with amoxycillin alone. The difference was significant (P less than 0.05) for both lesion diameter and inflammation score after day 6 of treatment. A trial was carried out in clinical cases of skin disease which were randomly allocated to twice daily treatment with either amoxycillin alone (10 or 20 mg/kg), or with clavulanate-potentiated amoxycillin (12.5 or 25 mg/kg of a 1:4 ratio). The required duration of treatment was shorter (P less than 0.5) for the potentiated amoxycillin treatments, and the success rate (judged by cure or substantial improvement) was higher (P less than 0.05) for this group, especially (P less than 0.01) where amoxycillin resistant organisms were isolated. It was concluded that clavulanate-potentiated amoxycillin was an effective treatment of skin infections both under experimental and clinical conditions. 相似文献
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Bywater RJ 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2004,51(8-9):361-363
Antimicrobials are essential for treatment of sick animals, but even if used correctly, may eventually lead to antimicrobial resistance. While this represents a potential hazard to humans, the great majority of resistant human pathogens, especially the more important ones, are unrelated to animal sources. A survey of informed medical opinion suggested that of the human antimicrobial resistance problem, <4% was seen as potentially linked to animal sources. This proportion related largely to zoonotic bacteria which by definition have the capacity to carry resistance between species, although the evidence for resulting harm remains limited. A recent study compared resistance among chicken, pig and cattle isolates of Salmonella spp., Campylobacter spp. and Escherichia coli from a series of EU countries. When tested against antimicrobial agents, this survey showed variation of resistance between countries, between hosts and between organisms. Such variation may give insight into preferred methods of antimicrobial administration or disease control, but it is clear that the epidemiology of antimicrobial resistance induction and dissemination in animals remains complex and is yet to be fully understood. 相似文献
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前言 人类医学中抗菌药抗药性问题正日趋严重.虽然这一现象被公认为主要由人医中抗菌药的使用造成的,但是人们一直关注因在动物中使用抗菌药而产生的抗药性能否转移给人的病原菌. 相似文献
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A. C. Bywater 《Agricultural Systems》1976,1(4):261-279
This paper is the second in a series describing a computer-based simulation model designed for use as a management control aid for the dairy herd and concerned with the intake and partition of nutrients by the cow. Milk production is represented in the model in two parts; the first estimates the potential milk yield for each 24 h simulation interval and the second is concerned with matching the available metabolites to the requirements associated with the potential yield. In each case, a conceptual scheme for inclusion in the model is outlined in relation to the relevant literature and the manner in which these schemes are represented in the model is described. 相似文献
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A.C. Bywater 《Agricultural Systems》1984,13(3):167-186
A generalised dynamic model for estimating voluntary consumption and digestion of feed by lactating dairy cows is described. Feed intake is assumed to be regulated either by metabolic factors relating energy intake to energy expenditure, or by physical factors associated with the capacity of the rumen to hold feed cell wall components. A representation of rumen function defined on an hourly basis provides estimates of digestion and passage of cell wall, and of the quantity of residue remaining in the rumen prior to the next meal from which physical intake limitations are calculated. Changes in regulation of energy intake and in maximum rumen capacity in response to changes in energy expenditure are subject to adjustment delays and are recalculated daily.Both qualitatively and quantitatively the model behaves well with respect to interactions between rumen function and short-term regulatory mechanisms over a wide range of feedstuffs. However, the dynamics of model behaviour over the long term-one lactation-indicate a systematic error in estimating changes in feed intake which is particularly evident in early lactation. The main cause of this error is thought to involve inadequacies in the representation of adjustment delays in the regulatory system. 相似文献
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