Restricted energy intake and elevated calcium and phosphorus intake for gilts during growth. IV. Characterization of metacarpal, metatarsal, femur, humerus and turbinate bones of sows during three parities     

S R Arthur  E T Kornegay  H R Thomas  H P Veit  D R Notter  K E Webb  J L Baker 《Journal of animal science》1983,57(5):1200-1214

The effect of early nutrition on subsequent bone development was studied using gilts that had previously been fed ad libitum or 75% ad libitum intake and 100 or 150% National Research Council-recommended daily Ca and P from weaning to 100 kg. During the three-parity reproductive study, sows were fed a 14% protein diet. Metacarpals and metatarsals were taken from sows culled due to lameness or failure to breed and from sows after completing three parities. Femur and humerus articular cartilage and turbinates were described at necropsy. Metacarpals and metatarsals were heavier and tended to have thicker walls when sows were previously fed ad libitum or fed 150% Ca and P. Energy intake produced the greater response. Metacarpal breaking strength was greatest for sows previously fed ad libitum. Metatarsals were not affected by energy intake. Stiffness, Young's modulus of elasticity (YME) and flexural modulus for metacarpals and metatarsals were not affected by energy intake. Previously fed Ca and P intakes did not affect any of the mechanical bone characteristics. Metacarpals were heavier, had a greater breaking strength, were more elastic and exhibited slightly less resistance to bending than the metatarsals. The ether extract, ash, Ca and P content and the Ca:P ratio of metacarpals and metatarsals were not affected by previously fed energy or Ca and P intakes. The ether extract content tended to decrease and the ash, Ca and P content tended to increase with age. Articular cartilage and turbinate scores were not influenced by previously fed energy or Ca and P intakes. The YME and flexural modulus were the only bone characteristics that were even poorly correlated (average r = .25) with soundness scores, suggesting that high values result in poorer soundness scores. Energy and Ca and P intakes during growth and development had only minimal effects on bone characteristics and no apparent effect on structural soundness and longevity of sows kept for three parities.  相似文献   

Pulmonary vascular reactivity of the newborn pony foal     

W H Drummond  I R Sanchez  P C Kosch  A I Webb 《Equine veterinary journal》1989,21(3):181-185

Adult ponies develop pulmonary hypertension at altitude (Bisgard, Orr and Will 1975), but the neonatal response to acute hypoxaemia is unknown. Seven foals aged five days were instrumented with a systemic and a Swan-Ganz pulmonary artery catheter while anesthetised and intubated. Cardiac index, pulmonary (PAP) and systemic (SAP) vascular pressures were measured as the foals breathed gas mixtures with FI02 of 8 to 94 per cent. Because foramen ovale or ductus arteriosus shunts might have altered thermodilution cardiac index measurements in the stressed foals, the ratio, PAP/SAP was calculated to define relative circulatory reactivity. Three foals, two of which were full siblings, had very marked elevation of PAP/SAP from 0.6 to 1.41 at low inspired oxygen tensions. Four different foals attained maximal PAP/SAP of only 0.2 to 0.92 at similarly low oxygen tensions (P less than 0.0001). Thus, pulmonary vascular reactivity to ventilatory hypoxaemia varied greatly in pony foals of the same age. The exaggerated reactivity in related foals suggested that, as in cattle, a genetic predisposition to develop reactive pulmonary hypertension under hypoxaemic stress may exist.  相似文献   

A critical path analysis of fruit production in strawberry     

R.A. Webb  Judith V. Purves  B.A. White  R. Ellis 《Scientia Horticulturae》1974,2(2):175-184

The method of Critical Path Analysis has been applied to strawberry fruit production from runner propagation to first harvest in an experimental situation. The quantitative components of yield and the stages of their creation have been identified and arranged in sequential order.Analysis of crop data showed that large variations in yield potential arose early in development, from causes not identified in the experiment. In the fruiting season there was a substantial shortfall in realisation of existing potential due to inefficient fertilisation of ovules and poor berry development.The analysis indicates three phases of development where factors not yet examined can have a large effect on yield.  相似文献   

Effect of dietary potassium on absorption of magnesium and other macroelements in sheep fed different levels of magnesium   总被引：1，自引：0，他引：1  

L W Greene  J P Fontenot  K E Webb 《Journal of animal science》1983,56(5):1208-1213

Two metabolism trials were conducted with 24 crossbred wether lambs. Two levels of Mg (.1 and .2%) and four levels of K (.6, 1.2, 2.4 and 4.8%) were fed in a 2 x 4 factorial arrangement of treatments. Each trial consisted of a 10-d preliminary period followed by a 10-d collection of feed, feces and urine. Increasing levels of dietary K resulted in a linear increase in fecal Mg excretion and a linear decrease in Mg absorption. A large depression in Mg absorption occurred when K was increased from 1.2 to 2.4% with a further decrease when K was increased to 4.8%. Lambs fed the high level of Mg (.2%) absorbed and retained more (P less than .05) total Mg (g/d, but not percentage of intake) compared with the low magnesium level (.1%). Dietary Mg did not affect the amount of K excreted, absorbed or retained. Increasing the level of dietary K resulted in a linear increase in urinary, fecal and total K excreted, absorbed and retained (P less than .05).  相似文献   

Callus and axillary-bud culture of Vitis vinifera ‘Sylvaner Riesling’     

R. Jona  K.Judith Webb 《Scientia Horticulturae》1978,9(1):55-60

Healthy growth of serially subcultured callus of the grape Vitis vinifera cultivar ‘Sylvaner’ was obtained by incubation at 30° C in continuous light in a defined culture medium containing 2% w/v sucrose, 1.0 mg l^?1 1-naphthaleneacetic acid (NAA) and 0.2 mg l^?1 kinetin (K). Organogenesis was not induced in this callus by alteration in the absolute or relative levels of NAA and K.Continued shoot initiation was obtained by culture of axillary buds in a medium containing 10^?5 M Benzyladenine (BA). Plantlets could be generated from these shoot buds by transfer to media containing 10^?7 M BA or lacking a cytokinin.  相似文献   

Influence of daylength and temperature on diagnosis of immunity from virus X in potato     

R. E. Webb  E. S. Schultz 《American Journal of Potato Research》1957,34(10):287-292

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A Herbicide-induced Abnormality in Sugar Beet     

A. E. W. Boyd  D. S. C. Erskine  W. J. Byford  D. J. Webb 《Plant pathology》1970,19(4):163-164

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Leucocytoclastic vasculitis associated with Staphylococcus intermedius in the pastern of a horse     

Risberg AI  Webb CB  Cooley AJ  Peek SF  Darien BJ 《The Veterinary record》2005,156(23):740-743

A pregnant quarterhorse mare became acutely lame as a result of severe swelling of its right hind leg, thought to have been caused by a fracture or a muscle tear. Diagnostic procedures ruled out a traumatic musculoskeletal cause and a physical examination revealed chronic pastern dermatitis ('scratches'/'grease heel'). Histopathological evaluation of biopsy samples from the right hind leg was consistent with a leucocytoclastic vasculitis, and culture yielded Staphylococcus intermedius. The treatment and infectious causes of pastern dermatitis are discussed.  相似文献   

Farm animal networks: unraveling the contact structure of the British sheep population     

Webb CR 《Preventive veterinary medicine》2005,68(1):3-17

The spatial and temporal dynamics of many farm animal diseases depend both on disease specific parameters and on the underlying contact structure between farms. Whilst many models for farm animal diseases focus on obtaining and estimating disease transmission parameters, relatively little attention has been given to modelling the underlying network of contacts. In this paper, we present an initial analysis of two relations underlying the contact network of individual sheep breeds in Great Britain. The first relation is based on geographical proximity and the second is based on attendance at agricultural shows. These relations are combined to give a risk-potential network that is based on these two levels of interaction. The structure of each network is investigated using techniques developed in graph theory and social network analysis.  相似文献   

Effect of formulation and route of administration on tissue residues and withdrawal times     

KuKanich B  Gehring R  Webb AI  Craigmill AL  Riviere JE 《Journal of the American Veterinary Medical Association》2005,227(10):1574-1577

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