A comparison of the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts after calving in cows also given internal teat sealants     

LK Whitfield  RA Laven 《New Zealand veterinary journal》2018,66(1):44-47

AIM: To compare, in cows treated with an internal teat sealant, the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts (SCC) after calving.

METHODS: Cows from a spring-calving, pasture-based dairy farm in the Manawatu-Whanganui region of New Zealand were randomly allocated to receive either a short-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=291) or a long-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=288) at the end of lactation. Cows were managed on-farm with routine husbandry procedures through the dry period and following calving. A multivariable logistic regression model was used to determine the association between length of action of dry-cow therapy and the proportion of cows with a SCC >150,000?cells/mL at the first herd test after calving.

RESULTS: Age of cow, mean SCC for the preceding season and interval from calving to the first post-calving herd test were all associated with the proportion of cows with an individual SCC >150,000?cells/mL at the first herd test (p<0.001) Treatment with the short-acting dry-cow therapy was not associated with decreased odds of cows having a SCC >150,000?cells/mL at the first herd test compared with treatment with long-acting dry-cow therapy (OR=0.724; 95% CI=0.40–1.30).

CONCLUSIONS AND CLINICAL RELEVANCE: In this herd, which routinely used internal teat sealants, the use of short-acting cloxacillin-based dry-cow therapy did not result in an increased proportion of cows with elevated SSC post-calving. This was a single farm, single year study but indicates that in this herd, changing from a long-acting to a short-acting antimicrobial may have no impact on the prevalence of subclinical mastitis.  相似文献   

Larval development of Gilchristella aestuaria (Gilchrist, 1914) (Pisces: Clupeidae) from southern Africa     

E.H. Haigh  A.K. Whitfield 《African Zoology》2013,48(4):168-172

The larval development ol the southern African endemic clupeid Gilchristella aestuaria is described and illustrated from specimens collected in the Swartvlei and Sundays estuarine systems of the Cape Province. Free embryos have no visible gut, unpigmented eyes and bodies, and are dependent on the yolk sac contents for nutrition. This stage lasts until about 4 mm body length (BL) when the eyes become pigmented and a gut becomes visible. Between 4 mm and 7 mm BL melanophores on the ventral aspect of the body form, and the dorsal and caudal lin anlagen develop. Between 7 mm and 8 mm BL the swimbladder lorms, flexion occurs and the anal fin anlage develops. By the 10 mm BL stage most of the skeletal elements have begun to differentiate, with the vertebral centra already showing signs of ossification. General ossification commences between 12 mm and 13 mm BL. All unpaired fins have the adult complement of rays by 15 mm BL. Scalation starts between 16 mm and 17 mm BL and is complete by 20 mm BL. Body depth increases gradually, from about 5% of BL in the early larval stages to >14% of BL in the juveniles. The pre-anal length decreases from about 87% of BL in the larvae to approximately 69% of BL in the juveniles. Head length increases from approximately 11% of BL in the larvae to 24-29% of BL in the juveniles. The larval snoui is initially 2% of BL, increasing to 7% of BL in the juvenile stages owing to the development of jaw elements.  相似文献   

Genetics. Who's the queen? Ask the genes     

Whitfield J 《Science (New York, N.Y.)》2007,318(5852):910-911

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Growth of lucerne (Medicago sativa,L.) in response to frequency of irrigation and gypsum application on a heavy clay soil     

D. M. Whitfield  G. C. Wright  O. A. Gyles  A. J. Taylor 《Irrigation Science》1986,7(1):37-52

Summary Effects of weekly (W) and fortnightly (F) irrigation schedules on established stands of lucerne (Medicago sativa L.) grown on gypsum treated (G) and untreated (C) heavy clay soil were investigated. Two irrigations were applied under the fortnightly regime and four under the weekly schedule during a single cutting cycle. Growth and light interception were measured during both the vegetative and mature phases of growth.Leaf expansion, light interception and dry matter production were greater under treatments W _G and W _C, with yield increasing from 3.4 t ha^–1 under the fortnightly schedule to 5.0 t ha-1 with weekly irrigation. Gypsum treatment was effective under the more frequent irrigation schedule. Specific leaf area and the proportion of stem were both increased by treatments W _G and W _C. The responses to irrigation were therefore characteristic of those elicited by a more favourable plant moisture status. Growth was analysed in terms of light interception, the efficiency of utilisation of intercepted light, the proportion of the daily dry matter gain retained by the leaves and leaf expansion. The analysis demonstrated that impaired leaf expansion contributed to a decline of approximately 15% in yield, and that impaired efficiencies of utilisation of intercepted light contributed to losses of approximately 30% under the less frequent irrigation schedule.A comparison of growth rates and efficiencies of energy conversion with published data showed that satisfactory rates of growth and levels of productivity were achieved on the heavy soils of the local region using gypsum treatment and the more frequent irrigation schedule.  相似文献   

Extensive umbilical herniation of the large colon in a foal     

C. J. Bodaan  L. Panizzi  A. J. Stewart  E. Cypher  L. Whitfield  C. B. Riley 《Equine Veterinary Education》2014,26(7):341-344

A 5‐month‐old Warmblood cross colt was presented with focal swelling of the ventral abdomen extending from the umbilicus to the scrotum in the absence of colic signs. Palpation and ultrasound examination revealed the presence of incarcerated large intestine within the subcutaneous space adjacent to the caudal ventral abdomen and prepuce. Surgery was performed and revealed that the umbilical hernia sac had ruptured, and confirmed that the left dorsal and ventral colon were present in the subcutaneous space. The mild degree of vascular compromise of the large colon did not necessitate resection and so it was replaced within the abdomen. The abdominal wall defect was closed and the subcutaneous dead space was reduced by using a walking suture pattern. Herniation of the large colon through the umbilicus with dissection through the subcutaneous tissues of the ventral abdominal wall and prepuce has not been previously reported in foals. Ultrasonography permits differentiation of herniated small intestine from large intestine.  相似文献   

Predictive mapping for management and conservation of seagrass beds in North Carolina     

Nina M. Kelly  Mark Fonseca  Paula Whitfield 《水产资源保护:海洋与淡水生态系统》2001,11(6):437-451

An Erratum has been published for this article in Aquatic Conservation: Marine and Freshwater Ecosystems 12(2), 2002 577

• 1. This research extends techniques of predictive mapping from their application in terrestrial environments to marine landscapes by investigating the relationship between seagrass and hydrodynamics in Core Sound, North Carolina, USA.
• 2. An empirically derived logistic multiple regression model and a Boolean logic suitability model were used to produce several predictive map products, including: susceptibility of seagrasses to storms, probability of seagrass cover, and suitability of areas for restoration of seagrasses. A visual comparison between these maps and conventional seagrass polygon maps allows for a discussion of ‘field’ versus ‘object’ mapping, and the ramifications for management based on different cartographic techniques.
• 3. The predictive method used here showed that only a small portion (19%) of the seagrass bed in the study area would be expected to have a high probability of seagrass coverage. The majority of the seagrass habitat in the study area was predicted to have less than 50% probability of seagrass cover. In addition, 16% of the nearly 2000 ha of seagrass within the study area were predicted to be highly susceptible to acute storm events. Moreover, using a conservative set of site selection criteria, only 7% of the study area encompassed by seagrass habitat was predicted to have a high probability of successful restoration if injured.
• 4. This method provides for an inexpensive way to scale‐up from high‐resolution data to a coarser scale that is often required for conservation and management.

Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Fish species redundancy in estuaries: A major conservation concern in temperate estuaries under global change pressures     

Alan K. Whitfield  Trevor D. Harrison 《水产资源保护:海洋与淡水生态系统》2021,31(4):979-983

1. Fish assemblages in estuaries have a much lower species richness (number of taxa) when compared with the combined numbers of freshwater and marine species from adjacent aquatic ecosystems. This is primarily because of the relatively harsh and fluctuating physico-chemical conditions in estuaries compared with the more stable freshwater and marine environments.
2. A comprehensive fish survey of estuaries in South Africa is used as a basis to determine fish species richness in subtropical, warm temperate, and cool temperate systems along the coast, and to assess the degree of redundancy in the different biogeographic regions.
3. In general, only one or two species belonging to each of the detritivorous, piscivorous, zoobenthivorous, and zooplanktivorous fish guilds are numerically well represented in the larger cool temperate estuaries, but between four and 10 species in each of these guilds are usually recorded in the larger subtropical estuaries.
4. Although the overall low redundancy of fish species groups in estuaries has already been formally recognized in the literature, this short note highlights the sensitivity of certain trophic guilds in temperate South African estuaries to any form of redundancy, a characteristic that may be equally applicable, based on declining species richness with increasing latitude, to temperate estuaries in other parts of the world.

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Unilateral ablation of the auditory cortex in the cat impairs complex sound localization     

J Cranford  R Ravizza  I T Diamond  I C Whitfield 《Science (New York, N.Y.)》1971,172(980):286-288

Unilateral ablation of the auditory cortex in the cat results in a profound deficit in attending to stimuli on the side contralateral to the lesion. The deficit is also manifested in an abnormal perception of left-right pulse pairs when the pulse which leads by a few milliseconds is contralateral to the damaged hemisphere.  相似文献   

The effects of persecution on age of breeding and territory occupation in golden eagles in Scotland     

D.P Whitfield  A.H Fielding  P.F Haworth 《Biological conservation》2004,118(2):249-259

Several studies have documented negative effects of persecution by humans on the population dynamics of large birds of prey. Several areas have seen a reduction in persecution in modern times, but the demography of large raptors still makes these birds vulnerable to such effects. In a GIS analysis, utilising data collected during two national censuses of the golden eagle Aquila chrysaetos in Scotland and contemporary data on the distribution of poisoning incidents (a common method of raptor persecution in Scotland), we show that persecution was associated with a reduction in the age of first breeding, territory vacancies, and the use of territories by non-breeding immatures. Persecution was therefore reducing adult survival and distribution and was probably creating ecological traps that attract mobile immatures, increasing subadult mortality in birds that may originate from persecution-free areas. Mapping a form of land management unique to moors managed for red grouse Lagopus lagopus scoticus shooting, where most poisoning occurs, we also show similar associations between golden eagle demography and grouse moor management. As such, persecution may be having a major impact on the golden eagle population of Scotland, since it occurs over a wide area and at least in some areas has continued unchecked over many decades.  相似文献   

Heterocyclic volatiles formed by heating cysteine or hydrogen sulfide with 4-hydroxy-5-methyl-3(2H)-furanone at pH 6.5     

Whitfield FB  Mottram DS 《Journal of agricultural and food chemistry》2001,49(2):816-822

The reaction of 4-hydroxy-5-methyl-3(2H)-furanone (HMF) with cysteine or hydrogen sulfide at pH 6.5 for 60 min at 140 degrees C produced complex mixtures of volatile compounds, the majority of these containing either sulfur or nitrogen. Of the 68 compounds detected, 63 were identified, some tentatively, by GC-MS. Among the identified compounds were thiophenes (10), thiophenones (6), thienothiophenes (5), thiazoles (5), trithiolanes (4), pyrazines (6), and oxazoles (4). More compounds were produced in the reaction of HMF with cysteine (63) than were formed in the reaction with hydrogen sulfide (33). In both systems, thiophenones were major reaction products, accounting for 25-36% of the total volatiles formed. Possible reasons for the differences in the composition of the two systems are discussed. The contributions of these reactions, and their products, to the flavor of heated foods are considered.  相似文献