Effect of pre‐milking teat disinfection on clinical mastitis incidence in a dairy herd in Northern Queensland,Australia          下载免费PDF全文

SM Rowe  WP Tranter  RA Laven 《Australian veterinary journal》2018,96(3):69-75

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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   

Estimating fetal age: how accurate is it really?     

Richard Laven 《New Zealand veterinary journal》2016,64(6)

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Systemic bioavailability of erythromycin in cattle when applied by footbath     

Hartog BJ  Tap SH  Pouw HJ  Poole DA  Laven RA 《The Veterinary record》2001,148(25):782-783

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Dietary protein and the reproductive performance of cows     

Laven RA  Drew SB 《The Veterinary record》1999,145(24):687-695

Increasing a cow's intake of dietary protein intake can increase its milk production, but can also reduce its fertility. This paper reviews the effects of increasing dietary protein on the fertility of the dairy cow, and the mechanisms that may produce them. The effects vary widely, but all stages of the reproductive cycle from the return to cyclicity after parturition, to the survival of the embryo, may be affected. However, the underlying cause of the link between protein intake and fertility is unclear. Fertility could be reduced by a direct toxic effect of protein breakdown products, but alternatively the increased energy demand for their metabolism could be responsible. The effect of protein degradability is also uncertain. Excess rumen degradable protein is commonly associated with reduced fertility, but similar effects are produced by diets that contain excess rumen undegradable protein. Increasing the intake of protein of all degradabilities has significantly different effects on blood biochemistry than a reduction in the intake of energy, suggesting that not all the effects of protein are due to energy imbalance. The primary site of action of the effect is also unclear. Limited evidence suggests that it is localised to the reproductive system, but effects on the pituitary and hypothalamus, as well as the ovary and uterus, have all been postulated. It is also uncertain what toxic principle is involved. Ammonia, nitrate and urea have all been suggested, but there is no conclusive evidence. Although a high protein intake has been postulated to have an effect on fertility for over 30 years, the evidence remains inconclusive, and the aetiology and pathogenesis of the effect remain obscure.  相似文献   

Farm animal disease surveillance     

Howe M  Laven R  Andrews T  Watson C  Biggs A  White M 《The Veterinary record》2003,152(9):270

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Meningoencephalitis in an adult cow due to Mortierella woifli.     

John S Munday  Richard A Laven  Geoff M B Orbell  Sushil K Pandey 《Journal of veterinary diagnostic investigation》2006,18(6):619-622

A 7-year-old dairy cow presented with clinical signs of neurologic disease. Despite treatment with penicillin, the cow died 36 hours after initial presentation. Necropsy examination revealed multiple foci of hemorrhage within the cerebrum and thickened meninges. Additionally, endometritis and consolidation of approximately 30% of both lungs was observed. Histology revealed necrotizing vasculitis, infarction, and hemorrhage within sections of the brain, uterus, and lung. Large numbers of intralesional fungal hyphae were visible. Because only formalin-fixed tissue was available, polymerase chain reaction was used to make an etiologic diagnosis of Mortierella wolfii.  相似文献   

Acute cortisol responses of calves to scoop dehorning using local anaesthesia and/or cautery of the wound   总被引：1，自引：0，他引：1  

SP SYLVESTER  DJ MELLOR  KJ STAFFORD  RA BRUCE  RN WARD 《Australian veterinary journal》1998,76(2):118-122

Objective To measure plasma cortisol responses in calves dehorned using a scoop after administration of local anaesthesia and/or cautery of the wounds.
Design A physiological study with controls.
Procedure There were six treatments: control handling with and without local anaesthesia, dehorning, dehorning after local anaesthesia, dehorning followed by wound cautery, and dehorning after local anaesthesia followed by wound cautery. Blood samples were taken before and after dehorning.
Results Dehorning caused an increase in plasma cortisol concentrations, which decreased a little to plateau values and then declined to pretreatment values 3 to 4 h after dehorning. The peak was smaller after local anaesthesia was administered but when its effects wore off, cortisol concentrations increased and thereafter were similar to those in the dehorned animals. The combination of local anaesthesia and cautery resulted in a plasma cortisol response similar to those in control calves with or without local anaesthesia.
Conclusions If plasma cortisol concentrations reflect the distress being experienced by the calves, then local anaesthesia reduces the acute distress for about 3 h after dehorning but not during the subsequent 3 to 4 h. Combining local anaesthetic and cautery prevented the significant increase in plasma cortisol following dehorning and may eliminate the acute distress caused by scoop dehorning.  相似文献   

Successful medical treatment of splenic abscesses in a horse     

CM STEEL  RA LONSDALE  JR BOLTON 《Australian veterinary journal》1998,76(8):541-542

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Genital pathology of feral male goats   总被引：1，自引：0，他引：1  

S TARIGAN  PW LADDS  RA FOSTER 《Australian veterinary journal》1990,67(8):286-290

Genitalia from 1000 feral male goats derived from western Queensland and New South Wales were examined after slaughter at an abattoir and the prevalence of abnormalities determined. Ulcerative balanoposthitis, considered due to caprine herpesvirus infection, was observed in 11 animals (1.1%); acidophilic intranuclear inclusions were found in 7 of these. Other conditions included focal hypoplasia of seminiferous tubules in 2 bucks (0.2%), segmental aplasia of the epididymis (one buck, 0.1%), bulbourethral gland cysts with contained aggregations (33 bucks, 3.3%) and haemangiosarcoma of the bulbourethral gland in one animal. The low prevalence of several conditions such as spermatic granuloma, cryptorchidism, and testicular hypoplasia, was attributed largely to the fact that the bucks examined were horned so that the recognised association between genital abnormalities and polledness did not apply.  相似文献