Dystocia in beef heifers: A review of genetic and nutritional influences     

RE Hickson  ST Morris  PR Kenyon  N Lopez-Villalobos 《New Zealand veterinary journal》2013,61(6):256-264

Breeding beef heifers for the first time at 15 months of age has potential to increase the efficiency of the beef breeding-cow herd. An increased incidence of dystocia in heifers calving at 2 years of age, compared to mature cows, is a major reason many farmers in New Zealand have not adopted the practice. The predominant type of dystocia affecting 2-year-old heifers is feto-maternal disproportion, a condition in which the fetus is too large relative to the size of the heifer's pelvis. Reducing birthweight of the calf is a means of reducing the incidence of dystocia. Birthweight and length of gestation are determined by genotype of the calf, maternal genetic effects and environmental effects.

Bulls with low estimated breeding values for birthweight have been selected for mating heifers; however, the positive genetic correlation between birthweight and mature weight meant that the progeny of these bulls tended to be lighter at finishing, making them less desirable in the beef industry. The genotype of the dam also plays a role in determining the risk of dystocia; the maternal ability of the dam to nurture the fetus influences birth- weight, and the dam's genetic potential for growth influences the size of her pelvic area. Heavy heifers tend to produce high- birthweight calves, counteracting the reduction in the incidence of dystocia resulting from the larger pelvis in larger heifers.

Manipulating feeding level during pregnancy offers an alternative method for manipulating the birthweight of calves. Little is known about the effects of nutrition in early gestation on placental development or birthweight of calves. No differences in the birthweight of calves have been observed in response to variation in feeding in mid-pregnancy, and variable responses in birthweight and the incidence of dystocia to feeding in the third trimester of pregnancy have been reported. Differences in birthweight have not always resulted in differences in the incidence of dystocia, primarily due to differences in liveweight of the heifer also induced by feeding regimens. Variability in the incidence of dystocia in response to feeding level in the third trimester of pregnancy makes it difficult to make recommendations for the feeding of heifers at this stage of gestation. More research is needed into the effects of nutrition in early gestation on fetal and placental development in cattle.  相似文献   

Assessment of perceived farming risks,communication of risk management practices,and evaluation of their efficiency in Pacific white shrimp (Penaeus vannamei) farming—a survey-based cross-sectional study     

M.  Kumaran  Anand  PR.  Kumar  J. Ashok  Muralidhar  M.  Vasagam  K. P. Kumaraguru  Vijayan  K. K. 《Aquaculture International》2021,29(6):2713-2730

Aquaculture International - Pacific white shrimp (Penaeus vannamei) farming is an important commercial aquaculture production system contributing substantially to the economic and societal...  相似文献   

SnakeMap: four years of experience with a national small animal snake envenomation registry     

M Boller  K Kelers  MA Stevenson  KD Winkel  S Hardjo  J Heller  PR Judge  HM Ong  AM Padula  C Reddrop  LCP Santos  CR Sharp  L Smart  KL Swindells  D Tabrett  JR Wierenga 《Australian veterinary journal》2020,98(9):442-448

SnakeMap is a national cloud-based, veterinary snakebite registry. It was designed to prospectively collect data of the clinical circumstances and temporospatial information on cases of snake envenomation in dogs and cats. We herein introduce the project and summarise the data from the first 4 years of SnakeMap. The registry is a veterinary community-based online database allowing case entry from veterinary hospitals across Australia. Registry data comprise hospital characteristics, patient characteristics, envenoming snake type, treatment and outcome variables, including time and geolocation of the snake bite. We present summative information on select key variables from the SnakeMap registry (1 July 2015 to 30 June 2019). Twenty-eight hospitals from 6 states/territories entered 624 cases into the registry, including 419 dogs (67%) and 205 cats (33%). Bite time was available in 216 animals of which 90 (42%) were reported to be bitten in the 3 hours between 03:00 pm and 05:59 pm; median bite to presentation interval was 60 (interquartile range [IQR] 30, 211) minutes in dogs and 95 (IQR 41, 238) minutes in cats. Bites occurred in the owner's yard in 356 dogs (85%) and 53 cats (26%). A snake venom detection kit was used in 172 cases (28%) and antivenom was administered in 523 cases (85%). Most animals (n = 534, 88%) survived to discharge (median hospitalisation of 25 [IQR 16, 62] hours). SnakeMap effectively collects relevant clinical data from dogs and cats with presumed snake bite and provides locally specific information on the epidemiology of snake envenomation in small animals.  相似文献   

Use of tilmicosin in a severe outbreak of respiratory disease in weaned beef calves   总被引：1，自引：0，他引：1  

PR SCOTT  M. McGOWAN  ND SARGISON  CD PENNY  BG LOWMAN† 《Australian veterinary journal》1996,73(2):62-64

Severe respiratory disease, associated with seroconversion to bovine respiratory syncitial virus (BRSV), caused the death of two cattle and necessitated antibiotic treatment of 70 calves (rectal temperature of 39.6°C or greater) from a group of 96 (73%) during an 8-day period. Tilmicosin injection resulted in a reduction in median rectal temperature from 40.3°C to 39.2°C and 39.0°C for the first and second days after treatment. The rectal temperature was 39.5°C or lower in 72% (48 of 67) and 96% (64 of 67) of cattle 1 and 2 days after tilmicosin treatment, respectively. Ten cattle were re-treated with tilmicosin 6 to 16 days after the first treatment. Our study demonstrated that bovine respiratory syncytial virus infection could cause severe respiratory disease in a beef herd that had no previous history of BRSV-related disease. Secondary bacterial invasion after BRSV infection was controlled effectively by tilmicosin treatment but repeat antibiotic treatments were occasionally necessary due to bacterial re-infection of the respiratory tract.  相似文献   

Control of clinical paratuberculosis in New Zealand pastoral livestock     

M Gautam  A Ridler  PR Wilson  C Heuer 《New Zealand veterinary journal》2018,66(1):1-8

This review summarises current control measures for clinical paratuberculosis (Johne’s disease; JD) in New Zealand pastoral livestock. Most New Zealand sheep, deer, beef and dairy cattle herds and flocks are infected by Mycobacterium avium ssp. paratuberculosis (Map). Dairy cattle and deer are mostly infected with bovine (Type II), and sheep and beef cattle with ovine (Type I) strains. Control in all industries is voluntary. While control in sheep and beef cattle is ad hoc, the dairy and deer industries have developed resources to assist development of farm-specific programmes.

The primary target for all livestock is reduction of the incidence rate of clinical disease rather than bacterial eradication per se. For dairy farms, a nationally instituted JD-specific programme provides guidelines for risk management, monitoring and testing clinically suspect animals. While there is no formal programme for sheep farms, for those with annual prevalences of clinical disease >2%, especially fine wool breeds, vaccination may be a cost effective control option. The deer industry proactively monitors infection by a national abattoir surveillance programme and farmers with an apparent high disease incidence are encouraged to engage with a national network of trained consultants for management and control advice. Evaluation of the biological and economic effectiveness of control in all industries remains to be undertaken. Nevertheless, opportunities exist for farmers, who perceive significant JD problems in their herds/flocks, to participate in systematic best-practice activities that are likely to reduce the number of clinical infections with Map on their farms, and therefore the overall prevalence of JD in New Zealand’s farming industries.  相似文献   

BVD virus type 2 in British cattle     

Cranwell MP  Jones JR  Wakeley PR 《The Veterinary record》2005,156(8):257-258

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BVD virus in a British alpaca     

Foster AP  Houlihan M  Higgins RJ  Errington J  Ibata G  Wakeley PR 《The Veterinary record》2005,156(22):718-719

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PEAT MATS FOR GERMINATION TESTS OF FOREST TREE SEEDS     

Wakeley PC 《Science (New York, N.Y.)》1932,76(1983):627-628

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Field comparison of the interferon-gamma assay and the intradermal tuberculin test for the diagnosis of bovine tuberculosis   总被引：13，自引：0，他引：13  

PR WOOD  LA CORNER  JS ROTHEL  C. BALDOCK†  SL JONES†  DB COUSINS§  BS McCORMICK¶  BR FRANCIS§  J. CREEPER¶  NE TWEDDLE 《Australian veterinary journal》1991,68(9):286-290

An extensive field comparison of the gamma interferon (IFN-gamma) assay and the single intradermal tuberculin test for the diagnosis of bovine tuberculosis was conducted in Australia. The specificity of the IFN-gamma assay was determined by testing more than 6000 cattle from tuberculosis-free herds and varied from 96.2% to 98.1%, depending on the cut-off point chosen to define a positive reactor. For the sensitivity trial, cattle from herds being de-populated because of bovine tuberculosis were examined with both assays. The sensitivity of the IFN-gamma assay was shown to be significantly higher than the single intradermal tuberculin test and varied from 76.8% to 93.6% depending on the method of interpretation. A maximum overall sensitivity of 95.2% was obtained by testing with the IFN-gamma and the tuberculin test in parallel. The superior sensitivity of the IFN-gamma assay and the ability to adjust the sensitivity of the system depending on the task involved, will provide the Australian Tuberculosis Eradication Campaign with a valuable additional test to enable it to accomplish its goals.  相似文献   

The effects of antigenic competition on the efficacy of multivalent footrot vaccines     

CL SCHWARTZKOFF  JR EGERTON†  DJ STEWART‡  PR LEHRBACH§  TC ELLEMAN¶  PA HOYNE¶ 《Australian veterinary journal》1993,70(4):123-126

SUMMARY A multivalent footrot vaccine has been developed, containing pilus antigens produced in recombinant Pseudomonas aeruginosa and representing all nine serogroups of Dichelobacter (Bacteroides) nodosus commonly recognised in the field. The responses of sheep to the multivalent vaccine have been compared with those to monovalent vaccines representing only a single serogroup. Antigenie competition between serogroups occurred in sheep immunised with the multivalent formulation, but high levels of protection were still achieved. The study showed that in multivalent footrot vaccines, antigenic competition is predominantly due to the presence of a family of immunologically-related pilus antigens rather than to interference by extraneous proteins.  相似文献