Reproductive performance in South Australian dairy herds     

TD WILSON  DM MCLEAN†  CF SALTER†  BD BARTSCH† 《Australian veterinary journal》1994,71(3):75-77

SUMMARY Herd breeding records (161) were examined from a random 10% sample of dairy farms (96) in South Australia with more than 40 cows and suitable breeding records for 1988 and/or 1989. Of these farms, 53 (55.2%) had a year-round calving pattern, 42 (43.8%) claimed to be seasonal and one was changing from a year-round to a seasonal pattern. Only 14.6% of farmers observed oestrous behaviour outside milking times and 18.8% used tailpaint. Overall, the average proportion of unobserved heats was estimated to be 32%. Artificial insemination (AI) was carried out on 85.4% of farms (16.7% used AI alone and 68.7% also used bulls) of which 32.9% used commercial technicians and 67.1% were do-it-yourself operators. Overall, the average 30-day submission rate was 59.9% and the average 49-day non-return to service rate was 58.9%. Investigation into the probable causes of suboptimal reproductive performance gave a tentative diagnosis of inefficient oestrous detection, deferral of service, inadequate nutrition, poor AI technique, insufficient bulls, and venereal/other diseases in 69.1, 32.1, 27.2, 28.4, 13.6 and 7.4% of records, respectively.  相似文献   

Effective treatment of bovine ephemeral fever     

TD St  GEORGE 《Australian veterinary journal》1997,75(3):221-222

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Australian bat lyssavirus     

TD St GEORGE 《Australian veterinary journal》1997,75(5):367-367

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Soil sulfur fractions dynamics and distribution in a tropical grass pasture amended with nitrogen and sulfur fertilizers     

Fabiana Schmidt  Fabiano Daniel De Bona  Cristiane Prezotto Silveira  Francisco Antonio Monteiro 《植物养料与土壤学杂志》2012,175(1):60-67

Soil sulfur (S) partitioning among the various pools and changes in tropical pasture ecosystems remain poorly understood. Our study aimed to investigate the dynamics and distribution of soil S fractions in an 8‐year‐old signal grass (Brachiaria decumbens Stapf.) pasture fertilized with nitrogen (N) and S. A factorial combination of two N rates (0 and 600 kg N ha^–1 y^–1, as NH₄NO₃) and two S rates (0 and 60 kg S ha^–1 y^–1, as gypsum) were applied to signal grass pastures during 2 y. Cattle grazing was controlled during the experimental period. Organic S was the major S pool found in the tropical pasture soil, and represented 97% to 99% of total S content. Among the organic S fractions, residual S was the most abundant (42% to 67% of total S), followed by ester‐bonded S (19% to 42%), and C‐bonded S (11% to 19%). Plant‐available inorganic SO₄‐S concentrations were very low, even for the treatments receiving S fertilizers. Low inorganic SO₄‐S stocks suggest that S losses may play a major role in S dynamics of sandy tropical soils. Nitrogen and S additions affected forage yield, S plant uptake, and organic S fractions in the soil. Among the various soil fractions, residual S showed the greatest changes in response to N and S fertilization. Soil organic S increased in plots fertilized with S following the residual S fraction increment (16.6% to 34.8%). Soils cultivated without N and S fertilization showed a decrease in all soil organic S fractions.  相似文献   

Nutrient Biogeochemistry of the Coastal Zone   总被引：4，自引：0，他引：4  

TD Jickells 《Science (New York, N.Y.)》1998,281(5374):217-221

The coastal seas are one of the most valuable and vulnerable of Earth's habitats. Significant inputs of nutrients to the coastal zone arrive via rivers, groundwater, and the atmosphere. Nutrient fluxes through these routes have been increased by human activity. In addition, the N:P:Si ratios of these inputs have been perturbed, and many coastal management practices exacerbate these perturbations. There is evidence of impacts arising from these changes (in phytoplankton numbers and relative species abundance, and deep-water oxygen declines) in areas of restricted water exchange. Elsewhere, the nutrient fluxes through the coastal zone appear to be still dominated by large inputs from the open ocean, and there is little evidence of anthropogenic perturbations.  相似文献   

牛奶巴氏消毒法可消灭牛传染性疱疹病毒4     

C.Bona  张乃锋  王吉峰 《中国畜牧兽医》2005,32(10):60

牛传染性疱疹病毒4(BoHV-4)是一种微疱疹病毒,普遍存在于牛群中,可以从感染牛的血清和牛奶中分离出来.研究结果表明,某些人体细胞对BoHV-4也有易感性,目前试验观察到人体细胞不会对BoHV-4持续感染,同时可以防止肿瘤坏死α-因子导致的细胞凋零.总之,所有现象表明,BoHV-4有害于公共健康.为了对人体通过牛奶和血清感染BoHV-4的率进行评估,对BoHV-4适当加热处理.对牛奶巴氏消毒以及血清加热脱补体作用进行灭活,可消除BoHV-4的传染性.因此,试验结果表明,经过适当处理可显著降低牛奶和血清中BoHV-4对人体感染的机率.  相似文献   

Impacts of major health conditions affecting the Australian sheepmeat value chain: a review     

E Dal Grande  C Caraguel  SJ Lee  TD Nielsen 《Australian veterinary journal》2021,99(1-2):32-39

Major health conditions in sheep contribute to substantial economic losses throughout the sheepmeat supply chain in Australia. A systematic review was undertaken to explore the measurable impact of six conditions: arthritis, sheep measles, pleurisy, pneumonia, grass seeds and rib fractures, on the production of lamb and mutton across the meat value chain. Peer‐reviewed scientific literature from three databases and non‐peer‐reviewed articles and reports from Australian government and non‐government websites were searched between 11 and 17 November 2019. Original articles, including studies conducted in Australia and New Zealand, that had measurable impacts on conditions of interest were included. The search yielded 16 articles and reports and were classified as producer impact and/or processor impact studies. Mortalities were quantified for pneumonia and arthritis, with pneumonia having the highest impact for producers. Grass seed infestation resulted in the highest impact on carcase and liveweight losses compared to arthritis and pneumonia. Arthritis had the highest trim weight losses for both lamb and mutton and the highest rate of carcase condemnation. Grass seed was the only condition where other impacts on the processor (chain speed and staff relocation to the boning room) were quantified. Although quantifiable production and processing losses were available for some conditions, this review has highlighted that limited quantifiable data based on scientifically sound research were not available for other conditions. The evidence for some conditions found in this review can be used to target future research activities and to further assist producers in making informed management decisions on prevention and control.  相似文献   

Volvulus of the colon in a horse associated with a mesocolic-umbilical band     

TD MOGG †  S. GROENENDYK  RH SUTTON ‡ 《Australian veterinary journal》1992,69(1):11-12

A 7-years-old Clydesdale mare was presented with severe abdominal distension and acute colic. Dilated large intestine was palpated per rectum and a ventral midline exploratory laparotomy was performed. A 180 degrees volvulus of the pelvic flexure was present, associated with an inelastic band of tissue connecting the mesocolon to the umbilicus. The band was ligated and transected, and the volvulus reduced. Postoperative complications included hyponatraemia, metabolic acidosis and laminitis. The possible aetiology of the mesocolic-umbilical band is discussed.  相似文献   

Juvenile Skeletal Structure and the Reproductive Habits of Dinosaurs     

NR Geist  TD Jones 《Science (New York, N.Y.)》1996,272(5262):712-714

Skeletal ontogeny in extant archosaurians (crocodilians and birds) indicates that the morphology of the perinatal pelvic girdle is an indicator of overall developmental maturity [that is, altriciality (nestbound) versus precociality (mobile and relatively independent)]. Comparison of the skeletal anatomy of perinatal extant archosaurians and perinatal dinosaurs suggests that known dinosaur hatchlings were precocial. These data are consistent with the overall similarity in nesting behavior of dinosaurs and modern crocodilians.  相似文献   

Growth of and potassium transport in winter wheat and durum wheat as affected by various aluminum exposure times     

Ferenc Zsoldos  Ágnes Vashegyi  Lajos Bona  Attila Pécsváradi  Zsolt Szegletes 《Journal of plant nutrition》2013,36(7):913-926

Effects of various aluminum (AlCl₃) concentration and exposure times (6, 12, and 24 h and 3 d) on growth and potassium (K) transport were studied in two wheat species (Triticum aestivum L. cv. Jubilejnaja 50 and Triticum durum Desf. cv. GK Betadur) grown in low salt conditions hydroponically. In longer (3 d) Al exposure times at pH 4.1, the inhibition of root growth appeared at 10 μM Al³⁺ treatment in GK Betadur, and at 50 μM Al³⁺ treatment in Jubilejnaja 50. Shoot growth was not influenced by Al³⁺ treatment, except at 100 μM in 7 d experiments. In 6, 12, and 24 h Al³⁺ exposure times, at low pH, the K⁺(⁸⁶Rb) influx in roots increased as the Al³⁺ concentration increased in the outer medium in both species. It also appeared in K⁺(⁸⁶Rb) transport toward the shoots, except by higher Al³⁺ treatments of GK Betadur seedlings. At the same time, in longer‐term (3 d) Al³⁺ treatments, a striking inhibition were observed in K⁺(⁸⁶Rb) influx and K⁺ concentration of roots and shoots. The K⁺concentration of roots and shoots measured at the end of 24 h Al³⁺ exposure times was significantly not affected by Al³⁺ treatment. Durum wheat proved to be more sensitive to the Al toxicity than common winter wheat.  相似文献