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排序方式: 共有350条查询结果,搜索用时 468 毫秒
111.
George Voorhout DVM PhD Richard C. Nap DVM PhD Herman A.W. Hazewinkel DVM PhD 《Veterinary radiology & ultrasound》1994,35(4):271-276
Radiographic examination of the antebrachium was performed in 16 healthy Great Danes, raised under standardized conditions, at six-week intervals from 9 to 27 weeks of age. The dogs were fed according to the National Research Council's nutrient requirements of dogs (1974). The development of the secondary ossification centers and the growth in length of the radius and ulna were noted. In the majority of dogs changes in the shape and structure of the distal ulnar metaphysis resembled disturbances in cartilage maturation and bone maturation and remodelling. An improvement in the radio-graphic appearance of the distal ulnar metaphysis was noted at the age of 27 weeks. It is concluded that the delicate processes that are involved in skeletal development may be frequently disturbed in fast growing, giant-breed dogs, without causing clinical problems. 相似文献
112.
In the present review, several cell biological and molecular aspects of virus-cell and virus-host (pig) interactions are reviewed for pseudorabies (Aujeszky's disease) virus. Concerning the virus-cell interactions, the complex cascade of events in the virus replication cycle is given together with the different mechanisms of cell-to-cell spread. The pathogenesis of pseudorabies virus infections in pigs is concentrated on the sequence of events in the respiratory tract. Finally, a short overview is given on the control of the disease and eradication of the virus by the combination of marker vaccines and discriminating ELISA. 相似文献
113.
Wapenaar W Barkema HW O'Handley RM Bartels CJ 《The Canadian veterinary journal. La revue veterinaire canadienne》2007,48(5):493-499
This study evaluated the use of bulk milk as a diagnostic tool for estimation of herd-level Neospora caninum exposure in Atlantic Canada; it was used to estimate the prevalence of dairy farms with a within-herd N. caninum-seroprevalence > or = 15% in Prince Edward Island (PEI). The variation over time of N. caninum antibodies in bulk milk is also reported. Skimmed bulk milk and individual serum samples were analyzed for N. caninum antibodies by using an enzyme-linked immunosorbent assay (ELISA). Bulk milk samples were collected in May 2004 (n = 235), May 2005 (n = 189), and June 2005 (n = 235). The prevalence of dairy farms with a within-herd seroprevalence > or = 15% on PEI was 6.4% in May 2004. In May and June 2005, respectively, 10.1% and 10.2% of farms had a > or = 15% within-herd seroprevalence. In 11 farms that were considered positive based on bulk milk samples, blood samples were collected from all adult cows in September 2005, in conjunction with a 4th bulk milk sample on the same day. The correlation coefficient between serology and bulk milk ELISA was 0.87. The results of this study demonstrate that the prevalence of N. caninum in dairy farms can be estimated by using a bulk milk ELISA. 相似文献
114.
115.
Fafetine JM Tijhaar E Paweska JT Neves LC Hendriks J Swanepoel R Coetzer JA Egberink HF Rutten VP 《Veterinary microbiology》2007,121(1-2):29-38
Serodiagnosis of Rift Valley fever (RVF) currently relies on the use of live or inactivated whole virus as antigens. The recombinant nucleocapsid (N) protein of RVF virus was tested for diagnostic applicability in an indirect enzyme-linked immunosorbent assay (I-ELISA), using sera from experimentally infected sheep (n=128), vaccinated sheep (n=240), and field-collected sera from sheep (n=251), goats (n=362) and cattle (n=100). The N-protein based I-ELISA performed at least as good as VN and HI tests. In goat the diagnostic sensitivity (D-Sn) and specificity (D-Sp) of the I-ELISA was 100% when using the anti-species IgG conjugate. Using protein G as a detection system, the D-Sn and D-Sp in goats were 99.4% and 99.5%, in sheep field sera both 100%, in cattle 100% and 98.3%, respectively. The I-ELISA based on recombinant N-protein has the potential to complement the traditional assays for serodiagnosis of RVF. Advantages of the N-protein are its safety, stability and cost-effectiveness in use and production. 相似文献
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Rienske A.R. Mortier Herman W. Barkema Karin Orsel Gregory P. Muench Janet M. Bystrom Oscar Illanes Jeroen De Buck 《The Canadian veterinary journal. La revue veterinaire canadienne》2015,56(12):1266-1270
Five calves were inoculated orally at 2 weeks of age with a dose of 5 × 109 colony-forming units of Mycobacterium avium subspecies paratuberculosis (MAP) on 2 consecutive days. Two calves developed clinical Johne’s disease at 12 and 16 months of age after being consistently positive for MAP on fecal culture and antibody enzyme-linked immunosorbent assay (ELISA), starting 2 to 3 weeks and 4 to 5 months after inoculation, respectively. 相似文献
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119.
Natural capital (land, water, air) consists of many resources, each with its own quality, dynamics and renewability, but with strong interactions. The increasing competition for the natural resources, especially land and water, calls for a basic redirection in the analysis of land use. 相似文献
120.
In the Northern Highlands of Ethiopia, integrated crop-livestock production within smallholder farms is the dominant form of agricultural production. Feed availability and quality are serious constraints to livestock production in Ethiopia in general, and in its Northern Highlands in particular. The objective of this study was to describe the relationship between feed availability and quality and live weight gain, milk and manure production and the soil C balance in Teghane, Northern Highlands of Ethiopia. The so-called JAVA model procedure, that essentially predicts metabolizable energy intake and animal production on the basis of feed quality and quantity, has been used and linked to a soil carbon balance. Forages were ranked according to their quality (on the basis of metabolizable energy intake by livestock) in descending order. Rations were formulated by stepwise including components of increasingly lower quality to calculate the trade-offs between feed quantity and quality. In the model, the soil C balance was described in relation to soil organic matter decomposition, C input from roots, grazing and/or harvesting losses, feed residues and manure. Moreover, an analysis of monetary values of live weight gain/loss, manure and draught power is included. The results of the model showed that mean daily live weight gain and milk production per TLU continuously increased with decreasing herd size, while total annual live weight gain reached a maximum (62 Mg) at the use of the 30% best feeds and a herd size of 630 TLU. Soil C balance at this level of feed use is negative and deteriorates with increasing feed use. The model estimated an optimum herd size of 926 TLU to attain the maximum combined monetary value of live weight gain, manure and draught power at 50% feed use. Actual herd size in the study area was 1506 TLU. Our results indicate that in areas where feeds of very different quality are available, maximum benefits from meat and/or milk production and soil C balance can be attained by selective utilization of the best quality feeds, through a storage and carry-over system. 相似文献