Hypercalcaemia in two dogs caused by excessive dietary supplementation of vitamin D

A three-year-old Border collie was presented with a two-week history of lethargy, stiff gait, polydipsia and polyuria. Biochemical analysis revealed hypercalcaemia. Serum concentrations of 25-hydroxyvitamin D (25[OH]D) and 1,25-dihydroxyvitamin D (1,25[OH]2D) were markedly elevated and parathyroid hormone was undetectable. Subsequent analysis of the dog's diet revealed that the food contained excessive amounts of vitamin D. The hypercalcaemia resolved following treatment with bisphosphonates and dietary change. Hypervitaminosis D was diagnosed in a second unrelated dog, which had been fed the same brand of dog food as case 1. The dog was also hypercalcaemic and had markedly elevated serum concentrations of 25(OH)D and 1,25(OH)2D. Hypervitaminosis D in dogs has been reported to occur secondarily to ingestion of either rodenticides containing cholecalciferol or antipsoriatic ointments that contain vitamin D analogues. Hypervitaminosis D has also been reported following the treatment of hypoparathyroidism. To the authors' knowledge, this is the first report of hypervitaminosis D in dogs following the accidental over supplementation of a commercial diet with vitamin D. While the benefits of adequate dietary vitamin D are well established in dogs, the potential deleterious effects of over supplementation of vitamin D should also be acknowledged.     

DETERMINATION OF ULTRA-VIOLET LIGHT ABSORPTION BY CERTAIN BACTERIOPHAGES

The absorption of ultra-violet light by three bacteriophages C13, C16 and C36, prepared with a strain of Escherichia communior has been determined. Each bacteriophage preparation showed a characteristic absorption curve, when the wave-length was plotted against the photographic density. Crude bacteriophage preparations absorbed more light than one such preparation obtained in a purer state, but the wavelength of maximum absorption remained the same.     

Biocontrol of soil-borne plant pathogens: Concepts and their application

A few soil-borne plant pathogens have been controlled successfully by commercial formulations of biocontrol agents, but many attempts to develop biocontrol inoculants, although promising under experimental conditions, have met with difficulties in practice. The reasons for this are discussed in this review, which outlines some of the major findings on the behaviour of microbial inoculants in soil. It is emphasized that biocontrol also occurs naturally in current agricultural practice and can be exploited purposely, but it is vulnerable to disruption by agrochemicals or mismanagement. The future of biocontrol of soilborne plant pathogens probably lies in integrated (biorational) control systems that combine the use of commercial inoculants, where appropriate, with management practices that maintain and enhance the natural biocontrol systems.     

Genetics of animal health and disease in cattle

There have been considerable recent advancements in animal breeding and genetics relevant to disease control in cattle, which can now be utilised as part of an overall programme for improved cattle health. This review summarises the contribution of genetic makeup to differences in resistance to many diseases affecting cattle. Significant genetic variation in susceptibility to disease does exist among cattle suggesting that genetic selection for improved resistance to disease will be fruitful. Deficiencies in accurately recorded data on individual animal susceptibility to disease are, however, currently hindering the inclusion of health and disease resistance traits in national breeding goals. Developments in 'omics' technologies, such as genomic selection, may help overcome some of the limitations of traditional breeding programmes and will be especially beneficial in breeding for lowly heritable disease traits that only manifest themselves following exposure to pathogens or environmental stressors in adulthood. However, access to large databases of phenotypes on health and disease will still be necessary. This review clearly shows that genetics make a significant contribution to the overall health and resistance to disease in cattle. Therefore, breeding programmes for improved animal health and disease resistance should be seen as an integral part of any overall national disease control strategy.     

Inbreeding effects on postweaning production traits, conformation, and calving performance in Irish beef cattle

The objective of this study was to quantify the effect of inbreeding on carcass quality, growth rate, live conformation measures, and calving performance in purebred populations of Charolais, Limousin, Simmental, Hereford, and Angus beef cattle using data from Irish commercial and pedigree herds. Variables analyzed are reflective of commercial farming practices. Inbreeding was included in a linear mixed model as either a class variable or a linear continuous variable. Nonlinear effects were nonsignificant across all traits. Inbred animals had decreased carcass weight and less carcass fat. The effects of inbreeding were more pronounced in the British beef breeds. Effects for carcass weight ranged from -0.87 kg (Charolais) to -1.90 kg (Hereford) per 1% increase in inbreeding. Inbred Charolais and Hereford animals were younger at slaughter by 3 and 5 d, respectively, per percentage of increase in inbreeding, whereas the effect of inbreeding on age at slaughter differed significantly with animal sex in the Limousin and Angus breeds. Inbred Limousin and Angus heifers were younger at slaughter by 5 and 7 d, respectively, per percentage of increase in inbreeding. Continental animals were more affected by inbreeding for live muscling and skeletal conformational measurements than the British breeds; inbred animals were smaller and narrower with poorer developed muscle. Calf inbreeding significantly affected perinatal mortality in Charolais, Simmental, and Hereford animals. The effects were dependent upon dam parity and calf sex; however, where significant, the association was always unfavorable. Dam inbreeding significantly affected perinatal mortality in Limousin and Hereford animals. Effects differed by parity in Limousins. Inbred first-parity Angus dams had a greater incidence of dystocia. Although the effects of inbreeding were some-times significant, they were small and are unlikely to make a large financial effect on commercial beef production in Ireland.