Osteomalacia as a result of phosphorus deficiency in beef cattle grazing subtropical native pastures in Uruguay.

We investigated 2 outbreaks of osteomalacia as a result of phosphorus (P) deficiency in herds of lactating beef cows grazing subtropical native pastures in Uruguay. Cows exhibited pica, difficulty to stand and walk, rib fractures, and body weight loss even with adequate forage availability. Osteopenia and severe osteomalacia were observed on gross and histologic examination. The concentrations of bicarbonate-extractable P in soil (4.0, 4.1 mg P/kg), total P in pasture (0.9, 1.1 g P/kg), inorganic P in serum (1.0, 0.71 mmol P/L), and P in bone (73 mg P/mL) were all low. Although injectable and mineral salt supplements provided additional P in both outbreaks, these supplementary amounts were insufficient to prevent P deficiency. The P ingested by the cows from the pasture and supplements would have provided 20-55% of their daily P requirements of ~21 g P/d. Osteomalacia occurred in cattle at the 2 ranches as a result of severe P deficiency in the soil and forage, and inadequate P supplementation. Following diagnosis, control of P deficiency in beef cattle requires estimation of the amount of pasture P ingested and provision of sufficient additional supplementary P to meet the animals' requirements.

Bócio em bovinos / Goiter in cattle

Bócio é o aumento não inflamatório e não neoplásico da glândula tireoide em animais adultos e recém-nascidos. Uma das principais causas envolvidas é a deficiência nutricional de iodo. Relata-se neste trabalho, a ocorrência de três surtos de bócio em bovinos. Na primeira propriedade (Propriedade A), 60 bezerros foram afetados, sendo que 20 morreram logo após o nascimento, 30 recuperaram-se e 10 permaneceram doentes e tiveram remissão dos sinais apenas após tratamento parenteral com iodo. Na segunda propriedade (Propriedade B) uma vaca e seu feto foram acometidos e na terceira (Propriedade C) dois bezerros foram afetados. Os principais sinais clínicos observados nos bezerros foram aumento de volume bilateral na região cervical ventral, emagrecimento, dificuldade respiratória, hipotricose e desenvolvimento corpóreo retardado. Na propriedade A foi relatada ainda a ocorrência de abortamentos. Macroscopicamente, os bezerros e o feto apresentavam tireoide aumentada, vermelho-escura, com vascularização evidente e edema subcutâneo cervical. No surto dois também foi observado, à necropsia, aumento de volume da glândula tireoide da vaca. Microscopicamente, a tiroide dos bezerros e do feto apresentava folículos tireoidianos hiperplásicos, heterogêneos, destituídos de coloide e com interstício acentuadamente vascularizado. A tireoide da vaca era semelhante à dos bezerros, no entanto, possuía quantidade maior de coloide. Em todos os casos a suplementação mineral era realizada por meio da mistura de sal mineral com sal branco. Na Propriedade A o sal branco era não iodado e misturado em partes iguais com o sal mineral. Na Propriedade B o sal também era misturado a um sal branco não iodado na proporção e 1:2, respectivamente. Na Propriedade C o sal mineral e o sal branco não iodado eram ofertados em cochos separados no campo e, segundo relato do proprietário, os animais priorizavam o consumo do sal branco. Em todas as propriedades acompanhadas foi recomendada a interrupção da adição de sal branco na mistura mineral e a administração de iodo aos bezerros acometidos. Após essas medidas não foram observados novos casos nas propriedades. Apesar de ser uma enfermidade bem conhecida, ainda são poucos os relatados de casos de bócios em bovinos no Brasil. Além disso, pouco se sabe sobre as reais deficiências minerais de cada região, e que simples orientações de manejo nutricional ainda são necessárias.(AU)

Goiter is a non-inflammatory and non-neoplastic enlargement of the thyroid gland in adults and neonates. One of the main causes involved is the nutritional deficiency of iodine. In this study three outbreaks of goiter in cattle are reported. In the first outbreak (Farm A) 60 calves were affected, of which 20 died soon after birth, 30 recovered and 10 remained sick. In the second outbreak (Farm B) a cow and its fetus were affected and in the third outbreak (Farm C) two calves were affected. The main clinical signs observed were bilaterally enlarged thyroid glands, weight loss, respiratory distress, hypotrichosis and myxedema. Additionally in the Farm A abortions were reported. Macroscopically the thyroid of the calves and fetus was enlarged, dark red with evident vascularization and cervical subcutaneous edema. In the Farm B the cow showed enlarged thyroid gland as well. Microscopically the calves and the fetus had hyperplastic and heterogeneous thyroid follicles with absence of colloid and vascularized interstitium. The thyroid of the cow was also hyperplastic, but had higher amount of colloid. In all outbreaks the mineral supplementation was performed by mixing non-iodized white salt with the mineral mixture. On the property A the white salt was non-iodized and mixed in equal parts with the mineral salt. At property B the salt was also mixed to a non-iodized white salt in ratio and 1:2, respectively. In the property C, mineral salt and non-iodized white salt were offered in separate troughs in the field, and according to the owner's report the animals prioritized the consumption of white salt. In all the monitored properties it was recommended to stop the addition of white salt in the mineral mixture and the administration of iodine to the affected calves. After these measurements no new cases were observed in the properties. Despite being a well-known disease, there are still few reported cases of goiter in cattle in Brazil. Moreover, little is known about the actual mineral deficiencies of each region, and that simple nutritional management guidelines are still needed.(AU)