Our objectives were to determine the effects of an injectable formulation of calcitriol on mineral metabolism and immune function in postpartum Holstein cows that received an acidogenic diet prepartum to minimize hypocalcemia. In experiment 1, cows within 6 h of calving received calcitriol (0, 200, or 300 μg) to determine the dose needed to increase plasma concentrations of Ca; 300 μg was sufficient to sustain Ca for at least 3 d. In experiment 2, multiparous cows were assigned randomly to receive only vehicle (control, n = 25) or 300 μg of calcitriol (n = 25) subcutaneously within the first 6 h after calving. Blood was sampled before treatment and 12 h later, then daily until 15 d in milk (DIM), and analyzed for concentrations of ionized Ca (iCa), total Ca (tCa), total Mg (tMg), and total P (tP), metabolites, and hormones. Urine was sampled in the first 7 DIM and analyzed for concentrations of tCa, tMg, and creatinine. Neutrophil function was evaluated in the first week postpartum. Dry matter intake and production performance were evaluated for the first 36 DIM. Calcitriol administration increased concentrations of calcitriol in plasma within 12 h of application from 51 to 427 pg/mL, which returned to baseline within 5 d. Concentrations of iCa and tCa increased 24 h after treatment with calcitriol. Concentrations of iCa (control = 1.08 vs. calcitriol = 1.20 mM), tCa (control = 2.23 vs. calcitriol = 2.33 mM), and tP (control = 1.47 vs. calcitriol = 1.81 mM) remained elevated in cows treated with calcitriol until 3, 5, and 7 DIM, respectively, whereas concentration of tMg (control = 0.76 vs. calcitriol = 0.67 mM) was less in calcitriol cows than control cows until 3 DIM. Concentrations of parathyroid hormone decreased in calcitriol cows compared with control cows (control = 441 vs. calcitriol = 336 pg/mL). Calcitriol tended to increase plasma concentrations of β-hydroxybutyrate and serotonin, but concentrations of glucose, nonesterified fatty acids, and C-telopeptide of type I collagen in plasma did not differ between treatments. Cows treated with calcitriol excreted more urinary tCa (control = 0.5 vs. calcitriol = 2.1 g/d) and tMg (control = 4.5 vs. calcitriol = 5.0 g/d) in the first 7 and 2 DIM, respectively, than control cows. Compared with control, calcitriol improved the proportion of neutrophils with oxidative burst (control = 31.9 vs. calcitriol = 40.6%), mean fluorescence intensity for oxidative burst (control = 90,900 vs. calcitriol = 99,746), and mean fluorescence intensity for phagocytosis (control = 23,887 vs. calcitriol = 28,080). Dry matter intake, yields of milk, and milk components did not differ between treatments. Administration of 300 μg of calcitriol at calving was safe and effective in increasing blood concentration of iCa and plasma concentrations of calcitriol, tCa, and tP for the first 6 d after treatment, and improved measures of innate immune function in early-lactation Holstein cows.
The purpose of this study was to investigate histological changes in dairy cows' hooves with or without injuries from naturally acquired laminitis. Cull cows with no clinical signs of hoof abnormalities (G1, n=9) and those with macroscopic lesions associated with laminitis without (G2, n=23) or with lameness (G3, n=7) were used in the study. After slaughter, samples of dermo-epidermal junctions of sole, axial and dorsal regions of the hoof were obtained and histologically processed using HE and PAS staining. Congestion, hemorrhage and inflammatory infiltrate in the dermis of sole, axial and dorsal regions were blindly and semiquantitatively evaluated by the same researcher. Inflammatory infiltrate was evaluated in the dermal laminae of axial and dorsal regions. The morphology of epidermal cells and the presence of irregularities in three regions of the basement membrane (BM) length were examined using PAS staining. Scores of lesions in different regions of the hoof in the same group and in different groups for each region of the hoof were compared using non-parametric analyses. Inflammatory infiltrate in the dermis of all regions of the hoof was detected in all groups with no significant statistical difference. Cows with no clinical signs of hoof abnormalities secondary to laminitis (G1) have inflammation scores and epidermal cell changes similar to those of groups with laminitis injuries, suggesting the existence of a prodromal phase for this disease in bovines. BM had irregularities with a variable intensity along its length, however, with no difference among groups. The pattern of BM irregularities found has not been reported so far and does not resemble the BM collapse described in horses and cattle with induced acute laminitis. Is it concluded that even in the absence of macroscopic hoof signs associated to laminitis, dairy cows have histological injuries compatible with inflammation of the dermo-epidermal junction as in affected animals. Basement membrane of cows with or without laminitis associated lesions had irregularities with an irregular distribution along its length which need to be further studied.
RESUMOCom o objetivo de se verificarem possíveis correlações entre a falange distal, o estojo córneo e a obesidade, 55 equinos de patrulhamento provenientes do Regimento de Cavalaria Alferes Tiradentes do Estado de Minas Gerais -RCAT tiveram seus dígitos torácicos radiografados. Posteriormente, os animais foram classificados quanto ao acúmulo de tecido adiposo regional por métodos subjetivos (escore corporal e escore de pescoço) e objetivos (índice de massa corporal, circunferência do pescoço e determinação de espessura do tecido adiposo por meio de ultrassonografia na inserção da cauda e do abdômen). Na população estudada, o índice de massa corporal evidenciou que 52,6% dos equinos se encontravam acima do peso. A circunferência do pescoço a 50% de seu comprimento dorsal e a medida ultrassonográfica na inserção da cauda se mostraram os melhores métodos objetivos para quantificar o acúmulo de tecido adiposo. Foram identificadas particularidades radiográficas características da população estudada que diferem de parâmetros internacionais. Observaram-se correlações significantes entre sinais de obesidade e medidas radiográficas indicadoras de laminite, sugerindo associação entre essas duas condições na população estudada. Palavras-chave: obesidade, composição corporal, laminite ABSTRACT With the aim to verify possible correlations between the spatial relationship between the distal phalanx and the hoof and signs of obesity, 55 horses from the Cavalry Regiment Alferes Tiradentes of Minas Gerais State Police -RCAT had x-rays taken from their thoracic hoofs. After that, horses were classified based on their subjective (body condition and neck scores) and objective (body mass index, neck circumferences, ultrasound measurement of fat tissue of the tail and on abdomen) methods for adiposity.Within the population, the body mass index showed that 52.6% of horses were overweight. Neck circumference at 50% of its dorsal length and ultrasound measurement of fat thickness on the insertion of the tail were the best objective methods. We identified specific radiographic characteristics of the population that were different from international parameters. Significant correlations among signs of obesity and measurements that indicate lamintis were found, suggesting association between these conditions in this horse population.
A alta incidência de afecções podais, que, ao se complicarem, disseminam a infecção para estruturas internas dos dedos, requer exame detalhado mediante emprego de técnicas auxiliares de diagnóstico. Objetivouse com este estudo determinar os aspectos morfológicos dos dígitos de bovinos claudicantes, classificando e quantificando a ocorrência de alterações macroscópicas e histopatológicas, bem como estabelecer correlações entre as variáveis macroscopia-microscopia, claudicaçãomacroscopia e claudicação-microscopia. Foram utilizados 18 bovinos mestiços, machos, manejados em sistema intensivo durante o período de 112 dias. Os animais foram divididos em três grupos: (GI) claudicação de escore 2; (GII) claudicação escore 3 e (GIII) claudicação escore 4, resultando em 72 membros a serem avaliados. Realizaram-se exames clínicos e histopatológicos em todas as extremidades dos membros, sendo coletadas amostras na porção dorsal e palmar/plantar para realização do histopatológico, totalizando 144 amostras. Observou-se que 15 (83,3%) dos 18 animais estudados apresentaram a associação de lesões macro com lesões microscópicas, sendo que seis animais pertenciam ao GIII, cinco ao GII e quatro ao GI. A erosão de talão acometeu 16,6% dos membros torácicos esquerdo, sendo a única lesão macroscópica deste membro. Na avaliação microscópica da derme constatou-se ausência de lesões em 68,7% das amostras e em 31,3% verificou-se infiltrado inflamatório mononuclear. O infiltrado inflamatório mononuclear multifocal predominou (43,1%) em relação ao infiltrado dos tipos difuso (15,2%) e focal (4,2%), sendo que três infiltrados inflamatórios do tipo focal eram leves e onze eram difusos e severos. De acordo com a metodologia empregada, pôde-se concluir que o escore de locomoção, associado à caracterização das lesões podais e ao exame histopatológico, auxiliou no diagnóstico de claudicação e que existe relação entre claudicação, lesões macroscópicas e alterações histopatológicas, mas não foi possível relacionar os tipos de lesões microscópicas às diferentes formas de manifestação das doenças podais nos bovinos estudados.
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