Response of cows with osteomalacia grazing sub-tropical native pastures to phosphorus supplementation with loose mineral mix or feed blocks.

Osteomalacia outbreaks often occur in cattle grazing native pastures in regions with endemic phosphorous (P) deficiency. This study evaluated the responses of two groups of cows, initially with clinical signs of chronic P deficiency, to P supplements (100 g P/kg) offered ad libitum for 13 weeks as a loose mineral mix (LMM group) or the same mineral mix offered as blocks (BMM group). Half of the cows in each group were categorized as 'with' or 'without' severe osteopenia according to a test that depended on the resistance to penetration of a needle through the left lateral process of the L4-L5 lumbar vertebra. The groups grazed two paddocks that were switched each 3 weeks. The liveweight, supplement intakes, and the P-concentrations in soil, forage, blood, and external cortical bone (ECB) of the ribs were measured. The bicarbonate-extractable P in soil was 3.5 mg/kg. The mean of total P in forage (0.95 g/kg/DM), inorganic P in serum (iP, 0.96 mmol/L), and total P in the ECB of the ribs (85 mg/mL) at the beginning of the experiment were all low and consistent with severe chronic P deficiency. The P supplementation allowed clinical recovery in 18/20 cows with their serum and ECB P and calcium approaching normal values and in the two remaining cows the only sign was abnormal gait. Cows consumed more of the LMM than BMM supplement (means 8.3 and 6.6 g P/day, respectively). After 13 weeks cows initially classified as 'with severe osteopenia' and supplemented with LMM had higher (P < 0.05) final liveweight (difference = 21.6 kg), iP (difference = 0.74 mmol/L), bone Ca (difference = 65.7 mg/mL) and bone P (difference = 26.5 mg/mL) concentrations and lower (P < 0.01) final serum Ca/iP ratio (difference = -0.65) than cows with severe osteopenia but supplemented with BMM. The treatment of severe P deficiency cows grazing P deficient sub-tropical grasslands by P supplementation for 13 weeks was more effective with LMM than BMM.

Epidemiological and clinicopathological findings in 15 fatal outbreaks of salmonellosis in dairy calves and virulence genes in the causative Salmonella enterica Typhimurium and Dublin strains.

Salmonella enterica is a major food-borne pathogen that affects cattle-rearing systems worldwide. Little information is available on the epidemiology and pathology of salmonellosis and the virulence genes (VGs) carried by Salmonella in spontaneous outbreaks in cattle. We describe epidemiological findings in 15 fatal outbreaks of salmonellosis in Uruguayan dairy farms and the age, clinical signs, and pathology in 20 affected calves. We also describe the serotypes and frequencies of 17 VGs in the causative Salmonella strains and explore their associations with epidemiological, clinical, and pathological findings. Salmonella Typhimurium and Dublin were identified in 11/15 and 4/15 outbreaks, respectively. The most frequent reason for consultation was digestive disease (8 outbreaks caused by S. Typhimurium), followed by sudden death (4 outbreaks, 3 caused by S. Dublin). Morbidity, mortality, and lethality ranged 4.8-100%, 3.8-78.9%, and 10-100%, without significant differences between serotypes. Diarrhea, the most common clinical sign (14 cases), was associated with the Typhimurium serotype (OR = 26.95), especially in ≤ 30-day-old calves with fibrinous enteritis as the main autopsy finding. The Dublin serotype affected ≥ 50-day-old calves and was associated with fibrinosuppurative splenitis (p = 0.01) and tubulointerstitial nephritis (OR = 48.95). The chances of the Dublin serotype increased significantly with age. There was low variability of VG across serotypes. The pefA gene was associated with the Typhimurium serotype (OR = 21.95), macroscopic enteritis (p = 0.03), and microscopic fibrinosuppurative splenitis (p = 0.04). Understanding the epidemiology, pathology, and virulence of S. enterica at the farm level is key to delineating prevention and control strategies to mitigate its impact on animal and human health.

Thyroid parafollicular cell hyperplasia and carcinoma in a sheep with enzootic calcinosis due to Nierembergia rivularis poisoning / [Hiperplasia e carcinoma de células parafoliculares da tireóide em ovino com calcinose enzoótica associada a intoxicação por Nierembergia rivularis]

Calcinose enzoótica, causada por Nierembergia rivularis, no Uruguai, e Nierembergia veitchii, no Brasil, é uma doença caracterizada por mineralização de tecidos moles, hiperplasia das células parafoliculares da tireoide e elevação nos níveis de cálcio e fósforo. Descreve-se um caso de hiperplasia e carcinoma de células parafoliculares bilateral em um ovino de quatro anos, com calcinose enzoótica associada à intoxicação por Nierembergia rivularis. O diagnóstico histológico de hiperplasia e carcinoma de células parafoliculares é suportado pelas marcações imuno-histoquímicas positivas para calcitonina, peptídeo relacionado ao gene da calcitonina e enolase neurônio específica. Como a hiperplasia de células parafoliculares é uma lesão pré-neoplásica induzida por hipercalcemia, sugere-se que a hipercalcemia crônica causada pela intoxicação por N. rivularis pode ter induzido hiperplasia de células parafoliculares seguida de transformação em carcinoma, neste caso. Os efeitos carcinogênicos das plantas calcinogênicas no sistema endócrino devem ser melhor explorados.(AU)

Antibiotic resistance in Salmonella enterica isolated from dairy calves in Uruguay.

Salmonella enterica is an important animal and human pathogen that can cause enteritis and septicaemia in calves. Generally, antibiotics are prescribed for the treatment of salmonellosis in dairy calves. Here, we report the isolation of antibiotic resistant S. enterica serotypes from calves, including multidrug-resistant isolates. A total of 544 faecal samples from live healthy and diarrheic dairy calves from 29 commercial dairy farms and organ samples from 19 deceased calves that succumbed to salmonellosis in 12 commercial dairy farms in Uruguay were processed for selective S. enterica culture. In total, 41 isolates were serotyped, and susceptibility to 14 antibiotics, from 9 classes of compounds, was evaluated by disk-diffusion test. The minimum inhibitory concentration (MIC) was determined by microdilution. Salmonella Typhimurium was the most frequent serotype, followed by S. Dublin and S. Anatum. Whether determined by diffusion assay or microdilution, resistance to tetracycline, streptomycin and ampicillin were the most frequently pattern found. Based on MIC, 5 isolates were resistant to at least one antibiotic, 21 were resistant to 2 antibiotics, and 14 were multidrug-resistant (resistant to at least one antibiotic in 3 different categories of antibiotics). Eleven different resistance patterns were found. Multidrug resistance in S. enterica is a concern for animal and public health not only because of its zoonotic potential but also due to the possibility of transfer resistance determinants to other bacterial genera. This represents the first report of the antibiotic resistance in S. enterica in dairy farms in Uruguay.

Urocystitis and Ureteritis in Holstein Calves with Septicaemia Caused by Salmonella enterica Serotype Dublin.

Salmonellosis is an enteric or multisystemic disease of global distribution that affects numerous animal species. Although Salmonella enterica has been associated with urinary tract lesions in man, information on urocystitis/ureteritis in cattle caused by salmonellae is lacking. This communication describes lesions of the inferior urinary tract in four Holstein calves with septicaemia caused by S. enterica subsp. enterica serotype Dublin. Examination of the urinary bladder revealed either diffuse irregular thickening (three cases) or petechiation (one case) of the mucosa. On histopathological examination, urocystitis with submucosal histiocytic, lymphocytic and plasmacytic infiltration and neutrophil transmigration through the urothelium was noted in all cases. In one case, a fibrinosuppurative ureteritis was detected. Salmonella Dublin was identified by culture, 16S rDNA sequencing and serotyping and Salmonella antigen was detected intralesionally by immunohistochemistry. Other lesions, indicative of septicaemia included hepatitis, enteritis, pericarditis, splenitis, lymphadenitis and pneumonia. We conclude that S. Dublin can be uropathogenic in cattle with septicaemia.