The sudden death of three calves, one diarrheic calf, and one aborted fetus from four farms in southern Brazil was investigated. Two Histophilus somni-associated syndromes were identified: systemic histophilosis (n = 4) and abortion (n = 1). The principal pathological findings included vasculitis, meningoencephalitis with thrombosis, necrotizing myocarditis, renal infarctions, hepatic abscesses, and bronchopneumonia. PCR assays were used to amplify specific amplicons of the ovine herpesvirus 2, bovine herpesvirus 1 and -5, Listeria monocytogenes, H. somni, and pestivirus; bovine group A rotavirus (BoRV-A) and bovine coronavirus (BCoV) were investigated in calves with diarrhea. H. somni DNA was amplified in tissues from all calves and the brain of the aborted fetus with pathological alterations consistent with histophilosis. All other PCR assays were negative; BoRV-A and BCoV were not identified. These findings confirm the participation of H. somni in the pathological alterations observed in this study and represent the first description of histophilosis in cattle from Brazil.

Listeriosis is a disease primarily of ruminants caused by the Gram-positive bacterium Listeria monocytogenes. Ruminants either demonstrate manifestations of the encephalitic, septicemic, or reproductive form of listeriosis. The pathological and molecular findings with encephalitic listeriosis in a 5.5-month-old, male, mixed-breed goat and a 3-year-old Texel-crossed sheep from northern Paraná, Brazil are described. Clinically, the kid demonstrated circling, lateral protrusion of the tongue, head tilt, and convulsions; the ewe presented ataxia, motor incoordination, and lateral decumbency. Brainstem dysfunctions were diagnosed clinically and listeriosis was suspected. Necropsy performed on both animals did not reveal remarkable gross lesions; significant histopathological alterations were restricted to the brainstem (medulla oblongata; rhombencephalitis) and were characterized as meningoencephalitis that consisted of extensive mononuclear perivascular cuffings, neutrophilic and macrophagic microabscesses, and neuroparenchymal necrosis. PCR assay and direct sequencing, using genomic bacterial DNA derived from the brainstem of both animals, amplified the desired 174 base pairs length amplicon of the listeriolysin O gene of L. monocytogenes. Phylogenetic analyses demonstrated that the strains associated with rhombencephalitis during this study clustered with known strains of L. monocytogenes lineage I from diverse geographical locations and from cattle of the state of Paraná with encephalitic listeriosis. Consequently, these strains should be classified as L. monocytogenes lineage I. These results confirm the active participation of lineage I strains of L. monocytogenes in the etiopathogenesis of the brainstem dysfunctions observed during this study, probably represent the first characterization of small ruminant listeriosis by molecular techniques in Latin America, and suggest that ruminants within the state of Paraná were infected by the strains of the same lineage of L. monocytogenes.

This study investigated the participation of infectious agents in spontaneous abortions and reproductive problems at eight dairy cattle herds from three geographical regions of Brazil. Fourteen aborted fetuses and the organ sections of one cow with history of repeated abortions were received for pathological evaluations and molecular diagnostics. PCR/RT-PCR assays targeted specific genes of abortifacient agents of cattle: bovine viral diarrhea virus (BVDV), bovine herpesvirus 1 (BoHV-1), Listeria monocytogenes, Neospora caninum, Leptospira spp., Brucella abortus, and Histophilus somni. Six fetuses were adequate for pathological investigations; one of these did not demonstrate remarkable pathological alterations. Significant histopathological findings included vasculitis, hemorrhage, and fibrinous thrombosis of the cerebrum (n = 4); necrotizing myocarditis (n = 3); and hemorrhagic enteritis (n = 3). The placenta and uterus of the cow as well as the kidney, pancreas, and liver of her aborted fetus contained H. somni DNA and demonstrated histopathological evidence of histophilosis. All fetuses contained H. somni DNA in multiple organs. Coinfections of H. somni with B. abortus (n = 2), N. caninum (n = 2), BVDV (n = 1), and BoHV-1 (n = 1) were identified; two fetuses demonstrated three pathogens. These findings suggest that H. somni was associated with the spontaneous abortions and reproductive problems of these herds. However, the exact cause of fetal death might not be attributed only to H. somni in all aborted fetuses, since some of these were infected with other abortifacient agents.

Bovine respiratory disease (BRD) is considered a major cause of morbidity and mortality in young calves and is caused by a range of infectious agents, including viruses and bacteria. This study aimed to determine the frequency of viral and bacterial pathogens detected in calves with BRD from high-production dairy cattle herds and to perform the molecular characterization of N and S1 genes in identified bovine coronavirus (BCoV) strains. Nasal swabs were collected from 166 heifer calves, namely, 85 symptomatic and 81 asymptomatic calves aged between 5 and 90 days, from 10 dairy cattle herds. Nasal swabs were evaluated using molecular techniques for the identification of viruses (BCoV, bovine alphaherpesvirus 1, bovine viral diarrhea virus, bovine parainfluenza virus 3, and bovine respiratory syncytial virus) and bacteria (Pasteurella multocida, Mannheimia haemolytica, Histophilus somni, and Mycoplasma bovis). In addition, five and two BCoV-positive samples were submitted to N and S1 gene amplification and nucleotide sequencing, respectively. The frequency of diagnosis of BCoV was higher (56%, 93/166) than the frequency of P. multocida (39.8%, 66/166) and M. haemolytica (33.1%, 55/166). The three microorganisms were identified in the calves of symptomatic and asymptomatic heifer calve groups. All other pathogens included in the analyses were negative. In the phylogenetic analysis of the S1 gene, the Brazilian strains formed a new branch, suggesting a new genotype, called # 15; from the N gene, the strains identified here belonged to cluster II. This study describes high rates of BCoV, P. multocida, and M. haemolytica in heifer calves from high-production dairy cattle herds with BRD. Additionally, the molecular characterization provides evidence that the circulating BCoV strains are ancestrally different from the prototype vaccine strains and even different BCoV strains previously described in Brazil.

<p class="Pa7">The aims of present study were to evaluate the effects of milk somatic cell count (SCC) and heat stress on yield and milk composition of cows in a herd for commercial production in a temperate region during the period 2008-2012. Data from the monthly milk test-day records of 161±9 Holstein, totaling 9,650 milkings, were provided by the Association of Holstein Cattle Breeders of Parana State, and analyzed by descriptive analysis, correlation, analysis of variance, and regression analysis. The average daily milk yield was 31.78 kg/cow, which decreased to 29.31% when the somatic cell score (SCS) was 9, and to 11% when the Equivalent Temperature Index (ETI) was 32 or above. Lactose content decreased from SCS 0 until 9 and fat content decreased from SCS 1 until 9, totaling decrease 7.88 and 9.23%, respectively, when the SCS was 9. An opposite effect was observed for the protein content, which increased by 3.6% at SCS 8, when compared to SCS 0. Losses were observed in the daily total solids production from the SCS 0, totaling 30.64% at SCS 9.The increase in ETI to 32 or above reduced all milk constituents as much as 3.42%, except protein. These results, combined with the losses in milk yield at that ETI level, led to a decrease of up to 12.74% of milk solids. It is concluded that since losses in milk quality and yield resulting from SCC and ETI are significant, actions to prevent infection in the mammary gland and to provide a comfortable environment for dairy cattle are needed even in temperate regions.</p>