Dairy calf rearing unit is a management system that is only recently being implemented by some milk producer’s cooperatives in southern Brazil. However, aspects related to the health profile of the heifer calves that arrive in the rearing unit as well as about biosecurity practices and microbiological challenges have not yet been evaluated in this rearing system in a tropical country. Diarrhea is the main and most frequent consequence of enteric infections in newborn calves. This study, through some etiological and epidemiological characteristics of an outbreak of neonatal diarrhea, has the aim to alert to the possibility of pathogenic microorganism spread in a dairy heifer calf rearing unit. The diarrhea outbreak presented some non-regular characteristics observed in bovine coronavirus (BCoV) enteric infections in dairy calves. The spread of infection was extremely rapid (1 week); the attack rate (> 50%) was much higher than that observed in calves subjected to conventional rearing; and the age range (5 to 90 days) of the affected heifer calves was much broader than that often observed in the BCoV diarrhea worldwide. These unusual epidemiological characteristics observed in this BCoV diarrhea outbreak raise awareness of the health threat present in calf rearing units as well as of the easy and rapid viral spread in a population of young animals from different dairy herds and, therefore, with very distinct immunological status.

Psychrotrophic microorganisms, especially Pseudomonas spp., are present in the microbiota of refrigerated milk as they can grow at refrigeration temperatures irrespective of their optimal growth temperature. Psychrotrophic counts ranging from 105 to 108 CFU/mL in refrigerated raw milk effect cheese quality, since the synthesized thermoresistant enzymes affect the nutritional value, sensory properties, and texture. Cheese is the dairy product with the highest growth rate in the food industry in Brazil in recent years and meets the current consumption trends of nutritious and practical foods. The objective of this review was to address the importance and influence of the psychrotrophic raw milk microbiota on the quality and sensory properties of cheese. The enzymes produced by psychrotrophic microorganisms lead to taste changes, undesirable clotting times, increased concentrations of free fatty acids and free amino acids, and a reduced shelf-life, in addition to negatively affecting cheese yields. Proteases from psychrotrophs are also associated with slicing problems and progressive loss of the elasticity of cheese, a bitter taste, and increased clotting times of cheese produced with pasteurized milk. On the other hand, their lipases increase the clotting time and have a negative effect on the sensory properties by providing a rancid, soap, metallic, or oxidized smell and taste. The control of the psychrotrophic population found in refrigerated raw milk contributes to better cheese production yields and desirable texture and sensory properties, which extends the shelf-life of cheese and improves consumer acceptance.

This study aims to determine the serological profile of high-yielding dairy cows for four main viruses (bovine alphaherpesvirus 1 (BoAHV1), bovine viral diarrhea virus (BVDV), bovine parainfluenza virus 3 (BPIV3), and bovine respiratory syncytial virus (BRSV)) related to bovine respiratory disease (BRD) in cattle herds worldwide. In this survey, 497 blood serum samples were collected from non-vaccinated dairy cows without clinical respiratory signs in 39 herds in the central-eastern mesoregion of Paraná State, South Brazil. The presence of neutralizing antibodies was determined by virus neutralization (VN) tests. VN antibodies against BoAHV1, BVDV, BPIV3, and BRSV were detected in 355 (71.4%), 280 (56.3%), 481 (96.8%), and 315 (63.4%) serum samples, respectively. The frequencies of seropositive herds for BoAHV1, BVDV, BPIV3, and BRSV were 79.5 (n = 31), 82.0 (n = 32), 100 (n = 39), and 84.6% (n = 33), respectively. The frequencies of seropositive cows varied according to the type of herd management and the number of cows in the herd. The detection of VN antibodies in unvaccinated dairy cattle herds demonstrated the endemic circulation of the four viruses in the herds evaluated. For BRD prevention, it is recommended to implement a vaccination program for cows that provides passive immunity in calves and active immunity in cows.