Oncogenic viral DNA related to human breast cancer found on cattle milk and meat.

Bovine leukemia virus (BLV) is a major cause of lymphoma in cattle and has been recently correlated to breast cancer in humans. How and whether BLV might reach humans remains unknown but it could be through cattle-derived milk and meat. Here our aim was to investigate whether BLV DNA could be found in fresh milk and raw meat destined to human consumption and whether anti-BLV antibodies could be detected in human blood at the same geographical region. Milk (n = 36) and meat (n = 54) samples were collected from cows knowingly seropositive or negative to BLV and evaluated by nested PCR targeting BLV tax gene. Human serum samples (n = 900) were tested by ELISA to detect anti-BLV antibodies. BLV DNA was detected in 39 % of the milk samples and in 32 % of meat samples from BLV positive cows. Anti-BLV antibodies were found in 4.1 % of the human serum samples. Our data further supports the hypothesis that BLV might cause a zoonotic infection and indicate that milk and meat from BLV-infected cattle might be considered a potential source of infection to humans.

Study of vaginal microbiota of Holstein cows submitted to an estrus synchronization protocol with the use of intravaginal progesterone device.

The characterization of vaginal microbiota will help to understand some of the reproductive problems and mechanisms to improve cattle reproduction. The objective of this study was to characterize the vaginal microbiota of cyclical Holstein cows with different parturition orders using 16S rDNA sequencing. Animals were submitted to an estrus synchronization protocol with the use of intravaginal progesterone (P4) implants and were treated or not with ceftiofur hydrochloride. DNA samples were extracted from vaginal swabs on day 0 and 10 of the synchronization, and sequenced with the Illumina MiSeq platform with an average coverage rate of 10.000 reads per samples using a Single-End library for fragments of 300 bp. The main bacterial phyla found in the vaginal tract of Holstein cows, were Firmicutes (37.61%), Tenericutes (29.45%), Proteobacteria (17.47%) and Bacteriodetes (13.73%), followed by Actinobacteria (0.82%) and Spirochaetae (0.45%). The use of intravaginal P4 devices has increased the relative abundance of the genera Family XIII AD3011 and Family XIII unclassified (p < .049). We have also observed an effect of the number of calving on the vaginal microbiota composition, showing that multiparous cows have a greater bacterial diversity than primiparous animals (p < .05). The use of ceftiofur hydrochloride was effective to reduce the vaginal bacteria proliferation. This study describes for the first time the vaginal microbiota of cows synchronized with intravaginal progesterone devices, different from the traditional methods such as microbiological culture and biochemical tests. We have identified a large number of microorganisms commonly found in the gastrointestinal tract of cows, colonizing the vaginal microbiota.

Milk composition of Holstein cows: a retrospective study / Caracterização da composição do leite de vacas Holandesas: estudo retrospectivo

ABSTRACT: Worldwide, milk analysis is an satisfactory measurement of milk quality on dairy farms. Milk composition is the base for payment systems, so knowledge of its characteristics at different periods is essential for modern dairy producer. The aim of the study was to evaluate the effects of year, season, stage of lactation, and lactation number on variations in milk yield and composition of Holstein cows (n=148,604). Milk yield estimated by multiple regression was 25,50L/cow/day. Winter was the season with the highest milk yield and the highest protein and lactose content. Milk fat was highest in the fall, in cows in late lactation and also in primiparous cows. Lactating cows from 6 to 60 days in lactation and those in 2nd or 3rd lactation showed the highest milk yield. Lactose concentration was positively correlated with milk yield. Somatic cell score was negatively correlated with milk yield and with lactose concentration. Most important variations in milk characteristics occur among seasons, lactation stages and parities. Mammary gland health is yet the greatest challenge to be overcome.

RESUMO: A determinação da qualidade do leite nas fazendas é um parâmetro mundialmente aceito e utilizado como base para os sistemas de pagamento. Os produtores modernos utilizam o conhecimento das características do leite para adotar medidas que visam melhorar produtividade e qualidade. O objetivo do estudo foi avaliar os efeitos do ano, estação, estágio de lactação e número de lactação sobre as variáveis produção e composição do leite de vacas Holandesas (n=148,604). A produção de leite estimada por regressão múltipla foi de 25,50L/vaca/dia. O inverno foi à estação com a maior produtividade e os maiores teores de proteína e lactose. A gordura de leite foi maior no outono em vacas primíparas e no final da lactação. As vacas com estágio de lactação entre 6 a 60 dias e aquelas que se encontram na segunda ou terceira lactação apresentaram a maior produtividade. A concentração de lactose correlacionou-se positivamente com a produção de leite. O escore das células somáticas correlacionou-se negativamente com a produtividade e com a concentração de lactose. As variações mais importantes nas características do leite ocorrem entre estações, estágios de lactação e número de partos. A saúde da glândula mamária ainda é o maior desafio a superar.