a b s t r a c tThe primary objective of this study was to identify compost bedding characteristics associated with mastitis epidemiologic indexes, cow cleanliness, and concentration of selected bacterial populations found in bulk tank milk. Secondary objectives were to monitor the occurrence of environmental mastitis outbreaks, and to describe the profile of pathogens isolated from mastitis cases of cows housed in the CBP system. Three dairies were visited monthly during 1 year. On each visit day, milk samples were collected from the bulk tank and from a sample of mammary quarters for microbiological examination. Milk samples were collected from all cases of clinical mastitis. Flank, leg, udder, and teat cleanliness were assessed using a score chart based on a 4-point scale (1 ¼ clean to 4 ¼very dirty). Bedding samples were collected to estimate concentrations of total bacteria, streptococci, and coliforms, moisture, organic matter, carbon-nitrogen ratio, pH, and density. Mixed models were used to identify factors associated with incidence and prevalence of mastitis, and cow cleanliness. Except for farm A, on which contagious pathogens caused most cases, Escherichia coli, coagulase-negative staphylococci, and environmental streptococci were the most frequent pathogens isolated from clinical mastitis cases. Corynebacterium bovis was the most frequent pathogen isolated from subclinical cases of farms B (17.6) and C (26.0%). Environmental pathogens were isolated from 17.2%, 10.1%, and 14.8% of all subclinical cases of farms, A, B, and C, respectively. No outbreaks of environmental mastitis were observed during the course of the study. Bedding moisture, carbon-nitrogen ratio, pH, and dry density were unconditionally associated with the incidence of environmental clinical mastitis. Nonetheless, bedding moisture remained as a sole predictor in the final model. The odds of a case of environmental clinical mastitis increased 5.7% for each one-unit increase in bedding moisture. The odds of a new case of subclinical mastitis, and of a cow having SCC Z200,000 cells/mL increased 32% and 16% for each one-unit increase in leg cleanliness score, respectively. Overall means for udder, teat, flank, and leg hygiene scores were less than 2.1 for all farms and did not vary among seasons of the year. Bedding wet density was positively associated with all cleanliness scores and bulk milk concentration of total bacteria. Results suggest that managing bedding to remain dry and loose will result in cleaner animals with decreased risk of mastitis.

Camas orgânicas estão sendo utilizadas em free stall no intuito de posterior aproveitamento para adubação. Objetivou-se avaliar o desempenho produtivo e reprodutivo de vacas da raça Holandesa em dois grupos de cama: maravalha de eucalipto (ME) e sabugo de milho triturado (SMT). Durante 180 dias foram coletados dados de mastite clínica, produção diária de leite e taxa de concepção à primeira inseminação artificial. Mensalmente, durante o período experimental, foram coletadas amostras de ME e SMT virgens e presente nas camas para determinar crescimento bacteriano e amostras de leite de cada vaca para análise eletrônica de contagem de células somáticas (CCS).  Os dados quantitativos foram submetidos ao teste de Tukey e os qualitativos ao teste Qui-quadrado. Vacas alojadas em SMT apresentaram maior CCS no terceiro mês de lactação e maior produção de leite em 180 dias de lactação do que vacas em ME. Não foi observada diferença nos dias em lactação no pico, produção de leite no pico, número de casos de mastite clínica, taxa de concepção e perda de prenhez entre os grupos avaliados. Conclui-se que maravalha de eucalipto e sabugo de milho triturado apresentaram resultados satisfatórios para serem utilizados como cama orgânica, pois apresentaram baixa contagem de células somáticas, não interferiram no número de casos de mastite clínica e na taxa de concepção à primeira inseminação artificial.

The present study assessed the influence of environmental variables at birth (birth season, temperature, relative humidity, THI - temperature and humidity index) and newborn serum protein level of 450 Holstein heifers on growth (body weight, and mortality rate) and reproductive performance (weight and age at puberty, age at first conception, and conception rate at first artificial insemination). The immune passive transfer was positively related to the weights at 30 and 60, with a trend at 90 days, which consequently affected weight at puberty, age at puberty, and age at conception. Therefore, it reinforces the importance of protocols with newborns that allow the assessment of the passive transfer of immunity. Calves born during the warmer months exhibited 4.2 and 12.28 kg less weight at weaning and puberty, respectively, compared to calves born during winter. Thus, calves born in an environment with higher THI showed changes in development, health, and reproductive efficiency in the short, medium, and long term. These findings reinforce the importance of adopting better colostrum management and welfare conditions, especially in warm season, to allow successful immune passive transfer and increase system efficiency.