G. H. F. A. Moreira

Utilização da vacina Escherichia coli J5 na imunização de vacas leiteiras contra mastites causadas por E. coli

We evaluated the use of Escherichia coli J5 vaccine immunization in dairy cows for the prevention and control of mastitis caused by E. coli. Were analyzed the prevalence of postpartum intramammary infections (IMM), occurrence and severity of clinical cases of mastitis in the first 100 days of lactation, influence on somatic cell count (SCC) and milk production. The experimental group consisted of 187 animals that were divided into two groups, vaccinated and unvaccinated cows. Immunizations occurred 60 days before calving, 30 days before calving and the first week postpartum. On the day of drying and seven days after birth, samples were collected for microbiological diagnosis of mastitis pathogens. The occurrence of clinical cases was verified by testing during the milking and data was recorded related to the intensity and duration. Samples were collected monthly starting at day ten of lactation to evaluate the CCS. Milk production was recorded monthly for the first 100 days of lactation. It was found in the vaccinated group reduction in the prevalence of E. coli in the postpartum period, the occurrence of clinical cases of E. coli in the first 100 days of lactation as well the intensity of these clinical cases. There were no statistically significant differences in CCS, however vaccinated cows had higher milk production, compared to unvaccinated cows. Vaccination with E. coli J5 was effective in reducing the prevalence of intramammary infections (IMM) at calving, occurrence and intensity of clinical cases and an increase in milk production in the first 100 days of lactation.

Avaliação do perfil metabólico de vacas da raça Holandesa durante o período de transição

O periodo de transicao e um momento de grande desafio para vacas de aptidao leiteira, uma vez que, a maioria dos problemas metabolicos ocorre nesta fase podendo prejudicar toda a expectativa de producao durante a lactacao, resultando em impacto economico significativo para fazendas de producao de leite. Este trabalho teve como objetivo avaliar o perfil metabolico de vacas da raca Holandesa durante o periodo de transicao. Doze vacas Holandesas foram avaliadas, tres semanas pre-parto ate tres semanas pos-parto, em sistema free-stall, localizado em Inhauma, Minas Gerais, no periodo de outubro a dezembro de 2012. Avaliou-se o perfil metabolico atraves da concentracao serica de acidos graxos nao esterificados (AGNE), beta hidroxibutirato (BHBA), colesterol (COLES), proteina total (PT), albumina (ALB), calcio, fosforo, magnesio bem como a atividade serica das enzimas aspartato transaminase (AST) e lactato desidrogenase (LDH). As concentracoes sericas de AGNE e BHBA foram diferentes entre o pre-parto e pos-parto (p 0,05) no periodo avaliado. A atividade enzimatica de AST e LDH foram maiores no periodo pos-parto (p<0,05). A avaliacao do perfil metabolico e uma importante ferramenta de monitoramento e, na situacao estudada, demonstrou alteracoes do perfil energetico das vacas entre os periodos pre e pos-parto, relacionadas provavelmente a diminuicao da ingestao de alimentos. A luz dos resultados do perfil metabolico, o rebanho avaliado possui pequeno risco para a ocorrencia de enfermidades no pos-parto relacionadas ao periodo de transicao

Testicular parameters and spermatogenesis in different birthweight boars

The present study investigated the effect of birthweight on testicular development and spermatogenesis in boars. Twenty-four pairs of littermate boars were selected: one piglet with the highest birthweight (HW) and the other with the lowest birthweight (LW) within the litter. Two subsets of 12 pairs of male littermates from each birthweight group were obtained after selection: one subset was orchiectomised at 8 days and the other at 8 months of age. HW boars had higher body and testicular weights at both ages (P<0.05). Testosterone concentrations and the relative expression of 17α-hydroxylase in the testis were similar between birthweight groups. Birthweight affected somatic and germ cell numbers in the neonatal testis, which were higher in HW boars (P<0.05). Moreover, a significant reduction in the number of pachytene spermatocytes and round spermatids was observed in LW boars (P<0.05) at 8 months of age, which caused a decrease in the total number of elongated spermatids and daily sperm production (P<0.05). Hence, HW boars have the potential to produce more spermatozoa and consequently more semen doses per ejaculate, and would be very valuable to an industry that relies on AI.

Estudo longitudinal da mastite subclínica e produção de leite em um rebanho mestiço Holandês-Zebu criado em sistema semi-intensivo

A herd of dairy cattle with different crossbreeding Holstein x Zebu (HZ), housed in a semi-intensive production system, was monitored for 15 months. We aimed to evaluate the longitudinal behavior of somatic cell count (SCC) and the influence of subclinical mastitis (SM) on the milk yield and on the peak yield of crossbred HZ dairy cows. Initially, individual milk samples were collected for microbiological analysis for identification of mastitis pathogens. The SCC was performed monthly to monitor subclinical mastitis. Additionally, milk production was evaluated weekly. To evaluate the effects of SCC on milk production, the cows were identified as falling into two groups: 0.05). SCC differed (P<0.01) between drying off and immediate postpartum. Maintaining high environmental risk conditions in a dairy herd, housed in semi-intensive system, can reduce the variations in the occurrence of SM in summer and winter periods. This can also decrease the variations in SM occurrence between cows of different crossbreeding HZ levels. In a herd characterized primarily by the presence of environmental mastitis, milk yield of primiparous cows with SCC above 200.000 cells/mL is reduced when compared to cows with SCC below 200.000 cells/mL. This finding was not observed for multiparous cows.

Estudo longitudinal da infecção por enteropatógenos em bezerros neonatos, com diarreia, sob diferentes estratégias de aleitamento

Seventeen Holstein newborn calves were used with the objective of evaluating the influence of milk replacer volume in the pattern of pathogens causing neonatal diarrhea. The animals were divided into two groups, 8 calves in group 1 and 9 calves in group 2. The calves were fed twice daily in the total of 4 liters of milk replacer to group 1 and 6 liters to group 2. From the 1st day of arrival of the calves feces were evaluated daily after the morning feeding for the classification of diarrheal feces or without diarrhea. The first day of diarrhea until the seventh day, feces were collected on alternate days (1st, 3rd, 5th and 7th day) directly from the rectum to evaluate enteropathogens. Were collected blood samples from calves with five days of age for determination of total protein. The average total protein was 6.33 and 6.21g/dL in groups 1 and 2, respectively. The group 2 tended (p 0.05). Also, there was no difference (p>0.05) on the pattern of the frequency of positive samples for evaluated pathogens. The frequency of pathogens in the samples was 100 and 75% for Cryptosporidium, 28.5 and 43.7% for Salmonella spp., 28.5 and 15.6% for E. coli pathotypes, 3.5 and 6.2% for Rotavirus and 10.7 and 9.4% for Giardia in groups 1 and 2, respectively. Serotypes of Salmonella infantis and muenster were found. The isolated pathotypes of E. coli isolates were classified as Escherichia coli enteropathogenic, enterotoxigenic and Shiga-toxin-producing 1 and 2. Associations between Cryptosporidium spp. and E. coli pathotypes, and between Cryptosporidium spp. and Salmonella spp. were found in 30% of the samples in group 1 and in 45.5% in group 2, respectively. Our results showed that the different volumes of milk replacer did not influence the incidence and etiology of neonatal diahrrea. Longitudinal evaluation of enteropathogens during patency demonstrated that the association between the etiologic agents starts from the first day of disease. This result highlighted the great importance of the infection by Cryptosporidium spp. which was present in every moments and animals evaluated.

Escherichia coli J5: imunização de fêmeas bovinas leiteiras contra mastites causadas por Escherichia coli

This paper aims to review the main aspects of coliform mastitis, specifically Escherichia coli, emphasizing the immunization of dairy cows with Escherichia coli J5 vaccine, as well as the animal risk factors. Coliforms are widespread in the environment and are of particular importance in farming systems in which the search for a greater milk quality guarantee low somatic cell counts (<150,000 cells ml-1). The dry period is an extremely important moment that plays crucial role in the occurrence of mastitis caused by environmental pathogens during the immediate postpartum. The dry cow therapy against environmental infections has lost effectiveness leading to the need for the combination with other methods such as immunization with Escherichia coli J5 vaccine. Due to a relatively exposed nuclear antigen, the Escherichia coli strain J5 can stimulate the production of immunoglobulins that cross-react with nuclear antigens from other bacteria. It results in immunity against a variety of bacterial genres and strains. It has been shown that the use of Escherichia coli J5 vaccine can reduce the occurrence, intensity and duration of clinical cases of Escherichia coli mastitis, besides increase the production of dairy cows. However, its role in reducing milk SCC is still controversial.