Effects of Neospora caninum on reproductive parameters in dairy cows from a closed herd in Brazil.

Dairy production and cattle reproductive parameters exhibit a strong relationship, which can be disrupted by infectious agents, such as Neospora caninum, that affect the reproductive tract of these animals. Neosporosis is a major cause of abortion in cattle worldwide and is responsible for substantial economic losses. We evaluated the impact of N. caninum infection on the reproductive parameters of 434 Holstein dairy cows from a herd in Brazil that had been closed for 4 years through the assessment of serological testing and reproductive parameters. Dairy cows older than 24 months and that required at least 2.2 inseminations to become pregnant had a higher frequency of seropositive results. Analysis of the medians of positive and negative cows revealed that seropositive cows tended to require more insemination efforts to achieve pregnancy and showed a 2-month increase in age at first calving. According to the reproductive parameters, the correlation coefficient was higher in seronegative animals, while no such correlation was detected in seropositive cows. Thus, we concluded that N. caninum negatively affects the reproductive parameters of dairy cows kept in a closed herd.

Use of the enzyme gamma-glutamyl transferase (GGT) as an indirect measure of passive transfer of immunity in holstein calves and association with the occurrence of diarrhea after birth / Uso da enzima gama-glutamiltransferase (GGT) como medida indireta de transferência de imunidade passiva em bezerras da raça holandesa e associação com a ocorrência de diarreia após o nascimento

The objective of this study was to determine the gamma-glutamyl transferase (GGT) levels and its relationship with diarrhea and passive transfer of immunity in Holstein calves within 24 hours and 30 days of life from Leopolis municipality, the north Parana region. Colostrum is rich in immunoglobulins and vital for immunity to newborn calves, since bovine placenta does not allow the passage of immunoglobulin to the fetus. Calves undergo various challenges that can lead to disease and death in the first month of life, including diarrhea. Diarrhea has a multifactorial etiology, and the passive immunity transferred through ingestion of colostrum is able to protect the calf against many of these etiologic agents. GGT measurements indirectly infer the amount of immunoglobulin ingested by the calf. Higher serum GGT levels (381.72 IU / L) were found at 24 hours, and a significant reduction was observed at 30 days (66.22 IU / L). When the presence or absence of diarrhea was associated with GGT levels above and below 200 IU / L, no statistical significance (P> 0.05) was observed, since 80% of animals with diarrhea had serum GGT levels higher than 200 IU / L. Under the conditions of this study, there was no relationship between the GGT concentration and the occurrence of diarrhea, and no mortality was observed despite some animals presented diarrhea.

O colostro é rico em imunoglobulinas e vital para a imunidade de bezerros recém-nascidos, uma vez que placenta bovina não permite a passagem de imunoglobulinas para o feto. Os bezerros são submetidos a diversos desafios que podem levar à doença e morte no primeiro mês de vida, dentre as quais a diarreia. A etiologia da diarreia é multifatorial e a imunidade passiva transferida através da ingestão de colostro é capaz de proteger o bezerro contra muitos desses agentes etiológicos. O objetivo deste estudo foi determinar a dosagem de gama-glutamil transferase (GGT) e sua relação com diarreia e a transferência de imunidade passiva em novilhas da raça Holandesa nos tempos de 24 horas e 30 dias de vida, no município de Leópolis, na região norte do Paraná. As mensurações de GGT infere indiretamente a quantidade de imunoglobulinas ingeridas pelo bezerro. Os níveis séricos de GGT demonstraram valores médios maiores 24 horas após o nascimento (381,72 UI / L) e uma redução significativa foi observada aos 30 dias de vida (66,22 UI/L). Quando a presença ou ausência de diarreia foi associada com níveis de GGT acima e abaixo de 200UI/L, não foi observado significância estatística (p>0,05), uma vez que 80% dos animais com diarreia tinham níveis séricos de GGT superior a 200 UI/L. Sob as condições que foi realizado o presente estudo, não houve relação entre a concentração de GGT e a ocorrência de diarréia, e nenhuma mortalidade foi observada apesar de alguns animais apresentarem diarreia.