Association between seropositivity for Neospora caninum and reproductive performance of beef heifers in the Pantanal of Mato Grosso do Sul, Brazil

Abstract

Neospora caninum is an obligate intracellular parasite that can infect domestic and wild canids, ruminants, and horses. The purpose of this study was to evaluate the association between the presence of antibodies to N. caninum and reproductive loss in beef heifers in the South Pantanal region of Mato Grosso, Brazil. A total of 1098 heifers were evaluated from breeding to calving with regard to reproductive performance, and serology for neosporosis was assayed by indirect immunofluorescence reaction. The prevalence of N. caninum in cows that had failed to conceive was 22.13% higher than in those that had conceived (p < 0.0001), indicating a significant correlation between non-conception and presence of anti-N. caninum antibodies. The extraction rates for seropositive and seronegative heifers were 28.24 and 50.12%, respectively, with a statistically significant value (p < 0.0001) that showed a decrease of 44% in the extraction rate of seropositive animals. The results emphasize the importance of diagnosis for monitoring of neosporosis in primiparous cows, and indicators of seropositive females as a factor in strategies for culling the beef cattle herd.Keywords: Reproduction, bovine, diagnostic, abortion, Neospora caninum. ResumoNeospora caninum é um parasita intracelular obrigatório que pode infectar canídeos domésticos e selvagens, ruminantes e equídeos. Neste trabalho estudou-se a associação entre soropositividade para Neospora caninum e perda reprodutiva em novilhas de corte na região do Pantanal Sul-Mato-Grossense. Foram avaliadas 1098 novilhas da estação de reprodução ao nascimento dos bezerros com relação ao desempenho reprodutivo e realizada a sorologia para N. caninum através da reação de imunofluorescência indireta. A soroprevalência de N. caninum nas vacas que falhara na concepção foi 22,13% maior que nas que conceberam (p < 0,0001), indicando que há uma correlação significativa entre a não concepção e a presença de anticorpos anti-N. caninum. As taxas de desfrute para as novilhas soropositivas e soronegativas para neosporose foram de 28,24 e 50,12%, respectivamente, mostrando uma redução de 44% na taxa de desfrute de novilhas soropositivas para N. caninum. Ressalta-se a importância do monitoramento do diagnóstico da neosporose em primíparas, e o indicador de fêmeas soropositivas como um fator nas estratégias de descarte no rebanho bovino de corte.Palavras-chave: Reprodução, bovinos, diagnóstico, aborto, Neospora caninum.

Toxoplasma gondii and Neospora caninum antibody seroprevalence and risk factors among dogs treated at Public Veterinary Hospitals in São Paulo, Brazil

“…None of the dogs younger than one year old had antibodies against N. caninum, and seven of the nine positive dogs were older than eight years of age, thus indicating, in the same way shown earlier regarding T. gondii, that the prevalence increased with increasing age of the animals. Other studies carried out in Brazil and in other countries have also observed higher prevalence among older animals (Andreotti et al, 2004;Oliveira et al, 2004;Capelli et al, 2004).…”

Seroprevalence, spatial analysis and risk factors of infection with Neospora caninum in cattle in Brazil’s northern Pantanal wetland

“…However, an additional study should be performed to analyze the aborted fetus to confirm the infection and lesions by N. caninum. Andreotti et al (2010) demonstrated in a study conducted in beef cattle herds from Brazil's southern Pantanal wetland of the Mato Grosso Sul state, that the presence of N. caninum seropositive heifers has caused a significant impact on reproduction, with a reduction of 21.88% in the extraction rate of the herd. Furthermore, there was a negative impact on the herd benefit rate with the presence Brazil (BARROS et al, 2011).…”

Neospora caninum infection in cattle in the state of Amazonas, Brazil: seroprevalence, spatial distribution and risk factors

“…Several studies have been conducted in different regions of Brazil to detect anti-N. caninum IgG antibodies in cattle, whose prevalence ranges from 9.1% to 97.2% (Hasegawa et al, 2004;Vianna et al, 2008;Andreotti et al, 2010;Amaral et al, 2012;Silva et al, 2017). In the Amazon region, N. caninum infection has been described in the states of Pará (Minervino et al, 2008;Silva et al, 2017), Rondônia (Aguiar et al, 2006;Boas et al, 2015) and Tocantins (Martins et al, 2011), with prevalence rates varying from 10.4% to 52%.…”