Banca de DEFESA: DANIELA CRISTINA ROCHA DE FREITAS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : DANIELA CRISTINA ROCHA DE FREITAS
DATE: 25/02/2025
TIME: 09:00
LOCAL: Sala 54 do Instituto de Veterinária
TITLE:

Influence of bovine neosporosis on the reproductive indices of Girolando cows. 

KEY WORDS:

Reproductive efficiency, Neospora caninum, reproductive disturbances.

PAGES: 36
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Reprodução Animal
SPECIALTY: Inseminação Artificial Animal
SUMMARY:

Neosporosis is a disease caused by the protozoan Neospora caninum, which uses cattle as an intermediate host to complete its life cycle. This protozoan can cause disorders affecting reproduction and negatively impact reproductive efficiency. N. caninum seropositive cows may experience abortion between the fifth and sixth month of pregnancy, an increase in the service period (SP) and calving interval (CI), as well as a decrease in conception rate. Therefore, this study had as its main objective to compare the reproductive indices of crossbred Girolando cows seropositive and seronegative for N. caninum. The experiment was conducted at Corrego da Serra farm in Santa Isabel do Rio Preto, district of Valença (RJ). The study included 144 Girolando cattle (cows, heifers, calves, and bull) fed a complete diet and given water ad libitum. Reproductive management was conducted via natural mating or artificial insemination. The animals were tested for N. caninum through blood samples analyzed by Indirect Immunofluorescence Assay (RIFI), which identified seropositive and seronegative animals. The reproductive indices evaluated included: number of services; SP; CI; reproductive efficiency (RE); conception rates in the 1st and 2nd services; pregnancy rates of cows with up to 2 services and at 150 days in milk (DIM) and abortion rate (%). Statistical analysis was conducted using SPSS software (version 26). Continuous variables were evaluated for residual normality and tested for homogeneity of variances. The dependent (parametric) variables were expressed as means. A one-way analysis of variance (ANOVA) was also applied. The significance level was set at 5%. The incidence of N. caninum in the herd was 29.9% (43/144). Among the 144 tested samples, 67 were from multiparous cows, and upon testing for N. caninum, 23.9% (16/67) were seropositive. Reproductive data were analyzed only for multiparous females. The number of services was 2.7 ± 0.2 and 2.1 ± 0.08 (P= 0.05) for seropositive and seronegative cows, respectively; the SP was 142.3 ± 11.5 and 107.9 ± 4.8 days (P= 0.01) for seropositive and seronegative cows, respectively. Regarding the IP, seropositive animals presented 413.6 ± 10.1 days and seronegative animals 387.7 ± 5.5 days (P = 0.07), the same trend was observed in relation to the ER, which presented 91.2% ± 2.5 for seropositive animals and 96.1% ± 1.6 for seronegative animals (P = 0.07). The conception rate at the 1st service was 32.7% (16/49) for seropositive animals and 40.7% for seronegative animals (P= 0.16). For the 2nd service, the conception rate was 42.4% for seropositive animals and 60.3% for seronegative animals (P= 0.04). The pregnancy rate for animals with up to 2 services was 61.2% for seropositive animals and 76.4% for seronegative animals (P= 0.02). The pregnancy rate at 150 DIM for seropositive and seronegative animals was 69.4% and 78.0%, respectively (P= 0.1). No significant difference was observed in the abortion rate between the groups (14.3% x 12.2%). It was concluded that N. caninum seropositive Girolando cows showed compromised key reproductive indices.

COMMITTEE MEMBERS:
Presidente - 1548043 - MARCO ROBERTO BOURG DE MELLO
Interno - 2202309 - JULIO CESAR FERRAZ JACOB
Interna - 6387102 - MARILENE DE FARIAS BRITO QUEIROZ
Externo à Instituição - GIDEÃO DA SILVA GALVÃO - UFRB
Externa à Instituição - LARA NOGUEIRA SILENCIATO - UBM