Impacto da ordem de parto, produção de leite e contagem de células somáticas sobre a reprodução de vacas da raça Holandesa

Abstract

Dairy cattle farming is an important agribusiness activity in Brazil. Herd nutrition and health are aspects that affect the reproductive and productive efficiency of dairy farming and interfere in the performance of bovine females, it is important to analyze the factors that affect the reproduction and milk production of these animals. Therefore, the objective was to analyze the reproductive and productive parameters and the somatic cell count in primiparous and multiparous cows from dairy herds in Campos Gerais, Paraná, and to correlate these parameters using dairy control records. 24,011 records of animals from 75 producers in the region between 2017 and 2018 were used. The effects of production levels and reproductive parameters of primiparous and multiparous cows for milk production and composition characteristics were analyzed: liters/cow/ day, somatic cell count (SCC), fat (F), protein (P) and urea nitrogen contents in milk, and reproductive characteristics: number of services per conception (S/C), service period (PS) and percentage of pregnant cows. Data were analyzed using multivariate logistic regression and the statistical differentiation between the classes of SCC and milk production considered the 5% level of significance. Milk production (MP) and SCC were higher in multiparous cows, as well as PS and S/C. The percentage of pregnant cows was higher when the SCC was less than 200 thousand cells/mL and significantly higher in primiparae. There was no negative effect of milk production on reproductive parameters in high producing cows (above 40 kg/milk/day), however, the percentage of pregnant cows with this level of production was significantly higher in first calving cows. The reproduction of specialized dairy cows is not affected by the level of production if the animals are kept in adequate environmental conditions (nutrition, health and facilities). Cows with SCC above 200 thousand cells/mL have reduced reproductive efficiency.