Phenotypic and genetic parameters of reproductive traits in Tunisian Holstein cows

espanolSe evaluaron de manera rutinaria diferentes factores que influyen en la reproduccion de las vacas lecheras Holstein y se estimaron los parametros geneticos de cuatro caracteres para evaluar la fertilidad de las vacas inseminadas artificialmente: el intervalo de parto a primer servicio (IPPS), el intervalo entre partos (IP), el intervalo de parto a concepcion (IPC) y el numero de servicios por concepcion (NSC). Los datos utilizados en esta investigacion consistieron de registros de eventos de inseminacion y partos en vacas Holstein de Tunez. Los registros fueron tomados desde 1994 hasta 2003 en 150 rebanos para estudiar los efectos de factores no geneticos y estimar las heredabilidades de los caracteres anteriormene senalados de fertilidad. Los factores examinados fueron: mes y ano de parto, rebano, paridad y ano-mes de parto. El efecto del mes y ano de parto (o inseminacion), rebano, paridad y ano-mes de parto se incluyeron en el modelo y fueron significativos (P EnglishVarious factors influencing reproduction in dairy Holstein cows were routinely evaluated and genetic parameters were estimated for four traits to assess fertility of artificially inseminated cows: Calving to first service interval (CFSI), calving interval (CI), calving to conception interval (CCI) and number of services per conception (NSC). Data used in this investigation consisted of records of insemination and calving events on Tunisian Holstein cows. The data included records from 1994 to 2003 in 150 herds. The aim of the study was to investigate the effects of non-genetic factors on reproductive traits and estimate their heritabilities. The factors examined were: month and year of calving, herd, parity, and year-month of calving. The effect of month and year of calving (or insemination), herd, parity and year-month of calving were included in the model and were significant (P Heritability for fertility traits was low ranging from 0.027 for NSC to 0.067 for CI. The results suggested that more attention should be paid to herds with too low fertility traits and that monitoring and intervention schemes should be tested in research approaches.