A. Cordova-Izquierdo  , V.M. Xolalpa Campos  , C. Gustavo Ruiz Lang  , J.A. Saltijeral Oaxaca  , S. Cortes Suarez  , C.A. Cordova-Jimenez  , M.S. Cordova-Jimenez  , S.D. Pena Betancurt  , J.E. Guerra Liera  , 
    Effects of the Offspring’s Sex on Open Days in Dairy Cattle,
    Journal of Animal and Veterinary Advances,
    Volume 7,Issue 10,
    2008,
    Pages 1329-1331,
    ISSN 1680-5593,
    javaa.2008.1329.1331,
    (https://makhillpublications.co/view-article.php?doi=javaa.2008.1329.1331)
    Abstract: With the purpose of determining the reproductive efficiency in a dairy farm, 412 registers of production were revised. The objective of this study was to value the effect of the sex of the calf on the open days up in a dairy farm. The study was carried out in a farm located in the municipality of Tizayuca, Hidalgo State, Mexico. The variables involved in this investigation are: number of childbirths, dates of childbirth, sex of the offspring and date of the service-conception. Of these the open days were obtained, with the objective to determine if the sex of the offspring influences in the open days. The registrations were divided in 2 groups (males and females), same that were subdivided in 6 groups by childbirth number. The analysis was carried out in Excel. The obtained results are the following ones: in general, the cows that birth males presented a smaller  period  of  open  days  (132.56 days)  that  those that birth females (143.69 days) with a difference of 11.13 days.
    Keywords: Sex of the offspring;open days;dairy cattle