Management factors associated to the duration of postpartum anoestrus interval in Brown Swiss and Pirenaica beef cows

A global analysis of several productive indicators and the postpartum anoestrous interval (PPI) of 549 beef cowswas carried out to determine the management factors related with postpartum ovarian reactivation in extensive mountainfarming systems. Multivariate statistic methods (Multiple Correspondence Analysis and Cluster Analysis) were usedto analyse the data due to the multifactorial nature of the processes involved. PPI was associated to four factors thatexplained 59% of the total inertia of the sample and were defined as follows: «Prepartum feeding level» (19% of theinertia), «Postpartum feeding level-Parity» (16.4%), «Suckling frequency» (13%) and «Calving difficulty» (10.5%).These factors were introduced into a Cluster Analysis that identified five types of cows: «Primiparous cows», «Twicedailysuckling», «Ad libitum suckling-Brown Swiss», «Autumn calving season» and «Spring calving season». Cowbreed was not related to PPI, although the Cluster Analysis associated the suckling-induced prolonged PPI with BrownSwiss animals. In Brown Swiss breed, PPI was longer in the spring than in the autumn due to nutritional differencesrather than to a seasonal effect. Autumn calving was better adapted to dry mountain conditions.
Para determinar los factores de explotación relacionados con la reactivación ovárica postparto en vacas nodrizas se realizó un análisis global de la serie de indicadores productivos y la duración del anestro postparto (APP) de 549 vacas explotadas en condiciones extensivas. Debido a la naturaleza multifactorial del proceso en estudio se eligió la metodología estadística multivariante (Análisis Factorial de Correspondencias Múltiples y Análisis Cluster). La duración del APP estuvo asociada a cuatro factores que explicaron el 59% de la heterogeneidad inicial de la muestra y que se definieron como : "Alimentación preparto" (19% de la inercia), "Alimentación postparto-Edad" (16.4% ), "Manejo del ternero" (13% ) y "Dificultad al parto" (10.5% ). Estos factores se introdujeron en un Análisis Cluster que identificó cinco grupos de vacas con características productivas y reproductivas diferentes, y que denominamos como "Primíaras", "Acceso restringido", "Acceso Libre-Parda de Montaña", "Parto de otoño" y "Parto de primavera" (...)