Influence of management and nutrition on postpartum interval in Brown Swiss and Pirenaica cows

Abstract

Data on productive and reproductive events of 549 cows (Brown Swiss and Pirenaica breeds) were collected in the Spanish Pyrenees from 1987 to 1998, in order to determine the factors that could be associated with the postpartum interval (PPI). Blood was collected 3 times per week during lactation; PPI was established by progesterone radioimmunoassay. Eighteen variables traditionally related to PPI were initially considered. Multiple Correspondence Analysis (MCA) was used to analyse the variables. PPI was associated with four factors that explained 59% of the total inertia and were defined as follows: “Prepartum feeding level” (19% of the inertia), “Postpartum feeding level—Parity” (16.4%), “Suckling frequency” (13%) and, as a supplementary variable, “Calving difficulty” (10.5%). These factors were introduced in a cluster analysis that identified five homogeneous groups of cows with respect to the management, defined by body condition score (BCS) at calving and PPI as follows: “Primiparous cows” (BCS=2.77; PPI=54 days), “Twice-daily suckling” (BCS=2.63; PPI=33 days), “Ad libitum suckling—Brown Swiss” (BCS=2.48; PPI=111 days), “Autumn calving season” (BCS=2.75; PPI=31 days) and “Spring calving season” (BCS=2.34; PPI=66 days). Cow breed was not related to PPI, although the cluster analysis associated the suckling-induced prolonged PPI with Brown Swiss animals. PPI was longer in the spring than in the autumn due to nutritional differences rather than to a seasonal effect.