Breed, parity number and location effects on productive and reproductive parameters in bovine dairy herds

Abstract

Background: Both productive and reproductive parameters of dairy cattle in the high tropics can be affected by various factors related to management, but also by specific factors such as breed, calving, and herd location. Objective: To sample productive and reproductive data from specialized dairy herds in the Province of Antioquia (Colombia),in order to analyze the effects of breed, calving, and location on the efficiency of dairy herds. Methods: Productive and reproductive information was obtained from 5,440 records of cows of various breeds and crosses that had between 1 and 11 calvings. The animals belonged to 57 herds from 16 municipalities from the Province of Antioquia in three regions (North-N, East-E and Valle de Aburrá-V) dedicated to milk production. The variables analyzed were milk production adjusted to 305 days (PLa), kilograms of protein per lactation (KgPRO), kilograms of fat per lactation (KgF); somatic cell score (SCS), number of services per conception (S/C), mean days open (DO), and calving interval in days (CI). The independent variables collected in the field were associated with the aforementioned parameters through a generalized linear model (GLM). Results: The average PLa was 5,492.6 (±1,027.2) kg/lactation, for KgPROa and KgFa values were 177.1 (±29.5) and 215.1 (±37.1) kg/lactation, respectively; for SCS an average value of 3.62 (±1.6) was found. The results of the reproductive parameters were S/C of 2.02 (±1.4), CI of 385.7 (±52.8) days and for DO it was 110.9 (±55.4) days. The Ayrshire-Holstein crossbred cows, which were located in region V, presented lower PLa (58%); Holstein cows in their third parturition presented lower PLa (31%), somewhat similar to the decrease in PLa in Ayrshire in the second calving (56%); also, decreased milk production was detected in Angus x Holstein cows (46% less PLa) and in Brown Swiss breed in region V, with 41% less milk per lactation. The KgFa data decreased when compared to the general average with values of 172.9±24.7 kg for the Holstein breed, 132.5±46.2 Kg in Ayrshire x Holstein cross breeds in the E region and 102.2±26.5 kg in Ayrshire x Jersey cows. The longest CI was significantly (p<0.05) associated with the third parity and with the Holstein breed (37% increase) and with the BON x Holstein cross (57% increase). Conclusions: The results obtained in the specialized dairy cows of the three regions analyzed indicated that the productive and reproductive parameters are variable and there are multiple independent variables, such as breed, parity number and location, which when interacting lead to a decrease or increase in the parameters of interest.