title: Breed differences in calving interval in the humid Mexican tropic.
abstract: The objective of this study was to evaluate the influence of breed, breed and sex of the calf, farm, calving number (CN), type of calving, and their interactions on CI using records from four different beef breeds performing in the humid tropical environment of Mexico. The influence of these factors on CN was also evaluated. CI and CN varied with farm, breed of the dam, and with breed of the dam by calf breed interaction (P<0.001), while CI also varied with CN. Significant differences between Bos indicus and Bos taurus breeds for CI (432 vs. 488 days) and for CN (2.13 vs. 1.92) were observed (P<0.001). The interaction effects observed between breed of the dam by breed of the calf on CI and on CN were due to a favorable F(1) calf effect on CI observed only in Angus cows, although with an apparent unexpected negative impact on CN.
authors.affiliation: Departamento de Producción Agrícola y Animal, Universidad Autónoma Metropolitana, Unidad Xochimilco, Distrito Federal, México.
authors.forename: Aída Lorena
authors.initials: AL
authors.lastname: Murillo Medina
authors.forename: Alejandro
authors.initials: A
authors.lastname: Córdova-Izquierdo
authors.forename: Ramón
authors.initials: R
authors.lastname: Soriano Robles
authors.forename: Germán David
authors.initials: GD
authors.lastname: Mendoza Martínez
authors.forename: Héctor
authors.initials: H
authors.lastname: Castillo-Juárez
mesh_terms: D000818:Animals; D001947:Breeding / Q000379:methods / Q000706:statistics & numerical data*; D002417:Cattle / Q000235:genetics / Q000502:physiology*; D016018:Least-Squares Analysis; D008800:Mexico; D012098:Reproduction / Q000502:physiology*; D013045:Species Specificity; D014329:Tropical Climate