Search

Copyright of Revista Acadêmica: Ciência Animal is the property of Revista Academica: Ciencia Animal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Crossbreeding effects were evaluated in three dual purpose bovine sub-populations in the tropics, and 5,040 lactations, 4,429 birth weights and adjusted weights at 205 [3,878], 365 [3,017] and 540 [2,276] days (PN, P205, P365 y P540, respectively) from Zebu cattle (CE) and its crosses with Holstein (HS), Brown Swiss (SP) and Simmental (SM). Additive direct breed effects (PG), heterozygosity (HT) and recombination loss (RC) were estimated by a regression analysis within breed group with mixed models. Evaluated fixed effects were herd and year of freshening, season, lactation number and offspring gender for milk yield (PL) and herd, birth year and season for growth traits. Random effects for PL were direct (animal) and permanent environment and for growth traits were genetic direct and maternal and permanent maternal environmental effects. PG/HS, PG/SP y HT/SM had effects (P<0.10) on PL while PG/SP, PG/SM, HT/SM and RC/HS on PN. PG/HS y PG/SP presented effects (P<0.10) on P205, P365 and P540 while PG/SM only on P205. HT and RC had effects (P<0.10) on P205, P365 y P540 for all crosses. Results hereby presented will allow the formulation of strategies for the use of additive and non-additive genetic effects of the crossbred populations present in the Mexican humid tropical regions. [ABSTRACT FROM AUTHOR]

The article titled "Ovarian function and response to estrus synchronization in Criollo cattle in Mexico. Review" analyzes the ovarian function and response to estrus synchronization in Criollo cattle in Mexico. It highlights that Criollo cattle are valuable due to their adaptability to difficult environmental conditions and their resistance to parasites. However, it has been observed that Criollo cows do not respond adequately to hormonal synchronization protocols and achieve lower pregnancy rates compared to other breeds. The objective of the review is to gather existing information on the use of estrus and ovulation synchronization protocols in Criollo cattle in Mexico, in order to identify the necessary research lines for the development of appropriate protocols for this type of cattle. [Extracted from the article]

El objetivo del presente estudio fue evaluar el impacto de la inclusión de información extranjera de sementales de la raza Holstein, sobre su evaluación genética para las características de producción de leche (PL), grasa (PG) y proteína (PP) en kilogramos. Lo anterior, se logró mediante la comparación de valores genéticos (VG) y confiabilidades (CF), agrupación de sementales por número de hijas, ordenamiento de los sementales y la superioridad genética esperada por año (ΔIs/ys), con diferentes escenarios determinados por la intensidad de selección (ips) de sementales usados en la evaluación genética nacional (EGMEX), los incorporados a la evaluación genética internacional con hijas en México (EG-I) y la evaluación genética internacional con o sin hijas en México (EG-MACE). En total, se analizó la información de 5,825 sementales en la para PL y 3,914 para PG y PP. El impacto de la información extranjera en la EG-MEX es positivo, debido a que mejora la CF de los VG de los sementales usados en México. También, permitió observar diferencias importantes de los VG y CF entre las evaluaciones, generando una oportunidad de mejoramiento en la población Holstein mexicana; por lo que, es recomendable continuar con la participación en el programa de Interbull, y considerar el uso de la información validada de manera internacional en los procesos de selección de animales productores de leche y sus componentes. Estas acciones pueden contribuir de manera importante en el incremento del progreso genético productivo a nivel nacional. [ABSTRACT FROM AUTHOR]