Abstract
We studied 257 herds of 257 farms, totaling 79,051 observations in eight States of the Federation, which genetic and phenotypic parameters were estimated for the weights to 205 (P205), 365 (P365) and 550 days old (P550) of Nelore, included in the system of development Control by weight (CDP) conducted by the Brazilian Association of Zebu breeders (ABCZ) and raised in the northern region and sub-region Means North. Estimates of variance components and genetic parameters were obtained by the MTDFREML application, which uses the methodology of the Restricted Maximum Likelihood Derivative Free with an animal model that considers as fixed the effects of the farm such as year, month of birth, and gender. The heredity for P205 was 0.13 ± 0.02 and for P365 was 0.18 ± 0.05, which may indicate little additional genetic variation for these characteristics. For P550 days the estimated heredity was 0.23 ± 0.07, considered average, what indicates that at this age it is possible to select for weight gain. The genetic, phenotypical and environmental likeness among the weights in different ages were: P205-P365 = 0.92, 0.72 and 0.79; P205-P550 = 0.89, 0.61 and 0.87 and P365-550 = 0.98, 0.80 and 0.87. The genetic tendency in P365, for direct effect was significant and positive equals 0.455 kg (P < 0.001). Genetic trends in P205, P365 and P550 for direct effect were significant and positive, equal to 0.272 kg (P < 0.001), 0.455 kg (P < 0.001) and 0.744 kg (P < 0.001), respectively.
Highlights
Beef production in Brazil is characterized by extensive raising, and in this aspect the Zebu breeds and their cross-bred have stood out as the most efficient solution for this kind of system and its use has contributed to the development of livestock, meat production, and production of milk
We studied 257 herds of 257 farms, totaling 79,051 observations in eight States of the Federation, which genetic and phenotypic parameters were estimated for the weights to 205 (P205), 365 (P365) and 550 days old (P550) of Nelore, included in the system of development Control by weight (CDP) conducted by the Brazilian Association of Zebu breeders (ABCZ) and raised in the northern region and sub-region Means North
Estimates of variance components and genetic parameters were obtained by the MTDFREML application, which uses the methodology of the Restricted Maximum Likelihood Derivative Free with an animal model that considers as fixed the effects of the farm such as year, month of birth, and gender
Summary
Beef production in Brazil is characterized by extensive raising, and in this aspect the Zebu breeds and their cross-bred have stood out as the most efficient solution for this kind of system and its use has contributed to the development of livestock, meat production, and production of milk. The genetic improvement depends on the proper use of genetic variation of the selected characteristics In this context, the heredity of a character expresses the rate of the total variance that is attributed to the average effects of the genes, which determine the degree of similarity among the relationship. The aim was to raise the estimates of the components of co-variance to allow the assessment of environmental and genetic parameters for weights of 205, 365 and 550 days of age, and to assess the genetic and phenotypic changes in the weights at 205, 365 and 550 days of age in order to provide data to adopt appropriate criteria to establish breeding programs specific to the northern region and sub-region of the Middle-North, Brazil
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
