Estimation of genetic parameters for body weights, scrotal circumference, and testicular volume measured at different ages in Nellore cattle1

Background: The testicular biometry such as scrotal circumference (SC) and scrotal volume, affect semen quality hence bull fertility and thus testicular biometry can be used for breeding soundness of bulls. Methods: The present study was carried out to study the testicular parameters of 77 Sahiwal males of different ages and to establish its importance for selection of breeding bulls during 2015-2016 at ICAR-NDRI, Karnal. The testicular biometry of each male was done at monthly intervals using Vernier calliper, cloth tap and ultrasonography. Result: The semen quality parameters were significantly (P less than 0.05) more in the group having higher scrotal circumference. The scrotal circumference follows the curvilinear manner of growth from 12 months to greater than 72 months (correlation value of 0.92 and R2 0.84). The paired testicular volume (PTV) differed significantly (P less than 0.05) between different age group males. Scrotal circumference and paired testicular volume are directly related to semen quality hence bull fertility. Thus, testicular biometry is an important criterion for breeding soundness for selecting Sahiwal males.

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Genotype x Environment Interaction for reproductive traits in brazilian Nellore breed cattle

Revista Brasileira de Saúde e Produção Animal ◽

10.1590/s1519-9940200512019 ◽

2019 ◽

Vol 20 ◽

Cited By ~ 1

Author(s):

Caio Victor Damasceno Carvalho ◽

Raphael Bermal Costa ◽

Gregório Miguel Ferreira de Camargo ◽

Thereza Cristina Calmon Bittencourt

Keyword(s):

Bayesian Inference ◽

Genetic Correlation ◽

Genetic Parameters ◽

Reproductive Traits ◽

Northern Region ◽

Environment Interaction ◽

Genotype X Environment ◽

Scrotal Circumference ◽

Genotype Environment Interaction ◽

Different Ages

SUMMARY The objective of this study was to evaluate the effect of the genotype-environment interaction (GEI) for scrotal circumference traits measured at different ages, 365 (SC365), 450 (SC450) and 550 (SC550) days of age, and age at first calving (AFC) for Nellore animals raised in different regions of Brazil. For the evaluation, the herds were grouped in the following regions of the country: North, Southeast and Central-west, using information from 26,619, 28,730, 14,476, 15,397 for the traits SC365, SC450, SC550 and AFC respectively. Genetic parameters, as well as the assessment of GEI were performed using Bayesian inference, using the programs of the BLUPF90. The estimated heritabilities were: 0.465 ± 0.021, 0.500 ± 0.022, 0.492 ± 0.026, 0.117 ± 0.017 for SC365, SC450, SC550 and AFC respectively. The results obtained in the analysis, indicated that this interaction was not significant for SC at different ages (genetic correlation, rg> 0.8). For AFC, significant effect of GEI was observed for combinations involving the Northern region (rg<0.8), indicating that this interaction should be considered by the genetic evaluation programs in this region.

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