Inbreeding depression in Zebu cattle traits

Area of Science:

• Animal Science
• Genetics
• Livestock Management

Background:

• Inbreeding depression can reduce herd productivity and livestock performance.
• Understanding the intensity of inbreeding effects is vital for effective breeding programs.

Purpose of the Study:

• To estimate the extent of inbreeding depression in productive and reproductive traits of five Zebu breeds in Brazil.
• To quantify the impact of inbreeding on various livestock performance indicators.

Main Methods:

• Analysis of 13 productive and reproductive traits across five Zebu breeds.
• Inclusion of individual inbreeding rate as a linear covariate in genetic evaluation models.
• Estimation of inbreeding depression using scaled regression coefficients (βm and βσ).

Main Results:

• Inbreeding significantly compromised animal performance across most traits, except gestation length.
• Average inbreeding depression was -0.222% (βm) and -0.859% (βσ) per 1% inbreeding.
• Weight/growth traits showed more pronounced inbreeding depression (-0.269% βm, -1.202% βσ) than reproductive traits (-0.174% βm, -0.546% βσ).

Conclusions:

• Inbreeding depression poses a significant threat to Zebu cattle productivity in Brazil.
• Weight/growth traits are more susceptible to inbreeding depression than reproductive traits.
• Active management of inbreeding is essential for the success of Zebu cattle breeding programs.