Genetic improvement of the dairy cattle in the tropical countries: A review

Firas R Al-Samarai Firas R Al-Samarai,Tamara N Dawood Tamara N Dawood,Ahmed M Al-Nedawi Ahmed M Al-Nedawi,Oday K Luaibi Oday K Luaibi

doi:10.30574/ijsra.2021.3.2.0138

Firas R Al-Samarai Firas R Al-Samarai, Tamara N Dawood Tamara N Dawood + Show 2 more

Open Access

https://doi.org/10.30574/ijsra.2021.3.2.0138

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Abstract

The principles of genetic improvement included the use of crossbreeding. An alternative method is the genetic improvement of the indigenous cattle by selection. The low reproductive performance and high calf mortality in the indigenous cattle caused a reduction in the selection intensity. Moreover, the generation interval is long in cattle because of the late sexual maturity and the long calving intervals. The most important problem is the absence of a milk recording system in many temperate countries. In such a case, the approach to improving the cattle through selection is limited and we will need to start with a single nucleus. Two types of selection can be adopted; without progeny testing which means the selection of bulls on pedigree information only and with progeny testing to identify the elite bulls according to the performance of their daughters.

Highlights

The zebu (Bos indicus) type included most tropical cattle
The low reproductive performance and high calf mortality in the indigenous cattle caused a reduction in the selection intensity
In the absence of AI and semen storage facilities, there is a risk represented by the fact that the bulls have to be kept alive until their daughters have finished the first lactation to be able to make the progeny test

Summary

Introduction

The zebu (Bos indicus) type included most tropical cattle. These cattle are characterized as are well adapted to the harsh environmental conditions in the tropics. The strategies that were used to improve the dairy performance of tropical cattle represented by imported the dairy breeds of the European (Bos Taurus) type, either as a stock of both sexes in large numbers or by acquiring bulls (or semen) for crossbreeding with indigenous females. Both approaches have been applied, and the results have been different. The results obtained by selection in many temperate breeds suggest that there should be a good chance for improving the dairy performance of tropical cattle by the same method there is a high genetic variation among individuals. If any of these three parts is low, genetic progress through selection will be slow

Genetic variability

Selection after breeding

Selection for sex-limited traits

Generation interval

Strategies for genetic improvement in a closed herd

Conclusion