Legacy of draught cattle breeds of South India: Insights into population structure, genetic admixture and maternal origin.

Vandana Manomohan,Krovvidi Sudhakar,Ramasamy Saravanan,Rudolf Pichler,Kathiravan Periasamy,Raja K Nachiappan,Nagarajan Murali,Karuppusamy Sivakumar,Tzen-Yuh Chiang

doi:10.1371/journal.pone.0246497

Abstract

The present study is the first comprehensive report on diversity, population structure, genetic admixture and mitochondrial DNA variation in South Indian draught type zebu cattle. The diversity of South Indian cattle was moderately high. A significantly strong negative correlation coefficient of -0.674 (P<0.05) was observed between the effective population size of different breeds and their estimated FIS. The genetic structure analysis revealed the distinctness of Kangayam, Vechur and Punganur cattle from the rest of the zebu breeds. The results showed the influence of Hallikar breed in the development of most Mysore type cattle breeds of South India with the exception of Kangayam. Bayesian clustering analysis was performed to assess the taurine admixture in South Indian zebu cattle using purebred Jersey and Holstein-Friesian as reference genotypes. Relatively high levels of taurine admixture (>6.25%) was observed in Punganur, Vechur, Umblachery and Pulikulam cattle breeds. Two major maternal haplogroups, I1 and I2, typical of zebu cattle were observed, with the former being predominant than the later. The pairwise differences among the I2 haplotypes of South Indian cattle were relatively higher than West Indian (Indus valley site) zebu cattle. The results indicated the need for additional sampling and comprehensive analysis of mtDNA control region variations to unravel the probable location of origin and domestication of I2 zebu lineage. The present study also revealed major concerns on South Indian zebu cattle (i) risk of endangerment due to small effective population size and high rate of inbreeding (ii) lack of sufficient purebred zebu bulls for breeding and (iii) increasing level of taurine admixture in zebu cattle. Availability of purebred semen for artificial insemination, incorporation of genomic/molecular information to identify purebred animals and increased awareness among farmers will help to maintain breed purity, conserve and improve these important draught cattle germplasms of South India.

Highlights

Ever since domestication, animals have been used as an important source of draught power for agricultural production
The present study revealed moderate levels of genetic diversity existing in South Indian zebu cattle
It established the genetic distinctness of Kangayam, Vechur and Punganur cattle from the rest of the South Indian zebu cattle

Summary

Introduction

Animals have been used as an important source of draught power for agricultural production. With increasing mechanization of agriculture, the use of draught cattle in farm operations reduced significantly and became negligible in advanced economies. In developing countries, in small holder production systems and in hilly and mountainous regions, agricultural production still relies on draught animal power [1]. The annual use of draught animals declined from about 1200–1800 hours to 300–500 hours per pair per year [3]. The population of draught cattle steadily decreased at a negative annual compound growth rate of about -0.85% between 1972 and 2019, resulting in significant decline of purebred native breeds [4, 5]

Methods

Results

Discussion

Conclusion