Pedigree Completeness and Genetic Structure of Lithuanian Red and Black-and-White Cattle Populations

Abstract

Pedigree completeness and genetic diversity are essential factors in evaluating the sustainability and breeding potential of livestock populations. This study investigates the genetic structure and pedigree completeness of Lithuanian Red (LR) and Lithuanian Black-and-White (LBW) cattle, focusing on both open and old genotype populations. The analysis utilized PopReport software and data from the Lithuanian Agricultural Data Center. The LR open population comprised 313214 animals, while the LBW open population included 354201. The old genotype LR population consisted of 1266 recorded animals, of which 77% were bred under a pure-breeding system. The old genotype LBW population contained 9058 animals, with 58% maintained through pure breeding. Pedigree completeness in the first generation was 100% across all populations, except for old genotype LR (93.8%). A progressive decline was observed in subsequent generations, with fourth- and fifth-generation completeness averaging 88.2% and 83.0%, respectively. The sixth generation exhibited the lowest completeness: 72.5% in old genotype LR and 69.3% in LBW populations. Age distribution analysis revealed that open populations comprised younger cows and heifers (3.3 years for LR, 3.2 years for LBW), suggesting higher reproductive potential. In contrast, old genotype populations exhibited older age averages (3.8 years for LR, 4.4 years for LBW), indicating reduced reproductive intensity. The reproductive age peaked in 2009 (7.3 years for LR, 5.3 years for LBW) but declined significantly by 2021 (3.3 and 3.7 years, respectively). Between 2005 and 2020, generation interval decreased by 3.6 years for males and 1.2 years for females in LR open populations, and by 3.1 years and 0.8 years, respectively, in LBW open populations. Conversely, between 2005 and 2015, the LR old genotype bull interval increased by 1.1 years, while in LBW old genotype populations, it declined by 4.6 years. The study emphasizes the importance of managing genetic diversity and optimizing breeding strategies to ensure sustainable cattle production in a changing agricultural environment.