Evaluation of genetic trends for traits of economic importance in South African Holstein cattle

Abstract

Genetic evaluation for the South African dairy industry has kept pace with global advances in statistical methodology. Increasingly accurate estimated breeding values (EBVs), produced routinely in the past two or three decades, have aided selection decisions. This has been coupled with an increase in the number of traits officially recorded and for which EBVs are calculated. Currently, EBVs are routinely published for more than 20 traits for the major dairy breeds. The current study was conducted to assess the genetic trends realized for traits of economic importance in the South African Holstein population, for the period from 1983 to 2008. Performance and pedigree data of 1 231 930 animals were used to calculate EBVs for these traits by a multi-trait animal model. The resulting EBVs in turn were used to compute annual mean rates of genetic change. Genetic trends for yield decreased by approximately 57% during the decade from 1990 to 2000 and reached stasis in 2005 -2007. Calving interval and somatic cell count also deteriorated over much or all of the period investigated. Given the widespread availability of genetic evaluations for these traits and the noted potential for selection to implement favourable genetic trends, development of strategies to improve the South African Holstein appears to be urgently needed.

Assessment of Friesian Cattle Performance Sustainability Through the Evaluation of Phenotypic and Genetic Parameters and Trends of some Economic Traits Under Egyptian Conditions

“…The current range of BVs for CI was shorter than the ranges from -8.14 to 11.91, -5.72 to 10.60 and -5.92 to 10.6 days obtained by Ayied et al (2011), El-Awady et al (2017 and Abdel-Hamid et al (2017), respectively. However, the slight positive improvement in GT was close to the values of 0.03, 0.06, 1.34 and 0.82 d/yr, as reported by Abdelharith (2008), Ibrahim et al (2009), Ramatsoma et al (2014) and Zahed et al (2019), respectively.…”

Effects of season and age at first calving on genetic and phenotypic characteristics of lactation curve parameters in Holstein cows

“…Katok and Yanar [ 55 ] reported that estimated annual genetic and phenotypic trends were 3.73 ± 4.07 and −17.73 ± 9.64 kg for 305-d milk yield of Holstein Frisian cows in Turkey but Hallowell et al [ 59 ] and Osman et al [ 60 ] found a positive trend in EBV 19 and 18.97 kg/year for the first lactation milk yield in South African Ayrshire and Holstein cattle, respectively. In another study Ramatsoma et al [ 61 ] reported a quadratic regression line for describing the genetic trend in milk yield over a specific period. The lower genetic trend for 305-d milk yield in our study may be due to smaller estimation of 305-d milk yield heritability.…”

Genetic and Phenotypic Parameters and Trends for Milk Yield, Service Period and Calving Interval and The Economic Impact of Extending A Calving Interval on-Farm Profitability in Friesian Cows in Egypt

“…CI has increased over time, resulting in longer calving interval (Wall et al, 2003). The genetic trend in CI was increased by 1.34 d/yr (Ramatsoma et al, 2014). In contrary, Atil and Khattab (2005) estimated genetic trend for CI to be -0.95 d/yr.…”