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<p>This study assessed lifetime milk production traits (LtMPts) in Holstein Friesian (HF) cattle under semi-arid conditions using data from a commercial farm. The analysis included 9000 records from 2050 HF cows at El-Alamia farm in Egypt, spanning from 1996 to 2023 G.C. LtMPts included longevity (LON), life production age (LPA), lifetime milk yield (LTY), lifetime daily milk yield (LDY), complete lactations number (CLN), age at first calving (AFC), age at last calving (ALC), and incidences of mastitis and lameness. Effects such as age at first calving, year of first calving, and season of first calving were also examined, along with the genetic background of the cattle, utilizing genomic global databases and the latest findings from genetic research. Heritability estimates were calculated to determine the genetic influence on various traits. Correlation analysis was conducted to identify potential relationships and genetic architectures. Results indicated significantly earlier AFC (<i>p</i> &lt; 0.0001), prolonged AFC (<i>p</i> &lt; 0.001), extended LPA (<i>p</i> &lt; 0.0001), lower CLN (<i>p</i> &lt; 0.0001), no significant change in LON (<i>p</i> = 0.5418), higher LTY (<i>p</i> &lt; 0.0001) and higher LDY (<i>p</i> &lt; 0.0001). Sire significantly affected the year and season of first calving (<i>p</i> &lt; 0.0001). Low incidences of mastitis and lameness were observed. The year and season of first calving significantly impacted several LtMPts (<i>p</i> &lt; 0.05). Heritability estimates indicated varying levels of genetic influence on the studied traits, with notable heritability for complete lactations (<i>h</i><sup><i>2</i></sup> = 0.60) and longevity (<i>h</i><sup><i>2</i></sup> = 0.66). However, the estimates for lifetime milk yield (<i>h</i><sup><i>2</i></sup> = 0.11), life production age (<i>h</i><sup><i>2</i></sup> = 0.12), and daily milk yield (<i>h</i><sup><i>2</i></sup> = 0.12) were low, suggesting limited genetic influence on these traits. Also, this study provides important insights into the LtMPts of HF cattle under semi-arid conditions. The identification of numerous quantitative trait loci (QTLs) across various traits highlights the genetic complexity of the cattle population and underscores the potential for genetic improvement. These findings support optimised breeding strategies and management practices to enhance productivity and health outcomes in similar regions.</p>

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Comprehensive assessment of lifetime performance traits and their genetic background in Holstein cows under semi-arid conditions

  • 期刊论文

  • 发表日期：

    2026年1月5日

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  • Ahmed. A. Saleh,
  • Tarek G.M. Hassan,
  • Dalia K.A. EL-Hedainy,
  • Adel S. A. El-Barbary,
  • Mahmoud A. Sharaby,
  • Amr M.A. Rashad

摘要

This study assessed lifetime milk production traits (LtMPts) in Holstein Friesian (HF) cattle under semi-arid conditions using data from a commercial farm. The analysis included 9000 records from 2050 HF cows at El-Alamia farm in Egypt, spanning from 1996 to 2023 G.C. LtMPts included longevity (LON), life production age (LPA), lifetime milk yield (LTY), lifetime daily milk yield (LDY), complete lactations number (CLN), age at first calving (AFC), age at last calving (ALC), and incidences of mastitis and lameness. Effects such as age at first calving, year of first calving, and season of first calving were also examined, along with the genetic background of the cattle, utilizing genomic global databases and the latest findings from genetic research. Heritability estimates were calculated to determine the genetic influence on various traits. Correlation analysis was conducted to identify potential relationships and genetic architectures. Results indicated significantly earlier AFC (p < 0.0001), prolonged AFC (p < 0.001), extended LPA (p < 0.0001), lower CLN (p < 0.0001), no significant change in LON (p = 0.5418), higher LTY (p < 0.0001) and higher LDY (p < 0.0001). Sire significantly affected the year and season of first calving (p < 0.0001). Low incidences of mastitis and lameness were observed. The year and season of first calving significantly impacted several LtMPts (p < 0.05). Heritability estimates indicated varying levels of genetic influence on the studied traits, with notable heritability for complete lactations (h2 = 0.60) and longevity (h2 = 0.66). However, the estimates for lifetime milk yield (h2 = 0.11), life production age (h2 = 0.12), and daily milk yield (h2 = 0.12) were low, suggesting limited genetic influence on these traits. Also, this study provides important insights into the LtMPts of HF cattle under semi-arid conditions. The identification of numerous quantitative trait loci (QTLs) across various traits highlights the genetic complexity of the cattle population and underscores the potential for genetic improvement. These findings support optimised breeding strategies and management practices to enhance productivity and health outcomes in similar regions.