Genetic analysis of longevity and their associations with fertility traits in Holstein cattle

• Published in: Animal (Cambridge, England) England), 2023-06, Vol.17 (6), p.100851-100851, Article 100851
• Main Authors: Hu, H.H., Li, F., Mu, T., Han, L.Y., Feng, X.F., Ma, Y.F., Jiang, Y., Xue, X.S., Du, B.Q., Li, R.R., Ma, Y.
• Format: Article
• Language: English
• Subjects: Genetic correlation; Heritability; Life span; Phenotypic correlation; Variance components
• ISSN: 1751-7311; 1751-732X
• DOI: 10.1016/j.animal.2023.100851

•The study focuses on longevity and fertility traits in Holstein cattle.•The number of parities traits (number of days between first calving and the end of first lactation or culling; number of days between first calving and the end of the second lactation or culling; number of days between first calving and the end of the third lactation or culling; number of days between first calving and the end of the fourth lactation or culling) were beneficial to the early direct breeding of longevity traits.•The genetic and phenotypic correlations between longevity and fertility traits were investigated.•Most of the fertility traits showed negative correlations with longevity traits in different parities.•The results are beneficial for balanced breeding in Holstein cattle. The increase of longevity is intended to reduce involuntary culling rates, not extend the life span, and it reflects the ability of animals to successfully cope with the environment and disease during production. Sire model, animal model and repeatability animal models were used to estimate the (co) variance components of longevity and fertility traits. Six longevity and thirteen fertility traits were analysed, including herd life (HL), productive life (PL), number of days between first calving and the end of first lactation or culling (L1); number of days between first calving and the end of the second lactation or culling (L2); number of days between first calving and the end of the third lactation or culling (L3); number of days between first calving and the end of the fourth lactation or culling (L4); age at first service, age at first calving (AFC), the interval from first to last inseminations in heifer (IFLh), conception rate of first insemination in heifer, days open (DO), calving interval, gestation length, interval from calving to first insemination (ICF), interval from first to last inseminations in cow (IFLc), conception rate of first insemination in cow, calving ease (CE), birth weight, and calf survival. The estimated heritabilities (±SE) were 0.018 (±0.003), 0.015 (±0.003), 0.049 (±0.004), 0.025 (±0.003), 0.009 (±0.002) and 0.011 (±0.002) for HL, PL, L1, L2, L3 and L4, respectively. Strong correlations were appeared in HL and PL; the genetic and phenotypic correlation coefficients were 0.998 and 0.985, respectively. There were high genetic and phenotypic correlations which were observed in L1 and L2, L2 and L3, L3 and L4, respectively. All fertility traits of heifer showed medium to