F. R. Allaire and C. Y. Lin, Heritability of age at first calving, J. Dairy Sci, vol.63, pp.171-173, 1980.

P. J. Boettcher, J. Fatehi, and M. M. Schutz, Genotype x environment interactions in conventional versus pasture-based dairies in Canada, J. Dairy Sci, vol.86, pp.383-389, 2003.

F. Buckley, D. P. Berry, and P. Dillon, Evidence of genotype by environment interaction for fertility in dairy cattle, Reprod. Domest. Anim, vol.38, p.319, 2003.

M. P. Calus, J. J. Windig, and R. F. Veerkamp, Associations among descriptors of herd management and phenotypic and genetic levels of health and fertility, J. Dairy Sci, vol.88, pp.2178-2189, 2005.

M. F. Ceron-munoz, H. Tonhati, C. N. Costa, J. Maldonado-estrada, and D. Rojas-sarmiento, Genotype x environment interaction for age at first calving in Brazilian and Colombian Holsteins, J. Dairy Sci, vol.87, pp.2455-2458, 2004.

C. N. Costa, R. W. Blake, E. J. Pollak, P. A. Oltenacu, R. L. Quaas et al., Genetic analysis of Holstein cattle populations in Brazil and the United States, J. Dairy Sci, vol.83, pp.2963-2974, 2000.

P. De-ponte-bouwer, B. E. Mostert, and C. Visser, Genetic parameters for production traits and somatic cell score of the SA Dairy Swiss population, S. Afr. J. Anim. Sci, vol.43, pp.113-122, 2013.

W. J. Fulkerson, T. M. Davison, S. C. Garcia, G. Hough, M. E. Goddard et al., Holstein-Friesian dairy cows under a predominantly grazing system: Interaction between genotype and environment, J. Dairy Sci, vol.91, pp.826-83, 2008.

A. R. Gilmour, B. J. Gogel, B. R. Cullis, and R. Thompson, ASReml User Guide Release 3.0 VSN International Ltd, 2009.

M. Haile-mariam, M. J. Carrick, and M. E. Goddard, Genotype by environment interaction for fertility, survival, and milk production traits in Australian dairy cattle, J. Dairy Sci, vol.91, pp.4840-4853, 2008.

H. Hammami, B. Rekik, H. Soyeurt, C. Bastin, J. Stoll et al., Genotype × environment interaction for milk yield in Holsteins using Luxembourg and Tunisian populations, J. Dairy Sci, vol.91, pp.3661-3671, 2009.

M. J. Haskell, S. Brotherstone, A. B. Lawrence, and I. M. White, Characterisation of the dairy environment in Great Britain and the effect of the farm environment on cow life span, J. Dairy Sci, vol.90, pp.5316-5323, 2007.

J. F. Kearney, M. M. Schutz, and P. J. Boettcher, Genotype x environment interaction for grazing vs. confinement. II. Health and reproduction traits, J. Dairy Sci, vol.87, pp.510-516, 2004.

A. Maiwashe, K. A. Nephawe, and H. E. Theron, Estimates of genetic parameters and effects of inbreeding on milk yield and composition in South African Jersey cows, S. Afr. J. Anim. Sci, vol.38, pp.119-125, 2008.

P. Mantysaari, M. Ojala, and . E. Mäntysaari, Measures of before and after breeding daily gains of dairy replacement heifers and their relationship with first lactation milk production traits, Livest. Prod. Sci, vol.75, pp.313-322, 2002.

J. F. Mee, Reproductive issues arising from different management systems in the dairy industry, Reprod. Domest. Anim. 47 Suppl, vol.5, pp.42-50, 2012.

R. K. Moore, P. P. Kennedy, L. R. Schaeffer, and . J. Moxley, Relationships between age and body weight at calving and production in first lactation Ayrshires and Holsteins, J. Dairy Sci, vol.74, pp.269-278, 1991.

R. K. Moore, P. P. Kennedy, L. R. Schaeffer, and . J. Moxley, Relationships between age and body weight at calving, feed intake, production, days open and selection indexes in Ayrshires and Holsteins, J. Dairy Sci, vol.75, pp.294-306, 1992.

B. E. Mostert, H. E. Theron, F. H. Kanfer, and E. Van-marle-köster, Comparison of breeding values and genetic trends for production traits estimated by a lactation model and a fixed regression test-day model, S. Afr. J. Anim. Sci, vol.36, pp.71-78, 2006.

M. A. Nilforooshan and M. A. Edriss, Effect of age at first calving on some productive and longevity traits in Iranian Holsteins of the Isfahan province, J. Dairy Sci, vol.87, pp.2130-2135, 2004.

J. M. Ojango and G. E. Pollott, Genetics of milk yield and fertility traits in Holstein-Friesian cattle on large-scale Kenyan farms, J. Anim. Sci, vol.79, pp.1742-1750, 2001.

J. M. Ojango and G. E. Pollott, The relationship between Holstein bull breeding values for milk yield derived in both the UK and Kenya, Livest. Prod. Sci, vol.74, pp.1-12, 2002.

J. E. Pryce, B. L. Nielsen, R. F. Veerkamp, and G. Simm, Genotype and feeding system effects and interactions for health and fertility traits in dairy cattle, Livest. Prod. Sci, vol.57, pp.193-220, 1999.

E. Strandberg, S. Brotherstone, E. Wall, and M. P. Coffey, Genotype by environment interaction for first-lactation female fertility traits in UK dairy cattle, J. Dairy Sci, vol.92, pp.3437-3446, 2009.

T. L. Stanton, R. W. Blake, R. L. Quaas, L. D. Van-vleck, and M. J. Carabaño, Genotype by environment interaction for Holstein milk yield in Colombia, Mexico and Puerto Rico, J. Dairy Sci, vol.74, pp.1700-1714, 1991.

P. M. Vanraden and E. J. Klaaskate, Genetic evaluation of length of productive life including predicted longevity of live cows, J. Dairy Sci, vol.76, pp.2758-2764, 1993.

R. F. Veerkamp, G. Simm, and J. D. Oldham, Effects of interaction between genotype and feeding system on milk production, feed intake, efficiency and body tissue mobilization in dairy cows, Livest. Prod. Sci, vol.39, pp.229-241, 1994.

K. A. Weigel, R. Rekaya, N. R. Zwald, and W. F. Fikse, International genetic evaluation of dairy sires using a multipletrait model with individual animal performance records, J. Dairy Sci, vol.84, pp.2789-2795, 2001.

J. I. Weller and E. Ezra, Genetic analysis of the Israeli Holstein dairy cattle population for production and non-production traits with a multitrait animal model, J. Dairy Sci, vol.87, pp.1519-1527, 2004.