Production, reproduction, health, and growth traits in backcross Holstein × Jersey cows and their Holstein contemporaries1

A total of 648 purebred Holstein and 319 backcross Holstein × Jersey dairy cattle were compared for production, reproduction, health, linear type, and growth traits. Animals were born between 2003 and 2009 and were housed in the University of Wisconsin–Madison Integrated Dairy Facility. All animals had Holstein dams; lactating dams were mated to unproven Holstein sires to produce purebred (control) Holsteins or to unproven F1 Jersey × Holstein crossbred sires to produce backcross animals, whereas nulliparous dams were mated to proven Holstein sires to produce purebred (other) Holsteins. Traits were analyzed using mixed linear models with effects of season of birth, age of dam, sire, birth year of sire, days in milk, lactation, and linear type score evaluator. Control Holsteins had greater 305-d milk yield (12,645 vs. 11,456kg), 305-d mature equivalent milk yield (13,420 vs. 12,180kg), peak daily milk yield (49.5 vs. 46.4kg), total lactation milk yield (11,556 vs. 10,796kg), and daily fat-corrected milk yield (43 vs. 40kg) compared with backcrosses. Days open and services per conception as a heifer or cow did not differ between control Holsteins, other Holsteins, or backcrosses. The proportion of first-parity births that required assistance was less in control Holsteins than in backcross cows (3.7 vs. 11.2%). The incidence of scours or respiratory problems in calves did not differ between control Holsteins, other Holsteins, and backcrosses, nor did the incidence of mastitis, injury, or feet problems. Control Holstein heifers were heavier (629 vs. 557kg), with greater hip height (145 vs. 139cm), body length (167 vs. 163cm), heart girth (205 vs. 198cm), and hip width (54 vs. 53cm) at 22 mo of age. On a 50-point scale for linear type traits, Holsteins were larger in stature compared with backcrosses (41 vs. 28), had wider rumps (37 vs. 33), and wider rear udders (34 vs. 32). Results of this study suggest that backcross Holstein × Jersey cattle have decreased production but fail to demonstrate an advantage in health and reproduction compared with purebred Holsteins.