title: Crossbreds of Jersey x Holstein compared with pure Holsteins for production, fertility, and body and udder measurements during first lactation.
abstract: Jersey x Holstein crossbreds (JxH; n = 76) were compared with pure Holsteins (n = 73) for 305-d milk, fat, and protein production; conception rate; days open; proportion of cows pregnant within fixed intervals postpartum; and body and udder measurements during first lactation. Cows were housed at 2 research locations of the University of Minnesota and calved from September 2003 to May 2005. The JxH were mated to Montbeliarde sires, and Holstein cows were mated to Holstein sires. Best Prediction was used to determine actual production (milk, fat, and protein) for 305-d lactations with adjustment for age at calving, and records less than 305 d were projected to 305 d. The JxH (274 kg) and pure Holsteins (277 kg) were not significantly different for fat production, but JxH had significantly less milk (7,147 vs. 7,705 kg) and protein (223 vs. 238 kg) production than pure Holsteins. The JxH had significantly fewer days open than pure Holsteins (127 vs. 150 d). Also, a significantly greater proportion of JxH were pregnant at 150 and 180 d postpartum than pure Holsteins (75 vs. 59% and 77 vs. 61%, respectively). The JxH had significantly less body weight (60 kg) at calving, but significantly greater body condition (2.80 vs. 2.71). Furthermore, JxH had significantly less udder clearance from the ground to the bottom of the udder than pure Holsteins (47.7 vs. 54.6 cm), and greater distance between front teats (15.8 vs. 14.0 cm) than pure Holsteins during first lactation.
authors.affiliation: Department of Animal Science, University of Minnesota, St. Paul 55108, USA. hein0106@umn.edu
authors.forename: B J
authors.initials: BJ
authors.lastname: Heins
authors.forename: L B
authors.initials: LB
authors.lastname: Hansen
authors.forename: A J
authors.initials: AJ
authors.lastname: Seykora
authors.forename: D G
authors.initials: DG
authors.lastname: Johnson
authors.forename: J G
authors.initials: JG
authors.lastname: Linn
authors.forename: J E
authors.initials: JE
authors.lastname: Romano
authors.forename: A R
authors.initials: AR
authors.lastname: Hazel
mesh_terms: D000818:Animals; D001823:Body Composition; D002417:Cattle / Q000033:anatomy & histology / Q000235:genetics* / Q000502:physiology; D003433:Crosses, Genetic; D005223:Fats / Q000032:analysis; D005260:Female; D005298:Fertility / Q000235:genetics*; D007774:Lactation / Q000235:genetics*; D008297:Male; D008321:Mammary Glands, Animal / Q000033:anatomy & histology*; D008892:Milk / Q000737:chemistry / Q000166:cytology; D008894:Milk Proteins / Q000032:analysis; D011247:Pregnancy
chemical_list: D005223:Fats; D008894:Milk Proteins