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ABSTRACT
Jersey × Holstein crossbred (J×H) cows (n = 24) were compared with pure Holstein cows (n = 17) for body weight, body condition score, dry matter intake (DMI), and feed efficiency during the first 150 d of first lactation. Cows were housed in the University of Minnesota dairy facility at the St. Paul campus and calved from September 2004 to January 2005. The J×H cows were mated by artificial insemination with Montbeliarde bulls, and Holstein cows were mated by artificial insemination with Holstein bulls. Cows were weighed and body condition was scored every other week. Cows were individually fed a TMR twice daily, and feed refusals were measured once daily. The DMI of cows was measured daily and averaged across 7-d periods. Milk production and milk composition were from monthly Dairy Herd Improvement records. Best Prediction was used to calculate actual production (milk, fat, protein) for each cow from the 4th to 150th day of first lactation. The J×H cows had significantly less body weight (467 vs. 500 kg) and significantly higher body condition scores (2.90 vs. 2.76) than pure Holstein cows. The J×H cows had significantly less milk production (4,388 vs. 4,644 kg) during the 4th to 150th day of lactation than did pure Holstein cows. However, fat plus protein production during the first 150 d of lactation was not significantly different for J×H (302 kg) and Holstein (309 kg) cows. The J×H and pure Holstein cows did not differ significantly for daily DMI (22.0 vs. 22.7 kg, respectively), and the J×H (4.7%) and pure Holstein (4.5%) cows consumed similar DMI based on percentage of body weight. Consequently, feed efficiency for the 4th to 150th day of lactation did not differ for J×H and pure Holstein cows.
Key words: crossbreeding, feed efficiency, body condition score, body weight
INTRODUCTION
Crossbreeding of dairy cattle is a topic of growing interest because of dairy producers' concerns regarding heifer and cow fertility, cow health, and calf survival (Funk, 2006). In a survey by Weigel and Barlass (2003), dairy producers indicated crossbreeding improved the fertility, survival, and profitability of dairy cows.
Recent research has documented the effects of crossbreeding in dairy cattle (Heins et al., 2006a,b,c; Auldist et al., 2007; Dechow et al., 2007; Heins et...