Heins B J, Hansen L B, Seykora A J, Hazel A R, Johnson D G, Linn J G
Department of Animal Science, University of Minnesota, St. Paul 55108, USA.
J Dairy Sci. 2008 Sep;91(9):3716-22. doi: 10.3168/jds.2008-1094.
Jersey x Holstein crossbred (JxH) 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 JxH 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 JxH 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 JxH 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 JxH (302 kg) and Holstein (309 kg) cows. The JxH and pure Holstein cows did not differ significantly for daily DMI (22.0 vs. 22.7 kg, respectively), and the JxH (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 JxH and pure Holstein cows.
在首次产犊的前150天,对24头泽西×荷斯坦杂交(JxH)奶牛与17头纯种荷斯坦奶牛的体重、体况评分、干物质摄入量(DMI)和饲料效率进行了比较。奶牛饲养在明尼苏达大学圣保罗校区的奶牛场,于2004年9月至2005年1月产犊。JxH奶牛通过人工授精与蒙贝利亚公牛配种,荷斯坦奶牛通过人工授精与荷斯坦公牛配种。每隔一周对奶牛进行称重并进行体况评分。每天给奶牛分两次单独投喂全混合日粮(TMR),每天测量一次剩料量。每天测量奶牛的DMI,并计算7天周期的平均值。牛奶产量和牛奶成分来自每月的奶牛群改良记录。使用最佳预测法计算每头奶牛在首次产犊第4天至第150天的实际产量(牛奶、脂肪、蛋白质)。与纯种荷斯坦奶牛相比,JxH奶牛的体重显著较轻(467千克对500千克),体况评分显著较高(2.90对2.76)。在泌乳第4天至第150天,JxH奶牛的产奶量显著低于纯种荷斯坦奶牛(4388千克对4644千克)。然而,在泌乳的前150天,JxH奶牛(302千克)和荷斯坦奶牛(309千克)的脂肪加蛋白质产量没有显著差异。JxH奶牛和纯种荷斯坦奶牛的每日DMI没有显著差异(分别为22.0千克和22.7千克),基于体重百分比,JxH奶牛(4.7%)和纯种荷斯坦奶牛(4.5%)消耗的DMI相似。因此,JxH奶牛和纯种荷斯坦奶牛在泌乳第4天至第150天的饲料效率没有差异。