科研之友
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摘要
The main research question "Can high producing dairy cows be fed without concentrates?" has become even more relevant within the last years, due to significant increases in the prices of energy and concentrates (grain). In several countries (New Zealand, Ireland, Switzerland and Austria), producers are becoming increasingly interested in lighter-weight cows that can use forages from grasslands more efficiently. In 1997, twenty-six calves (13 dual-purpose Simmental, 13 Holstein Friesian) were purchased: Seven of the calves, Holstein Friesians (HFL), came from a specific lifetime performance breeding program and 6 Holstein Friesian calves were from a conventional breeding program (HFK). Including the offspring of the original animals, 71 lactations were concluded by 26 Simmental dairy cows (2.7/cow) and 58 lactations were concluded by 21 Holstein Friesian cows (2.8/cow). The latter ones consisted of 27 lactations from 10 HFK and 31 lactations from 11 HFL cows. LS-Means for milk performance (ECM, kg) are as follows: Simmental cows (FV) 6,646, HFK 7,870 and HFL 6,814; live weight (kg): FV 720, HFK 688 and HFL 597. The calculated total (maintenance and lactation) energy requirements (MJ NEL) for each kg ECM produced were about 10% lower in Holstein Friesian as compared to FV cows. This can be attributed mostly to the higher milk performance (plus 1,224 kg = 18%) of HFK cows and the lower live weight (minus 123 kg = 17%) of HFL cows. There were no significant differences between groups regarding reasons for animal losses, index of insemination, veterinary expenses, fertility, blood parameters and longevity. The marked differences in milk and fattening performance (Second communication in preparation) between the three groups of cows in the current study allow for the characterization of three different types of cows which suit different production systems.
- 出版日期2010-4
