Montaño-Bermudez M, Nielsen M K, Deutscher G H
University of Nebraska, Lincoln 68583-0908.
J Anim Sci. 1990 Aug;68(8):2279-88. doi: 10.2527/1990.6882279x.
Maintenance energy requirements were estimated in two gestation and one lactation feeding trials for three groups of cows. All cows in the second gestation trial completed the first gestation and lactation trials. The three groups were chosen to represent cattle similar in growth rate and mature size but different in amount of milk provided to their calves. The low (L) group included Hereford x Angus, the medium (M) group included Red Poll x Angus and the high (H) group included Milking Shorthorn x Angus cows. Cows were individually fed to maintain net body weight (minus gravid uterus for gestation) constant. Allowances were made in energy intake for gestation and lactation. Cow weights were adjusted to an average condition score in each trial. Daily maintenance requirements during gestation were 18% lower than those during lactation. The H and M cows required 12% more energy per unit metabolic weight than L cows to maintain body weight during both gestation and lactation. Differences in milk production explained 23% of the variation in maintenance requirements, suggesting that important differences exist beyond those associated with milk production potential. Repeatabilities of maintenance requirement measurements ranged from .44 to .64. Maintenance requirements for calves under feedlot conditions in the postweaning phase were estimated from data collected from 494 calves, half-sibs and offspring of the cows described previously. Energy requirements were 11% higher for the H and M groups than for the L group.
在两项妊娠和一项泌乳饲养试验中，对三组奶牛的维持能量需求进行了估算。第二项妊娠试验中的所有奶牛都完成了第一次妊娠和泌乳试验。选择这三组奶牛是为了代表生长速度和成熟体型相似，但给犊牛提供的奶量不同的牛群。低产（L）组包括赫里福德×安格斯牛，中产（M）组包括红白花×安格斯牛，高产（H）组包括乳用短角×安格斯牛。单独饲喂奶牛以保持净体重（妊娠时减去妊娠子宫）恒定。在能量摄入量中考虑了妊娠和泌乳的需求。在每次试验中，将奶牛体重调整到平均体况评分。妊娠期间的每日维持需求比泌乳期间低18%。在妊娠和泌乳期间，H组和M组奶牛每单位代谢体重维持体重所需的能量比L组奶牛多12%。产奶量的差异解释了维持需求变化的23%，这表明除了与产奶潜力相关的差异外，还存在重要差异。维持需求测量的重复性范围为0.44至0.64。根据从494头犊牛（上述奶牛的半同胞和后代）收集的数据，估算了育肥条件下断奶后犊牛的维持需求。H组和M组的能量需求比L组高11%。
