Rearing Dairy Heifers on Pastures Fertilized at Moderate Levels With or Without Supplemental Concentrates at Different Stages.
Rearing Dairy Heifers on Pastures Fertilized at Moderate Levels With or Without Supplemental Concentrates at Different Stages.
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在适度施肥的牧场上饲养奶牛小母牛，在不同阶段添加或不添加补充精肥。
DOI：
10.46429/jaupr.v70i2.7086
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
J. Vélez
中科院分区：
文献类型：
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作者：
P. Randel;J. Vélez
试验分3个阶段在科罗萨隆混草牧场饲养荷斯坦小母牛，3次施氮、P2O5和K20用量分别为168、56和112 kg/hm2。平均初龄9个月，体重167公斤。在试验1阶段(91天)，39头未饲喂5只/hm2的对照动物日增重0.41 kg，低于相同日增重(P<；0.01)，日增重添加14%粗蛋白精料2 kg(0.64 kg)，每多增重8.6 kg精料。在第二阶段(182天)，每公顷放养4头的32头动物的人均增重低于3头/公顷的24头(0.53比0.59公斤/公顷)，但前者每公顷的总增重高出16.4%。在阶段3的259天内，3组每组19头母羊保持完好，不添加精料的处理1以3.75头/hm2放牧的增重低于处理2和处理3(P=0.01)，在预期分娩前200天或125天开始，每天添加2.5或4公斤精料(分别为0.57比0.64和0.62公斤)，但补饲提高增重的效率非常低。平均日增重从3组的318 kg分别增加到处理1、2和3的485、513和497 kg。只有后两组的小母牛在返回凯伊和马纳蒂的家乡农场后继续接受浓缩饲料，直到第一次产犊。所有动物均在产后接受常规的羊群管理。试验3期的18只对照牛平均305天第一次哺乳产奶量为4292 kg，分别超过(P=0.05)处理2和处理3的3,771和3,869 kg(P=0.05)。每个阶段采用的放牧率似乎与可用的牧场相适应，在这种条件下饲养小母牛不需要精料补充。
The experiment involved 3 successive phases in rearing Holstein heifers at Corozalon pastures of mixed grasses, fertilized annually with 168, 56 and 112 kg/ha of N, P 2 O 5 and K 2 0, respectively, in 3 applications. Mean initial age was 9 months and liveweight (LW) 167 kg. In phase 1 (91 days), 39 control animals stocked at 5/ha and not supplemented gained 0.41 kg daily, inferior (P < 0.01) to the gain of a like number supplemented with 2 kg daily of 14% crude protein concentrate (0.64 kg), 8.6 kg of concentrate per kg of extra gain over the control. In phase 2 (182 days), 32 animals stocked at 4/ha gained less (P = 0.01) per head than 24 stocked at 3/ha (0.53 vs. 0.59 kg daily), but total gain per ha was 16.4% greater for the former. During 259 days of phase 3, while 3 groups of 19 each remained intact, grazing at 3.75 animals/ha without supplementation (treatment 1) resulted in lower (P = 0.01) gain than treatments 2 and 3, involving concentrate supplementation at 2.5 or 4 kg daily beginning 200 or 125 days before expected parturition (0.57 vs. 0.64 and 0.62 kg, respectively), but supplementation increased gains over the control very inefficiently. Mean LW increased from 318 kg in all 3 groups to 485, 513 and 497 kg in treatments 1, 2 and 3, respectively. Only heifers of the latter 2 groups continued to receive concentrates after returning to their home farms in Cayey and Manati until first calving. All animals received usual herd management postpartum. Mean 305-day first lactation milk production was 4292 kg in 18 control animals of phase 3, surpassing (not significantly, P = 0.05) productions of 3,771 and 3,869 kg by 16 and 17 former treatment 2 and treatment 3 animals, respectively. Stocking rates employed at each stage seemed suited to available pastures, and concentrate supplementation was unnecessary for rearing dairy heifers under these conditions.