Reinhart G A, Mahan D C, Cera K R
Ohio State University, Columbus.
J Anim Sci. 1989 Oct;67(10):2684-91. doi: 10.2527/jas1989.67102684x.
An experiment was conducted to determine the effects of feeding regimen and group size on nutrient (N, Lipid, Ca, P) balance measurements with weanling swine. Treatments imposed were 1) one pig pair-fed to 90% of treatment 3, 2) three pigs pair-fed to 90% of treatment 3 and 3) three pigs with ad libitum access to their diet. A total of 28 barrows weaned at 21 d of age (initial BW 5.9 kg) were allotted by weight and litter in a randomized complete block design with repeated measurements over time to the three treatments in four replicates. The pigs were placed in .6-m x 1.13-m stainless steel metabolism crates and fed the same experimental diet for an initial 4-d adjustment period. This was followed by a 5-d collection of urine and feces with a 2-d interval between collection periods each week of a 4-wk postweaning period. When feed was restricted, N intake, urine N, fecal N and retained N were similar whether pigs were fed as singles or in groups of three. Individually fed pigs had a higher urinary Ca but lower urinary P compared with those fed in groups of three. Lipid and P retention values were similar for individual and group-penned, restricted-fed animals. Pigs provided ad libitum access to feed had greater weight gains and nutrient intakes, excretions (urine, fecal) and retentions (P less than .01) than pigs that were limit-fed. Similar responses among treatments occurred each week of the 4-wk trial. These results suggest that effective weekly balance data can be collected each week sequentially with 21-d weanling pigs penned in groups and allowed to consume feed ad libitum, a situation more similar to natural nursery conditions.
进行了一项实验，以确定饲喂方式和饲养密度对断奶仔猪营养物质（氮、脂质、钙、磷）平衡测定的影响。实验设置的处理为：1）1头猪按处理3的90%进行配对饲喂；2）3头猪按处理3的90%进行配对饲喂；3）3头猪自由采食日粮。总共28头21日龄断奶的公猪（初始体重5.9千克），按体重和窝别，采用随机完全区组设计，随时间重复测量，分为4个重复，接受三种处理。将猪置于0.6米×1.13米的不锈钢代谢笼中，在初始4天的适应期内饲喂相同的实验日粮。随后是4周断奶后时期，每周收集5天的尿液和粪便，收集期之间间隔2天。当饲料受限，无论猪是单头饲养还是三头一组饲养，氮摄入量、尿氮、粪氮和留存氮都相似。与三头一组饲养的猪相比，单头饲养的猪尿钙较高但尿磷较低。单头饲养和群养、限饲的动物脂质和磷的留存值相似。自由采食的猪比限饲的猪体重增加更多、营养物质摄入量、排泄量（尿液、粪便）和留存量（磷差异小于0.01）更大。在4周试验的每周，各处理间都出现了类似的反应。这些结果表明，对于21日龄断奶、群养且自由采食饲料的仔猪，可以每周依次收集有效的平衡数据，这种情况更类似于自然的保育条件。
