Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE.
Animal Breeding and Genomics, Scotland's Rural College (SRUC), Edinburgh, UK.
J Anim Sci. 2020 Apr 1;98(4). doi: 10.1093/jas/skaa087.
Feed intake changes as animals age and grow. A constraint of most functional forms used to describe this relationship is that intake is maximum only once an animal reaches its mature weight. Often such is not the case and maximum intake is achieved earlier. Our aim was to describe a form unburdened by such a constraint and to determine its utility to describe the relationship between feed intake and liveweight across multiple species. Twelve data sets representing seven domestic animal species (cattle, chicken, dog, pig, rat, sheep, and turkey) with a wide range of mature weights were used. Average daily ad libitum feed intakes and liveweights were available on either a weekly or fortnightly basis. Rates of intake were scaled to mature intake. Within each set, the quadratic regression of scaled intake on the degree of maturity in weight was fitted. This form provided a very good description of the relationship between these variables (R2 > 0.86) and, for all but one case, a realistic prediction of mature intake. With one exception, intake reached its maximum value at a liveweight below its mature value. Furthermore, by appropriately scaling the relationship between intake and liveweight, the data could be described by a function with a single parameter with general relevance across species. By expressing the rate of intake as a function of its value at maturity, a quadratic form provides a robust and general description of the relationship between feed intake scaled to mature intake and degree of maturity in weight.
随着动物的衰老和生长，采食量会发生变化。大多数用于描述这种关系的功能形式都受到一个限制，即只有当动物达到成熟体重时，采食量才达到最大值。但通常情况并非如此，最大采食量会提前达到。我们的目的是描述一种不受这种限制的形式，并确定它在描述多种物种的采食量与活体重之间关系方面的效用。我们使用了 12 个数据集，代表了 7 个家畜物种（牛、鸡、狗、猪、鼠、羊和火鸡），它们的成熟体重范围很广。每周或每两周都有平均每日随意采食量和活重的数据。采食量的速率与成熟采食量相适应。在每个集合中，将缩放后的采食量与体重成熟度的二次回归拟合。这种形式很好地描述了这些变量之间的关系（R2 > 0.86），并且除了一种情况外，还可以对成熟采食量进行现实的预测。除了一种情况外，采食量在活重低于成熟值时达到最大值。此外，通过适当缩放采食量和活重之间的关系，可以用一个通用的参数来描述适用于所有物种的数据。通过将采食量的速率表示为其在成熟时的值的函数，可以用二次形式很好地描述与成熟采食量相适应的采食量与体重成熟度之间的关系。
