Renkema J A, Stelwagen J
Tijdschr Diergeneeskd. 1977 May 15;102(10):630-7.
The current situation regarding the replacement of dairy cows is discussed. Attention is successively paid to the duration of herd life and the replacement rate, the reasons for disposal and the relationship between age and the probability of disposal. Little research including all the required elements at the same time has been done in this field. Therefore, the literature can offer only a rough idea of the current situation regarding the replacement of dairy cows (Tables 1 and 2). Further research along a few lines presented in this paper is advocated. However, the findings derived from the literature may be used in an economic model to quantify the economic significance of differences in the herd life of dairy cows. This subject will be elaborated in two subsequent papers.
本文讨论了奶牛更换的现状。依次关注了牛群寿命的时长和更换率、淘汰原因以及年龄与淘汰概率之间的关系。该领域同时涵盖所有所需要素的研究较少。因此，文献只能大致呈现奶牛更换的现状（表1和表2）。提倡沿着本文提出的几条思路开展进一步研究。然而，从文献中得出的研究结果可用于经济模型，以量化奶牛群寿命差异的经济意义。这个主题将在随后的两篇论文中详细阐述。
