Physiological parameter values for physiologically based pharmacokinetic models in food-producing animals. Part III: Sheep and goat

Abstract

This report is the third in a series of studies that aimed to compile physiological parameters related to develop physiologically based pharmacokinetic (PBPK) models for drugs and environmental chemicals in food-producing animals including swine and cattle (Part I), chickens and turkeys (Part II), and finally sheep and goats (the focus of this manuscript). Literature searches were conducted in multiple databases (PubMed, Google Scholar, ScienceDirect, and ProQuest), with data on relevant parameters including body weight, relative organ weight (% of body weight), cardiac output, relative organ blood flow (% of cardiac output), residual blood volume (% of organ weight), and hematocrit reviewed and statistically summarized. The mean and standard deviation of each parameter are presented in tables. Equations describing the growth curves of sheep and goats are presented in figures. When data are sufficient, parameter values are reported for different ages or production classes of sheep, including fetal sheep, lambs, and market-age sheep (mature sheep). These data provide a reference database for developing standardized PBPK models to predict drug withdrawal intervals in sheep and goats, and also provide a basis for extrapolating PBPK models from major species such as cattle to minor species such as sheep and goats.

Keywords: blood flow; food animal residue avoidance databank; food safety; organ weight; physiologically based pharmacokinetic model.

Figure 1

A brief flowchart for the process of literature search, inclusion, exclusion, data extraction, and analysis for physiological parameters in sheep and goats [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 2

The growth curve of fetal body weight for sheep from 106 gestational days to 45 days after birth. The data of fetal body weights within 45 days of birth from the previous studies of Moss et al. (2005), Robillard and Weitzman (1980), and Singh et al. (2018) were pooled together to generate the growth curve. The reported 148 days as the average gestation days for sheep was considered as the time of birth [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 3

The growth curve for sheep from around 2 months to 3 years age. The data were pooled and calculated from previous studies of Moss et al. (2005) and Singh et al. (2018) [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 4

The growth curve for goats from 0 month to around 6 months age. The data were pooled and calculated from previous studies of Mahgoub (1997) and Mahgoub and Lodge (1998)