对于牧人来说，需要掌握牧草枯荣的规律和天气寒暑的变化情况，以便在适当的时候配种、接羔，使幼畜能安全地度过酷冬。
For the shepherd , they needed to grasp the regularity of grass flourishing and withering and the changes of weather in order to mate animals at the appropriate time , deliver lambs and help young animals safely pass through the cool winter .
接羔