Sentence:  Also I would call attention to the fact that the heifers were wider through the <WSD>thurls</WSD> at five months of age than through the hips, but after they had become mature cows they were wider through (or across) their hips, than across their <WSD>thurls</WSD>. 
Meaning of the word marked with <WSD> tags:  Either of the rear hip joints where the hip connects to the upper leg in certain animals, particularly cattle; often used as a reference point for measurement.