I’m not really sure of the number of yards. The challenge was to take yarn et al from your stash, so there was no label . I weighed it, and it is approximately 19 grams, and will figure out yardage later. The halter top is done in a stitch with paired 1X1 cables , each pair separated from the next with a Rev St.St. I don’t know the name of the stitch -- saw it on a Japanese pattern, so call it Cable Butterfly. Around the entire halteer is a 3X3 cable. The top of the halter is the same paired butterfly stitch separated by 5 stitches in a simple lace stitch.
If the person you are giving the halter to is pregnant, then the option is to NOT sew the side seams , and supply 2 triangles which button on to the side of the halter. Then, after the baby is born, the triangles (and buttons if you want) are removed, and the sides sewn up, and you have the basic halter.