
yes buy the ones from the chemlist they are call reagent strips for urinalysis for diabetics,,which shows up glucose,if this change colour you know the bitch is readly in 24 hours,i have use them twice and both bitch were in whelp,the book which i got it from was dogs breeding and showing by catherine g,sutton on page 16 it say if you think the bitch is ready insert a small strip of the tape in the vagina and if it turns green within a minute or so then the bitch is readlt to be mated 24 hours later,beacuse the bitch glocose gos high just be ovualtion,and that why you some time see a dog licking the bitch wee,and the teeth munch together,
hope is helps
terri