If you are just looking to put the beast in the freezer, so steers would do, You could try looking for some cross luings, shorthorns, angus's, devons as well as the galloways. All these breeds will face the conditions of winter just as well but might be easier to find depending on where you are in the country. Your gallowayas will be worth roughly similar per kilo as these other breeds in the local mart so that might geve you a sensible ball park figure as to their value (Note that the cross angus, hereford and shorthorns may be worth more because of various supermarket promotions!)