Beef can be harvested from cows, bulls, heifers or steers. It is a common condition in weaned calves, young bulls, and heifers. The compound also seems to reduce the fertility of ewes and heifers. Heifer International started as Heifers for Relief in 1944. Beef from steers and heifers is similar. The slaughter of female cows and of heifers is totally forbidden. It is not recommended to rebreed heifers or cows that have this disease. Meat came from the farm's supply of bulls, hogs, and heifers. Dairy farmers usually begin breeding or artificially inseminating heifers around 13 months of age. Smaller birth weights reduce dystocia for first-calf heifers. Holstein heifers reach puberty at an average body weight between 550 and 650 lbs. Due to equal occurrence in heifers and bulls, dwarfism is not considered a sex-linked characteristic. Beef-cross heifers have long been sought after as ideal suckler cow replacements. Depending on economics, the number of heifers kept for breeding varies. Young stock, heifers, would have to be trained to remain still to be milked.