Show PUREBRED PURE BRED BULLS VARY VERY MU MUCH CH figures recently compiled from records of the cow testing associations of N new ew jersey and from the united states bureau of dairy industry where a study Is made of association records from all parts of the th united states indicate adwate that that a wide variation exists in the transmitting ability of purebred pure bred dairy bulls for milk mil if production and butterfat test announces the college of agriculture at now new Brun brunswick snick records show that of 0 purebred pure bred dairy bulls one third increase herd production one third barely maintain it and the other third lower it it in other words the college explains only one purebred pure bred sire out of three Is really desirable this Is not presented as an argument against the use of purebred pure bred sires but as an argument in favor of more careful selection of dairy sires and the retention of those sires until their daughters come into production oUn unfortunately fortunately says saya the college I nearly all bulls are butchered after reaching the age of three or tour four years dairymen are beginning to see that this Is a mistake in order to prevent inbreeding a plan la is now being put into operation by a number of dairymen whereby bulls are swapped after they are three years old two or three years later th the e animals are swapped back if the original owners want them A bull having five daughters that excel their dams in production Is known as a proved sire the college asserts that it Is now reasonably certain that if proved sires are used for five or six generations a dairyman can develop a herd of 0 cows everyone of which will be a heavy all their daughters will be high producers and all their sons will transmit great production |